* [PATCH v2 0/7] kexec: add generic support for elf kernel images @ 2019-07-09 19:43 ` Sven Schnelle 0 siblings, 0 replies; 20+ messages in thread From: Sven Schnelle @ 2019-07-09 19:43 UTC (permalink / raw) To: kexec; +Cc: Sven Schnelle, deller, linuxppc-dev Hi List, i've split up the patch a bit more. The first one move the generic elf stuff out of arch/powerpc to linux/kexec_elf.c, and prefixes the exposed functions with kexec_. That other patches remove stuff that is not used as proposed in the review. Changes to v1: - split up patch into smaller pieces - rebase onto powerpc/next - remove unused variable in kexec_elf_load() Changes to RFC version: - remove unused Elf_Rel macro - remove section header parsing - remove PURGATORY_STACK_SIZE - change order of elf_*_to_cpu() functions - remove elf_addr_to_cpu macro Sven Schnelle (7): kexec: add KEXEC_ELF kexec_elf: change order of elf_*_to_cpu() functions kexec_elf: remove parsing of section headers kexec_elf: remove PURGATORY_STACK_SIZE kexec_elf: remove elf_addr_to_cpu macro kexec_elf: remove Elf_Rel macro kexec_elf: remove unused variable in kexec_elf_load() arch/Kconfig | 3 + arch/powerpc/Kconfig | 1 + arch/powerpc/kernel/kexec_elf_64.c | 551 +---------------------------- include/linux/kexec.h | 23 ++ kernel/Makefile | 1 + kernel/kexec_elf.c | 389 ++++++++++++++++++++ 6 files changed, 427 insertions(+), 541 deletions(-) create mode 100644 kernel/kexec_elf.c -- 2.20.1 ^ permalink raw reply [flat|nested] 20+ messages in thread
* [PATCH v2 0/7] kexec: add generic support for elf kernel images @ 2019-07-09 19:43 ` Sven Schnelle 0 siblings, 0 replies; 20+ messages in thread From: Sven Schnelle @ 2019-07-09 19:43 UTC (permalink / raw) To: kexec; +Cc: Sven Schnelle, deller, linuxppc-dev Hi List, i've split up the patch a bit more. The first one move the generic elf stuff out of arch/powerpc to linux/kexec_elf.c, and prefixes the exposed functions with kexec_. That other patches remove stuff that is not used as proposed in the review. Changes to v1: - split up patch into smaller pieces - rebase onto powerpc/next - remove unused variable in kexec_elf_load() Changes to RFC version: - remove unused Elf_Rel macro - remove section header parsing - remove PURGATORY_STACK_SIZE - change order of elf_*_to_cpu() functions - remove elf_addr_to_cpu macro Sven Schnelle (7): kexec: add KEXEC_ELF kexec_elf: change order of elf_*_to_cpu() functions kexec_elf: remove parsing of section headers kexec_elf: remove PURGATORY_STACK_SIZE kexec_elf: remove elf_addr_to_cpu macro kexec_elf: remove Elf_Rel macro kexec_elf: remove unused variable in kexec_elf_load() arch/Kconfig | 3 + arch/powerpc/Kconfig | 1 + arch/powerpc/kernel/kexec_elf_64.c | 551 +---------------------------- include/linux/kexec.h | 23 ++ kernel/Makefile | 1 + kernel/kexec_elf.c | 389 ++++++++++++++++++++ 6 files changed, 427 insertions(+), 541 deletions(-) create mode 100644 kernel/kexec_elf.c -- 2.20.1 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec ^ permalink raw reply [flat|nested] 20+ messages in thread
* [PATCH v2 1/7] kexec: add KEXEC_ELF 2019-07-09 19:43 ` Sven Schnelle @ 2019-07-09 19:43 ` Sven Schnelle -1 siblings, 0 replies; 20+ messages in thread From: Sven Schnelle @ 2019-07-09 19:43 UTC (permalink / raw) To: kexec; +Cc: Sven Schnelle, deller, linuxppc-dev Right now powerpc provides an implementation to read elf files with the kexec_file() syscall. Make that available as a public kexec interface so it can be re-used on other architectures. Signed-off-by: Sven Schnelle <svens@stackframe.org> --- arch/Kconfig | 3 + arch/powerpc/Kconfig | 1 + arch/powerpc/kernel/kexec_elf_64.c | 551 +---------------------------- include/linux/kexec.h | 24 ++ kernel/Makefile | 1 + kernel/kexec_elf.c | 537 ++++++++++++++++++++++++++++ 6 files changed, 576 insertions(+), 541 deletions(-) create mode 100644 kernel/kexec_elf.c diff --git a/arch/Kconfig b/arch/Kconfig index c47b328eada0..30694aca4316 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -18,6 +18,9 @@ config KEXEC_CORE select CRASH_CORE bool +config KEXEC_ELF + bool + config HAVE_IMA_KEXEC bool diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 12cee37f15c4..addc2dad78e0 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -510,6 +510,7 @@ config KEXEC_FILE select KEXEC_CORE select HAVE_IMA_KEXEC select BUILD_BIN2C + select KEXEC_ELF depends on PPC64 depends on CRYPTO=y depends on CRYPTO_SHA256=y diff --git a/arch/powerpc/kernel/kexec_elf_64.c b/arch/powerpc/kernel/kexec_elf_64.c index ba4f18a43ee8..30bd57a93c17 100644 --- a/arch/powerpc/kernel/kexec_elf_64.c +++ b/arch/powerpc/kernel/kexec_elf_64.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * Load ELF vmlinux file for the kexec_file_load syscall. * @@ -10,15 +11,6 @@ * Based on kexec-tools' kexec-elf-exec.c and kexec-elf-ppc64.c. * Heavily modified for the kernel by * Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>. - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation (version 2 of the License). - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. */ #define pr_fmt(fmt) "kexec_elf: " fmt @@ -39,532 +31,6 @@ #define Elf_Rel Elf64_Rel #endif /* Elf_Rel */ -struct elf_info { - /* - * Where the ELF binary contents are kept. - * Memory managed by the user of the struct. - */ - const char *buffer; - - const struct elfhdr *ehdr; - const struct elf_phdr *proghdrs; - struct elf_shdr *sechdrs; -}; - -static inline bool elf_is_elf_file(const struct elfhdr *ehdr) -{ - return memcmp(ehdr->e_ident, ELFMAG, SELFMAG) == 0; -} - -static uint64_t elf64_to_cpu(const struct elfhdr *ehdr, uint64_t value) -{ - if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) - value = le64_to_cpu(value); - else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) - value = be64_to_cpu(value); - - return value; -} - -static uint16_t elf16_to_cpu(const struct elfhdr *ehdr, uint16_t value) -{ - if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) - value = le16_to_cpu(value); - else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) - value = be16_to_cpu(value); - - return value; -} - -static uint32_t elf32_to_cpu(const struct elfhdr *ehdr, uint32_t value) -{ - if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) - value = le32_to_cpu(value); - else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) - value = be32_to_cpu(value); - - return value; -} - -/** - * elf_is_ehdr_sane - check that it is safe to use the ELF header - * @buf_len: size of the buffer in which the ELF file is loaded. - */ -static bool elf_is_ehdr_sane(const struct elfhdr *ehdr, size_t buf_len) -{ - if (ehdr->e_phnum > 0 && ehdr->e_phentsize != sizeof(struct elf_phdr)) { - pr_debug("Bad program header size.\n"); - return false; - } else if (ehdr->e_shnum > 0 && - ehdr->e_shentsize != sizeof(struct elf_shdr)) { - pr_debug("Bad section header size.\n"); - return false; - } else if (ehdr->e_ident[EI_VERSION] != EV_CURRENT || - ehdr->e_version != EV_CURRENT) { - pr_debug("Unknown ELF version.\n"); - return false; - } - - if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) { - size_t phdr_size; - - /* - * e_phnum is at most 65535 so calculating the size of the - * program header cannot overflow. - */ - phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum; - - /* Sanity check the program header table location. */ - if (ehdr->e_phoff + phdr_size < ehdr->e_phoff) { - pr_debug("Program headers at invalid location.\n"); - return false; - } else if (ehdr->e_phoff + phdr_size > buf_len) { - pr_debug("Program headers truncated.\n"); - return false; - } - } - - if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) { - size_t shdr_size; - - /* - * e_shnum is at most 65536 so calculating - * the size of the section header cannot overflow. - */ - shdr_size = sizeof(struct elf_shdr) * ehdr->e_shnum; - - /* Sanity check the section header table location. */ - if (ehdr->e_shoff + shdr_size < ehdr->e_shoff) { - pr_debug("Section headers at invalid location.\n"); - return false; - } else if (ehdr->e_shoff + shdr_size > buf_len) { - pr_debug("Section headers truncated.\n"); - return false; - } - } - - return true; -} - -static int elf_read_ehdr(const char *buf, size_t len, struct elfhdr *ehdr) -{ - struct elfhdr *buf_ehdr; - - if (len < sizeof(*buf_ehdr)) { - pr_debug("Buffer is too small to hold ELF header.\n"); - return -ENOEXEC; - } - - memset(ehdr, 0, sizeof(*ehdr)); - memcpy(ehdr->e_ident, buf, sizeof(ehdr->e_ident)); - if (!elf_is_elf_file(ehdr)) { - pr_debug("No ELF header magic.\n"); - return -ENOEXEC; - } - - if (ehdr->e_ident[EI_CLASS] != ELF_CLASS) { - pr_debug("Not a supported ELF class.\n"); - return -ENOEXEC; - } else if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB && - ehdr->e_ident[EI_DATA] != ELFDATA2MSB) { - pr_debug("Not a supported ELF data format.\n"); - return -ENOEXEC; - } - - buf_ehdr = (struct elfhdr *) buf; - if (elf16_to_cpu(ehdr, buf_ehdr->e_ehsize) != sizeof(*buf_ehdr)) { - pr_debug("Bad ELF header size.\n"); - return -ENOEXEC; - } - - ehdr->e_type = elf16_to_cpu(ehdr, buf_ehdr->e_type); - ehdr->e_machine = elf16_to_cpu(ehdr, buf_ehdr->e_machine); - ehdr->e_version = elf32_to_cpu(ehdr, buf_ehdr->e_version); - ehdr->e_entry = elf_addr_to_cpu(ehdr, buf_ehdr->e_entry); - ehdr->e_phoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_phoff); - ehdr->e_shoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_shoff); - ehdr->e_flags = elf32_to_cpu(ehdr, buf_ehdr->e_flags); - ehdr->e_phentsize = elf16_to_cpu(ehdr, buf_ehdr->e_phentsize); - ehdr->e_phnum = elf16_to_cpu(ehdr, buf_ehdr->e_phnum); - ehdr->e_shentsize = elf16_to_cpu(ehdr, buf_ehdr->e_shentsize); - ehdr->e_shnum = elf16_to_cpu(ehdr, buf_ehdr->e_shnum); - ehdr->e_shstrndx = elf16_to_cpu(ehdr, buf_ehdr->e_shstrndx); - - return elf_is_ehdr_sane(ehdr, len) ? 0 : -ENOEXEC; -} - -/** - * elf_is_phdr_sane - check that it is safe to use the program header - * @buf_len: size of the buffer in which the ELF file is loaded. - */ -static bool elf_is_phdr_sane(const struct elf_phdr *phdr, size_t buf_len) -{ - - if (phdr->p_offset + phdr->p_filesz < phdr->p_offset) { - pr_debug("ELF segment location wraps around.\n"); - return false; - } else if (phdr->p_offset + phdr->p_filesz > buf_len) { - pr_debug("ELF segment not in file.\n"); - return false; - } else if (phdr->p_paddr + phdr->p_memsz < phdr->p_paddr) { - pr_debug("ELF segment address wraps around.\n"); - return false; - } - - return true; -} - -static int elf_read_phdr(const char *buf, size_t len, struct elf_info *elf_info, - int idx) -{ - /* Override the const in proghdrs, we are the ones doing the loading. */ - struct elf_phdr *phdr = (struct elf_phdr *) &elf_info->proghdrs[idx]; - const char *pbuf; - struct elf_phdr *buf_phdr; - - pbuf = buf + elf_info->ehdr->e_phoff + (idx * sizeof(*buf_phdr)); - buf_phdr = (struct elf_phdr *) pbuf; - - phdr->p_type = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_type); - phdr->p_offset = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_offset); - phdr->p_paddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_paddr); - phdr->p_vaddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_vaddr); - phdr->p_flags = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_flags); - - /* - * The following fields have a type equivalent to Elf_Addr - * both in 32 bit and 64 bit ELF. - */ - phdr->p_filesz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_filesz); - phdr->p_memsz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_memsz); - phdr->p_align = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_align); - - return elf_is_phdr_sane(phdr, len) ? 0 : -ENOEXEC; -} - -/** - * elf_read_phdrs - read the program headers from the buffer - * - * This function assumes that the program header table was checked for sanity. - * Use elf_is_ehdr_sane() if it wasn't. - */ -static int elf_read_phdrs(const char *buf, size_t len, - struct elf_info *elf_info) -{ - size_t phdr_size, i; - const struct elfhdr *ehdr = elf_info->ehdr; - - /* - * e_phnum is at most 65535 so calculating the size of the - * program header cannot overflow. - */ - phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum; - - elf_info->proghdrs = kzalloc(phdr_size, GFP_KERNEL); - if (!elf_info->proghdrs) - return -ENOMEM; - - for (i = 0; i < ehdr->e_phnum; i++) { - int ret; - - ret = elf_read_phdr(buf, len, elf_info, i); - if (ret) { - kfree(elf_info->proghdrs); - elf_info->proghdrs = NULL; - return ret; - } - } - - return 0; -} - -/** - * elf_is_shdr_sane - check that it is safe to use the section header - * @buf_len: size of the buffer in which the ELF file is loaded. - */ -static bool elf_is_shdr_sane(const struct elf_shdr *shdr, size_t buf_len) -{ - bool size_ok; - - /* SHT_NULL headers have undefined values, so we can't check them. */ - if (shdr->sh_type == SHT_NULL) - return true; - - /* Now verify sh_entsize */ - switch (shdr->sh_type) { - case SHT_SYMTAB: - size_ok = shdr->sh_entsize == sizeof(Elf_Sym); - break; - case SHT_RELA: - size_ok = shdr->sh_entsize == sizeof(Elf_Rela); - break; - case SHT_DYNAMIC: - size_ok = shdr->sh_entsize == sizeof(Elf_Dyn); - break; - case SHT_REL: - size_ok = shdr->sh_entsize == sizeof(Elf_Rel); - break; - case SHT_NOTE: - case SHT_PROGBITS: - case SHT_HASH: - case SHT_NOBITS: - default: - /* - * This is a section whose entsize requirements - * I don't care about. If I don't know about - * the section I can't care about it's entsize - * requirements. - */ - size_ok = true; - break; - } - - if (!size_ok) { - pr_debug("ELF section with wrong entry size.\n"); - return false; - } else if (shdr->sh_addr + shdr->sh_size < shdr->sh_addr) { - pr_debug("ELF section address wraps around.\n"); - return false; - } - - if (shdr->sh_type != SHT_NOBITS) { - if (shdr->sh_offset + shdr->sh_size < shdr->sh_offset) { - pr_debug("ELF section location wraps around.\n"); - return false; - } else if (shdr->sh_offset + shdr->sh_size > buf_len) { - pr_debug("ELF section not in file.\n"); - return false; - } - } - - return true; -} - -static int elf_read_shdr(const char *buf, size_t len, struct elf_info *elf_info, - int idx) -{ - struct elf_shdr *shdr = &elf_info->sechdrs[idx]; - const struct elfhdr *ehdr = elf_info->ehdr; - const char *sbuf; - struct elf_shdr *buf_shdr; - - sbuf = buf + ehdr->e_shoff + idx * sizeof(*buf_shdr); - buf_shdr = (struct elf_shdr *) sbuf; - - shdr->sh_name = elf32_to_cpu(ehdr, buf_shdr->sh_name); - shdr->sh_type = elf32_to_cpu(ehdr, buf_shdr->sh_type); - shdr->sh_addr = elf_addr_to_cpu(ehdr, buf_shdr->sh_addr); - shdr->sh_offset = elf_addr_to_cpu(ehdr, buf_shdr->sh_offset); - shdr->sh_link = elf32_to_cpu(ehdr, buf_shdr->sh_link); - shdr->sh_info = elf32_to_cpu(ehdr, buf_shdr->sh_info); - - /* - * The following fields have a type equivalent to Elf_Addr - * both in 32 bit and 64 bit ELF. - */ - shdr->sh_flags = elf_addr_to_cpu(ehdr, buf_shdr->sh_flags); - shdr->sh_size = elf_addr_to_cpu(ehdr, buf_shdr->sh_size); - shdr->sh_addralign = elf_addr_to_cpu(ehdr, buf_shdr->sh_addralign); - shdr->sh_entsize = elf_addr_to_cpu(ehdr, buf_shdr->sh_entsize); - - return elf_is_shdr_sane(shdr, len) ? 0 : -ENOEXEC; -} - -/** - * elf_read_shdrs - read the section headers from the buffer - * - * This function assumes that the section header table was checked for sanity. - * Use elf_is_ehdr_sane() if it wasn't. - */ -static int elf_read_shdrs(const char *buf, size_t len, - struct elf_info *elf_info) -{ - size_t shdr_size, i; - - /* - * e_shnum is at most 65536 so calculating - * the size of the section header cannot overflow. - */ - shdr_size = sizeof(struct elf_shdr) * elf_info->ehdr->e_shnum; - - elf_info->sechdrs = kzalloc(shdr_size, GFP_KERNEL); - if (!elf_info->sechdrs) - return -ENOMEM; - - for (i = 0; i < elf_info->ehdr->e_shnum; i++) { - int ret; - - ret = elf_read_shdr(buf, len, elf_info, i); - if (ret) { - kfree(elf_info->sechdrs); - elf_info->sechdrs = NULL; - return ret; - } - } - - return 0; -} - -/** - * elf_read_from_buffer - read ELF file and sets up ELF header and ELF info - * @buf: Buffer to read ELF file from. - * @len: Size of @buf. - * @ehdr: Pointer to existing struct which will be populated. - * @elf_info: Pointer to existing struct which will be populated. - * - * This function allows reading ELF files with different byte order than - * the kernel, byte-swapping the fields as needed. - * - * Return: - * On success returns 0, and the caller should call elf_free_info(elf_info) to - * free the memory allocated for the section and program headers. - */ -int elf_read_from_buffer(const char *buf, size_t len, struct elfhdr *ehdr, - struct elf_info *elf_info) -{ - int ret; - - ret = elf_read_ehdr(buf, len, ehdr); - if (ret) - return ret; - - elf_info->buffer = buf; - elf_info->ehdr = ehdr; - if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) { - ret = elf_read_phdrs(buf, len, elf_info); - if (ret) - return ret; - } - if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) { - ret = elf_read_shdrs(buf, len, elf_info); - if (ret) { - kfree(elf_info->proghdrs); - return ret; - } - } - - return 0; -} - -/** - * elf_free_info - free memory allocated by elf_read_from_buffer - */ -void elf_free_info(struct elf_info *elf_info) -{ - kfree(elf_info->proghdrs); - kfree(elf_info->sechdrs); - memset(elf_info, 0, sizeof(*elf_info)); -} -/** - * build_elf_exec_info - read ELF executable and check that we can use it - */ -static int build_elf_exec_info(const char *buf, size_t len, struct elfhdr *ehdr, - struct elf_info *elf_info) -{ - int i; - int ret; - - ret = elf_read_from_buffer(buf, len, ehdr, elf_info); - if (ret) - return ret; - - /* Big endian vmlinux has type ET_DYN. */ - if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN) { - pr_err("Not an ELF executable.\n"); - goto error; - } else if (!elf_info->proghdrs) { - pr_err("No ELF program header.\n"); - goto error; - } - - for (i = 0; i < ehdr->e_phnum; i++) { - /* - * Kexec does not support loading interpreters. - * In addition this check keeps us from attempting - * to kexec ordinay executables. - */ - if (elf_info->proghdrs[i].p_type == PT_INTERP) { - pr_err("Requires an ELF interpreter.\n"); - goto error; - } - } - - return 0; -error: - elf_free_info(elf_info); - return -ENOEXEC; -} - -static int elf64_probe(const char *buf, unsigned long len) -{ - struct elfhdr ehdr; - struct elf_info elf_info; - int ret; - - ret = build_elf_exec_info(buf, len, &ehdr, &elf_info); - if (ret) - return ret; - - elf_free_info(&elf_info); - - return elf_check_arch(&ehdr) ? 0 : -ENOEXEC; -} - -/** - * elf_exec_load - load ELF executable image - * @lowest_load_addr: On return, will be the address where the first PT_LOAD - * section will be loaded in memory. - * - * Return: - * 0 on success, negative value on failure. - */ -static int elf_exec_load(struct kimage *image, struct elfhdr *ehdr, - struct elf_info *elf_info, - unsigned long *lowest_load_addr) -{ - unsigned long base = 0, lowest_addr = UINT_MAX; - int ret; - size_t i; - struct kexec_buf kbuf = { .image = image, .buf_max = ppc64_rma_size, - .top_down = false }; - - /* Read in the PT_LOAD segments. */ - for (i = 0; i < ehdr->e_phnum; i++) { - unsigned long load_addr; - size_t size; - const struct elf_phdr *phdr; - - phdr = &elf_info->proghdrs[i]; - if (phdr->p_type != PT_LOAD) - continue; - - size = phdr->p_filesz; - if (size > phdr->p_memsz) - size = phdr->p_memsz; - - kbuf.buffer = (void *) elf_info->buffer + phdr->p_offset; - kbuf.bufsz = size; - kbuf.memsz = phdr->p_memsz; - kbuf.buf_align = phdr->p_align; - kbuf.buf_min = phdr->p_paddr + base; - ret = kexec_add_buffer(&kbuf); - if (ret) - goto out; - load_addr = kbuf.mem; - - if (load_addr < lowest_addr) - lowest_addr = load_addr; - } - - /* Update entry point to reflect new load address. */ - ehdr->e_entry += base; - - *lowest_load_addr = lowest_addr; - ret = 0; - out: - return ret; -} - static void *elf64_load(struct kimage *image, char *kernel_buf, unsigned long kernel_len, char *initrd, unsigned long initrd_len, char *cmdline, @@ -577,17 +43,18 @@ static void *elf64_load(struct kimage *image, char *kernel_buf, void *fdt; const void *slave_code; struct elfhdr ehdr; - struct elf_info elf_info; + struct kexec_elf_info elf_info; struct kexec_buf kbuf = { .image = image, .buf_min = 0, .buf_max = ppc64_rma_size }; struct kexec_buf pbuf = { .image = image, .buf_min = 0, - .buf_max = ppc64_rma_size, .top_down = true }; + .buf_max = ppc64_rma_size, .top_down = true, + .mem = KEXEC_BUF_MEM_UNKNOWN }; - ret = build_elf_exec_info(kernel_buf, kernel_len, &ehdr, &elf_info); + ret = kexec_build_elf_info(kernel_buf, kernel_len, &ehdr, &elf_info); if (ret) goto out; - ret = elf_exec_load(image, &ehdr, &elf_info, &kernel_load_addr); + ret = kexec_elf_load(image, &ehdr, &elf_info, &kbuf, &kernel_load_addr); if (ret) goto out; @@ -606,6 +73,7 @@ static void *elf64_load(struct kimage *image, char *kernel_buf, kbuf.bufsz = kbuf.memsz = initrd_len; kbuf.buf_align = PAGE_SIZE; kbuf.top_down = false; + kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; ret = kexec_add_buffer(&kbuf); if (ret) goto out; @@ -638,6 +106,7 @@ static void *elf64_load(struct kimage *image, char *kernel_buf, kbuf.bufsz = kbuf.memsz = fdt_size; kbuf.buf_align = PAGE_SIZE; kbuf.top_down = true; + kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; ret = kexec_add_buffer(&kbuf); if (ret) goto out; @@ -652,13 +121,13 @@ static void *elf64_load(struct kimage *image, char *kernel_buf, pr_err("Error setting up the purgatory.\n"); out: - elf_free_info(&elf_info); + kexec_free_elf_info(&elf_info); /* Make kimage_file_post_load_cleanup free the fdt buffer for us. */ return ret ? ERR_PTR(ret) : fdt; } const struct kexec_file_ops kexec_elf64_ops = { - .probe = elf64_probe, + .probe = kexec_elf_probe, .load = elf64_load, }; diff --git a/include/linux/kexec.h b/include/linux/kexec.h index b9b1bc5f9669..da2a6b1d69e7 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -216,6 +216,30 @@ extern int crash_prepare_elf64_headers(struct crash_mem *mem, int kernel_map, void **addr, unsigned long *sz); #endif /* CONFIG_KEXEC_FILE */ +#ifdef CONFIG_KEXEC_ELF +struct kexec_elf_info { + /* + * Where the ELF binary contents are kept. + * Memory managed by the user of the struct. + */ + const char *buffer; + + const struct elfhdr *ehdr; + const struct elf_phdr *proghdrs; + struct elf_shdr *sechdrs; +}; + +int kexec_build_elf_info(const char *buf, size_t len, struct elfhdr *ehdr, + struct kexec_elf_info *elf_info); + +int kexec_elf_load(struct kimage *image, struct elfhdr *ehdr, + struct kexec_elf_info *elf_info, + struct kexec_buf *kbuf, + unsigned long *lowest_load_addr); + +void kexec_free_elf_info(struct kexec_elf_info *elf_info); +int kexec_elf_probe(const char *buf, unsigned long len); +#endif struct kimage { kimage_entry_t head; kimage_entry_t *entry; diff --git a/kernel/Makefile b/kernel/Makefile index 33824f0385b3..7062306de9b7 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -64,6 +64,7 @@ obj-$(CONFIG_CRASH_CORE) += crash_core.o obj-$(CONFIG_KEXEC_CORE) += kexec_core.o obj-$(CONFIG_KEXEC) += kexec.o obj-$(CONFIG_KEXEC_FILE) += kexec_file.o +obj-$(CONFIG_KEXEC_ELF) += kexec_elf.o obj-$(CONFIG_BACKTRACE_SELF_TEST) += backtracetest.o obj-$(CONFIG_COMPAT) += compat.o obj-$(CONFIG_CGROUPS) += cgroup/ diff --git a/kernel/kexec_elf.c b/kernel/kexec_elf.c new file mode 100644 index 000000000000..6e9f52171ede --- /dev/null +++ b/kernel/kexec_elf.c @@ -0,0 +1,537 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#define pr_fmt(fmt) "kexec_elf: " fmt + +#include <linux/elf.h> +#include <linux/kexec.