* [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
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http://lists.infradead.org/mailman/listinfo/kexec
^ 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
@ 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
* 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
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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