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/types.h> + +#define PURGATORY_STACK_SIZE (16 * 1024) + +#define elf_addr_to_cpu elf64_to_cpu + +#ifndef Elf_Rel +#define Elf_Rel Elf64_Rel +#endif /* Elf_Rel */ + +static inline bool elf_is_elf_file(const struct elfhdr *ehdr) +{ + return memcmp(ehdr->e_ident, ELFMAG, SELFMAG) == 0; +} + +static uint64_t elf64_to_cpu(const struct elfhdr *ehdr, uint64_t value) +{ + if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) + value = le64_to_cpu(value); + else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) + value = be64_to_cpu(value); + + return value; +} + +static uint16_t elf16_to_cpu(const struct elfhdr *ehdr, uint16_t value) +{ + if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) + value = le16_to_cpu(value); + else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) + value = be16_to_cpu(value); + + return value; +} + +static uint32_t elf32_to_cpu(const struct elfhdr *ehdr, uint32_t value) +{ + if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) + value = le32_to_cpu(value); + else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) + value = be32_to_cpu(value); + + return value; +} + +/** + * elf_is_ehdr_sane - check that it is safe to use the ELF header + * @buf_len: size of the buffer in which the ELF file is loaded. + */ +static bool elf_is_ehdr_sane(const struct elfhdr *ehdr, size_t buf_len) +{ + if (ehdr->e_phnum > 0 && ehdr->e_phentsize != sizeof(struct elf_phdr)) { + pr_debug("Bad program header size.\n"); + return false; + } else if (ehdr->e_shnum > 0 && + ehdr->e_shentsize != sizeof(struct elf_shdr)) { + pr_debug("Bad section header size.\n"); + return false; + } else if (ehdr->e_ident[EI_VERSION] != EV_CURRENT || + ehdr->e_version != EV_CURRENT) { + pr_debug("Unknown ELF version.\n"); + return false; + } + + if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) { + size_t phdr_size; + + /* + * e_phnum is at most 65535 so calculating the size of the + * program header cannot overflow. + */ + phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum; + + /* Sanity check the program header table location. */ + if (ehdr->e_phoff + phdr_size < ehdr->e_phoff) { + pr_debug("Program headers at invalid location.\n"); + return false; + } else if (ehdr->e_phoff + phdr_size > buf_len) { + pr_debug("Program headers truncated.\n"); + return false; + } + } + + if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) { + size_t shdr_size; + + /* + * e_shnum is at most 65536 so calculating + * the size of the section header cannot overflow. + */ + shdr_size = sizeof(struct elf_shdr) * ehdr->e_shnum; + + /* Sanity check the section header table location. */ + if (ehdr->e_shoff + shdr_size < ehdr->e_shoff) { + pr_debug("Section headers at invalid location.\n"); + return false; + } else if (ehdr->e_shoff + shdr_size > buf_len) { + pr_debug("Section headers truncated.\n"); + return false; + } + } + + return true; +} + +static int elf_read_ehdr(const char *buf, size_t len, struct elfhdr *ehdr) +{ + struct elfhdr *buf_ehdr; + + if (len < sizeof(*buf_ehdr)) { + pr_debug("Buffer is too small to hold ELF header.\n"); + return -ENOEXEC; + } + + memset(ehdr, 0, sizeof(*ehdr)); + memcpy(ehdr->e_ident, buf, sizeof(ehdr->e_ident)); + if (!elf_is_elf_file(ehdr)) { + pr_debug("No ELF header magic.\n"); + return -ENOEXEC; + } + + if (ehdr->e_ident[EI_CLASS] != ELF_CLASS) { + pr_debug("Not a supported ELF class.\n"); + return -ENOEXEC; + } else if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB && + ehdr->e_ident[EI_DATA] != ELFDATA2MSB) { + pr_debug("Not a supported ELF data format.\n"); + return -ENOEXEC; + } + + buf_ehdr = (struct elfhdr *) buf; + if (elf16_to_cpu(ehdr, buf_ehdr->e_ehsize) != sizeof(*buf_ehdr)) { + pr_debug("Bad ELF header size.\n"); + return -ENOEXEC; + } + + ehdr->e_type = elf16_to_cpu(ehdr, buf_ehdr->e_type); + ehdr->e_machine = elf16_to_cpu(ehdr, buf_ehdr->e_machine); + ehdr->e_version = elf32_to_cpu(ehdr, buf_ehdr->e_version); + ehdr->e_entry = elf_addr_to_cpu(ehdr, buf_ehdr->e_entry); + ehdr->e_phoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_phoff); + ehdr->e_shoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_shoff); + ehdr->e_flags = elf32_to_cpu(ehdr, buf_ehdr->e_flags); + ehdr->e_phentsize = elf16_to_cpu(ehdr, buf_ehdr->e_phentsize); + ehdr->e_phnum = elf16_to_cpu(ehdr, buf_ehdr->e_phnum); + ehdr->e_shentsize = elf16_to_cpu(ehdr, buf_ehdr->e_shentsize); + ehdr->e_shnum = elf16_to_cpu(ehdr, buf_ehdr->e_shnum); + ehdr->e_shstrndx = elf16_to_cpu(ehdr, buf_ehdr->e_shstrndx); + + return elf_is_ehdr_sane(ehdr, len) ? 0 : -ENOEXEC; +} + +/** + * elf_is_phdr_sane - check that it is safe to use the program header + * @buf_len: size of the buffer in which the ELF file is loaded. + */ +static bool elf_is_phdr_sane(const struct elf_phdr *phdr, size_t buf_len) +{ + + if (phdr->p_offset + phdr->p_filesz < phdr->p_offset) { + pr_debug("ELF segment location wraps around.\n"); + return false; + } else if (phdr->p_offset + phdr->p_filesz > buf_len) { + pr_debug("ELF segment not in file.\n"); + return false; + } else if (phdr->p_paddr + phdr->p_memsz < phdr->p_paddr) { + pr_debug("ELF segment address wraps around.\n"); + return false; + } + + return true; +} + +static int elf_read_phdr(const char *buf, size_t len, + struct kexec_elf_info *elf_info, + int idx) +{ + /* Override the const in proghdrs, we are the ones doing the loading. */ + struct elf_phdr *phdr = (struct elf_phdr *) &elf_info->proghdrs[idx]; + const char *pbuf; + struct elf_phdr *buf_phdr; + + pbuf = buf + elf_info->ehdr->e_phoff + (idx * sizeof(*buf_phdr)); + buf_phdr = (struct elf_phdr *) pbuf; + + phdr->p_type = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_type); + phdr->p_offset = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_offset); + phdr->p_paddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_paddr); + phdr->p_vaddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_vaddr); + phdr->p_flags = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_flags); + + /* + * The following fields have a type equivalent to Elf_Addr + * both in 32 bit and 64 bit ELF. + */ + phdr->p_filesz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_filesz); + phdr->p_memsz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_memsz); + phdr->p_align = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_align); + + return elf_is_phdr_sane(phdr, len) ? 0 : -ENOEXEC; +} + +/** + * elf_read_phdrs - read the program headers from the buffer + * + * This function assumes that the program header table was checked for sanity. + * Use elf_is_ehdr_sane() if it wasn't. + */ +static int elf_read_phdrs(const char *buf, size_t len, + struct kexec_elf_info *elf_info) +{ + size_t phdr_size, i; + const struct elfhdr *ehdr = elf_info->ehdr; + + /* + * e_phnum is at most 65535 so calculating the size of the + * program header cannot overflow. + */ + phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum; + + elf_info->proghdrs = kzalloc(phdr_size, GFP_KERNEL); + if (!elf_info->proghdrs) + return -ENOMEM; + + for (i = 0; i < ehdr->e_phnum; i++) { + int ret; + + ret = elf_read_phdr(buf, len, elf_info, i); + if (ret) { + kfree(elf_info->proghdrs); + elf_info->proghdrs = NULL; + return ret; + } + } + + return 0; +} + +/** + * elf_is_shdr_sane - check that it is safe to use the section header + * @buf_len: size of the buffer in which the ELF file is loaded. + */ +static bool elf_is_shdr_sane(const struct elf_shdr *shdr, size_t buf_len) +{ + bool size_ok; + + /* SHT_NULL headers have undefined values, so we can't check them. */ + if (shdr->sh_type == SHT_NULL) + return true; + + /* Now verify sh_entsize */ + switch (shdr->sh_type) { + case SHT_SYMTAB: + size_ok = shdr->sh_entsize == sizeof(Elf_Sym); + break; + case SHT_RELA: + size_ok = shdr->sh_entsize == sizeof(Elf_Rela); + break; + case SHT_DYNAMIC: + size_ok = shdr->sh_entsize == sizeof(Elf_Dyn); + break; + case SHT_REL: + size_ok = shdr->sh_entsize == sizeof(Elf_Rel); + break; + case SHT_NOTE: + case SHT_PROGBITS: + case SHT_HASH: + case SHT_NOBITS: + default: + /* + * This is a section whose entsize requirements + * I don't care about. If I don't know about + * the section I can't care about it's entsize + * requirements. + */ + size_ok = true; + break; + } + + if (!size_ok) { + pr_debug("ELF section with wrong entry size.\n"); + return false; + } else if (shdr->sh_addr + shdr->sh_size < shdr->sh_addr) { + pr_debug("ELF section address wraps around.\n"); + return false; + } + + if (shdr->sh_type != SHT_NOBITS) { + if (shdr->sh_offset + shdr->sh_size < shdr->sh_offset) { + pr_debug("ELF section location wraps around.\n"); + return false; + } else if (shdr->sh_offset + shdr->sh_size > buf_len) { + pr_debug("ELF section not in file.\n"); + return false; + } + } + + return true; +} + +static int elf_read_shdr(const char *buf, size_t len, + struct kexec_elf_info *elf_info, + int idx) +{ + struct elf_shdr *shdr = &elf_info->sechdrs[idx]; + const struct elfhdr *ehdr = elf_info->ehdr; + const char *sbuf; + struct elf_shdr *buf_shdr; + + sbuf = buf + ehdr->e_shoff + idx * sizeof(*buf_shdr); + buf_shdr = (struct elf_shdr *) sbuf; + + shdr->sh_name = elf32_to_cpu(ehdr, buf_shdr->sh_name); + shdr->sh_type = elf32_to_cpu(ehdr, buf_shdr->sh_type); + shdr->sh_addr = elf_addr_to_cpu(ehdr, buf_shdr->sh_addr); + shdr->sh_offset = elf_addr_to_cpu(ehdr, buf_shdr->sh_offset); + shdr->sh_link = elf32_to_cpu(ehdr, buf_shdr->sh_link); + shdr->sh_info = elf32_to_cpu(ehdr, buf_shdr->sh_info); + + /* + * The following fields have a type equivalent to Elf_Addr + * both in 32 bit and 64 bit ELF. + */ + shdr->sh_flags = elf_addr_to_cpu(ehdr, buf_shdr->sh_flags); + shdr->sh_size = elf_addr_to_cpu(ehdr, buf_shdr->sh_size); + shdr->sh_addralign = elf_addr_to_cpu(ehdr, buf_shdr->sh_addralign); + shdr->sh_entsize = elf_addr_to_cpu(ehdr, buf_shdr->sh_entsize); + + return elf_is_shdr_sane(shdr, len) ? 0 : -ENOEXEC; +} + +/** + * elf_read_shdrs - read the section headers from the buffer + * + * This function assumes that the section header table was checked for sanity. + * Use elf_is_ehdr_sane() if it wasn't. + */ +static int elf_read_shdrs(const char *buf, size_t len, + struct kexec_elf_info *elf_info) +{ + size_t shdr_size, i; + + /* + * e_shnum is at most 65536 so calculating + * the size of the section header cannot overflow. + */ + shdr_size = sizeof(struct elf_shdr) * elf_info->ehdr->e_shnum; + + elf_info->sechdrs = kzalloc(shdr_size, GFP_KERNEL); + if (!elf_info->sechdrs) + return -ENOMEM; + + for (i = 0; i < elf_info->ehdr->e_shnum; i++) { + int ret; + + ret = elf_read_shdr(buf, len, elf_info, i); + if (ret) { + kfree(elf_info->sechdrs); + elf_info->sechdrs = NULL; + return ret; + } + } + + return 0; +} + +/** + * elf_read_from_buffer - read ELF file and sets up ELF header and ELF info + * @buf: Buffer to read ELF file from. + * @len: Size of @buf. + * @ehdr: Pointer to existing struct which will be populated. + * @elf_info: Pointer to existing struct which will be populated. + * + * This function allows reading ELF files with different byte order than + * the kernel, byte-swapping the fields as needed. + * + * Return: + * On success returns 0, and the caller should call + * kexec_free_elf_info(elf_info) to free the memory allocated for the section + * and program headers. + */ +static int elf_read_from_buffer(const char *buf, size_t len, + struct elfhdr *ehdr, + struct kexec_elf_info *elf_info) +{ + int ret; + + ret = elf_read_ehdr(buf, len, ehdr); + if (ret) + return ret; + + elf_info->buffer = buf; + elf_info->ehdr = ehdr; + if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) { + ret = elf_read_phdrs(buf, len, elf_info); + if (ret) + return ret; + } + if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) { + ret = elf_read_shdrs(buf, len, elf_info); + if (ret) { + kfree(elf_info->proghdrs); + return ret; + } + } + + return 0; +} + +/** + * kexec_free_elf_info - free memory allocated by elf_read_from_buffer + */ +void kexec_free_elf_info(struct kexec_elf_info *elf_info) +{ + kfree(elf_info->proghdrs); + kfree(elf_info->sechdrs); + memset(elf_info, 0, sizeof(*elf_info)); +} +/** + * kexec_build_elf_info - read ELF executable and check that we can use it + */ +int kexec_build_elf_info(const char *buf, size_t len, struct elfhdr *ehdr, + struct kexec_elf_info *elf_info) +{ + int i; + int ret; + + ret = elf_read_from_buffer(buf, len, ehdr, elf_info); + if (ret) + return ret; + + /* Big endian vmlinux has type ET_DYN. */ + if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN) { + pr_err("Not an ELF executable.\n"); + goto error; + } else if (!elf_info->proghdrs) { + pr_err("No ELF program header.\n"); + goto error; + } + + for (i = 0; i < ehdr->e_phnum; i++) { + /* + * Kexec does not support loading interpreters. + * In addition this check keeps us from attempting + * to kexec ordinay executables. + */ + if (elf_info->proghdrs[i].p_type == PT_INTERP) { + pr_err("Requires an ELF interpreter.\n"); + goto error; + } + } + + return 0; +error: + kexec_free_elf_info(elf_info); + return -ENOEXEC; +} + + +int kexec_elf_probe(const char *buf, unsigned long len) +{ + struct elfhdr ehdr; + struct kexec_elf_info elf_info; + int ret; + + ret = kexec_build_elf_info(buf, len, &ehdr, &elf_info); + if (ret) + return ret; + + kexec_free_elf_info(&elf_info); + + return elf_check_arch(&ehdr) ? 0 : -ENOEXEC; +} + +/** + * kexec_elf_load - load ELF executable image + * @lowest_load_addr: On return, will be the address where the first PT_LOAD + * section will be loaded in memory. + * + * Return: + * 0 on success, negative value on failure. + */ +int kexec_elf_load(struct kimage *image, struct elfhdr *ehdr, + struct kexec_elf_info *elf_info, + struct kexec_buf *kbuf, + unsigned long *lowest_load_addr) +{ + unsigned long base = 0, lowest_addr = UINT_MAX; + int ret; + size_t i; + + /* Read in the PT_LOAD segments. */ + for (i = 0; i < ehdr->e_phnum; i++) { + unsigned long load_addr; + size_t size; + const struct elf_phdr *phdr; + + phdr = &elf_info->proghdrs[i]; + if (phdr->p_type != PT_LOAD) + continue; + + size = phdr->p_filesz; + if (size > phdr->p_memsz) + size = phdr->p_memsz; + + kbuf->buffer = (void *) elf_info->buffer + phdr->p_offset; + kbuf->bufsz = size; + kbuf->memsz = phdr->p_memsz; + kbuf->buf_align = phdr->p_align; + kbuf->buf_min = phdr->p_paddr + base; + ret = kexec_add_buffer(kbuf); + if (ret) + goto out; + load_addr = kbuf->mem; + + if (load_addr < lowest_addr) + lowest_addr = load_addr; + } + + /* Update entry point to reflect new load address. */ + ehdr->e_entry += base; + + *lowest_load_addr = lowest_addr; + ret = 0; + out: + return ret; +} + + -- 2.20.1 ^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v2 1/7] kexec: add KEXEC_ELF @ 2019-07-09 19:43 ` Sven Schnelle 0 siblings, 0 replies; 20+ messages in thread From: Sven Schnelle @ 2019-07-09 19:43 UTC (permalink / raw) To: kexec; +Cc: Sven Schnelle, deller, linuxppc-dev Right now powerpc provides an implementation to read elf files with the kexec_file() syscall. Make that available as a public kexec interface so it can be re-used on other architectures. Signed-off-by: Sven Schnelle <svens@stackframe.org> --- arch/Kconfig | 3 + arch/powerpc/Kconfig | 1 + arch/powerpc/kernel/kexec_elf_64.c | 551 +---------------------------- include/linux/kexec.h | 24 ++ kernel/Makefile | 1 + kernel/kexec_elf.c | 537 ++++++++++++++++++++++++++++ 6 files changed, 576 insertions(+), 541 deletions(-) create mode 100644 kernel/kexec_elf.c diff --git a/arch/Kconfig b/arch/Kconfig index c47b328eada0..30694aca4316 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -18,6 +18,9 @@ config KEXEC_CORE select CRASH_CORE bool +config KEXEC_ELF + bool + config HAVE_IMA_KEXEC bool diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 12cee37f15c4..addc2dad78e0 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -510,6 +510,7 @@ config KEXEC_FILE select KEXEC_CORE select HAVE_IMA_KEXEC select BUILD_BIN2C + select KEXEC_ELF depends on PPC64 depends on CRYPTO=y depends on CRYPTO_SHA256=y diff --git a/arch/powerpc/kernel/kexec_elf_64.c b/arch/powerpc/kernel/kexec_elf_64.c index ba4f18a43ee8..30bd57a93c17 100644 --- a/arch/powerpc/kernel/kexec_elf_64.c +++ b/arch/powerpc/kernel/kexec_elf_64.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * Load ELF vmlinux file for the kexec_file_load syscall. * @@ -10,15 +11,6 @@ * Based on kexec-tools' kexec-elf-exec.c and kexec-elf-ppc64.c. * Heavily modified for the kernel by * Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>. - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation (version 2 of the License). - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. */ #define pr_fmt(fmt) "kexec_elf: " fmt @@ -39,532 +31,6 @@ #define Elf_Rel Elf64_Rel #endif /* Elf_Rel */ -struct elf_info { - /* - * Where the ELF binary contents are kept. - * Memory managed by the user of the struct. - */ - const char *buffer; - - const struct elfhdr *ehdr; - const struct elf_phdr *proghdrs; - struct elf_shdr *sechdrs; -}; - -static inline bool elf_is_elf_file(const struct elfhdr *ehdr) -{ - return memcmp(ehdr->e_ident, ELFMAG, SELFMAG) == 0; -} - -static uint64_t elf64_to_cpu(const struct elfhdr *ehdr, uint64_t value) -{ - if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) - value = le64_to_cpu(value); - else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) - value = be64_to_cpu(value); - - return value; -} - -static uint16_t elf16_to_cpu(const struct elfhdr *ehdr, uint16_t value) -{ - if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) - value = le16_to_cpu(value); - else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) - value = be16_to_cpu(value); - - return value; -} - -static uint32_t elf32_to_cpu(const struct elfhdr *ehdr, uint32_t value) -{ - if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) - value = le32_to_cpu(value); - else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) - value = be32_to_cpu(value); - - return value; -} - -/** - * elf_is_ehdr_sane - check that it is safe to use the ELF header - * @buf_len: size of the buffer in which the ELF file is loaded. - */ -static bool elf_is_ehdr_sane(const struct elfhdr *ehdr, size_t buf_len) -{ - if (ehdr->e_phnum > 0 && ehdr->e_phentsize != sizeof(struct elf_phdr)) { - pr_debug("Bad program header size.\n"); - return false; - } else if (ehdr->e_shnum > 0 && - ehdr->e_shentsize != sizeof(struct elf_shdr)) { - pr_debug("Bad section header size.\n"); - return false; - } else if (ehdr->e_ident[EI_VERSION] != EV_CURRENT || - ehdr->e_version != EV_CURRENT) { - pr_debug("Unknown ELF version.\n"); - return false; - } - - if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) { - size_t phdr_size; - - /* - * e_phnum is at most 65535 so calculating the size of the - * program header cannot overflow. - */ - phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum; - - /* Sanity check the program header table location. */ - if (ehdr->e_phoff + phdr_size < ehdr->e_phoff) { - pr_debug("Program headers at invalid location.\n"); - return false; - } else if (ehdr->e_phoff + phdr_size > buf_len) { - pr_debug("Program headers truncated.\n"); - return false; - } - } - - if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) { - size_t shdr_size; - - /* - * e_shnum is at most 65536 so calculating - * the size of the section header cannot overflow. - */ - shdr_size = sizeof(struct elf_shdr) * ehdr->e_shnum; - - /* Sanity check the section header table location. */ - if (ehdr->e_shoff + shdr_size < ehdr->e_shoff) { - pr_debug("Section headers at invalid location.\n"); - return false; - } else if (ehdr->e_shoff + shdr_size > buf_len) { - pr_debug("Section headers truncated.\n"); - return false; - } - } - - return true; -} - -static int elf_read_ehdr(const char *buf, size_t len, struct elfhdr *ehdr) -{ - struct elfhdr *buf_ehdr; - - if (len < sizeof(*buf_ehdr)) { - pr_debug("Buffer is too small to hold ELF header.\n"); - return -ENOEXEC; - } - - memset(ehdr, 0, sizeof(*ehdr)); - memcpy(ehdr->e_ident, buf, sizeof(ehdr->e_ident)); - if (!elf_is_elf_file(ehdr)) { - pr_debug("No ELF header magic.\n"); - return -ENOEXEC; - } - - if (ehdr->e_ident[EI_CLASS] != ELF_CLASS) { - pr_debug("Not a supported ELF class.\n"); - return -ENOEXEC; - } else if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB && - ehdr->e_ident[EI_DATA] != ELFDATA2MSB) { - pr_debug("Not a supported ELF data format.\n"); - return -ENOEXEC; - } - - buf_ehdr = (struct elfhdr *) buf; - if (elf16_to_cpu(ehdr, buf_ehdr->e_ehsize) != sizeof(*buf_ehdr)) { - pr_debug("Bad ELF header size.\n"); - return -ENOEXEC; - } - - ehdr->e_type = elf16_to_cpu(ehdr, buf_ehdr->e_type); - ehdr->e_machine = elf16_to_cpu(ehdr, buf_ehdr->e_machine); - ehdr->e_version = elf32_to_cpu(ehdr, buf_ehdr->e_version); - ehdr->e_entry = elf_addr_to_cpu(ehdr, buf_ehdr->e_entry); - ehdr->e_phoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_phoff); - ehdr->e_shoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_shoff); - ehdr->e_flags = elf32_to_cpu(ehdr, buf_ehdr->e_flags); - ehdr->e_phentsize = elf16_to_cpu(ehdr, buf_ehdr->e_phentsize); - ehdr->e_phnum = elf16_to_cpu(ehdr, buf_ehdr->e_phnum); - ehdr->e_shentsize = elf16_to_cpu(ehdr, buf_ehdr->e_shentsize); - ehdr->e_shnum = elf16_to_cpu(ehdr, buf_ehdr->e_shnum); - ehdr->e_shstrndx = elf16_to_cpu(ehdr, buf_ehdr->e_shstrndx); - - return elf_is_ehdr_sane(ehdr, len) ? 0 : -ENOEXEC; -} - -/** - * elf_is_phdr_sane - check that it is safe to use the program header - * @buf_len: size of the buffer in which the ELF file is loaded. - */ -static bool elf_is_phdr_sane(const struct elf_phdr *phdr, size_t buf_len) -{ - - if (phdr->p_offset + phdr->p_filesz < phdr->p_offset) { - pr_debug("ELF segment location wraps around.\n"); - return false; - } else if (phdr->p_offset + phdr->p_filesz > buf_len) { - pr_debug("ELF segment not in file.\n"); - return false; - } else if (phdr->p_paddr + phdr->p_memsz < phdr->p_paddr) { - pr_debug("ELF segment address wraps around.\n"); - return false; - } - - return true; -} - -static int elf_read_phdr(const char *buf, size_t len, struct elf_info *elf_info, - int idx) -{ - /* Override the const in proghdrs, we are the ones doing the loading. */ - struct elf_phdr *phdr = (struct elf_phdr *) &elf_info->proghdrs[idx]; - const char *pbuf; - struct elf_phdr *buf_phdr; - - pbuf = buf + elf_info->ehdr->e_phoff + (idx * sizeof(*buf_phdr)); - buf_phdr = (struct elf_phdr *) pbuf; - - phdr->p_type = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_type); - phdr->p_offset = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_offset); - phdr->p_paddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_paddr); - phdr->p_vaddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_vaddr); - phdr->p_flags = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_flags); - - /* - * The following fields have a type equivalent to Elf_Addr - * both in 32 bit and 64 bit ELF. - */ - phdr->p_filesz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_filesz); - phdr->p_memsz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_memsz); - phdr->p_align = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_align); - - return elf_is_phdr_sane(phdr, len) ? 0 : -ENOEXEC; -} - -/** - * elf_read_phdrs - read the program headers from the buffer - * - * This function assumes that the program header table was checked for sanity. - * Use elf_is_ehdr_sane() if it wasn't. - */ -static int elf_read_phdrs(const char *buf, size_t len, - struct elf_info *elf_info) -{ - size_t phdr_size, i; - const struct elfhdr *ehdr = elf_info->ehdr; - - /* - * e_phnum is at most 65535 so calculating the size of the - * program header cannot overflow. - */ - phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum; - - elf_info->proghdrs = kzalloc(phdr_size, GFP_KERNEL); - if (!elf_info->proghdrs) - return -ENOMEM; - - for (i = 0; i < ehdr->e_phnum; i++) { - int ret; - - ret = elf_read_phdr(buf, len, elf_info, i); - if (ret) { - kfree(elf_info->proghdrs); - elf_info->proghdrs = NULL; - return ret; - } - } - - return 0; -} - -/** - * elf_is_shdr_sane - check that it is safe to use the section header - * @buf_len: size of the buffer in which the ELF file is loaded. - */ -static bool elf_is_shdr_sane(const struct elf_shdr *shdr, size_t buf_len) -{ - bool size_ok; - - /* SHT_NULL headers have undefined values, so we can't check them. */ - if (shdr->sh_type == SHT_NULL) - return true; - - /* Now verify sh_entsize */ - switch (shdr->sh_type) { - case SHT_SYMTAB: - size_ok = shdr->sh_entsize == sizeof(Elf_Sym); - break; - case SHT_RELA: - size_ok = shdr->sh_entsize == sizeof(Elf_Rela); - break; - case SHT_DYNAMIC: - size_ok = shdr->sh_entsize == sizeof(Elf_Dyn); - break; - case SHT_REL: - size_ok = shdr->sh_entsize == sizeof(Elf_Rel); - break; - case SHT_NOTE: - case SHT_PROGBITS: - case SHT_HASH: - case SHT_NOBITS: - default: - /* - * This is a section whose entsize requirements - * I don't care about. If I don't know about - * the section I can't care about it's entsize - * requirements. - */ - size_ok = true; - break; - } - - if (!size_ok) { - pr_debug("ELF section with wrong entry size.\n"); - return false; - } else if (shdr->sh_addr + shdr->sh_size < shdr->sh_addr) { - pr_debug("ELF section address wraps around.\n"); - return false; - } - - if (shdr->sh_type != SHT_NOBITS) { - if (shdr->sh_offset + shdr->sh_size < shdr->sh_offset) { - pr_debug("ELF section location wraps around.\n"); - return false; - } else if (shdr->sh_offset + shdr->sh_size > buf_len) { - pr_debug("ELF section not in file.\n"); - return false; - } - } - - return true; -} - -static int elf_read_shdr(const char *buf, size_t len, struct elf_info *elf_info, - int idx) -{ - struct elf_shdr *shdr = &elf_info->sechdrs[idx]; - const struct elfhdr *ehdr = elf_info->ehdr; - const char *sbuf; - struct elf_shdr *buf_shdr; - - sbuf = buf + ehdr->e_shoff + idx * sizeof(*buf_shdr); - buf_shdr = (struct elf_shdr *) sbuf; - - shdr->sh_name = elf32_to_cpu(ehdr, buf_shdr->sh_name); - shdr->sh_type = elf32_to_cpu(ehdr, buf_shdr->sh_type); - shdr->sh_addr = elf_addr_to_cpu(ehdr, buf_shdr->sh_addr); - shdr->sh_offset = elf_addr_to_cpu(ehdr, buf_shdr->sh_offset); - shdr->sh_link = elf32_to_cpu(ehdr, buf_shdr->sh_link); - shdr->sh_info = elf32_to_cpu(ehdr, buf_shdr->sh_info); - - /* - * The following fields have a type equivalent to Elf_Addr - * both in 32 bit and 64 bit ELF. - */ - shdr->sh_flags = elf_addr_to_cpu(ehdr, buf_shdr->sh_flags); - shdr->sh_size = elf_addr_to_cpu(ehdr, buf_shdr->sh_size); - shdr->sh_addralign = elf_addr_to_cpu(ehdr, buf_shdr->sh_addralign); - shdr->sh_entsize = elf_addr_to_cpu(ehdr, buf_shdr->sh_entsize); - - return elf_is_shdr_sane(shdr, len) ? 0 : -ENOEXEC; -} - -/** - * elf_read_shdrs - read the section headers from the buffer - * - * This function assumes that the section header table was checked for sanity. - * Use elf_is_ehdr_sane() if it wasn't. - */ -static int elf_read_shdrs(const char *buf, size_t len, - struct elf_info *elf_info) -{ - size_t shdr_size, i; - - /* - * e_shnum is at most 65536 so calculating - * the size of the section header cannot overflow. - */ - shdr_size = sizeof(struct elf_shdr) * elf_info->ehdr->e_shnum; - - elf_info->sechdrs = kzalloc(shdr_size, GFP_KERNEL); - if (!elf_info->sechdrs) - return -ENOMEM; - - for (i = 0; i < elf_info->ehdr->e_shnum; i++) { - int ret; - - ret = elf_read_shdr(buf, len, elf_info, i); - if (ret) { - kfree(elf_info->sechdrs); - elf_info->sechdrs = NULL; - return ret; - } - } - - return 0; -} - -/** - * elf_read_from_buffer - read ELF file and sets up ELF header and ELF info - * @buf: Buffer to read ELF file from. - * @len: Size of @buf. - * @ehdr: Pointer to existing struct which will be populated. - * @elf_info: Pointer to existing struct which will be populated. - * - * This function allows reading ELF files with different byte order than - * the kernel, byte-swapping the fields as needed. - * - * Return: - * On success returns 0, and the caller should call elf_free_info(elf_info) to - * free the memory allocated for the section and program headers. - */ -int elf_read_from_buffer(const char *buf, size_t len, struct elfhdr *ehdr, - struct elf_info *elf_info) -{ - int ret; - - ret = elf_read_ehdr(buf, len, ehdr); - if (ret) - return ret; - - elf_info->buffer = buf; - elf_info->ehdr = ehdr; - if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) { - ret = elf_read_phdrs(buf, len, elf_info); - if (ret) - return ret; - } - if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) { - ret = elf_read_shdrs(buf, len, elf_info); - if (ret) { - kfree(elf_info->proghdrs); - return ret; - } - } - - return 0; -} - -/** - * elf_free_info - free memory allocated by elf_read_from_buffer - */ -void elf_free_info(struct elf_info *elf_info) -{ - kfree(elf_info->proghdrs); - kfree(elf_info->sechdrs); - memset(elf_info, 0, sizeof(*elf_info)); -} -/** - * build_elf_exec_info - read ELF executable and check that we can use it - */ -static int build_elf_exec_info(const char *buf, size_t len, struct elfhdr *ehdr, - struct elf_info *elf_info) -{ - int i; - int ret; - - ret = elf_read_from_buffer(buf, len, ehdr, elf_info); - if (ret) - return ret; - - /* Big endian vmlinux has type ET_DYN. */ - if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN) { - pr_err("Not an ELF executable.\n"); - goto error; - } else if (!elf_info->proghdrs) { - pr_err("No ELF program header.\n"); - goto error; - } - - for (i = 0; i < ehdr->e_phnum; i++) { - /* - * Kexec does not support loading interpreters. - * In addition this check keeps us from attempting - * to kexec ordinay executables. - */ - if (elf_info->proghdrs[i].p_type == PT_INTERP) { - pr_err("Requires an ELF interpreter.\n"); - goto error; - } - } - - return 0; -error: - elf_free_info(elf_info); - return -ENOEXEC; -} - -static int elf64_probe(const char *buf, unsigned long len) -{ - struct elfhdr ehdr; - struct elf_info elf_info; - int ret; - - ret = build_elf_exec_info(buf, len, &ehdr, &elf_info); - if (ret) - return ret; - - elf_free_info(&elf_info); - - return elf_check_arch(&ehdr) ? 0 : -ENOEXEC; -} - -/** - * elf_exec_load - load ELF executable image - * @lowest_load_addr: On return, will be the address where the first PT_LOAD - * section will be loaded in memory. - * - * Return: - * 0 on success, negative value on failure. - */ -static int elf_exec_load(struct kimage *image, struct elfhdr *ehdr, - struct elf_info *elf_info, - unsigned long *lowest_load_addr) -{ - unsigned long base = 0, lowest_addr = UINT_MAX; - int ret; - size_t i; - struct kexec_buf kbuf = { .image = image, .buf_max = ppc64_rma_size, - .top_down = false }; - - /* Read in the PT_LOAD segments. */ - for (i = 0; i < ehdr->e_phnum; i++) { - unsigned long load_addr; - size_t size; - const struct elf_phdr *phdr; - - phdr = &elf_info->proghdrs[i]; - if (phdr->p_type != PT_LOAD) - continue; - - size = phdr->p_filesz; - if (size > phdr->p_memsz) - size = phdr->p_memsz; - - kbuf.buffer = (void *) elf_info->buffer + phdr->p_offset; - kbuf.bufsz = size; - kbuf.memsz = phdr->p_memsz; - kbuf.buf_align = phdr->p_align; - kbuf.buf_min = phdr->p_paddr + base; - ret = kexec_add_buffer(&kbuf); - if (ret) - goto out; - load_addr = kbuf.mem; - - if (load_addr < lowest_addr) - lowest_addr = load_addr; - } - - /* Update entry point to reflect new load address. */ - ehdr->e_entry += base; - - *lowest_load_addr = lowest_addr; - ret = 0; - out: - return ret; -} - static void *elf64_load(struct kimage *image, char *kernel_buf, unsigned long kernel_len, char *initrd, unsigned long initrd_len, char *cmdline, @@ -577,17 +43,18 @@ static void *elf64_load(struct kimage *image, char *kernel_buf, void *fdt; const void *slave_code; struct elfhdr ehdr; - struct elf_info elf_info; + struct kexec_elf_info elf_info; struct kexec_buf kbuf = { .image = image, .buf_min = 0, .buf_max = ppc64_rma_size }; struct kexec_buf pbuf = { .image = image, .buf_min = 0, - .buf_max = ppc64_rma_size, .top_down = true }; + .buf_max = ppc64_rma_size, .top_down = true, + .mem = KEXEC_BUF_MEM_UNKNOWN }; - ret = build_elf_exec_info(kernel_buf, kernel_len, &ehdr, &elf_info); + ret = kexec_build_elf_info(kernel_buf, kernel_len, &ehdr, &elf_info); if (ret) goto out; - ret = elf_exec_load(image, &ehdr, &elf_info, &kernel_load_addr); + ret = kexec_elf_load(image, &ehdr, &elf_info, &kbuf, &kernel_load_addr); if (ret) goto out; @@ -606,6 +73,7 @@ static void *elf64_load(struct kimage *image, char *kernel_buf, kbuf.bufsz = kbuf.memsz = initrd_len; kbuf.buf_align = PAGE_SIZE; kbuf.top_down = false; + kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; ret = kexec_add_buffer(&kbuf); if (ret) goto out; @@ -638,6 +106,7 @@ static void *elf64_load(struct kimage *image, char *kernel_buf, kbuf.bufsz = kbuf.memsz = fdt_size; kbuf.buf_align = PAGE_SIZE; kbuf.top_down = true; + kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; ret = kexec_add_buffer(&kbuf); if (ret) goto out; @@ -652,13 +121,13 @@ static void *elf64_load(struct kimage *image, char *kernel_buf, pr_err("Error setting up the purgatory.\n"); out: - elf_free_info(&elf_info); + kexec_free_elf_info(&elf_info); /* Make kimage_file_post_load_cleanup free the fdt buffer for us. */ return ret ? ERR_PTR(ret) : fdt; } const struct kexec_file_ops kexec_elf64_ops = { - .probe = elf64_probe, + .probe = kexec_elf_probe, .load = elf64_load, }; diff --git a/include/linux/kexec.h b/include/linux/kexec.h index b9b1bc5f9669..da2a6b1d69e7 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -216,6 +216,30 @@ extern int crash_prepare_elf64_headers(struct crash_mem *mem, int kernel_map, void **addr, unsigned long *sz); #endif /* CONFIG_KEXEC_FILE */ +#ifdef CONFIG_KEXEC_ELF +struct kexec_elf_info { + /* + * Where the ELF binary contents are kept. + * Memory managed by the user of the struct. + */ + const char *buffer; + + const struct elfhdr *ehdr; + const struct elf_phdr *proghdrs; + struct elf_shdr *sechdrs; +}; + +int kexec_build_elf_info(const char *buf, size_t len, struct elfhdr *ehdr, + struct kexec_elf_info *elf_info); + +int kexec_elf_load(struct kimage *image, struct elfhdr *ehdr, + struct kexec_elf_info *elf_info, + struct kexec_buf *kbuf, + unsigned long *lowest_load_addr); + +void kexec_free_elf_info(struct kexec_elf_info *elf_info); +int kexec_elf_probe(const char *buf, unsigned long len); +#endif struct kimage { kimage_entry_t head; kimage_entry_t *entry; diff --git a/kernel/Makefile b/kernel/Makefile index 33824f0385b3..7062306de9b7 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -64,6 +64,7 @@ obj-$(CONFIG_CRASH_CORE) += crash_core.o obj-$(CONFIG_KEXEC_CORE) += kexec_core.o obj-$(CONFIG_KEXEC) += kexec.o obj-$(CONFIG_KEXEC_FILE) += kexec_file.o +obj-$(CONFIG_KEXEC_ELF) += kexec_elf.o obj-$(CONFIG_BACKTRACE_SELF_TEST) += backtracetest.o obj-$(CONFIG_COMPAT) += compat.o obj-$(CONFIG_CGROUPS) += cgroup/ diff --git a/kernel/kexec_elf.c b/kernel/kexec_elf.c new file mode 100644 index 000000000000..6e9f52171ede --- /dev/null +++ b/kernel/kexec_elf.c @@ -0,0 +1,537 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#define pr_fmt(fmt) "kexec_elf: " fmt + +#include <linux/elf.h> +#include <linux/kexec.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/types.h> + +#define PURGATORY_STACK_SIZE (16 * 1024) + +#define elf_addr_to_cpu elf64_to_cpu + +#ifndef Elf_Rel +#define Elf_Rel Elf64_Rel +#endif /* Elf_Rel */ + +static inline bool elf_is_elf_file(const struct elfhdr *ehdr) +{ + return memcmp(ehdr->e_ident, ELFMAG, SELFMAG) == 0; +} + +static uint64_t elf64_to_cpu(const struct elfhdr *ehdr, uint64_t value) +{ + if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) + value = le64_to_cpu(value); + else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) + value = be64_to_cpu(value); + + return value; +} + +static uint16_t elf16_to_cpu(const struct elfhdr *ehdr, uint16_t value) +{ + if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) + value = le16_to_cpu(value); + else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) + value = be16_to_cpu(value); + + return value; +} + +static uint32_t elf32_to_cpu(const struct elfhdr *ehdr, uint32_t value) +{ + if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) + value = le32_to_cpu(value); + else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) + value = be32_to_cpu(value); + + return value; +} + +/** + * elf_is_ehdr_sane - check that it is safe to use the ELF header + * @buf_len: size of the buffer in which the ELF file is loaded. + */ +static bool elf_is_ehdr_sane(const struct elfhdr *ehdr, size_t buf_len) +{ + if (ehdr->e_phnum > 0 && ehdr->e_phentsize != sizeof(struct elf_phdr)) { + pr_debug("Bad program header size.\n"); + return false; + } else if (ehdr->e_shnum > 0 && + ehdr->e_shentsize != sizeof(struct elf_shdr)) { + pr_debug("Bad section header size.\n"); + return false; + } else if (ehdr->e_ident[EI_VERSION] != EV_CURRENT || + ehdr->e_version != EV_CURRENT) { + pr_debug("Unknown ELF version.\n"); + return false; + } + + if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) { + size_t phdr_size; + + /* + * e_phnum is at most 65535 so calculating the size of the + * program header cannot overflow. + */ + phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum; + + /* Sanity check the program header table location. */ + if (ehdr->e_phoff + phdr_size < ehdr->e_phoff) { + pr_debug("Program headers at invalid location.\n"); + return false; + } else if (ehdr->e_phoff + phdr_size > buf_len) { + pr_debug("Program headers truncated.\n"); + return false; + } + } + + if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) { + size_t shdr_size; + + /* + * e_shnum is at most 65536 so calculating + * the size of the section header cannot overflow. + */ + shdr_size = sizeof(struct elf_shdr) * ehdr->e_shnum; + + /* Sanity check the section header table location. */ + if (ehdr->e_shoff + shdr_size < ehdr->e_shoff) { + pr_debug("Section headers at invalid location.\n"); + return false; + } else if (ehdr->e_shoff + shdr_size > buf_len) { + pr_debug("Section headers truncated.\n"); + return false; + } + } + + return true; +} + +static int elf_read_ehdr(const char *buf, size_t len, struct elfhdr *ehdr) +{ + struct elfhdr *buf_ehdr; + + if (len < sizeof(*buf_ehdr)) { + pr_debug("Buffer is too small to hold ELF header.\n"); + return -ENOEXEC; + } + + memset(ehdr, 0, sizeof(*ehdr)); + memcpy(ehdr->e_ident, buf, sizeof(ehdr->e_ident)); + if (!elf_is_elf_file(ehdr)) { + pr_debug("No ELF header magic.\n"); + return -ENOEXEC; + } + + if (ehdr->e_ident[EI_CLASS] != ELF_CLASS) { + pr_debug("Not a supported ELF class.\n"); + return -ENOEXEC; + } else if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB && + ehdr->e_ident[EI_DATA] != ELFDATA2MSB) { + pr_debug("Not a supported ELF data format.\n"); + return -ENOEXEC; + } + + buf_ehdr = (struct elfhdr *) buf; + if (elf16_to_cpu(ehdr, buf_ehdr->e_ehsize) != sizeof(*buf_ehdr)) { + pr_debug("Bad ELF header size.\n"); + return -ENOEXEC; + } + + ehdr->e_type = elf16_to_cpu(ehdr, buf_ehdr->e_type); + ehdr->e_machine = elf16_to_cpu(ehdr, buf_ehdr->e_machine); + ehdr->e_version = elf32_to_cpu(ehdr, buf_ehdr->e_version); + ehdr->e_entry = elf_addr_to_cpu(ehdr, buf_ehdr->e_entry); + ehdr->e_phoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_phoff); + ehdr->e_shoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_shoff); + ehdr->e_flags = elf32_to_cpu(ehdr, buf_ehdr->e_flags); + ehdr->e_phentsize = elf16_to_cpu(ehdr, buf_ehdr->e_phentsize); + ehdr->e_phnum = elf16_to_cpu(ehdr, buf_ehdr->e_phnum); + ehdr->e_shentsize = elf16_to_cpu(ehdr, buf_ehdr->e_shentsize); + ehdr->e_shnum = elf16_to_cpu(ehdr, buf_ehdr->e_shnum); + ehdr->e_shstrndx = elf16_to_cpu(ehdr, buf_ehdr->e_shstrndx); + + return elf_is_ehdr_sane(ehdr, len) ? 0 : -ENOEXEC; +} + +/** + * elf_is_phdr_sane - check that it is safe to use the program header + * @buf_len: size of the buffer in which the ELF file is loaded. + */ +static bool elf_is_phdr_sane(const struct elf_phdr *phdr, size_t buf_len) +{ + + if (phdr->p_offset + phdr->p_filesz < phdr->p_offset) { + pr_debug("ELF segment location wraps around.\n"); + return false; + } else if (phdr->p_offset + phdr->p_filesz > buf_len) { + pr_debug("ELF segment not in file.\n"); + return false; + } else if (phdr->p_paddr + phdr->p_memsz < phdr->p_paddr) { + pr_debug("ELF segment address wraps around.\n"); + return false; + } + + return true; +} + +static int elf_read_phdr(const char *buf, size_t len, + struct kexec_elf_info *elf_info, + int idx) +{ + /* Override the const in proghdrs, we are the ones doing the loading. */ + struct elf_phdr *phdr = (struct elf_phdr *) &elf_info->proghdrs[idx]; + const char *pbuf; + struct elf_phdr *buf_phdr; + + pbuf = buf + elf_info->ehdr->e_phoff + (idx * sizeof(*buf_phdr)); + buf_phdr = (struct elf_phdr *) pbuf; + + phdr->p_type = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_type); + phdr->p_offset = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_offset); + phdr->p_paddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_paddr); + phdr->p_vaddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_vaddr); + phdr->p_flags = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_flags); + + /* + * The following fields have a type equivalent to Elf_Addr + * both in 32 bit and 64 bit ELF. + */ + phdr->p_filesz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_filesz); + phdr->p_memsz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_memsz); + phdr->p_align = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_align); + + return elf_is_phdr_sane(phdr, len) ? 0 : -ENOEXEC; +} + +/** + * elf_read_phdrs - read the program headers from the buffer + * + * This function assumes that the program header table was checked for sanity. + * Use elf_is_ehdr_sane() if it wasn't. + */ +static int elf_read_phdrs(const char *buf, size_t len, + struct kexec_elf_info *elf_info) +{ + size_t phdr_size, i; + const struct elfhdr *ehdr = elf_info->ehdr; + + /* + * e_phnum is at most 65535 so calculating the size of the + * program header cannot overflow. + */ + phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum; + + elf_info->proghdrs = kzalloc(phdr_size, GFP_KERNEL); + if (!elf_info->proghdrs) + return -ENOMEM; + + for (i = 0; i < ehdr->e_phnum; i++) { + int ret; + + ret = elf_read_phdr(buf, len, elf_info, i); + if (ret) { + kfree(elf_info->proghdrs); + elf_info->proghdrs = NULL; + return ret; + } + } + + return 0; +} + +/** + * elf_is_shdr_sane - check that it is safe to use the section header + * @buf_len: size of the buffer in which the ELF file is loaded. + */ +static bool elf_is_shdr_sane(const struct elf_shdr *shdr, size_t buf_len) +{ + bool size_ok; + + /* SHT_NULL headers have undefined values, so we can't check them. */ + if (shdr->sh_type == SHT_NULL) + return true; + + /* Now verify sh_entsize */ + switch (shdr->sh_type) { + case SHT_SYMTAB: + size_ok = shdr->sh_entsize == sizeof(Elf_Sym); + break; + case SHT_RELA: + size_ok = shdr->sh_entsize == sizeof(Elf_Rela); + break; + case SHT_DYNAMIC: + size_ok = shdr->sh_entsize == sizeof(Elf_Dyn); + break; + case SHT_REL: + size_ok = shdr->sh_entsize == sizeof(Elf_Rel); + break; + case SHT_NOTE: + case SHT_PROGBITS: + case SHT_HASH: + case SHT_NOBITS: + default: + /* + * This is a section whose entsize requirements + * I don't care about. If I don't know about + * the section I can't care about it's entsize + * requirements. + */ + size_ok = true; + break; + } + + if (!size_ok) { + pr_debug("ELF section with wrong entry size.\n"); + return false; + } else if (shdr->sh_addr + shdr->sh_size < shdr->sh_addr) { + pr_debug("ELF section address wraps around.\n"); + return false; + } + + if (shdr->sh_type != SHT_NOBITS) { + if (shdr->sh_offset + shdr->sh_size < shdr->sh_offset) { + pr_debug("ELF section location wraps around.\n"); + return false; + } else if (shdr->sh_offset + shdr->sh_size > buf_len) { + pr_debug("ELF section not in file.\n"); + return false; + } + } + + return true; +} + +static int elf_read_shdr(const char *buf, size_t len, + struct kexec_elf_info *elf_info, + int idx) +{ + struct elf_shdr *shdr = &elf_info->sechdrs[idx]; + const struct elfhdr *ehdr = elf_info->ehdr; + const char *sbuf; + struct elf_shdr *buf_shdr; + + sbuf = buf + ehdr->e_shoff + idx * sizeof(*buf_shdr); + buf_shdr = (struct elf_shdr *) sbuf; + + shdr->sh_name = elf32_to_cpu(ehdr, buf_shdr->sh_name); + shdr->sh_type = elf32_to_cpu(ehdr, buf_shdr->sh_type); + shdr->sh_addr = elf_addr_to_cpu(ehdr, buf_shdr->sh_addr); + shdr->sh_offset = elf_addr_to_cpu(ehdr, buf_shdr->sh_offset); + shdr->sh_link = elf32_to_cpu(ehdr, buf_shdr->sh_link); + shdr->sh_info = elf32_to_cpu(ehdr, buf_shdr->sh_info); + + /* + * The following fields have a type equivalent to Elf_Addr + * both in 32 bit and 64 bit ELF. + */ + shdr->sh_flags = elf_addr_to_cpu(ehdr, buf_shdr->sh_flags); + shdr->sh_size = elf_addr_to_cpu(ehdr, buf_shdr->sh_size); + shdr->sh_addralign = elf_addr_to_cpu(ehdr, buf_shdr->sh_addralign); + shdr->sh_entsize = elf_addr_to_cpu(ehdr, buf_shdr->sh_entsize); + + return elf_is_shdr_sane(shdr, len) ? 0 : -ENOEXEC; +} + +/** + * elf_read_shdrs - read the section headers from the buffer + * + * This function assumes that the section header table was checked for sanity. + * Use elf_is_ehdr_sane() if it wasn't. + */ +static int elf_read_shdrs(const char *buf, size_t len, + struct kexec_elf_info *elf_info) +{ + size_t shdr_size, i; + + /* + * e_shnum is at most 65536 so calculating + * the size of the section header cannot overflow. + */ + shdr_size = sizeof(struct elf_shdr) * elf_info->ehdr->e_shnum; + + elf_info->sechdrs = kzalloc(shdr_size, GFP_KERNEL); + if (!elf_info->sechdrs) + return -ENOMEM; + + for (i = 0; i < elf_info->ehdr->e_shnum; i++) { + int ret; + + ret = elf_read_shdr(buf, len, elf_info, i); + if (ret) { + kfree(elf_info->sechdrs); + elf_info->sechdrs = NULL; + return ret; + } + } + + return 0; +} + +/** + * elf_read_from_buffer - read ELF file and sets up ELF header and ELF info + * @buf: Buffer to read ELF file from. + * @len: Size of @buf. + * @ehdr: Pointer to existing struct which will be populated. + * @elf_info: Pointer to existing struct which will be populated. + * + * This function allows reading ELF files with different byte order than + * the kernel, byte-swapping the fields as needed. + * + * Return: + * On success returns 0, and the caller should call + * kexec_free_elf_info(elf_info) to free the memory allocated for the section + * and program headers. + */ +static int elf_read_from_buffer(const char *buf, size_t len, + struct elfhdr *ehdr, + struct kexec_elf_info *elf_info) +{ + int ret; + + ret = elf_read_ehdr(buf, len, ehdr); + if (ret) + return ret; + + elf_info->buffer = buf; + elf_info->ehdr = ehdr; + if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) { + ret = elf_read_phdrs(buf, len, elf_info); + if (ret) + return ret; + } + if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) { + ret = elf_read_shdrs(buf, len, elf_info); + if (ret) { + kfree(elf_info->proghdrs); + return ret; + } + } + + return 0; +} + +/** + * kexec_free_elf_info - free memory allocated by elf_read_from_buffer + */ +void kexec_free_elf_info(struct kexec_elf_info *elf_info) +{ + kfree(elf_info->proghdrs); + kfree(elf_info->sechdrs); + memset(elf_info, 0, sizeof(*elf_info)); +} +/** + * kexec_build_elf_info - read ELF executable and check that we can use it + */ +int kexec_build_elf_info(const char *buf, size_t len, struct elfhdr *ehdr, + struct kexec_elf_info *elf_info) +{ + int i; + int ret; + + ret = elf_read_from_buffer(buf, len, ehdr, elf_info); + if (ret) + return ret; + + /* Big endian vmlinux has type ET_DYN. */ + if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN) { + pr_err("Not an ELF executable.\n"); + goto error; + } else if (!elf_info->proghdrs) { + pr_err("No ELF program header.\n"); + goto error; + } + + for (i = 0; i < ehdr->e_phnum; i++) { + /* + * Kexec does not support loading interpreters. + * In addition this check keeps us from attempting + * to kexec ordinay executables. + */ + if (elf_info->proghdrs[i].p_type == PT_INTERP) { + pr_err("Requires an ELF interpreter.\n"); + goto error; + } + } + + return 0; +error: + kexec_free_elf_info(elf_info); + return -ENOEXEC; +} + + +int kexec_elf_probe(const char *buf, unsigned long len) +{ + struct elfhdr ehdr; + struct kexec_elf_info elf_info; + int ret; + + ret = kexec_build_elf_info(buf, len, &ehdr, &elf_info); + if (ret) + return ret; + + kexec_free_elf_info(&elf_info); + + return elf_check_arch(&ehdr) ? 0 : -ENOEXEC; +} + +/** + * kexec_elf_load - load ELF executable image + * @lowest_load_addr: On return, will be the address where the first PT_LOAD + * section will be loaded in memory. + * + * Return: + * 0 on success, negative value on failure. + */ +int kexec_elf_load(struct kimage *image, struct elfhdr *ehdr, + struct kexec_elf_info *elf_info, + struct kexec_buf *kbuf, + unsigned long *lowest_load_addr) +{ + unsigned long base = 0, lowest_addr = UINT_MAX; + int ret; + size_t i; + + /* Read in the PT_LOAD segments. */ + for (i = 0; i < ehdr->e_phnum; i++) { + unsigned long load_addr; + size_t size; + const struct elf_phdr *phdr; + + phdr = &elf_info->proghdrs[i]; + if (phdr->p_type != PT_LOAD) + continue; + + size = phdr->p_filesz; + if (size > phdr->p_memsz) + size = phdr->p_memsz; + + kbuf->buffer = (void *) elf_info->buffer + phdr->p_offset; + kbuf->bufsz = size; + kbuf->memsz = phdr->p_memsz; + kbuf->buf_align = phdr->p_align; + kbuf->buf_min = phdr->p_paddr + base; + ret = kexec_add_buffer(kbuf); + if (ret) + goto out; + load_addr = kbuf->mem; + + if (load_addr < lowest_addr) + lowest_addr = load_addr; + } + + /* Update entry point to reflect new load address. */ + ehdr->e_entry += base; + + *lowest_load_addr = lowest_addr; + ret = 0; + out: + return ret; +} + + -- 2.20.1 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec ^ permalink raw reply related [flat|nested] 20+ messages in thread
* Re: [PATCH v2 1/7] kexec: add KEXEC_ELF 2019-07-09 19:43 ` Sven Schnelle @ 2019-07-10 13:19 ` Christophe Leroy -1 siblings, 0 replies; 20+ messages in thread From: Christophe Leroy @ 2019-07-10 13:19 UTC (permalink / raw) To: Sven Schnelle, kexec; +Cc: deller, linuxppc-dev Hi Sven, On 07/09/2019 07:43 PM, Sven Schnelle wrote: > Right now powerpc provides an implementation to read elf files > with the kexec_file() syscall. Make that available as a public > kexec interface so it can be re-used on other architectures. > > Signed-off-by: Sven Schnelle <svens@stackframe.org> > --- > arch/Kconfig | 3 + > arch/powerpc/Kconfig | 1 + > arch/powerpc/kernel/kexec_elf_64.c | 551 +---------------------------- > include/linux/kexec.h | 24 ++ > kernel/Makefile | 1 + > kernel/kexec_elf.c | 537 ++++++++++++++++++++++++++++ > 6 files changed, 576 insertions(+), 541 deletions(-) > create mode 100644 kernel/kexec_elf.c Why are you persisting at not using -C when creating your patch ? Do you want to hide the changes you did while copying arch/powerpc/kernel/kexec_elf_64.c to kernel/kexec_elf.c ? Or you want to make life harder for the reviewers ? git format-patch -C shows: arch/Kconfig | 3 + arch/powerpc/Kconfig | 1 + arch/powerpc/kernel/kexec_elf_64.c | 551 +-------------------- include/linux/kexec.h | 24 + kernel/Makefile | 1 + .../kernel/kexec_elf_64.c => kernel/kexec_elf.c | 199 ++------ 6 files changed, 75 insertions(+), 704 deletions(-) copy arch/powerpc/kernel/kexec_elf_64.c => kernel/kexec_elf.c (71%) I mentionned it a couple of times, I even resent your last patch formatted that way to show the advantage. I can ear if you find it worthless, but tell what your concern are with that, don't just ignore it please. Cheers Christophe > > diff --git a/arch/Kconfig b/arch/Kconfig > index c47b328eada0..30694aca4316 100644 > --- a/arch/Kconfig > +++ b/arch/Kconfig > @@ -18,6 +18,9 @@ config KEXEC_CORE > select CRASH_CORE > bool > > +config KEXEC_ELF > + bool > + > config HAVE_IMA_KEXEC > bool > > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig > index 12cee37f15c4..addc2dad78e0 100644 > --- a/arch/powerpc/Kconfig > +++ b/arch/powerpc/Kconfig > @@ -510,6 +510,7 @@ config KEXEC_FILE > select KEXEC_CORE > select HAVE_IMA_KEXEC > select BUILD_BIN2C > + select KEXEC_ELF > depends on PPC64 > depends on CRYPTO=y > depends on CRYPTO_SHA256=y > diff --git a/arch/powerpc/kernel/kexec_elf_64.c b/arch/powerpc/kernel/kexec_elf_64.c > index ba4f18a43ee8..30bd57a93c17 100644 > --- a/arch/powerpc/kernel/kexec_elf_64.c > +++ b/arch/powerpc/kernel/kexec_elf_64.c > @@ -1,3 +1,4 @@ > +// SPDX-License-Identifier: GPL-2.0-only > /* > * Load ELF vmlinux file for the kexec_file_load syscall. > * > @@ -10,15 +11,6 @@ > * Based on kexec-tools' kexec-elf-exec.c and kexec-elf-ppc64.c. > * Heavily modified for the kernel by > * Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>. > - * > - * This program is free software; you can redistribute it and/or modify > - * it under the terms of the GNU General Public License as published by > - * the Free Software Foundation (version 2 of the License). > - * > - * This program is distributed in the hope that it will be useful, > - * but WITHOUT ANY WARRANTY; without even the implied warranty of > - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > - * GNU General Public License for more details. > */ > > #define pr_fmt(fmt) "kexec_elf: " fmt > @@ -39,532 +31,6 @@ > #define Elf_Rel Elf64_Rel > #endif /* Elf_Rel */ > > -struct elf_info { > - /* > - * Where the ELF binary contents are kept. > - * Memory managed by the user of the struct. > - */ > - const char *buffer; > - > - const struct elfhdr *ehdr; > - const struct elf_phdr *proghdrs; > - struct elf_shdr *sechdrs; > -}; > - > -static inline bool elf_is_elf_file(const struct elfhdr *ehdr) > -{ > - return memcmp(ehdr->e_ident, ELFMAG, SELFMAG) == 0; > -} > - > -static uint64_t elf64_to_cpu(const struct elfhdr *ehdr, uint64_t value) > -{ > - if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) > - value = le64_to_cpu(value); > - else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) > - value = be64_to_cpu(value); > - > - return value; > -} > - > -static uint16_t elf16_to_cpu(const struct elfhdr *ehdr, uint16_t value) > -{ > - if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) > - value = le16_to_cpu(value); > - else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) > - value = be16_to_cpu(value); > - > - return value; > -} > - > -static uint32_t elf32_to_cpu(const struct elfhdr *ehdr, uint32_t value) > -{ > - if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) > - value = le32_to_cpu(value); > - else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) > - value = be32_to_cpu(value); > - > - return value; > -} > - > -/** > - * elf_is_ehdr_sane - check that it is safe to use the ELF header > - * @buf_len: size of the buffer in which the ELF file is loaded. > - */ > -static bool elf_is_ehdr_sane(const struct elfhdr *ehdr, size_t buf_len) > -{ > - if (ehdr->e_phnum > 0 && ehdr->e_phentsize != sizeof(struct elf_phdr)) { > - pr_debug("Bad program header size.\n"); > - return false; > - } else if (ehdr->e_shnum > 0 && > - ehdr->e_shentsize != sizeof(struct elf_shdr)) { > - pr_debug("Bad section header size.\n"); > - return false; > - } else if (ehdr->e_ident[EI_VERSION] != EV_CURRENT || > - ehdr->e_version != EV_CURRENT) { > - pr_debug("Unknown ELF version.\n"); > - return false; > - } > - > - if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) { > - size_t phdr_size; > - > - /* > - * e_phnum is at most 65535 so calculating the size of the > - * program header cannot overflow. > - */ > - phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum; > - > - /* Sanity check the program header table location. */ > - if (ehdr->e_phoff + phdr_size < ehdr->e_phoff) { > - pr_debug("Program headers at invalid location.\n"); > - return false; > - } else if (ehdr->e_phoff + phdr_size > buf_len) { > - pr_debug("Program headers truncated.\n"); > - return false; > - } > - } > - > - if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) { > - size_t shdr_size; > - > - /* > - * e_shnum is at most 65536 so calculating > - * the size of the section header cannot overflow. > - */ > - shdr_size = sizeof(struct elf_shdr) * ehdr->e_shnum; > - > - /* Sanity check the section header table location. */ > - if (ehdr->e_shoff + shdr_size < ehdr->e_shoff) { > - pr_debug("Section headers at invalid location.\n"); > - return false; > - } else if (ehdr->e_shoff + shdr_size > buf_len) { > - pr_debug("Section headers truncated.\n"); > - return false; > - } > - } > - > - return true; > -} > - > -static int elf_read_ehdr(const char *buf, size_t len, struct elfhdr *ehdr) > -{ > - struct elfhdr *buf_ehdr; > - > - if (len < sizeof(*buf_ehdr)) { > - pr_debug("Buffer is too small to hold ELF header.\n"); > - return -ENOEXEC; > - } > - > - memset(ehdr, 0, sizeof(*ehdr)); > - memcpy(ehdr->e_ident, buf, sizeof(ehdr->e_ident)); > - if (!elf_is_elf_file(ehdr)) { > - pr_debug("No ELF header magic.\n"); > - return -ENOEXEC; > - } > - > - if (ehdr->e_ident[EI_CLASS] != ELF_CLASS) { > - pr_debug("Not a supported ELF class.\n"); > - return -ENOEXEC; > - } else if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB && > - ehdr->e_ident[EI_DATA] != ELFDATA2MSB) { > - pr_debug("Not a supported ELF data format.\n"); > - return -ENOEXEC; > - } > - > - buf_ehdr = (struct elfhdr *) buf; > - if (elf16_to_cpu(ehdr, buf_ehdr->e_ehsize) != sizeof(*buf_ehdr)) { > - pr_debug("Bad ELF header size.\n"); > - return -ENOEXEC; > - } > - > - ehdr->e_type = elf16_to_cpu(ehdr, buf_ehdr->e_type); > - ehdr->e_machine = elf16_to_cpu(ehdr, buf_ehdr->e_machine); > - ehdr->e_version = elf32_to_cpu(ehdr, buf_ehdr->e_version); > - ehdr->e_entry = elf_addr_to_cpu(ehdr, buf_ehdr->e_entry); > - ehdr->e_phoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_phoff); > - ehdr->e_shoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_shoff); > - ehdr->e_flags = elf32_to_cpu(ehdr, buf_ehdr->e_flags); > - ehdr->e_phentsize = elf16_to_cpu(ehdr, buf_ehdr->e_phentsize); > - ehdr->e_phnum = elf16_to_cpu(ehdr, buf_ehdr->e_phnum); > - ehdr->e_shentsize = elf16_to_cpu(ehdr, buf_ehdr->e_shentsize); > - ehdr->e_shnum = elf16_to_cpu(ehdr, buf_ehdr->e_shnum); > - ehdr->e_shstrndx = elf16_to_cpu(ehdr, buf_ehdr->e_shstrndx); > - > - return elf_is_ehdr_sane(ehdr, len) ? 0 : -ENOEXEC; > -} > - > -/** > - * elf_is_phdr_sane - check that it is safe to use the program header > - * @buf_len: size of the buffer in which the ELF file is loaded. > - */ > -static bool elf_is_phdr_sane(const struct elf_phdr *phdr, size_t buf_len) > -{ > - > - if (phdr->p_offset + phdr->p_filesz < phdr->p_offset) { > - pr_debug("ELF segment location wraps around.\n"); > - return false; > - } else if (phdr->p_offset + phdr->p_filesz > buf_len) { > - pr_debug("ELF segment not in file.\n"); > - return false; > - } else if (phdr->p_paddr + phdr->p_memsz < phdr->p_paddr) { > - pr_debug("ELF segment address wraps around.\n"); > - return false; > - } > - > - return true; > -} > - > -static int elf_read_phdr(const char *buf, size_t len, struct elf_info *elf_info, > - int idx) > -{ > - /* Override the const in proghdrs, we are the ones doing the loading. */ > - struct elf_phdr *phdr = (struct elf_phdr *) &elf_info->proghdrs[idx]; > - const char *pbuf; > - struct elf_phdr *buf_phdr; > - > - pbuf = buf + elf_info->ehdr->e_phoff + (idx * sizeof(*buf_phdr)); > - buf_phdr = (struct elf_phdr *) pbuf; > - > - phdr->p_type = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_type); > - phdr->p_offset = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_offset); > - phdr->p_paddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_paddr); > - phdr->p_vaddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_vaddr); > - phdr->p_flags = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_flags); > - > - /* > - * The following fields have a type equivalent to Elf_Addr > - * both in 32 bit and 64 bit ELF. > - */ > - phdr->p_filesz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_filesz); > - phdr->p_memsz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_memsz); > - phdr->p_align = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_align); > - > - return elf_is_phdr_sane(phdr, len) ? 0 : -ENOEXEC; > -} > - > -/** > - * elf_read_phdrs - read the program headers from the buffer > - * > - * This function assumes that the program header table was checked for sanity. > - * Use elf_is_ehdr_sane() if it wasn't. > - */ > -static int elf_read_phdrs(const char *buf, size_t len, > - struct elf_info *elf_info) > -{ > - size_t phdr_size, i; > - const struct elfhdr *ehdr = elf_info->ehdr; > - > - /* > - * e_phnum is at most 65535 so calculating the size of the > - * program header cannot overflow. > - */ > - phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum; > - > - elf_info->proghdrs = kzalloc(phdr_size, GFP_KERNEL); > - if (!elf_info->proghdrs) > - return -ENOMEM; > - > - for (i = 0; i < ehdr->e_phnum; i++) { > - int ret; > - > - ret = elf_read_phdr(buf, len, elf_info, i); > - if (ret) { > - kfree(elf_info->proghdrs); > - elf_info->proghdrs = NULL; > - return ret; > - } > - } > - > - return 0; > -} > - > -/** > - * elf_is_shdr_sane - check that it is safe to use the section header > - * @buf_len: size of the buffer in which the ELF file is loaded. > - */ > -static bool elf_is_shdr_sane(const struct elf_shdr *shdr, size_t buf_len) > -{ > - bool size_ok; > - > - /* SHT_NULL headers have undefined values, so we can't check them. */ > - if (shdr->sh_type == SHT_NULL) > - return true; > - > - /* Now verify sh_entsize */ > - switch (shdr->sh_type) { > - case SHT_SYMTAB: > - size_ok = shdr->sh_entsize == sizeof(Elf_Sym); > - break; > - case SHT_RELA: > - size_ok = shdr->sh_entsize == sizeof(Elf_Rela); > - break; > - case SHT_DYNAMIC: > - size_ok = shdr->sh_entsize == sizeof(Elf_Dyn); > - break; > - case SHT_REL: > - size_ok = shdr->sh_entsize == sizeof(Elf_Rel); > - break; > - case SHT_NOTE: > - case SHT_PROGBITS: > - case SHT_HASH: > - case SHT_NOBITS: > - default: > - /* > - * This is a section whose entsize requirements > - * I don't care about. If I don't know about > - * the section I can't care about it's entsize > - * requirements. > - */ > - size_ok = true; > - break; > - } > - > - if (!size_ok) { > - pr_debug("ELF section with wrong entry size.\n"); > - return false; > - } else if (shdr->sh_addr + shdr->sh_size < shdr->sh_addr) { > - pr_debug("ELF section address wraps around.\n"); > - return false; > - } > - > - if (shdr->sh_type != SHT_NOBITS) { > - if (shdr->sh_offset + shdr->sh_size < shdr->sh_offset) { > - pr_debug("ELF section location wraps around.\n"); > - return false; > - } else if (shdr->sh_offset + shdr->sh_size > buf_len) { > - pr_debug("ELF section not in file.\n"); > - return false; > - } > - } > - > - return true; > -} > - > -static int elf_read_shdr(const char *buf, size_t len, struct elf_info *elf_info, > - int idx) > -{ > - struct elf_shdr *shdr = &elf_info->sechdrs[idx]; > - const struct elfhdr *ehdr = elf_info->ehdr; > - const char *sbuf; > - struct elf_shdr *buf_shdr; > - > - sbuf = buf + ehdr->e_shoff + idx * sizeof(*buf_shdr); > - buf_shdr = (struct elf_shdr *) sbuf; > - > - shdr->sh_name = elf32_to_cpu(ehdr, buf_shdr->sh_name); > - shdr->sh_type = elf32_to_cpu(ehdr, buf_shdr->sh_type); > - shdr->sh_addr = elf_addr_to_cpu(ehdr, buf_shdr->sh_addr); > - shdr->sh_offset = elf_addr_to_cpu(ehdr, buf_shdr->sh_offset); > - shdr->sh_link = elf32_to_cpu(ehdr, buf_shdr->sh_link); > - shdr->sh_info = elf32_to_cpu(ehdr, buf_shdr->sh_info); > - > - /* > - * The following fields have a type equivalent to Elf_Addr > - * both in 32 bit and 64 bit ELF. > - */ > - shdr->sh_flags = elf_addr_to_cpu(ehdr, buf_shdr->sh_flags); > - shdr->sh_size = elf_addr_to_cpu(ehdr, buf_shdr->sh_size); > - shdr->sh_addralign = elf_addr_to_cpu(ehdr, buf_shdr->sh_addralign); > - shdr->sh_entsize = elf_addr_to_cpu(ehdr, buf_shdr->sh_entsize); > - > - return elf_is_shdr_sane(shdr, len) ? 0 : -ENOEXEC; > -} > - > -/** > - * elf_read_shdrs - read the section headers from the buffer > - * > - * This function assumes that the section header table was checked for sanity. > - * Use elf_is_ehdr_sane() if it wasn't. > - */ > -static int elf_read_shdrs(const char *buf, size_t len, > - struct elf_info *elf_info) > -{ > - size_t shdr_size, i; > - > - /* > - * e_shnum is at most 65536 so calculating > - * the size of the section header cannot overflow. > - */ > - shdr_size = sizeof(struct elf_shdr) * elf_info->ehdr->e_shnum; > - > - elf_info->sechdrs = kzalloc(shdr_size, GFP_KERNEL); > - if (!elf_info->sechdrs) > - return -ENOMEM; > - > - for (i = 0; i < elf_info->ehdr->e_shnum; i++) { > - int ret; > - > - ret = elf_read_shdr(buf, len, elf_info, i); > - if (ret) { > - kfree(elf_info->sechdrs); > - elf_info->sechdrs = NULL; > - return ret; > - } > - } > - > - return 0; > -} > - > -/** > - * elf_read_from_buffer - read ELF file and sets up ELF header and ELF info > - * @buf: Buffer to read ELF file from. > - * @len: Size of @buf. > - * @ehdr: Pointer to existing struct which will be populated. > - * @elf_info: Pointer to existing struct which will be populated. > - * > - * This function allows reading ELF files with different byte order than > - * the kernel, byte-swapping the fields as needed. > - * > - * Return: > - * On success returns 0, and the caller should call elf_free_info(elf_info) to > - * free the memory allocated for the section and program headers. > - */ > -int elf_read_from_buffer(const char *buf, size_t len, struct elfhdr *ehdr, > - struct elf_info *elf_info) > -{ > - int ret; > - > - ret = elf_read_ehdr(buf, len, ehdr); > - if (ret) > - return ret; > - > - elf_info->buffer = buf; > - elf_info->ehdr = ehdr; > - if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) { > - ret = elf_read_phdrs(buf, len, elf_info); > - if (ret) > - return ret; > - } > - if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) { > - ret = elf_read_shdrs(buf, len, elf_info); > - if (ret) { > - kfree(elf_info->proghdrs); > - return ret; > - } > - } > - > - return 0; > -} > - > -/** > - * elf_free_info - free memory allocated by elf_read_from_buffer > - */ > -void elf_free_info(struct elf_info *elf_info) > -{ > - kfree(elf_info->proghdrs); > - kfree(elf_info->sechdrs); > - memset(elf_info, 0, sizeof(*elf_info)); > -} > -/** > - * build_elf_exec_info - read ELF executable and check that we can use it > - */ > -static int build_elf_exec_info(const char *buf, size_t len, struct elfhdr *ehdr, > - struct elf_info *elf_info) > -{ > - int i; > - int ret; > - > - ret = elf_read_from_buffer(buf, len, ehdr, elf_info); > - if (ret) > - return ret; > - > - /* Big endian vmlinux has type ET_DYN. */ > - if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN) { > - pr_err("Not an ELF executable.\n"); > - goto error; > - } else if (!elf_info->proghdrs) { > - pr_err("No ELF program header.\n"); > - goto error; > - } > - > - for (i = 0; i < ehdr->e_phnum; i++) { > - /* > - * Kexec does not support loading interpreters. > - * In addition this check keeps us from attempting > - * to kexec ordinay executables. > - */ > - if (elf_info->proghdrs[i].p_type == PT_INTERP) { > - pr_err("Requires an ELF interpreter.\n"); > - goto error; > - } > - } > - > - return 0; > -error: > - elf_free_info(elf_info); > - return -ENOEXEC; > -} > - > -static int elf64_probe(const char *buf, unsigned long len) > -{ > - struct elfhdr ehdr; > - struct elf_info elf_info; > - int ret; > - > - ret = build_elf_exec_info(buf, len, &ehdr, &elf_info); > - if (ret) > - return ret; > - > - elf_free_info(&elf_info); > - > - return elf_check_arch(&ehdr) ? 0 : -ENOEXEC; > -} > - > -/** > - * elf_exec_load - load ELF executable image > - * @lowest_load_addr: On return, will be the address where the first PT_LOAD > - * section will be loaded in memory. > - * > - * Return: > - * 0 on success, negative value on failure. > - */ > -static int elf_exec_load(struct kimage *image, struct elfhdr *ehdr, > - struct elf_info *elf_info, > - unsigned long *lowest_load_addr) > -{ > - unsigned long base = 0, lowest_addr = UINT_MAX; > - int ret; > - size_t i; > - struct kexec_buf kbuf = { .image = image, .buf_max = ppc64_rma_size, > - .top_down = false }; > - > - /* Read in the PT_LOAD segments. */ > - for (i = 0; i < ehdr->e_phnum; i++) { > - unsigned long load_addr; > - size_t size; > - const struct elf_phdr *phdr; > - > - phdr = &elf_info->proghdrs[i]; > - if (phdr->p_type != PT_LOAD) > - continue; > - > - size = phdr->p_filesz; > - if (size > phdr->p_memsz) > - size = phdr->p_memsz; > - > - kbuf.buffer = (void *) elf_info->buffer + phdr->p_offset; > - kbuf.bufsz = size; > - kbuf.memsz = phdr->p_memsz; > - kbuf.buf_align = phdr->p_align; > - kbuf.buf_min = phdr->p_paddr + base; > - ret = kexec_add_buffer(&kbuf); > - if (ret) > - goto out; > - load_addr = kbuf.mem; > - > - if (load_addr < lowest_addr) > - lowest_addr = load_addr; > - } > - > - /* Update entry point to reflect new load address. */ > - ehdr->e_entry += base; > - > - *lowest_load_addr = lowest_addr; > - ret = 0; > - out: > - return ret; > -} > - > static void *elf64_load(struct kimage *image, char *kernel_buf, > unsigned long kernel_len, char *initrd, > unsigned long initrd_len, char *cmdline, > @@ -577,17 +43,18 @@ static void *elf64_load(struct kimage *image, char *kernel_buf, > void *fdt; > const void *slave_code; > struct elfhdr ehdr; > - struct elf_info elf_info; > + struct kexec_elf_info elf_info; > struct kexec_buf kbuf = { .image = image, .buf_min = 0, > .buf_max = ppc64_rma_size }; > struct kexec_buf pbuf = { .image = image, .buf_min = 0, > - .buf_max = ppc64_rma_size, .top_down = true }; > + .buf_max = ppc64_rma_size, .top_down = true, > + .mem = KEXEC_BUF_MEM_UNKNOWN }; > > - ret = build_elf_exec_info(kernel_buf, kernel_len, &ehdr, &elf_info); > + ret = kexec_build_elf_info(kernel_buf, kernel_len, &ehdr, &elf_info); > if (ret) > goto out; > > - ret = elf_exec_load(image, &ehdr, &elf_info, &kernel_load_addr); > + ret = kexec_elf_load(image, &ehdr, &elf_info, &kbuf, &kernel_load_addr); > if (ret) > goto out; > > @@ -606,6 +73,7 @@ static void *elf64_load(struct kimage *image, char *kernel_buf, > kbuf.bufsz = kbuf.memsz = initrd_len; > kbuf.buf_align = PAGE_SIZE; > kbuf.top_down = false; > + kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; > ret = kexec_add_buffer(&kbuf); > if (ret) > goto out; > @@ -638,6 +106,7 @@ static void *elf64_load(struct kimage *image, char *kernel_buf, > kbuf.bufsz = kbuf.memsz = fdt_size; > kbuf.buf_align = PAGE_SIZE; > kbuf.top_down = true; > + kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; > ret = kexec_add_buffer(&kbuf); > if (ret) > goto out; > @@ -652,13 +121,13 @@ static void *elf64_load(struct kimage *image, char *kernel_buf, > pr_err("Error setting up the purgatory.\n"); > > out: > - elf_free_info(&elf_info); > + kexec_free_elf_info(&elf_info); > > /* Make kimage_file_post_load_cleanup free the fdt buffer for us. */ > return ret ? ERR_PTR(ret) : fdt; > } > > const struct kexec_file_ops kexec_elf64_ops = { > - .probe = elf64_probe, > + .probe = kexec_elf_probe, > .load = elf64_load, > }; > diff --git a/include/linux/kexec.h b/include/linux/kexec.h > index b9b1bc5f9669..da2a6b1d69e7 100644 > --- a/include/linux/kexec.h > +++ b/include/linux/kexec.h > @@ -216,6 +216,30 @@ extern int crash_prepare_elf64_headers(struct crash_mem *mem, int kernel_map, > void **addr, unsigned long *sz); > #endif /* CONFIG_KEXEC_FILE */ > > +#ifdef CONFIG_KEXEC_ELF > +struct kexec_elf_info { > + /* > + * Where the ELF binary contents are kept. > + * Memory managed by the user of the struct. > + */ > + const char *buffer; > + > + const struct elfhdr *ehdr; > + const struct elf_phdr *proghdrs; > + struct elf_shdr *sechdrs; > +}; > + > +int kexec_build_elf_info(const char *buf, size_t len, struct elfhdr *ehdr, > + struct kexec_elf_info *elf_info); > + > +int kexec_elf_load(struct kimage *image, struct elfhdr *ehdr, > + struct kexec_elf_info *elf_info, > + struct kexec_buf *kbuf, > + unsigned long *lowest_load_addr); > + > +void kexec_free_elf_info(struct kexec_elf_info *elf_info); > +int kexec_elf_probe(const char *buf, unsigned long len); > +#endif > struct kimage { > kimage_entry_t head; > kimage_entry_t *entry; > diff --git a/kernel/Makefile b/kernel/Makefile > index 33824f0385b3..7062306de9b7 100644 > --- a/kernel/Makefile > +++ b/kernel/Makefile > @@ -64,6 +64,7 @@ obj-$(CONFIG_CRASH_CORE) += crash_core.o > obj-$(CONFIG_KEXEC_CORE) += kexec_core.o > obj-$(CONFIG_KEXEC) += kexec.o > obj-$(CONFIG_KEXEC_FILE) += kexec_file.o > +obj-$(CONFIG_KEXEC_ELF) += kexec_elf.o > obj-$(CONFIG_BACKTRACE_SELF_TEST) += backtracetest.o > obj-$(CONFIG_COMPAT) += compat.o > obj-$(CONFIG_CGROUPS) += cgroup/ > diff --git a/kernel/kexec_elf.c b/kernel/kexec_elf.c > new file mode 100644 > index 000000000000..6e9f52171ede > --- /dev/null > +++ b/kernel/kexec_elf.c > @@ -0,0 +1,537 @@ > +// SPDX-License-Identifier: GPL-2.0-only > + > +#define pr_fmt(fmt) "kexec_elf: " fmt > + > +#include <linux/elf.h> > +#include <linux/kexec.h> > +#include <linux/module.h> > +#include <linux/slab.h> > +#include <linux/types.h> > + > +#define PURGATORY_STACK_SIZE (16 * 1024) > + > +#define elf_addr_to_cpu elf64_to_cpu > + > +#ifndef Elf_Rel > +#define Elf_Rel Elf64_Rel > +#endif /* Elf_Rel */ > + > +static inline bool elf_is_elf_file(const struct elfhdr *ehdr) > +{ > + return memcmp(ehdr->e_ident, ELFMAG, SELFMAG) == 0; > +} > + > +static uint64_t elf64_to_cpu(const struct elfhdr *ehdr, uint64_t value) > +{ > + if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) > + value = le64_to_cpu(value); > + else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) > + value = be64_to_cpu(value); > + > + return value; > +} > + > +static uint16_t elf16_to_cpu(const struct elfhdr *ehdr, uint16_t value) > +{ > + if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) > + value = le16_to_cpu(value); > + else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) > + value = be16_to_cpu(value); > + > + return value; > +} > + > +static uint32_t elf32_to_cpu(const struct elfhdr *ehdr, uint32_t value) > +{ > + if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) > + value = le32_to_cpu(value); > + else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) > + value = be32_to_cpu(value); > + > + return value; > +} > + > +/** > + * elf_is_ehdr_sane - check that it is safe to use the ELF header > + * @buf_len: size of the buffer in which the ELF file is loaded. > + */ > +static bool elf_is_ehdr_sane(const struct elfhdr *ehdr, size_t buf_len) > +{ > + if (ehdr->e_phnum > 0 && ehdr->e_phentsize != sizeof(struct elf_phdr)) { > + pr_debug("Bad program header size.\n"); > + return false; > + } else if (ehdr->e_shnum > 0 && > + ehdr->e_shentsize != sizeof(struct elf_shdr)) { > + pr_debug("Bad section header size.\n"); > + return false; > + } else if (ehdr->e_ident[EI_VERSION] != EV_CURRENT || > + ehdr->e_version != EV_CURRENT) { > + pr_debug("Unknown ELF version.\n"); > + return false; > + } > + > + if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) { > + size_t phdr_size; > + > + /* > + * e_phnum is at most 65535 so calculating the size of the > + * program header cannot overflow. > + */ > + phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum; > + > + /* Sanity check the program header table location. */ > + if (ehdr->e_phoff + phdr_size < ehdr->e_phoff) { > + pr_debug("Program headers at invalid location.\n"); > + return false; > + } else if (ehdr->e_phoff + phdr_size > buf_len) { > + pr_debug("Program headers truncated.\n"); > + return false; > + } > + } > + > + if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) { > + size_t shdr_size; > + > + /* > + * e_shnum is at most 65536 so calculating > + * the size of the section header cannot overflow. > + */ > + shdr_size = sizeof(struct elf_shdr) * ehdr->e_shnum; > + > + /* Sanity check the section header table location. */ > + if (ehdr->e_shoff + shdr_size < ehdr->e_shoff) { > + pr_debug("Section headers at invalid location.\n"); > + return false; > + } else if (ehdr->e_shoff + shdr_size > buf_len) { > + pr_debug("Section headers truncated.\n"); > + return false; > + } > + } > + > + return true; > +} > + > +static int elf_read_ehdr(const char *buf, size_t len, struct elfhdr *ehdr) > +{ > + struct elfhdr *buf_ehdr; > + > + if (len < sizeof(*buf_ehdr)) { > + pr_debug("Buffer is too small to hold ELF header.\n"); > + return -ENOEXEC; > + } > + > + memset(ehdr, 0, sizeof(*ehdr)); > + memcpy(ehdr->e_ident, buf, sizeof(ehdr->e_ident)); > + if (!elf_is_elf_file(ehdr)) { > + pr_debug("No ELF header magic.\n"); > + return -ENOEXEC; > + } > + > + if (ehdr->e_ident[EI_CLASS] != ELF_CLASS) { > + pr_debug("Not a supported ELF class.\n"); > + return -ENOEXEC; > + } else if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB && > + ehdr->e_ident[EI_DATA] != ELFDATA2MSB) { > + pr_debug("Not a supported ELF data format.\n"); > + return -ENOEXEC; > + } > + > + buf_ehdr = (struct elfhdr *) buf; > + if (elf16_to_cpu(ehdr, buf_ehdr->e_ehsize) != sizeof(*buf_ehdr)) { > + pr_debug("Bad ELF header size.\n"); > + return -ENOEXEC; > + } > + > + ehdr->e_type = elf16_to_cpu(ehdr, buf_ehdr->e_type); > + ehdr->e_machine = elf16_to_cpu(ehdr, buf_ehdr->e_machine); > + ehdr->e_version = elf32_to_cpu(ehdr, buf_ehdr->e_version); > + ehdr->e_entry = elf_addr_to_cpu(ehdr, buf_ehdr->e_entry); > + ehdr->e_phoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_phoff); > + ehdr->e_shoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_shoff); > + ehdr->e_flags = elf32_to_cpu(ehdr, buf_ehdr->e_flags); > + ehdr->e_phentsize = elf16_to_cpu(ehdr, buf_ehdr->e_phentsize); > + ehdr->e_phnum = elf16_to_cpu(ehdr, buf_ehdr->e_phnum); > + ehdr->e_shentsize = elf16_to_cpu(ehdr, buf_ehdr->e_shentsize); > + ehdr->e_shnum = elf16_to_cpu(ehdr, buf_ehdr->e_shnum); > + ehdr->e_shstrndx = elf16_to_cpu(ehdr, buf_ehdr->e_shstrndx); > + > + return elf_is_ehdr_sane(ehdr, len) ? 0 : -ENOEXEC; > +} > + > +/** > + * elf_is_phdr_sane - check that it is safe to use the program header > + * @buf_len: size of the buffer in which the ELF file is loaded. > + */ > +static bool elf_is_phdr_sane(const struct elf_phdr *phdr, size_t buf_len) > +{ > + > + if (phdr->p_offset + phdr->p_filesz < phdr->p_offset) { > + pr_debug("ELF segment location wraps around.\n"); > + return false; > + } else if (phdr->p_offset + phdr->p_filesz > buf_len) { > + pr_debug("ELF segment not in file.\n"); > + return false; > + } else if (phdr->p_paddr + phdr->p_memsz < phdr->p_paddr) { > + pr_debug("ELF segment address wraps around.\n"); > + return false; > + } > + > + return true; > +} > + > +static int elf_read_phdr(const char *buf, size_t len, > + struct kexec_elf_info *elf_info, > + int idx) > +{ > + /* Override the const in proghdrs, we are the ones doing the loading. */ > + struct elf_phdr *phdr = (struct elf_phdr *) &elf_info->proghdrs[idx]; > + const char *pbuf; > + struct elf_phdr *buf_phdr; > + > + pbuf = buf + elf_info->ehdr->e_phoff + (idx * sizeof(*buf_phdr)); > + buf_phdr = (struct elf_phdr *) pbuf; > + > + phdr->p_type = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_type); > + phdr->p_offset = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_offset); > + phdr->p_paddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_paddr); > + phdr->p_vaddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_vaddr); > + phdr->p_flags = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_flags); > + > + /* > + * The following fields have a type equivalent to Elf_Addr > + * both in 32 bit and 64 bit ELF. > + */ > + phdr->p_filesz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_filesz); > + phdr->p_memsz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_memsz); > + phdr->p_align = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_align); > + > + return elf_is_phdr_sane(phdr, len) ? 0 : -ENOEXEC; > +} > + > +/** > + * elf_read_phdrs - read the program headers from the buffer > + * > + * This function assumes that the program header table was checked for sanity. > + * Use elf_is_ehdr_sane() if it wasn't. > + */ > +static int elf_read_phdrs(const char *buf, size_t len, > + struct kexec_elf_info *elf_info) > +{ > + size_t phdr_size, i; > + const struct elfhdr *ehdr = elf_info->ehdr; > + > + /* > + * e_phnum is at most 65535 so calculating the size of the > + * program header cannot overflow. > + */ > + phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum; > + > + elf_info->proghdrs = kzalloc(phdr_size, GFP_KERNEL); > + if (!elf_info->proghdrs) > + return -ENOMEM; > + > + for (i = 0; i < ehdr->e_phnum; i++) { > + int ret; > + > + ret = elf_read_phdr(buf, len, elf_info, i); > + if (ret) { > + kfree(elf_info->proghdrs); > + elf_info->proghdrs = NULL; > + return ret; > + } > + } > + > + return 0; > +} > + > +/** > + * elf_is_shdr_sane - check that it is safe to use the section header > + * @buf_len: size of the buffer in which the ELF file is loaded. > + */ > +static bool elf_is_shdr_sane(const struct elf_shdr *shdr, size_t buf_len) > +{ > + bool size_ok; > + > + /* SHT_NULL headers have undefined values, so we can't check them. */ > + if (shdr->sh_type == SHT_NULL) > + return true; > + > + /* Now verify sh_entsize */ > + switch (shdr->sh_type) { > + case SHT_SYMTAB: > + size_ok = shdr->sh_entsize == sizeof(Elf_Sym); > + break; > + case SHT_RELA: > + size_ok = shdr->sh_entsize == sizeof(Elf_Rela); > + break; > + case SHT_DYNAMIC: > + size_ok = shdr->sh_entsize == sizeof(Elf_Dyn); > + break; > + case SHT_REL: > + size_ok = shdr->sh_entsize == sizeof(Elf_Rel); > + break; > + case SHT_NOTE: > + case SHT_PROGBITS: > + case SHT_HASH: > + case SHT_NOBITS: > + default: > + /* > + * This is a section whose entsize requirements > + * I don't care about. If I don't know about > + * the section I can't care about it's entsize > + * requirements. > + */ > + size_ok = true; > + break; > + } > + > + if (!size_ok) { > + pr_debug("ELF section with wrong entry size.\n"); > + return false; > + } else if (shdr->sh_addr + shdr->sh_size < shdr->sh_addr) { > + pr_debug("ELF section address wraps around.\n"); > + return false; > + } > + > + if (shdr->sh_type != SHT_NOBITS) { > + if (shdr->sh_offset + shdr->sh_size < shdr->sh_offset) { > + pr_debug("ELF section location wraps around.\n"); > + return false; > + } else if (shdr->sh_offset + shdr->sh_size > buf_len) { > + pr_debug("ELF section not in file.\n"); > + return false; > + } > + } > + > + return true; > +} > + > +static int elf_read_shdr(const char *buf, size_t len, > + struct kexec_elf_info *elf_info, > + int idx) > +{ > + struct elf_shdr *shdr = &elf_info->sechdrs[idx]; > + const struct elfhdr *ehdr = elf_info->ehdr; > + const char *sbuf; > + struct elf_shdr *buf_shdr; > + > + sbuf = buf + ehdr->e_shoff + idx * sizeof(*buf_shdr); > + buf_shdr = (struct elf_shdr *) sbuf; > + > + shdr->sh_name = elf32_to_cpu(ehdr, buf_shdr->sh_name); > + shdr->sh_type = elf32_to_cpu(ehdr, buf_shdr->sh_type); > + shdr->sh_addr = elf_addr_to_cpu(ehdr, buf_shdr->sh_addr); > + shdr->sh_offset = elf_addr_to_cpu(ehdr, buf_shdr->sh_offset); > + shdr->sh_link = elf32_to_cpu(ehdr, buf_shdr->sh_link); > + shdr->sh_info = elf32_to_cpu(ehdr, buf_shdr->sh_info); > + > + /* > + * The following fields have a type equivalent to Elf_Addr > + * both in 32 bit and 64 bit ELF. > + */ > + shdr->sh_flags = elf_addr_to_cpu(ehdr, buf_shdr->sh_flags); > + shdr->sh_size = elf_addr_to_cpu(ehdr, buf_shdr->sh_size); > + shdr->sh_addralign = elf_addr_to_cpu(ehdr, buf_shdr->sh_addralign); > + shdr->sh_entsize = elf_addr_to_cpu(ehdr, buf_shdr->sh_entsize); > + > + return elf_is_shdr_sane(shdr, len) ? 0 : -ENOEXEC; > +} > + > +/** > + * elf_read_shdrs - read the section headers from the buffer > + * > + * This function assumes that the section header table was checked for sanity. > + * Use elf_is_ehdr_sane() if it wasn't. > + */ > +static int elf_read_shdrs(const char *buf, size_t len, > + struct kexec_elf_info *elf_info) > +{ > + size_t shdr_size, i; > + > + /* > + * e_shnum is at most 65536 so calculating > + * the size of the section header cannot overflow. > + */ > + shdr_size = sizeof(struct elf_shdr) * elf_info->ehdr->e_shnum; > + > + elf_info->sechdrs = kzalloc(shdr_size, GFP_KERNEL); > + if (!elf_info->sechdrs) > + return -ENOMEM; > + > + for (i = 0; i < elf_info->ehdr->e_shnum; i++) { > + int ret; > + > + ret = elf_read_shdr(buf, len, elf_info, i); > + if (ret) { > + kfree(elf_info->sechdrs); > + elf_info->sechdrs = NULL; > + return ret; > + } > + } > + > + return 0; > +} > + > +/** > + * elf_read_from_buffer - read ELF file and sets up ELF header and ELF info > + * @buf: Buffer to read ELF file from. > + * @len: Size of @buf. > + * @ehdr: Pointer to existing struct which will be populated. > + * @elf_info: Pointer to existing struct which will be populated. > + * > + * This function allows reading ELF files with different byte order than > + * the kernel, byte-swapping the fields as needed. > + * > + * Return: > + * On success returns 0, and the caller should call > + * kexec_free_elf_info(elf_info) to free the memory allocated for the section > + * and program headers. > + */ > +static int elf_read_from_buffer(const char *buf, size_t len, > + struct elfhdr *ehdr, > + struct kexec_elf_info *elf_info) > +{ > + int ret; > + > + ret = elf_read_ehdr(buf, len, ehdr); > + if (ret) > + return ret; > + > + elf_info->buffer = buf; > + elf_info->ehdr = ehdr; > + if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) { > + ret = elf_read_phdrs(buf, len, elf_info); > + if (ret) > + return ret; > + } > + if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) { > + ret = elf_read_shdrs(buf, len, elf_info); > + if (ret) { > + kfree(elf_info->proghdrs); > + return ret; > + } > + } > + > + return 0; > +} > + > +/** > + * kexec_free_elf_info - free memory allocated by elf_read_from_buffer > + */ > +void kexec_free_elf_info(struct kexec_elf_info *elf_info) > +{ > + kfree(elf_info->proghdrs); > + kfree(elf_info->sechdrs); > + memset(elf_info, 0, sizeof(*elf_info)); > +} > +/** > + * kexec_build_elf_info - read ELF executable and check that we can use it > + */ > +int kexec_build_elf_info(const char *buf, size_t len, struct elfhdr *ehdr, > + struct kexec_elf_info *elf_info) > +{ > + int i; > + int ret; > + > + ret = elf_read_from_buffer(buf, len, ehdr, elf_info); > + if (ret) > + return ret; > + > + /* Big endian vmlinux has type ET_DYN. */ > + if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN) { > + pr_err("Not an ELF executable.\n"); > + goto error; > + } else if (!elf_info->proghdrs) { > + pr_err("No ELF program header.\n"); > + goto error; > + } > + > + for (i = 0; i < ehdr->e_phnum; i++) { > + /* > + * Kexec does not support loading interpreters. > + * In addition this check keeps us from attempting > + * to kexec ordinay executables. > + */ > + if (elf_info->proghdrs[i].p_type == PT_INTERP) { > + pr_err("Requires an ELF interpreter.\n"); > + goto error; > + } > + } > + > + return 0; > +error: > + kexec_free_elf_info(elf_info); > + return -ENOEXEC; > +} > + > + > +int kexec_elf_probe(const char *buf, unsigned long len) > +{ > + struct elfhdr ehdr; > + struct kexec_elf_info elf_info; > + int ret; > + > + ret = kexec_build_elf_info(buf, len, &ehdr, &elf_info); > + if (ret) > + return ret; > + > + kexec_free_elf_info(&elf_info); > + > + return elf_check_arch(&ehdr) ? 0 : -ENOEXEC; > +} > + > +/** > + * kexec_elf_load - load ELF executable image > + * @lowest_load_addr: On return, will be the address where the first PT_LOAD > + * section will be loaded in memory. > + * > + * Return: > + * 0 on success, negative value on failure. > + */ > +int kexec_elf_load(struct kimage *image, struct elfhdr *ehdr, > + struct kexec_elf_info *elf_info, > + struct kexec_buf *kbuf, > + unsigned long *lowest_load_addr) > +{ > + unsigned long base = 0, lowest_addr = UINT_MAX; > + int ret; > + size_t i; > + > + /* Read in the PT_LOAD segments. */ > + for (i = 0; i < ehdr->e_phnum; i++) { > + unsigned long load_addr; > + size_t size; > + const struct elf_phdr *phdr; > + > + phdr = &elf_info->proghdrs[i]; > + if (phdr->p_type != PT_LOAD) > + continue; > + > + size = phdr->p_filesz; > + if (size > phdr->p_memsz) > + size = phdr->p_memsz; > + > + kbuf->buffer = (void *) elf_info->buffer + phdr->p_offset; > + kbuf->bufsz = size; > + kbuf->memsz = phdr->p_memsz; > + kbuf->buf_align = phdr->p_align; > + kbuf->buf_min = phdr->p_paddr + base; > + ret = kexec_add_buffer(kbuf); > + if (ret) > + goto out; > + load_addr = kbuf->mem; > + > + if (load_addr < lowest_addr) > + lowest_addr = load_addr; > + } > + > + /* Update entry point to reflect new load address. */ > + ehdr->e_entry += base; > + > + *lowest_load_addr = lowest_addr; > + ret = 0; > + out: > + return ret; > +} > + > + > ^ permalink raw reply [flat|nested] 20+ messages in thread
* Re: [PATCH v2 1/7] kexec: add KEXEC_ELF @ 2019-07-10 13:19 ` Christophe Leroy 0 siblings, 0 replies; 20+ messages in thread From: Christophe Leroy @ 2019-07-10 13:19 UTC (permalink / raw) To: Sven Schnelle, kexec; +Cc: deller, linuxppc-dev Hi Sven, On 07/09/2019 07:43 PM, Sven Schnelle wrote: > Right now powerpc provides an implementation to read elf files > with the kexec_file() syscall. Make that available as a public > kexec interface so it can be re-used on other architectures. > > Signed-off-by: Sven Schnelle <svens@stackframe.org> > --- > arch/Kconfig | 3 + > arch/powerpc/Kconfig | 1 + > arch/powerpc/kernel/kexec_elf_64.c | 551 +---------------------------- > include/linux/kexec.h | 24 ++ > kernel/Makefile | 1 + > kernel/kexec_elf.c | 537 ++++++++++++++++++++++++++++ > 6 files changed, 576 insertions(+), 541 deletions(-) > create mode 100644 kernel/kexec_elf.c Why are you persisting at not using -C when creating your patch ? Do you want to hide the changes you did while copying arch/powerpc/kernel/kexec_elf_64.c to kernel/kexec_elf.c ? Or you want to make life harder for the reviewers ? git format-patch -C shows: arch/Kconfig | 3 + arch/powerpc/Kconfig | 1 + arch/powerpc/kernel/kexec_elf_64.c | 551 +-------------------- include/linux/kexec.h | 24 + kernel/Makefile | 1 + .../kernel/kexec_elf_64.c => kernel/kexec_elf.c | 199 ++------ 6 files changed, 75 insertions(+), 704 deletions(-) copy arch/powerpc/kernel/kexec_elf_64.c => kernel/kexec_elf.c (71%) I mentionned it a couple of times, I even resent your last patch formatted that way to show the advantage. I can ear if you find it worthless, but tell what your concern are with that, don't just ignore it please. Cheers Christophe > > diff --git a/arch/Kconfig b/arch/Kconfig > index c47b328eada0..30694aca4316 100644 > --- a/arch/Kconfig > +++ b/arch/Kconfig > @@ -18,6 +18,9 @@ config KEXEC_CORE > select CRASH_CORE > bool > > +config KEXEC_ELF > + bool > + > config HAVE_IMA_KEXEC > bool > > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig > index 12cee37f15c4..addc2dad78e0 100644 > --- a/arch/powerpc/Kconfig > +++ b/arch/powerpc/Kconfig > @@ -510,6 +510,7 @@ config KEXEC_FILE > select KEXEC_CORE > select HAVE_IMA_KEXEC > select BUILD_BIN2C > + select KEXEC_ELF > depends on PPC64 > depends on CRYPTO=y > depends on CRYPTO_SHA256=y > diff --git a/arch/powerpc/kernel/kexec_elf_64.c b/arch/powerpc/kernel/kexec_elf_64.c > index ba4f18a43ee8..30bd57a93c17 100644 > --- a/arch/powerpc/kernel/kexec_elf_64.c > +++ b/arch/powerpc/kernel/kexec_elf_64.c > @@ -1,3 +1,4 @@ > +// SPDX-License-Identifier: GPL-2.0-only > /* > * Load ELF vmlinux file for the kexec_file_load syscall. > * > @@ -10,15 +11,6 @@ > * Based on kexec-tools' kexec-elf-exec.c and kexec-elf-ppc64.c. > * Heavily modified for the kernel by > * Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>. > - * > - * This program is free software; you can redistribute it and/or modify > - * it under the terms of the GNU General Public License as published by > - * the Free Software Foundation (version 2 of the License). > - * > - * This program is distributed in the hope that it will be useful, > - * but WITHOUT ANY WARRANTY; without even the implied warranty of > - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > - * GNU General Public License for more details. > */ > > #define pr_fmt(fmt) "kexec_elf: " fmt > @@ -39,532 +31,6 @@ > #define Elf_Rel Elf64_Rel > #endif /* Elf_Rel */ > > -struct elf_info { > - /* > - * Where the ELF binary contents are kept. > - * Memory managed by the user of the struct. > - */ > - const char *buffer; > - > - const struct elfhdr *ehdr; > - const struct elf_phdr *proghdrs; > - struct elf_shdr *sechdrs; > -}; > - > -static inline bool elf_is_elf_file(const struct elfhdr *ehdr) > -{ > - return memcmp(ehdr->e_ident, ELFMAG, SELFMAG) == 0; > -} > - > -static uint64_t elf64_to_cpu(const struct elfhdr *ehdr, uint64_t value) > -{ > - if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) > - value = le64_to_cpu(value); > - else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) > - value = be64_to_cpu(value); > - > - return value; > -} > - > -static uint16_t elf16_to_cpu(const struct elfhdr *ehdr, uint16_t value) > -{ > - if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) > - value = le16_to_cpu(value); > - else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) > - value = be16_to_cpu(value); > - > - return value; > -} > - > -static uint32_t elf32_to_cpu(const struct elfhdr *ehdr, uint32_t value) > -{ > - if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) > - value = le32_to_cpu(value); > - else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) > - value = be32_to_cpu(value); > - > - return value; > -} > - > -/** > - * elf_is_ehdr_sane - check that it is safe to use the ELF header > - * @buf_len: size of the buffer in which the ELF file is loaded. > - */ > -static bool elf_is_ehdr_sane(const struct elfhdr *ehdr, size_t buf_len) > -{ > - if (ehdr->e_phnum > 0 && ehdr->e_phentsize != sizeof(struct elf_phdr)) { > - pr_debug("Bad program header size.\n"); > - return false; > - } else if (ehdr->e_shnum > 0 && > - ehdr->e_shentsize != sizeof(struct elf_shdr)) { > - pr_debug("Bad section header size.\n"); > - return false; > - } else if (ehdr->e_ident[EI_VERSION] != EV_CURRENT || > - ehdr->e_version != EV_CURRENT) { > - pr_debug("Unknown ELF version.\n"); > - return false; > - } > - > - if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) { > - size_t phdr_size; > - > - /* > - * e_phnum is at most 65535 so calculating the size of the > - * program header cannot overflow. > - */ > - phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum; > - > - /* Sanity check the program header table location. */ > - if (ehdr->e_phoff + phdr_size < ehdr->e_phoff) { > - pr_debug("Program headers at invalid location.\n"); > - return false; > - } else if (ehdr->e_phoff + phdr_size > buf_len) { > - pr_debug("Program headers truncated.\n"); > - return false; > - } > - } > - > - if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) { > - size_t shdr_size; > - > - /* > - * e_shnum is at most 65536 so calculating > - * the size of the section header cannot overflow. > - */ > - shdr_size = sizeof(struct elf_shdr) * ehdr->e_shnum; > - > - /* Sanity check the section header table location. */ > - if (ehdr->e_shoff + shdr_size < ehdr->e_shoff) { > - pr_debug("Section headers at invalid location.\n"); > - return false; > - } else if (ehdr->e_shoff + shdr_size > buf_len) { > - pr_debug("Section headers truncated.\n"); > - return false; > - } > - } > - > - return true; > -} > - > -static int elf_read_ehdr(const char *buf, size_t len, struct elfhdr *ehdr) > -{ > - struct elfhdr *buf_ehdr; > - > - if (len < sizeof(*buf_ehdr)) { > - pr_debug("Buffer is too small to hold ELF header.\n"); > - return -ENOEXEC; > - } > - > - memset(ehdr, 0, sizeof(*ehdr)); > - memcpy(ehdr->e_ident, buf, sizeof(ehdr->e_ident)); > - if (!elf_is_elf_file(ehdr)) { > - pr_debug("No ELF header magic.\n"); > - return -ENOEXEC; > - } > - > - if (ehdr->e_ident[EI_CLASS] != ELF_CLASS) { > - pr_debug("Not a supported ELF class.\n"); > - return -ENOEXEC; > - } else if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB && > - ehdr->e_ident[EI_DATA] != ELFDATA2MSB) { > - pr_debug("Not a supported ELF data format.\n"); > - return -ENOEXEC; > - } > - > - buf_ehdr = (struct elfhdr *) buf; > - if (elf16_to_cpu(ehdr, buf_ehdr->e_ehsize) != sizeof(*buf_ehdr)) { > - pr_debug("Bad ELF header size.\n"); > - return -ENOEXEC; > - } > - > - ehdr->e_type = elf16_to_cpu(ehdr, buf_ehdr->e_type); > - ehdr->e_machine = elf16_to_cpu(ehdr, buf_ehdr->e_machine); > - ehdr->e_version = elf32_to_cpu(ehdr, buf_ehdr->e_version); > - ehdr->e_entry = elf_addr_to_cpu(ehdr, buf_ehdr->e_entry); > - ehdr->e_phoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_phoff); > - ehdr->e_shoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_shoff); > - ehdr->e_flags = elf32_to_cpu(ehdr, buf_ehdr->e_flags); > - ehdr->e_phentsize = elf16_to_cpu(ehdr, buf_ehdr->e_phentsize); > - ehdr->e_phnum = elf16_to_cpu(ehdr, buf_ehdr->e_phnum); > - ehdr->e_shentsize = elf16_to_cpu(ehdr, buf_ehdr->e_shentsize); > - ehdr->e_shnum = elf16_to_cpu(ehdr, buf_ehdr->e_shnum); > - ehdr->e_shstrndx = elf16_to_cpu(ehdr, buf_ehdr->e_shstrndx); > - > - return elf_is_ehdr_sane(ehdr, len) ? 0 : -ENOEXEC; > -} > - > -/** > - * elf_is_phdr_sane - check that it is safe to use the program header > - * @buf_len: size of the buffer in which the ELF file is loaded. > - */ > -static bool elf_is_phdr_sane(const struct elf_phdr *phdr, size_t buf_len) > -{ > - > - if (phdr->p_offset + phdr->p_filesz < phdr->p_offset) { > - pr_debug("ELF segment location wraps around.\n"); > - return false; > - } else if (phdr->p_offset + phdr->p_filesz > buf_len) { > - pr_debug("ELF segment not in file.\n"); > - return false; > - } else if (phdr->p_paddr + phdr->p_memsz < phdr->p_paddr) { > - pr_debug("ELF segment address wraps around.\n"); > - return false; > - } > - > - return true; > -} > - > -static int elf_read_phdr(const char *buf, size_t len, struct elf_info *elf_info, > - int idx) > -{ > - /* Override the const in proghdrs, we are the ones doing the loading. */ > - struct elf_phdr *phdr = (struct elf_phdr *) &elf_info->proghdrs[idx]; > - const char *pbuf; > - struct elf_phdr *buf_phdr; > - > - pbuf = buf + elf_info->ehdr->e_phoff + (idx * sizeof(*buf_phdr)); > - buf_phdr = (struct elf_phdr *) pbuf; > - > - phdr->p_type = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_type); > - phdr->p_offset = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_offset); > - phdr->p_paddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_paddr); > - phdr->p_vaddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_vaddr); > - phdr->p_flags = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_flags); > - > - /* > - * The following fields have a type equivalent to Elf_Addr > - * both in 32 bit and 64 bit ELF. > - */ > - phdr->p_filesz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_filesz); > - phdr->p_memsz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_memsz); > - phdr->p_align = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_align); > - > - return elf_is_phdr_sane(phdr, len) ? 0 : -ENOEXEC; > -} > - > -/** > - * elf_read_phdrs - read the program headers from the buffer > - * > - * This function assumes that the program header table was checked for sanity. > - * Use elf_is_ehdr_sane() if it wasn't. > - */ > -static int elf_read_phdrs(const char *buf, size_t len, > - struct elf_info *elf_info) > -{ > - size_t phdr_size, i; > - const struct elfhdr *ehdr = elf_info->ehdr; > - > - /* > - * e_phnum is at most 65535 so calculating the size of the > - * program header cannot overflow. > - */ > - phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum; > - > - elf_info->proghdrs = kzalloc(phdr_size, GFP_KERNEL); > - if (!elf_info->proghdrs) > - return -ENOMEM; > - > - for (i = 0; i < ehdr->e_phnum; i++) { > - int ret; > - > - ret = elf_read_phdr(buf, len, elf_info, i); > - if (ret) { > - kfree(elf_info->proghdrs); > - elf_info->proghdrs = NULL; > - return ret; > - } > - } > - > - return 0; > -} > - > -/** > - * elf_is_shdr_sane - check that it is safe to use the section header > - * @buf_len: size of the buffer in which the ELF file is loaded. > - */ > -static bool elf_is_shdr_sane(const struct elf_shdr *shdr, size_t buf_len) > -{ > - bool size_ok; > - > - /* SHT_NULL headers have undefined values, so we can't check them. */ > - if (shdr->sh_type == SHT_NULL) > - return true; > - > - /* Now verify sh_entsize */ > - switch (shdr->sh_type) { > - case SHT_SYMTAB: > - size_ok = shdr->sh_entsize == sizeof(Elf_Sym); > - break; > - case SHT_RELA: > - size_ok = shdr->sh_entsize == sizeof(Elf_Rela); > - break; > - case SHT_DYNAMIC: > - size_ok = shdr->sh_entsize == sizeof(Elf_Dyn); > - break; > - case SHT_REL: > - size_ok = shdr->sh_entsize == sizeof(Elf_Rel); > - break; > - case SHT_NOTE: > - case SHT_PROGBITS: > - case SHT_HASH: > - case SHT_NOBITS: > - default: > - /* > - * This is a section whose entsize requirements > - * I don't care about. If I don't know about > - * the section I can't care about it's entsize > - * requirements. > - */ > - size_ok = true; > - break; > - } > - > - if (!size_ok) { > - pr_debug("ELF section with wrong entry size.\n"); > - return false; > - } else if (shdr->sh_addr + shdr->sh_size < shdr->sh_addr) { > - pr_debug("ELF section address wraps around.\n"); > - return false; > - } > - > - if (shdr->sh_type != SHT_NOBITS) { > - if (shdr->sh_offset + shdr->sh_size < shdr->sh_offset) { > - pr_debug("ELF section location wraps around.\n"); > - return false; > - } else if (shdr->sh_offset + shdr->sh_size > buf_len) { > - pr_debug("ELF section not in file.\n"); > - return false; > - } > - } > - > - return true; > -} > - > -static int elf_read_shdr(const char *buf, size_t len, struct elf_info *elf_info, > - int idx) > -{ > - struct elf_shdr *shdr = &elf_info->sechdrs[idx]; > - const struct elfhdr *ehdr = elf_info->ehdr; > - const char *sbuf; > - struct elf_shdr *buf_shdr; > - > - sbuf = buf + ehdr->e_shoff + idx * sizeof(*buf_shdr); > - buf_shdr = (struct elf_shdr *) sbuf; > - > - shdr->sh_name = elf32_to_cpu(ehdr, buf_shdr->sh_name); > - shdr->sh_type = elf32_to_cpu(ehdr, buf_shdr->sh_type); > - shdr->sh_addr = elf_addr_to_cpu(ehdr, buf_shdr->sh_addr); > - shdr->sh_offset = elf_addr_to_cpu(ehdr, buf_shdr->sh_offset); > - shdr->sh_link = elf32_to_cpu(ehdr, buf_shdr->sh_link); > - shdr->sh_info = elf32_to_cpu(ehdr, buf_shdr->sh_info); > - > - /* > - * The following fields have a type equivalent to Elf_Addr > - * both in 32 bit and 64 bit ELF. > - */ > - shdr->sh_flags = elf_addr_to_cpu(ehdr, buf_shdr->sh_flags); > - shdr->sh_size = elf_addr_to_cpu(ehdr, buf_shdr->sh_size); > - shdr->sh_addralign = elf_addr_to_cpu(ehdr, buf_shdr->sh_addralign); > - shdr->sh_entsize = elf_addr_to_cpu(ehdr, buf_shdr->sh_entsize); > - > - return elf_is_shdr_sane(shdr, len) ? 0 : -ENOEXEC; > -} > - > -/** > - * elf_read_shdrs - read the section headers from the buffer > - * > - * This function assumes that the section header table was checked for sanity. > - * Use elf_is_ehdr_sane() if it wasn't. > - */ > -static int elf_read_shdrs(const char *buf, size_t len, > - struct elf_info *elf_info) > -{ > - size_t shdr_size, i; > - > - /* > - * e_shnum is at most 65536 so calculating > - * the size of the section header cannot overflow. > - */ > - shdr_size = sizeof(struct elf_shdr) * elf_info->ehdr->e_shnum; > - > - elf_info->sechdrs = kzalloc(shdr_size, GFP_KERNEL); > - if (!elf_info->sechdrs) > - return -ENOMEM; > - > - for (i = 0; i < elf_info->ehdr->e_shnum; i++) { > - int ret; > - > - ret = elf_read_shdr(buf, len, elf_info, i); > - if (ret) { > - kfree(elf_info->sechdrs); > - elf_info->sechdrs = NULL; > - return ret; > - } > - } > - > - return 0; > -} > - > -/** > - * elf_read_from_buffer - read ELF file and sets up ELF header and ELF info > - * @buf: Buffer to read ELF file from. > - * @len: Size of @buf. > - * @ehdr: Pointer to existing struct which will be populated. > - * @elf_info: Pointer to existing struct which will be populated. > - * > - * This function allows reading ELF files with different byte order than > - * the kernel, byte-swapping the fields as needed. > - * > - * Return: > - * On success returns 0, and the caller should call elf_free_info(elf_info) to > - * free the memory allocated for the section and program headers. > - */ > -int elf_read_from_buffer(const char *buf, size_t len, struct elfhdr *ehdr, > - struct elf_info *elf_info) > -{ > - int ret; > - > - ret = elf_read_ehdr(buf, len, ehdr); > - if (ret) > - return ret; > - > - elf_info->buffer = buf; > - elf_info->ehdr = ehdr; > - if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) { > - ret = elf_read_phdrs(buf, len, elf_info); > - if (ret) > - return ret; > - } > - if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) { > - ret = elf_read_shdrs(buf, len, elf_info); > - if (ret) { > - kfree(elf_info->proghdrs); > - return ret; > - } > - } > - > - return 0; > -} > - > -/** > - * elf_free_info - free memory allocated by elf_read_from_buffer > - */ > -void elf_free_info(struct elf_info *elf_info) > -{ > - kfree(elf_info->proghdrs); > - kfree(elf_info->sechdrs); > - memset(elf_info, 0, sizeof(*elf_info)); > -} > -/** > - * build_elf_exec_info - read ELF executable and check that we can use it > - */ > -static int build_elf_exec_info(const char *buf, size_t len, struct elfhdr *ehdr, > - struct elf_info *elf_info) > -{ > - int i; > - int ret; > - > - ret = elf_read_from_buffer(buf, len, ehdr, elf_info); > - if (ret) > - return ret; > - > - /* Big endian vmlinux has type ET_DYN. */ > - if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN) { > - pr_err("Not an ELF executable.\n"); > - goto error; > - } else if (!elf_info->proghdrs) { > - pr_err("No ELF program header.\n"); > - goto error; > - } > - > - for (i = 0; i < ehdr->e_phnum; i++) { > - /* > - * Kexec does not support loading interpreters. > - * In addition this check keeps us from attempting > - * to kexec ordinay executables. > - */ > - if (elf_info->proghdrs[i].p_type == PT_INTERP) { > - pr_err("Requires an ELF interpreter.\n"); > - goto error; > - } > - } > - > - return 0; > -error: > - elf_free_info(elf_info); > - return -ENOEXEC; > -} > - > -static int elf64_probe(const char *buf, unsigned long len) > -{ > - struct elfhdr ehdr; > - struct elf_info elf_info; > - int ret; > - > - ret = build_elf_exec_info(buf, len, &ehdr, &elf_info); > - if (ret) > - return ret; > - > - elf_free_info(&elf_info); > - > - return elf_check_arch(&ehdr) ? 0 : -ENOEXEC; > -} > - > -/** > - * elf_exec_load - load ELF executable image > - * @lowest_load_addr: On return, will be the address where the first PT_LOAD > - * section will be loaded in memory. > - * > - * Return: > - * 0 on success, negative value on failure. > - */ > -static int elf_exec_load(struct kimage *image, struct elfhdr *ehdr, > - struct elf_info *elf_info, > - unsigned long *lowest_load_addr) > -{ > - unsigned long base = 0, lowest_addr = UINT_MAX; > - int ret; > - size_t i; > - struct kexec_buf kbuf = { .image = image, .buf_max = ppc64_rma_size, > - .top_down = false }; > - > - /* Read in the PT_LOAD segments. */ > - for (i = 0; i < ehdr->e_phnum; i++) { > - unsigned long load_addr; > - size_t size; > - const struct elf_phdr *phdr; > - > - phdr = &elf_info->proghdrs[i]; > - if (phdr->p_type != PT_LOAD) > - continue; > - > - size = phdr->p_filesz; > - if (size > phdr->p_memsz) > - size = phdr->p_memsz; > - > - kbuf.buffer = (void *) elf_info->buffer + phdr->p_offset; > - kbuf.bufsz = size; > - kbuf.memsz = phdr->p_memsz; > - kbuf.buf_align = phdr->p_align; > - kbuf.buf_min = phdr->p_paddr + base; > - ret = kexec_add_buffer(&kbuf); > - if (ret) > - goto out; > - load_addr = kbuf.mem; > - > - if (load_addr < lowest_addr) > - lowest_addr = load_addr; > - } > - > - /* Update entry point to reflect new load address. */ > - ehdr->e_entry += base; > - > - *lowest_load_addr = lowest_addr; > - ret = 0; > - out: > - return ret; > -} > - > static void *elf64_load(struct kimage *image, char *kernel_buf, > unsigned long kernel_len, char *initrd, > unsigned long initrd_len, char *cmdline, > @@ -577,17 +43,18 @@ static void *elf64_load(struct kimage *image, char *kernel_buf, > void *fdt; > const void *slave_code; > struct elfhdr ehdr; > - struct elf_info elf_info; > + struct kexec_elf_info elf_info; > struct kexec_buf kbuf = { .image = image, .buf_min = 0, > .buf_max = ppc64_rma_size }; > struct kexec_buf pbuf = { .image = image, .buf_min = 0, > - .buf_max = ppc64_rma_size, .top_down = true }; > + .buf_max = ppc64_rma_size, .top_down = true, > + .mem = KEXEC_BUF_MEM_UNKNOWN }; > > - ret = build_elf_exec_info(kernel_buf, kernel_len, &ehdr, &elf_info); > + ret = kexec_build_elf_info(kernel_buf, kernel_len, &ehdr, &elf_info); > if (ret) > goto out; > > - ret = elf_exec_load(image, &ehdr, &elf_info, &kernel_load_addr); > + ret = kexec_elf_load(image, &ehdr, &elf_info, &kbuf, &kernel_load_addr); > if (ret) > goto out; > > @@ -606,6 +73,7 @@ static void *elf64_load(struct kimage *image, char *kernel_buf, > kbuf.bufsz = kbuf.memsz = initrd_len; > kbuf.buf_align = PAGE_SIZE; > kbuf.top_down = false; > + kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; > ret = kexec_add_buffer(&kbuf); > if (ret) > goto out; > @@ -638,6 +106,7 @@ static void *elf64_load(struct kimage *image, char *kernel_buf, > kbuf.bufsz = kbuf.memsz = fdt_size; > kbuf.buf_align = PAGE_SIZE; > kbuf.top_down = true; > + kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; > ret = kexec_add_buffer(&kbuf); > if (ret) > goto out; > @@ -652,13 +121,13 @@ static void *elf64_load(struct kimage *image, char *kernel_buf, > pr_err("Error setting up the purgatory.\n"); > > out: > - elf_free_info(&elf_info); > + kexec_free_elf_info(&elf_info); > > /* Make kimage_file_post_load_cleanup free the fdt buffer for us. */ > return ret ? ERR_PTR(ret) : fdt; > } > > const struct kexec_file_ops kexec_elf64_ops = { > - .probe = elf64_probe, > + .probe = kexec_elf_probe, > .load = elf64_load, > }; > diff --git a/include/linux/kexec.h b/include/linux/kexec.h > index b9b1bc5f9669..da2a6b1d69e7 100644 > --- a/include/linux/kexec.h > +++ b/include/linux/kexec.h > @@ -216,6 +216,30 @@ extern int crash_prepare_elf64_headers(struct crash_mem *mem, int kernel_map, > void **addr, unsigned long *sz); > #endif /* CONFIG_KEXEC_FILE */ > > +#ifdef CONFIG_KEXEC_ELF > +struct kexec_elf_info { > + /* > + * Where the ELF binary contents are kept. > + * Memory managed by the user of the struct. > + */ > + const char *buffer; > + > + const struct elfhdr *ehdr; > + const struct elf_phdr *proghdrs; > + struct elf_shdr *sechdrs; > +}; > + > +int kexec_build_elf_info(const char *buf, size_t len, struct elfhdr *ehdr, > + struct kexec_elf_info *elf_info); > + > +int kexec_elf_load(struct kimage *image, struct elfhdr *ehdr, > + struct kexec_elf_info *elf_info, > + struct kexec_buf *kbuf, > + unsigned long *lowest_load_addr); > + > +void kexec_free_elf_info(struct kexec_elf_info *elf_info); > +int kexec_elf_probe(const char *buf, unsigned long len); > +#endif > struct kimage { > kimage_entry_t head; > kimage_entry_t *entry; > diff --git a/kernel/Makefile b/kernel/Makefile > index 33824f0385b3..7062306de9b7 100644 > --- a/kernel/Makefile > +++ b/kernel/Makefile > @@ -64,6 +64,7 @@ obj-$(CONFIG_CRASH_CORE) += crash_core.o > obj-$(CONFIG_KEXEC_CORE) += kexec_core.o > obj-$(CONFIG_KEXEC) += kexec.o > obj-$(CONFIG_KEXEC_FILE) += kexec_file.o > +obj-$(CONFIG_KEXEC_ELF) += kexec_elf.o > obj-$(CONFIG_BACKTRACE_SELF_TEST) += backtracetest.o > obj-$(CONFIG_COMPAT) += compat.o > obj-$(CONFIG_CGROUPS) += cgroup/ > diff --git a/kernel/kexec_elf.c b/kernel/kexec_elf.c > new file mode 100644 > index 000000000000..6e9f52171ede > --- /dev/null > +++ b/kernel/kexec_elf.c > @@ -0,0 +1,537 @@ > +// SPDX-License-Identifier: GPL-2.0-only > + > +#define pr_fmt(fmt) "kexec_elf: " fmt > + > +#include <linux/elf.h> > +#include <linux/kexec.h> > +#include <linux/module.h> > +#include <linux/slab.h> > +#include <linux/types.h> > + > +#define PURGATORY_STACK_SIZE (16 * 1024) > + > +#define elf_addr_to_cpu elf64_to_cpu > + > +#ifndef Elf_Rel > +#define Elf_Rel Elf64_Rel > +#endif /* Elf_Rel */ > + > +static inline bool elf_is_elf_file(const struct elfhdr *ehdr) > +{ > + return memcmp(ehdr->e_ident, ELFMAG, SELFMAG) == 0; > +} > + > +static uint64_t elf64_to_cpu(const struct elfhdr *ehdr, uint64_t value) > +{ > + if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) > + value = le64_to_cpu(value); > + else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) > + value = be64_to_cpu(value); > + > + return value; > +} > + > +static uint16_t elf16_to_cpu(const struct elfhdr *ehdr, uint16_t value) > +{ > + if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) > + value = le16_to_cpu(value); > + else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) > + value = be16_to_cpu(value); > + > + return value; > +} > + > +static uint32_t elf32_to_cpu(const struct elfhdr *ehdr, uint32_t value) > +{ > + if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) > + value = le32_to_cpu(value); > + else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) > + value = be32_to_cpu(value); > + > + return value; > +} > + > +/** > + * elf_is_ehdr_sane - check that it is safe to use the ELF header > + * @buf_len: size of the buffer in which the ELF file is loaded. > + */ > +static bool elf_is_ehdr_sane(const struct elfhdr *ehdr, size_t buf_len) > +{ > + if (ehdr->e_phnum > 0 && ehdr->e_phentsize != sizeof(struct elf_phdr)) { > + pr_debug("Bad program header size.\n"); > + return false; > + } else if (ehdr->e_shnum > 0 && > + ehdr->e_shentsize != sizeof(struct elf_shdr)) { > + pr_debug("Bad section header size.\n"); > + return false; > + } else if (ehdr->e_ident[EI_VERSION] != EV_CURRENT || > + ehdr->e_version != EV_CURRENT) { > + pr_debug("Unknown ELF version.\n"); > + return false; > + } > + > + if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) { > + size_t phdr_size; > + > + /* > + * e_phnum is at most 65535 so calculating the size of the > + * program header cannot overflow. > + */ > + phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum; > + > + /* Sanity check the program header table location. */ > + if (ehdr->e_phoff + phdr_size < ehdr->e_phoff) { > + pr_debug("Program headers at invalid location.\n"); > + return false; > + } else if (ehdr->e_phoff + phdr_size > buf_len) { > + pr_debug("Program headers truncated.\n"); > + return false; > + } > + } > + > + if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) { > + size_t shdr_size; > + > + /* > + * e_shnum is at most 65536 so calculating > + * the size of the section header cannot overflow. > + */ > + shdr_size = sizeof(struct elf_shdr) * ehdr->e_shnum; > + > + /* Sanity check the section header table location. */ > + if (ehdr->e_shoff + shdr_size < ehdr->e_shoff) { > + pr_debug("Section headers at invalid location.\n"); > + return false; > + } else if (ehdr->e_shoff + shdr_size > buf_len) { > + pr_debug("Section headers truncated.\n"); > + return false; > + } > + } > + > + return true; > +} > + > +static int elf_read_ehdr(const char *buf, size_t len, struct elfhdr *ehdr) > +{ > + struct elfhdr *buf_ehdr; > + > + if (len < sizeof(*buf_ehdr)) { > + pr_debug("Buffer is too small to hold ELF header.\n"); > + return -ENOEXEC; > + } > + > + memset(ehdr, 0, sizeof(*ehdr)); > + memcpy(ehdr->e_ident, buf, sizeof(ehdr->e_ident)); > + if (!elf_is_elf_file(ehdr)) { > + pr_debug("No ELF header magic.\n"); > + return -ENOEXEC; > + } > + > + if (ehdr->e_ident[EI_CLASS] != ELF_CLASS) { > + pr_debug("Not a supported ELF class.\n"); > + return -ENOEXEC; > + } else if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB && > + ehdr->e_ident[EI_DATA] != ELFDATA2MSB) { > + pr_debug("Not a supported ELF data format.\n"); > + return -ENOEXEC; > + } > + > + buf_ehdr = (struct elfhdr *) buf; > + if (elf16_to_cpu(ehdr, buf_ehdr->e_ehsize) != sizeof(*buf_ehdr)) { > + pr_debug("Bad ELF header size.\n"); > + return -ENOEXEC; > + } > + > + ehdr->e_type = elf16_to_cpu(ehdr, buf_ehdr->e_type); > + ehdr->e_machine = elf16_to_cpu(ehdr, buf_ehdr->e_machine); > + ehdr->e_version = elf32_to_cpu(ehdr, buf_ehdr->e_version); > + ehdr->e_entry = elf_addr_to_cpu(ehdr, buf_ehdr->e_entry); > + ehdr->e_phoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_phoff); > + ehdr->e_shoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_shoff); > + ehdr->e_flags = elf32_to_cpu(ehdr, buf_ehdr->e_flags); > + ehdr->e_phentsize = elf16_to_cpu(ehdr, buf_ehdr->e_phentsize); > + ehdr->e_phnum = elf16_to_cpu(ehdr, buf_ehdr->e_phnum); > + ehdr->e_shentsize = elf16_to_cpu(ehdr, buf_ehdr->e_shentsize); > + ehdr->e_shnum = elf16_to_cpu(ehdr, buf_ehdr->e_shnum); > + ehdr->e_shstrndx = elf16_to_cpu(ehdr, buf_ehdr->e_shstrndx); > + > + return elf_is_ehdr_sane(ehdr, len) ? 0 : -ENOEXEC; > +} > + > +/** > + * elf_is_phdr_sane - check that it is safe to use the program header > + * @buf_len: size of the buffer in which the ELF file is loaded. > + */ > +static bool elf_is_phdr_sane(const struct elf_phdr *phdr, size_t buf_len) > +{ > + > + if (phdr->p_offset + phdr->p_filesz < phdr->p_offset) { > + pr_debug("ELF segment location wraps around.\n"); > + return false; > + } else if (phdr->p_offset + phdr->p_filesz > buf_len) { > + pr_debug("ELF segment not in file.\n"); > + return false; > + } else if (phdr->p_paddr + phdr->p_memsz < phdr->p_paddr) { > + pr_debug("ELF segment address wraps around.\n"); > + return false; > + } > + > + return true; > +} > + > +static int elf_read_phdr(const char *buf, size_t len, > + struct kexec_elf_info *elf_info, > + int idx) > +{ > + /* Override the const in proghdrs, we are the ones doing the loading. */ > + struct elf_phdr *phdr = (struct elf_phdr *) &elf_info->proghdrs[idx]; > + const char *pbuf; > + struct elf_phdr *buf_phdr; > + > + pbuf = buf + elf_info->ehdr->e_phoff + (idx * sizeof(*buf_phdr)); > + buf_phdr = (struct elf_phdr *) pbuf; > + > + phdr->p_type = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_type); > + phdr->p_offset = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_offset); > + phdr->p_paddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_paddr); > + phdr->p_vaddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_vaddr); > + phdr->p_flags = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_flags); > + > + /* > + * The following fields have a type equivalent to Elf_Addr > + * both in 32 bit and 64 bit ELF. > + */ > + phdr->p_filesz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_filesz); > + phdr->p_memsz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_memsz); > + phdr->p_align = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_align); > + > + return elf_is_phdr_sane(phdr, len) ? 0 : -ENOEXEC; > +} > + > +/** > + * elf_read_phdrs - read the program headers from the buffer > + * > + * This function assumes that the program header table was checked for sanity. > + * Use elf_is_ehdr_sane() if it wasn't. > + */ > +static int elf_read_phdrs(const char *buf, size_t len, > + struct kexec_elf_info *elf_info) > +{ > + size_t phdr_size, i; > + const struct elfhdr *ehdr = elf_info->ehdr; > + > + /* > + * e_phnum is at most 65535 so calculating the size of the > + * program header cannot overflow. > + */ > + phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum; > + > + elf_info->proghdrs = kzalloc(phdr_size, GFP_KERNEL); > + if (!elf_info->proghdrs) > + return -ENOMEM; > + > + for (i = 0; i < ehdr->e_phnum; i++) { > + int ret; > + > + ret = elf_read_phdr(buf, len, elf_info, i); > + if (ret) { > + kfree(elf_info->proghdrs); > + elf_info->proghdrs = NULL; > + return ret; > + } > + } > + > + return 0; > +} > + > +/** > + * elf_is_shdr_sane - check that it is safe to use the section header > + * @buf_len: size of the buffer in which the ELF file is loaded. > + */ > +static bool elf_is_shdr_sane(const struct elf_shdr *shdr, size_t buf_len) > +{ > + bool size_ok; > + > + /* SHT_NULL headers have undefined values, so we can't check them. */ > + if (shdr->sh_type == SHT_NULL) > + return true; > + > + /* Now verify sh_entsize */ > + switch (shdr->sh_type) { > + case SHT_SYMTAB: > + size_ok = shdr->sh_entsize == sizeof(Elf_Sym); > + break; > + case SHT_RELA: > + size_ok = shdr->sh_entsize == sizeof(Elf_Rela); > + break; > + case SHT_DYNAMIC: > + size_ok = shdr->sh_entsize == sizeof(Elf_Dyn); > + break; > + case SHT_REL: > + size_ok = shdr->sh_entsize == sizeof(Elf_Rel); > + break; > + case SHT_NOTE: > + case SHT_PROGBITS: > + case SHT_HASH: > + case SHT_NOBITS: > + default: > + /* > + * This is a section whose entsize requirements > + * I don't care about. If I don't know about > + * the section I can't care about it's entsize > + * requirements. > + */ > + size_ok = true; > + break; > + } > + > + if (!size_ok) { > + pr_debug("ELF section with wrong entry size.\n"); > + return false; > + } else if (shdr->sh_addr + shdr->sh_size < shdr->sh_addr) { > + pr_debug("ELF section address wraps around.\n"); > + return false; > + } > + > + if (shdr->sh_type != SHT_NOBITS) { > + if (shdr->sh_offset + shdr->sh_size < shdr->sh_offset) { > + pr_debug("ELF section location wraps around.\n"); > + return false; > + } else if (shdr->sh_offset + shdr->sh_size > buf_len) { > + pr_debug("ELF section not in file.\n"); > + return false; > + } > + } > + > + return true; > +} > + > +static int elf_read_shdr(const char *buf, size_t len, > + struct kexec_elf_info *elf_info, > + int idx) > +{ > + struct elf_shdr *shdr = &elf_info->sechdrs[idx]; > + const struct elfhdr *ehdr = elf_info->ehdr; > + const char *sbuf; > + struct elf_shdr *buf_shdr; > + > + sbuf = buf + ehdr->e_shoff + idx * sizeof(*buf_shdr); > + buf_shdr = (struct elf_shdr *) sbuf; > + > + shdr->sh_name = elf32_to_cpu(ehdr, buf_shdr->sh_name); > + shdr->sh_type = elf32_to_cpu(ehdr, buf_shdr->sh_type); > + shdr->sh_addr = elf_addr_to_cpu(ehdr, buf_shdr->sh_addr); > + shdr->sh_offset = elf_addr_to_cpu(ehdr, buf_shdr->sh_offset); > + shdr->sh_link = elf32_to_cpu(ehdr, buf_shdr->sh_link); > + shdr->sh_info = elf32_to_cpu(ehdr, buf_shdr->sh_info); > + > + /* > + * The following fields have a type equivalent to Elf_Addr > + * both in 32 bit and 64 bit ELF. > + */ > + shdr->sh_flags = elf_addr_to_cpu(ehdr, buf_shdr->sh_flags); > + shdr->sh_size = elf_addr_to_cpu(ehdr, buf_shdr->sh_size); > + shdr->sh_addralign = elf_addr_to_cpu(ehdr, buf_shdr->sh_addralign); > + shdr->sh_entsize = elf_addr_to_cpu(ehdr, buf_shdr->sh_entsize); > + > + return elf_is_shdr_sane(shdr, len) ? 0 : -ENOEXEC; > +} > + > +/** > + * elf_read_shdrs - read the section headers from the buffer > + * > + * This function assumes that the section header table was checked for sanity. > + * Use elf_is_ehdr_sane() if it wasn't. > + */ > +static int elf_read_shdrs(const char *buf, size_t len, > + struct kexec_elf_info *elf_info) > +{ > + size_t shdr_size, i; > + > + /* > + * e_shnum is at most 65536 so calculating > + * the size of the section header cannot overflow. > + */ > + shdr_size = sizeof(struct elf_shdr) * elf_info->ehdr->e_shnum; > + > + elf_info->sechdrs = kzalloc(shdr_size, GFP_KERNEL); > + if (!elf_info->sechdrs) > + return -ENOMEM; > + > + for (i = 0; i < elf_info->ehdr->e_shnum; i++) { > + int ret; > + > + ret = elf_read_shdr(buf, len, elf_info, i); > + if (ret) { > + kfree(elf_info->sechdrs); > + elf_info->sechdrs = NULL; > + return ret; > + } > + } > + > + return 0; > +} > + > +/** > + * elf_read_from_buffer - read ELF file and sets up ELF header and ELF info > + * @buf: Buffer to read ELF file from. > + * @len: Size of @buf. > + * @ehdr: Pointer to existing struct which will be populated. > + * @elf_info: Pointer to existing struct which will be populated. > + * > + * This function allows reading ELF files with different byte order than > + * the kernel, byte-swapping the fields as needed. > + * > + * Return: > + * On success returns 0, and the caller should call > + * kexec_free_elf_info(elf_info) to free the memory allocated for the section > + * and program headers. > + */ > +static int elf_read_from_buffer(const char *buf, size_t len, > + struct elfhdr *ehdr, > + struct kexec_elf_info *elf_info) > +{ > + int ret; > + > + ret = elf_read_ehdr(buf, len, ehdr); > + if (ret) > + return ret; > + > + elf_info->buffer = buf; > + elf_info->ehdr = ehdr; > + if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) { > + ret = elf_read_phdrs(buf, len, elf_info); > + if (ret) > + return ret; > + } > + if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) { > + ret = elf_read_shdrs(buf, len, elf_info); > + if (ret) { > + kfree(elf_info->proghdrs); > + return ret; > + } > + } > + > + return 0; > +} > + > +/** > + * kexec_free_elf_info - free memory allocated by elf_read_from_buffer > + */ > +void kexec_free_elf_info(struct kexec_elf_info *elf_info) > +{ > + kfree(elf_info->proghdrs); > + kfree(elf_info->sechdrs); > + memset(elf_info, 0, sizeof(*elf_info)); > +} > +/** > + * kexec_build_elf_info - read ELF executable and check that we can use it > + */ > +int kexec_build_elf_info(const char *buf, size_t len, struct elfhdr *ehdr, > + struct kexec_elf_info *elf_info) > +{ > + int i; > + int ret; > + > + ret = elf_read_from_buffer(buf, len, ehdr, elf_info); > + if (ret) > + return ret; > + > + /* Big endian vmlinux has type ET_DYN. */ > + if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN) { > + pr_err("Not an ELF executable.\n"); > + goto error; > + } else if (!elf_info->proghdrs) { > + pr_err("No ELF program header.\n"); > + goto error; > + } > + > + for (i = 0; i < ehdr->e_phnum; i++) { > + /* > + * Kexec does not support loading interpreters. > + * In addition this check keeps us from attempting > + * to kexec ordinay executables. > + */ > + if (elf_info->proghdrs[i].p_type == PT_INTERP) { > + pr_err("Requires an ELF interpreter.\n"); > + goto error; > + } > + } > + > + return 0; > +error: > + kexec_free_elf_info(elf_info); > + return -ENOEXEC; > +} > + > + > +int kexec_elf_probe(const char *buf, unsigned long len) > +{ > + struct elfhdr ehdr; > + struct kexec_elf_info elf_info; > + int ret; > + > + ret = kexec_build_elf_info(buf, len, &ehdr, &elf_info); > + if (ret) > + return ret; > + > + kexec_free_elf_info(&elf_info); > + > + return elf_check_arch(&ehdr) ? 0 : -ENOEXEC; > +} > + > +/** > + * kexec_elf_load - load ELF executable image > + * @lowest_load_addr: On return, will be the address where the first PT_LOAD > + * section will be loaded in memory. > + * > + * Return: > + * 0 on success, negative value on failure. > + */ > +int kexec_elf_load(struct kimage *image, struct elfhdr *ehdr, > + struct kexec_elf_info *elf_info, > + struct kexec_buf *kbuf, > + unsigned long *lowest_load_addr) > +{ > + unsigned long base = 0, lowest_addr = UINT_MAX; > + int ret; > + size_t i; > + > + /* Read in the PT_LOAD segments. */ > + for (i = 0; i < ehdr->e_phnum; i++) { > + unsigned long load_addr; > + size_t size; > + const struct elf_phdr *phdr; > + > + phdr = &elf_info->proghdrs[i]; > + if (phdr->p_type != PT_LOAD) > + continue; > + > + size = phdr->p_filesz; > + if (size > phdr->p_memsz) > + size = phdr->p_memsz; > + > + kbuf->buffer = (void *) elf_info->buffer + phdr->p_offset; > + kbuf->bufsz = size; > + kbuf->memsz = phdr->p_memsz; > + kbuf->buf_align = phdr->p_align; > + kbuf->buf_min = phdr->p_paddr + base; > + ret = kexec_add_buffer(kbuf); > + if (ret) > + goto out; > + load_addr = kbuf->mem; > + > + if (load_addr < lowest_addr) > + lowest_addr = load_addr; > + } > + > + /* Update entry point to reflect new load address. */ > + ehdr->e_entry += base; > + > + *lowest_load_addr = lowest_addr; > + ret = 0; > + out: > + return ret; > +} > + > + > _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec ^ permalink raw reply [flat|nested] 20+ messages in thread
* Re: [PATCH v2 1/7] kexec: add KEXEC_ELF 2019-07-10 13:19 ` Christophe Leroy @ 2019-07-10 14:24 ` Sven Schnelle -1 siblings, 0 replies; 20+ messages in thread From: Sven Schnelle @ 2019-07-10 14:24 UTC (permalink / raw) To: Christophe Leroy; +Cc: linuxppc-dev, deller, kexec Hi Christophe, On Wed, Jul 10, 2019 at 01:19:13PM +0000, Christophe Leroy wrote: > Hi Sven, > > On 07/09/2019 07:43 PM, Sven Schnelle wrote: > > Right now powerpc provides an implementation to read elf files > > with the kexec_file() syscall. Make that available as a public > > kexec interface so it can be re-used on other architectures. > > > > Signed-off-by: Sven Schnelle <svens@stackframe.org> > > --- > > arch/Kconfig | 3 + > > arch/powerpc/Kconfig | 1 + > > arch/powerpc/kernel/kexec_elf_64.c | 551 +---------------------------- > > include/linux/kexec.h | 24 ++ > > kernel/Makefile | 1 + > > kernel/kexec_elf.c | 537 ++++++++++++++++++++++++++++ > > 6 files changed, 576 insertions(+), 541 deletions(-) > > create mode 100644 kernel/kexec_elf.c > > Why are you persisting at not using -C when creating your patch ? Do you > want to hide the changes you did while copying > arch/powerpc/kernel/kexec_elf_64.c to kernel/kexec_elf.c ? > Or you want to make life harder for the reviewers ? Sorry, never used -C before. I used: git send-email --annotate -v2 -7 --to kexec@lists.infradead.org --cc deller@gmx.de,linuxppc-dev@lists.ozlabs.org -v --format-patch -C -M However, it looks like it only works when started this way: git send-email --format-patch -M -C --annotate -v2 -7 --to kexec@lists.infradead.org --cc deller@gmx.de,linuxppc-dev@lists.ozlabs.org -v I'll resend v2. Best Regards, Sven ^ permalink raw reply [flat|nested] 20+ messages in thread
* Re: [PATCH v2 1/7] kexec: add KEXEC_ELF @ 2019-07-10 14:24 ` Sven Schnelle 0 siblings, 0 replies; 20+ messages in thread From: Sven Schnelle @ 2019-07-10 14:24 UTC (permalink / raw) To: Christophe Leroy; +Cc: linuxppc-dev, deller, kexec Hi Christophe, On Wed, Jul 10, 2019 at 01:19:13PM +0000, Christophe Leroy wrote: > Hi Sven, > > On 07/09/2019 07:43 PM, Sven Schnelle wrote: > > Right now powerpc provides an implementation to read elf files > > with the kexec_file() syscall. Make that available as a public > > kexec interface so it can be re-used on other architectures. > > > > Signed-off-by: Sven Schnelle <svens@stackframe.org> > > --- > > arch/Kconfig | 3 + > > arch/powerpc/Kconfig | 1 + > > arch/powerpc/kernel/kexec_elf_64.c | 551 +---------------------------- > > include/linux/kexec.h | 24 ++ > > kernel/Makefile | 1 + > > kernel/kexec_elf.c | 537 ++++++++++++++++++++++++++++ > > 6 files changed, 576 insertions(+), 541 deletions(-) > > create mode 100644 kernel/kexec_elf.c > > Why are you persisting at not using -C when creating your patch ? Do you > want to hide the changes you did while copying > arch/powerpc/kernel/kexec_elf_64.c to kernel/kexec_elf.c ? > Or you want to make life harder for the reviewers ? Sorry, never used -C before. I used: git send-email --annotate -v2 -7 --to kexec@lists.infradead.org --cc deller@gmx.de,linuxppc-dev@lists.ozlabs.org -v --format-patch -C -M However, it looks like it only works when started this way: git send-email --format-patch -M -C --annotate -v2 -7 --to kexec@lists.infradead.org --cc deller@gmx.de,linuxppc-dev@lists.ozlabs.org -v I'll resend v2. Best Regards, Sven _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec ^ permalink raw reply [flat|nested] 20+ messages in thread
* [PATCH v2 2/7] kexec_elf: change order of elf_*_to_cpu() functions 2019-07-09 19:43 ` Sven Schnelle @ 2019-07-09 19:43 ` Sven Schnelle -1 siblings, 0 replies; 20+ messages in thread From: Sven Schnelle @ 2019-07-09 19:43 UTC (permalink / raw) To: kexec; +Cc: Sven Schnelle, deller, linuxppc-dev Change the order to have a 64/32/16 order, no functional change. Signed-off-by: Sven Schnelle <svens@stackframe.org> --- kernel/kexec_elf.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/kernel/kexec_elf.c b/kernel/kexec_elf.c index 6e9f52171ede..76e7df64d715 100644 --- a/kernel/kexec_elf.c +++ b/kernel/kexec_elf.c @@ -31,22 +31,22 @@ static uint64_t elf64_to_cpu(const struct elfhdr *ehdr, uint64_t value) return value; } -static uint16_t elf16_to_cpu(const struct elfhdr *ehdr, uint16_t value) +static uint32_t elf32_to_cpu(const struct elfhdr *ehdr, uint32_t value) { if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) - value = le16_to_cpu(value); + value = le32_to_cpu(value); else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) - value = be16_to_cpu(value); + value = be32_to_cpu(value); return value; } -static uint32_t elf32_to_cpu(const struct elfhdr *ehdr, uint32_t value) +static uint16_t elf16_to_cpu(const struct elfhdr *ehdr, uint16_t value) { if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) - value = le32_to_cpu(value); + value = le16_to_cpu(value); else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) - value = be32_to_cpu(value); + value = be16_to_cpu(value); return value; } -- 2.20.1 ^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v2 2/7] kexec_elf: change order of elf_*_to_cpu() functions @ 2019-07-09 19:43 ` Sven Schnelle 0 siblings, 0 replies; 20+ messages in thread From: Sven Schnelle @ 2019-07-09 19:43 UTC (permalink / raw) To: kexec; +Cc: Sven Schnelle, deller, linuxppc-dev Change the order to have a 64/32/16 order, no functional change. Signed-off-by: Sven Schnelle <svens@stackframe.org> --- kernel/kexec_elf.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/kernel/kexec_elf.c b/kernel/kexec_elf.c index 6e9f52171ede..76e7df64d715 100644 --- a/kernel/kexec_elf.c +++ b/kernel/kexec_elf.c @@ -31,22 +31,22 @@ static uint64_t elf64_to_cpu(const struct elfhdr *ehdr, uint64_t value) return value; } -static uint16_t elf16_to_cpu(const struct elfhdr *ehdr, uint16_t value) +static uint32_t elf32_to_cpu(const struct elfhdr *ehdr, uint32_t value) { if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) - value = le16_to_cpu(value); + value = le32_to_cpu(value); else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) - value = be16_to_cpu(value); + value = be32_to_cpu(value); return value; } -static uint32_t elf32_to_cpu(const struct elfhdr *ehdr, uint32_t value) +static uint16_t elf16_to_cpu(const struct elfhdr *ehdr, uint16_t value) { if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB) - value = le32_to_cpu(value); + value = le16_to_cpu(value); else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) - value = be32_to_cpu(value); + value = be16_to_cpu(value); return value; } -- 2.20.1 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec ^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v2 3/7] kexec_elf: remove parsing of section headers 2019-07-09 19:43 ` Sven Schnelle @ 2019-07-09 19:43 ` Sven Schnelle -1 siblings, 0 replies; 20+ messages in thread From: Sven Schnelle @ 2019-07-09 19:43 UTC (permalink / raw) To: kexec; +Cc: Sven Schnelle, deller, linuxppc-dev We're not using them, so we can drop the parsing. Signed-off-by: Sven Schnelle <svens@stackframe.org> --- include/linux/kexec.h | 1 - kernel/kexec_elf.c | 137 ------------------------------------------ 2 files changed, 138 deletions(-) diff --git a/include/linux/kexec.h b/include/linux/kexec.h index da2a6b1d69e7..f0b809258ed3 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -226,7 +226,6 @@ struct kexec_elf_info { const struct elfhdr *ehdr; const struct elf_phdr *proghdrs; - struct elf_shdr *sechdrs; }; int kexec_build_elf_info(const char *buf, size_t len, struct elfhdr *ehdr, diff --git a/kernel/kexec_elf.c b/kernel/kexec_elf.c index 76e7df64d715..effe9dc0b055 100644 --- a/kernel/kexec_elf.c +++ b/kernel/kexec_elf.c @@ -244,134 +244,6 @@ static int elf_read_phdrs(const char *buf, size_t len, return 0; } -/** - * elf_is_shdr_sane - check that it is safe to use the section header - * @buf_len: size of the buffer in which the ELF file is loaded. - */ -static bool elf_is_shdr_sane(const struct elf_shdr *shdr, size_t buf_len) -{ - bool size_ok; - - /* SHT_NULL headers have undefined values, so we can't check them. */ - if (shdr->sh_type == SHT_NULL) - return true; - - /* Now verify sh_entsize */ - switch (shdr->sh_type) { - case SHT_SYMTAB: - size_ok = shdr->sh_entsize == sizeof(Elf_Sym); - break; - case SHT_RELA: - size_ok = shdr->sh_entsize == sizeof(Elf_Rela); - break; - case SHT_DYNAMIC: - size_ok = shdr->sh_entsize == sizeof(Elf_Dyn); - break; - case SHT_REL: - size_ok = shdr->sh_entsize == sizeof(Elf_Rel); - break; - case SHT_NOTE: - case SHT_PROGBITS: - case SHT_HASH: - case SHT_NOBITS: - default: - /* - * This is a section whose entsize requirements - * I don't care about. If I don't know about - * the section I can't care about it's entsize - * requirements. - */ - size_ok = true; - break; - } - - if (!size_ok) { - pr_debug("ELF section with wrong entry size.\n"); - return false; - } else if (shdr->sh_addr + shdr->sh_size < shdr->sh_addr) { - pr_debug("ELF section address wraps around.\n"); - return false; - } - - if (shdr->sh_type != SHT_NOBITS) { - if (shdr->sh_offset + shdr->sh_size < shdr->sh_offset) { - pr_debug("ELF section location wraps around.\n"); - return false; - } else if (shdr->sh_offset + shdr->sh_size > buf_len) { - pr_debug("ELF section not in file.\n"); - return false; - } - } - - return true; -} - -static int elf_read_shdr(const char *buf, size_t len, - struct kexec_elf_info *elf_info, - int idx) -{ - struct elf_shdr *shdr = &elf_info->sechdrs[idx]; - const struct elfhdr *ehdr = elf_info->ehdr; - const char *sbuf; - struct elf_shdr *buf_shdr; - - sbuf = buf + ehdr->e_shoff + idx * sizeof(*buf_shdr); - buf_shdr = (struct elf_shdr *) sbuf; - - shdr->sh_name = elf32_to_cpu(ehdr, buf_shdr->sh_name); - shdr->sh_type = elf32_to_cpu(ehdr, buf_shdr->sh_type); - shdr->sh_addr = elf_addr_to_cpu(ehdr, buf_shdr->sh_addr); - shdr->sh_offset = elf_addr_to_cpu(ehdr, buf_shdr->sh_offset); - shdr->sh_link = elf32_to_cpu(ehdr, buf_shdr->sh_link); - shdr->sh_info = elf32_to_cpu(ehdr, buf_shdr->sh_info); - - /* - * The following fields have a type equivalent to Elf_Addr - * both in 32 bit and 64 bit ELF. - */ - shdr->sh_flags = elf_addr_to_cpu(ehdr, buf_shdr->sh_flags); - shdr->sh_size = elf_addr_to_cpu(ehdr, buf_shdr->sh_size); - shdr->sh_addralign = elf_addr_to_cpu(ehdr, buf_shdr->sh_addralign); - shdr->sh_entsize = elf_addr_to_cpu(ehdr, buf_shdr->sh_entsize); - - return elf_is_shdr_sane(shdr, len) ? 0 : -ENOEXEC; -} - -/** - * elf_read_shdrs - read the section headers from the buffer - * - * This function assumes that the section header table was checked for sanity. - * Use elf_is_ehdr_sane() if it wasn't. - */ -static int elf_read_shdrs(const char *buf, size_t len, - struct kexec_elf_info *elf_info) -{ - size_t shdr_size, i; - - /* - * e_shnum is at most 65536 so calculating - * the size of the section header cannot overflow. - */ - shdr_size = sizeof(struct elf_shdr) * elf_info->ehdr->e_shnum; - - elf_info->sechdrs = kzalloc(shdr_size, GFP_KERNEL); - if (!elf_info->sechdrs) - return -ENOMEM; - - for (i = 0; i < elf_info->ehdr->e_shnum; i++) { - int ret; - - ret = elf_read_shdr(buf, len, elf_info, i); - if (ret) { - kfree(elf_info->sechdrs); - elf_info->sechdrs = NULL; - return ret; - } - } - - return 0; -} - /** * elf_read_from_buffer - read ELF file and sets up ELF header and ELF info * @buf: Buffer to read ELF file from. @@ -404,14 +276,6 @@ static int elf_read_from_buffer(const char *buf, size_t len, if (ret) return ret; } - if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) { - ret = elf_read_shdrs(buf, len, elf_info); - if (ret) { - kfree(elf_info->proghdrs); - return ret; - } - } - return 0; } @@ -421,7 +285,6 @@ static int elf_read_from_buffer(const char *buf, size_t len, void kexec_free_elf_info(struct kexec_elf_info *elf_info) { kfree(elf_info->proghdrs); - kfree(elf_info->sechdrs); memset(elf_info, 0, sizeof(*elf_info)); } /** -- 2.20.1 ^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v2 3/7] kexec_elf: remove parsing of section headers @ 2019-07-09 19:43 ` Sven Schnelle 0 siblings, 0 replies; 20+ messages in thread From: Sven Schnelle @ 2019-07-09 19:43 UTC (permalink / raw) To: kexec; +Cc: Sven Schnelle, deller, linuxppc-dev We're not using them, so we can drop the parsing. Signed-off-by: Sven Schnelle <svens@stackframe.org> --- include/linux/kexec.h | 1 - kernel/kexec_elf.c | 137 ------------------------------------------ 2 files changed, 138 deletions(-) diff --git a/include/linux/kexec.h b/include/linux/kexec.h index da2a6b1d69e7..f0b809258ed3 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -226,7 +226,6 @@ struct kexec_elf_info { const struct elfhdr *ehdr; const struct elf_phdr *proghdrs; - struct elf_shdr *sechdrs; }; int kexec_build_elf_info(const char *buf, size_t len, struct elfhdr *ehdr, diff --git a/kernel/kexec_elf.c b/kernel/kexec_elf.c index 76e7df64d715..effe9dc0b055 100644 --- a/kernel/kexec_elf.c +++ b/kernel/kexec_elf.c @@ -244,134 +244,6 @@ static int elf_read_phdrs(const char *buf, size_t len, return 0; } -/** - * elf_is_shdr_sane - check that it is safe to use the section header - * @buf_len: size of the buffer in which the ELF file is loaded. - */ -static bool elf_is_shdr_sane(const struct elf_shdr *shdr, size_t buf_len) -{ - bool size_ok; - - /* SHT_NULL headers have undefined values, so we can't check them. */ - if (shdr->sh_type == SHT_NULL) - return true; - - /* Now verify sh_entsize */ - switch (shdr->sh_type) { - case SHT_SYMTAB: - size_ok = shdr->sh_entsize == sizeof(Elf_Sym); - break; - case SHT_RELA: - size_ok = shdr->sh_entsize == sizeof(Elf_Rela); - break; - case SHT_DYNAMIC: - size_ok = shdr->sh_entsize == sizeof(Elf_Dyn); - break; - case SHT_REL: - size_ok = shdr->sh_entsize == sizeof(Elf_Rel); - break; - case SHT_NOTE: - case SHT_PROGBITS: - case SHT_HASH: - case SHT_NOBITS: - default: - /* - * This is a section whose entsize requirements - * I don't care about. If I don't know about - * the section I can't care about it's entsize - * requirements. - */ - size_ok = true; - break; - } - - if (!size_ok) { - pr_debug("ELF section with wrong entry size.\n"); - return false; - } else if (shdr->sh_addr + shdr->sh_size < shdr->sh_addr) { - pr_debug("ELF section address wraps around.\n"); - return false; - } - - if (shdr->sh_type != SHT_NOBITS) { - if (shdr->sh_offset + shdr->sh_size < shdr->sh_offset) { - pr_debug("ELF section location wraps around.\n"); - return false; - } else if (shdr->sh_offset + shdr->sh_size > buf_len) { - pr_debug("ELF section not in file.\n"); - return false; - } - } - - return true; -} - -static int elf_read_shdr(const char *buf, size_t len, - struct kexec_elf_info *elf_info, - int idx) -{ - struct elf_shdr *shdr = &elf_info->sechdrs[idx]; - const struct elfhdr *ehdr = elf_info->ehdr; - const char *sbuf; - struct elf_shdr *buf_shdr; - - sbuf = buf + ehdr->e_shoff + idx * sizeof(*buf_shdr); - buf_shdr = (struct elf_shdr *) sbuf; - - shdr->sh_name = elf32_to_cpu(ehdr, buf_shdr->sh_name); - shdr->sh_type = elf32_to_cpu(ehdr, buf_shdr->sh_type); - shdr->sh_addr = elf_addr_to_cpu(ehdr, buf_shdr->sh_addr); - shdr->sh_offset = elf_addr_to_cpu(ehdr, buf_shdr->sh_offset); - shdr->sh_link = elf32_to_cpu(ehdr, buf_shdr->sh_link); - shdr->sh_info = elf32_to_cpu(ehdr, buf_shdr->sh_info); - - /* - * The following fields have a type equivalent to Elf_Addr - * both in 32 bit and 64 bit ELF. - */ - shdr->sh_flags = elf_addr_to_cpu(ehdr, buf_shdr->sh_flags); - shdr->sh_size = elf_addr_to_cpu(ehdr, buf_shdr->sh_size); - shdr->sh_addralign = elf_addr_to_cpu(ehdr, buf_shdr->sh_addralign); - shdr->sh_entsize = elf_addr_to_cpu(ehdr, buf_shdr->sh_entsize); - - return elf_is_shdr_sane(shdr, len) ? 0 : -ENOEXEC; -} - -/** - * elf_read_shdrs - read the section headers from the buffer - * - * This function assumes that the section header table was checked for sanity. - * Use elf_is_ehdr_sane() if it wasn't. - */ -static int elf_read_shdrs(const char *buf, size_t len, - struct kexec_elf_info *elf_info) -{ - size_t shdr_size, i; - - /* - * e_shnum is at most 65536 so calculating - * the size of the section header cannot overflow. - */ - shdr_size = sizeof(struct elf_shdr) * elf_info->ehdr->e_shnum; - - elf_info->sechdrs = kzalloc(shdr_size, GFP_KERNEL); - if (!elf_info->sechdrs) - return -ENOMEM; - - for (i = 0; i < elf_info->ehdr->e_shnum; i++) { - int ret; - - ret = elf_read_shdr(buf, len, elf_info, i); - if (ret) { - kfree(elf_info->sechdrs); - elf_info->sechdrs = NULL; - return ret; - } - } - - return 0; -} - /** * elf_read_from_buffer - read ELF file and sets up ELF header and ELF info * @buf: Buffer to read ELF file from. @@ -404,14 +276,6 @@ static int elf_read_from_buffer(const char *buf, size_t len, if (ret) return ret; } - if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) { - ret = elf_read_shdrs(buf, len, elf_info); - if (ret) { - kfree(elf_info->proghdrs); - return ret; - } - } - return 0; } @@ -421,7 +285,6 @@ static int elf_read_from_buffer(const char *buf, size_t len, void kexec_free_elf_info(struct kexec_elf_info *elf_info) { kfree(elf_info->proghdrs); - kfree(elf_info->sechdrs); memset(elf_info, 0, sizeof(*elf_info)); } /** -- 2.20.1 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec ^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v2 4/7] kexec_elf: remove PURGATORY_STACK_SIZE 2019-07-09 19:43 ` Sven Schnelle @ 2019-07-09 19:43 ` Sven Schnelle -1 siblings, 0 replies; 20+ messages in thread From: Sven Schnelle @ 2019-07-09 19:43 UTC (permalink / raw) To: kexec; +Cc: Sven Schnelle, deller, linuxppc-dev It's not used anywhere so just drop it. Signed-off-by: Sven Schnelle <svens@stackframe.org> --- kernel/kexec_elf.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/kernel/kexec_elf.c b/kernel/kexec_elf.c index effe9dc0b055..70d31b8feeae 100644 --- a/kernel/kexec_elf.c +++ b/kernel/kexec_elf.c @@ -8,8 +8,6 @@ #include <linux/slab.h> #include <linux/types.h> -#define PURGATORY_STACK_SIZE (16 * 1024) - #define elf_addr_to_cpu elf64_to_cpu #ifndef Elf_Rel -- 2.20.1 ^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v2 4/7] kexec_elf: remove PURGATORY_STACK_SIZE @ 2019-07-09 19:43 ` Sven Schnelle 0 siblings, 0 replies; 20+ messages in thread From: Sven Schnelle @ 2019-07-09 19:43 UTC (permalink / raw) To: kexec; +Cc: Sven Schnelle, deller, linuxppc-dev It's not used anywhere so just drop it. Signed-off-by: Sven Schnelle <svens@stackframe.org> --- kernel/kexec_elf.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/kernel/kexec_elf.c b/kernel/kexec_elf.c index effe9dc0b055..70d31b8feeae 100644 --- a/kernel/kexec_elf.c +++ b/kernel/kexec_elf.c @@ -8,8 +8,6 @@ #include <linux/slab.h> #include <linux/types.h> -#define PURGATORY_STACK_SIZE (16 * 1024) - #define elf_addr_to_cpu elf64_to_cpu #ifndef Elf_Rel -- 2.20.1 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec ^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v2 5/7] kexec_elf: remove elf_addr_to_cpu macro 2019-07-09 19:43 ` Sven Schnelle @ 2019-07-09 19:43 ` Sven Schnelle -1 siblings, 0 replies; 20+ messages in thread From: Sven Schnelle @ 2019-07-09 19:43 UTC (permalink / raw) To: kexec; +Cc: Sven Schnelle, deller, linuxppc-dev It had only one definition, so just use the function directly. Signed-off-by: Sven Schnelle <svens@stackframe.org> --- kernel/kexec_elf.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) diff --git a/kernel/kexec_elf.c b/kernel/kexec_elf.c index 70d31b8feeae..99e6d63b5dfc 100644 --- a/kernel/kexec_elf.c +++ b/kernel/kexec_elf.c @@ -8,8 +8,6 @@ #include <linux/slab.h> #include <linux/types.h> -#define elf_addr_to_cpu elf64_to_cpu - #ifndef Elf_Rel #define Elf_Rel Elf64_Rel #endif /* Elf_Rel */ @@ -143,9 +141,9 @@ static int elf_read_ehdr(const char *buf, size_t len, struct elfhdr *ehdr) ehdr->e_type = elf16_to_cpu(ehdr, buf_ehdr->e_type); ehdr->e_machine = elf16_to_cpu(ehdr, buf_ehdr->e_machine); ehdr->e_version = elf32_to_cpu(ehdr, buf_ehdr->e_version); - ehdr->e_entry = elf_addr_to_cpu(ehdr, buf_ehdr->e_entry); - ehdr->e_phoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_phoff); - ehdr->e_shoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_shoff); + ehdr->e_entry = elf64_to_cpu(ehdr, buf_ehdr->e_entry); + ehdr->e_phoff = elf64_to_cpu(ehdr, buf_ehdr->e_phoff); + ehdr->e_shoff = elf64_to_cpu(ehdr, buf_ehdr->e_shoff); ehdr->e_flags = elf32_to_cpu(ehdr, buf_ehdr->e_flags); ehdr->e_phentsize = elf16_to_cpu(ehdr, buf_ehdr->e_phentsize); ehdr->e_phnum = elf16_to_cpu(ehdr, buf_ehdr->e_phnum); @@ -190,18 +188,18 @@ static int elf_read_phdr(const char *buf, size_t len, buf_phdr = (struct elf_phdr *) pbuf; phdr->p_type = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_type); - phdr->p_offset = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_offset); - phdr->p_paddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_paddr); - phdr->p_vaddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_vaddr); + phdr->p_offset = elf64_to_cpu(elf_info->ehdr, buf_phdr->p_offset); + phdr->p_paddr = elf64_to_cpu(elf_info->ehdr, buf_phdr->p_paddr); + phdr->p_vaddr = elf64_to_cpu(elf_info->ehdr, buf_phdr->p_vaddr); phdr->p_flags = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_flags); /* * The following fields have a type equivalent to Elf_Addr * both in 32 bit and 64 bit ELF. */ - phdr->p_filesz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_filesz); - phdr->p_memsz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_memsz); - phdr->p_align = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_align); + phdr->p_filesz = elf64_to_cpu(elf_info->ehdr, buf_phdr->p_filesz); + phdr->p_memsz = elf64_to_cpu(elf_info->ehdr, buf_phdr->p_memsz); + phdr->p_align = elf64_to_cpu(elf_info->ehdr, buf_phdr->p_align); return elf_is_phdr_sane(phdr, len) ? 0 : -ENOEXEC; } -- 2.20.1 ^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v2 5/7] kexec_elf: remove elf_addr_to_cpu macro @ 2019-07-09 19:43 ` Sven Schnelle 0 siblings, 0 replies; 20+ messages in thread From: Sven Schnelle @ 2019-07-09 19:43 UTC (permalink / raw) To: kexec; +Cc: Sven Schnelle, deller, linuxppc-dev It had only one definition, so just use the function directly. Signed-off-by: Sven Schnelle <svens@stackframe.org> --- kernel/kexec_elf.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) diff --git a/kernel/kexec_elf.c b/kernel/kexec_elf.c index 70d31b8feeae..99e6d63b5dfc 100644 --- a/kernel/kexec_elf.c +++ b/kernel/kexec_elf.c @@ -8,8 +8,6 @@ #include <linux/slab.h> #include <linux/types.h> -#define elf_addr_to_cpu elf64_to_cpu - #ifndef Elf_Rel #define Elf_Rel Elf64_Rel #endif /* Elf_Rel */ @@ -143,9 +141,9 @@ static int elf_read_ehdr(const char *buf, size_t len, struct elfhdr *ehdr) ehdr->e_type = elf16_to_cpu(ehdr, buf_ehdr->e_type); ehdr->e_machine = elf16_to_cpu(ehdr, buf_ehdr->e_machine); ehdr->e_version = elf32_to_cpu(ehdr, buf_ehdr->e_version); - ehdr->e_entry = elf_addr_to_cpu(ehdr, buf_ehdr->e_entry); - ehdr->e_phoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_phoff); - ehdr->e_shoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_shoff); + ehdr->e_entry = elf64_to_cpu(ehdr, buf_ehdr->e_entry); + ehdr->e_phoff = elf64_to_cpu(ehdr, buf_ehdr->e_phoff); + ehdr->e_shoff = elf64_to_cpu(ehdr, buf_ehdr->e_shoff); ehdr->e_flags = elf32_to_cpu(ehdr, buf_ehdr->e_flags); ehdr->e_phentsize = elf16_to_cpu(ehdr, buf_ehdr->e_phentsize); ehdr->e_phnum = elf16_to_cpu(ehdr, buf_ehdr->e_phnum); @@ -190,18 +188,18 @@ static int elf_read_phdr(const char *buf, size_t len, buf_phdr = (struct elf_phdr *) pbuf; phdr->p_type = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_type); - phdr->p_offset = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_offset); - phdr->p_paddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_paddr); - phdr->p_vaddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_vaddr); + phdr->p_offset = elf64_to_cpu(elf_info->ehdr, buf_phdr->p_offset); + phdr->p_paddr = elf64_to_cpu(elf_info->ehdr, buf_phdr->p_paddr); + phdr->p_vaddr = elf64_to_cpu(elf_info->ehdr, buf_phdr->p_vaddr); phdr->p_flags = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_flags); /* * The following fields have a type equivalent to Elf_Addr * both in 32 bit and 64 bit ELF. */ - phdr->p_filesz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_filesz); - phdr->p_memsz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_memsz); - phdr->p_align = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_align); + phdr->p_filesz = elf64_to_cpu(elf_info->ehdr, buf_phdr->p_filesz); + phdr->p_memsz = elf64_to_cpu(elf_info->ehdr, buf_phdr->p_memsz); + phdr->p_align = elf64_to_cpu(elf_info->ehdr, buf_phdr->p_align); return elf_is_phdr_sane(phdr, len) ? 0 : -ENOEXEC; } -- 2.20.1 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec ^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v2 6/7] kexec_elf: remove Elf_Rel macro 2019-07-09 19:43 ` Sven Schnelle @ 2019-07-09 19:43 ` Sven Schnelle -1 siblings, 0 replies; 20+ messages in thread From: Sven Schnelle @ 2019-07-09 19:43 UTC (permalink / raw) To: kexec; +Cc: Sven Schnelle, deller, linuxppc-dev It wasn't used anywhere, so lets drop it. Signed-off-by: Sven Schnelle <svens@stackframe.org> --- kernel/kexec_elf.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/kernel/kexec_elf.c b/kernel/kexec_elf.c index 99e6d63b5dfc..b7e47ddd7cad 100644 --- a/kernel/kexec_elf.c +++ b/kernel/kexec_elf.c @@ -8,10 +8,6 @@ #include <linux/slab.h> #include <linux/types.h> -#ifndef Elf_Rel -#define Elf_Rel Elf64_Rel -#endif /* Elf_Rel */ - static inline bool elf_is_elf_file(const struct elfhdr *ehdr) { return memcmp(ehdr->e_ident, ELFMAG, SELFMAG) == 0; -- 2.20.1 ^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v2 6/7] kexec_elf: remove Elf_Rel macro @ 2019-07-09 19:43 ` Sven Schnelle 0 siblings, 0 replies; 20+ messages in thread From: Sven Schnelle @ 2019-07-09 19:43 UTC (permalink / raw) To: kexec; +Cc: Sven Schnelle, deller, linuxppc-dev It wasn't used anywhere, so lets drop it. Signed-off-by: Sven Schnelle <svens@stackframe.org> --- kernel/kexec_elf.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/kernel/kexec_elf.c b/kernel/kexec_elf.c index 99e6d63b5dfc..b7e47ddd7cad 100644 --- a/kernel/kexec_elf.c +++ b/kernel/kexec_elf.c @@ -8,10 +8,6 @@ #include <linux/slab.h> #include <linux/types.h> -#ifndef Elf_Rel -#define Elf_Rel Elf64_Rel -#endif /* Elf_Rel */ - static inline bool elf_is_elf_file(const struct elfhdr *ehdr) { return memcmp(ehdr->e_ident, ELFMAG, SELFMAG) == 0; -- 2.20.1 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec ^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v2 7/7] kexec_elf: remove unused variable in kexec_elf_load() 2019-07-09 19:43 ` Sven Schnelle @ 2019-07-09 19:43 ` Sven Schnelle -1 siblings, 0 replies; 20+ messages in thread From: Sven Schnelle @ 2019-07-09 19:43 UTC (permalink / raw) To: kexec; +Cc: Sven Schnelle, deller, linuxppc-dev base was never unsigned, so we can remove it. Signed-off-by: Sven Schnelle <svens@stackframe.org> --- kernel/kexec_elf.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/kernel/kexec_elf.c b/kernel/kexec_elf.c index b7e47ddd7cad..a56ec5481e71 100644 --- a/kernel/kexec_elf.c +++ b/kernel/kexec_elf.c @@ -348,7 +348,7 @@ int kexec_elf_load(struct kimage *image, struct elfhdr *ehdr, struct kexec_buf *kbuf, unsigned long *lowest_load_addr) { - unsigned long base = 0, lowest_addr = UINT_MAX; + unsigned long lowest_addr = UINT_MAX; int ret; size_t i; @@ -370,7 +370,7 @@ int kexec_elf_load(struct kimage *image, struct elfhdr *ehdr, kbuf->bufsz = size; kbuf->memsz = phdr->p_memsz; kbuf->buf_align = phdr->p_align; - kbuf->buf_min = phdr->p_paddr + base; + kbuf->buf_min = phdr->p_paddr; ret = kexec_add_buffer(kbuf); if (ret) goto out; @@ -380,9 +380,6 @@ int kexec_elf_load(struct kimage *image, struct elfhdr *ehdr, lowest_addr = load_addr; } - /* Update entry point to reflect new load address. */ - ehdr->e_entry += base; - *lowest_load_addr = lowest_addr; ret = 0; out: -- 2.20.1 ^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v2 7/7] kexec_elf: remove unused variable in kexec_elf_load() @ 2019-07-09 19:43 ` Sven Schnelle 0 siblings, 0 replies; 20+ messages in thread From: Sven Schnelle @ 2019-07-09 19:43 UTC (permalink / raw) To: kexec; +Cc: Sven Schnelle, deller, linuxppc-dev base was never unsigned, so we can remove it. Signed-off-by: Sven Schnelle <svens@stackframe.org> --- kernel/kexec_elf.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/kernel/kexec_elf.c b/kernel/kexec_elf.c index b7e47ddd7cad..a56ec5481e71 100644 --- a/kernel/kexec_elf.c +++ b/kernel/kexec_elf.c @@ -348,7 +348,7 @@ int kexec_elf_load(struct kimage *image, struct elfhdr *ehdr, struct kexec_buf *kbuf, unsigned long *lowest_load_addr) { - unsigned long base = 0, lowest_addr = UINT_MAX; + unsigned long lowest_addr = UINT_MAX; int ret; size_t i; @@ -370,7 +370,7 @@ int kexec_elf_load(struct kimage *image, struct elfhdr *ehdr, kbuf->bufsz = size; kbuf->memsz = phdr->p_memsz; kbuf->buf_align = phdr->p_align; - kbuf->buf_min = phdr->p_paddr + base; + kbuf->buf_min = phdr->p_paddr; ret = kexec_add_buffer(kbuf); if (ret) goto out; @@ -380,9 +380,6 @@ int kexec_elf_load(struct kimage *image, struct elfhdr *ehdr, lowest_addr = load_addr; } - /* Update entry point to reflect new load address. */ - ehdr->e_entry += base; - *lowest_load_addr = lowest_addr; ret = 0; out: -- 2.20.1 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec ^ permalink raw reply related [flat|nested] 20+ messages in thread
end of thread, other threads:[~2019-07-10 14:30 UTC | newest] Thread overview: 20+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2019-07-09 19:43 [PATCH v2 0/7] kexec: add generic support for elf kernel images Sven Schnelle 2019-07-09 19:43 ` Sven Schnelle 2019-07-09 19:43 ` [PATCH v2 1/7] kexec: add KEXEC_ELF Sven Schnelle 2019-07-09 19:43 ` Sven Schnelle 2019-07-10 13:19 ` Christophe Leroy 2019-07-10 13:19 ` Christophe Leroy 2019-07-10 14:24 ` Sven Schnelle 2019-07-10 14:24 ` Sven Schnelle 2019-07-09 19:43 ` [PATCH v2 2/7] kexec_elf: change order of elf_*_to_cpu() functions Sven Schnelle 2019-07-09 19:43 ` Sven Schnelle 2019-07-09 19:43 ` [PATCH v2 3/7] kexec_elf: remove parsing of section headers Sven Schnelle 2019-07-09 19:43 ` Sven Schnelle 2019-07-09 19:43 ` [PATCH v2 4/7] kexec_elf: remove PURGATORY_STACK_SIZE Sven Schnelle 2019-07-09 19:43 ` Sven Schnelle 2019-07-09 19:43 ` [PATCH v2 5/7] kexec_elf: remove elf_addr_to_cpu macro Sven Schnelle 2019-07-09 19:43 ` Sven Schnelle 2019-07-09 19:43 ` [PATCH v2 6/7] kexec_elf: remove Elf_Rel macro Sven Schnelle 2019-07-09 19:43 ` Sven Schnelle 2019-07-09 19:43 ` [PATCH v2 7/7] kexec_elf: remove unused variable in kexec_elf_load() Sven Schnelle 2019-07-09 19:43 ` Sven Schnelle
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