From: Mark Brown <broonie@kernel.org> To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org> Cc: "Alexander Viro" <viro@zeniv.linux.org.uk>, "Paul Elliott" <paul.elliott@arm.com>, "Peter Zijlstra" <peterz@infradead.org>, "Yu-cheng Yu" <yu-cheng.yu@intel.com>, "Amit Kachhap" <amit.kachhap@arm.com>, "Vincenzo Frascino" <vincenzo.frascino@arm.com>, "Marc Zyngier" <maz@kernel.org>, "Eugene Syromiatnikov" <esyr@redhat.com>, "Szabolcs Nagy" <szabolcs.nagy@arm.com>, "H . J . Lu " <hjl.tools@gmail.com>, "Andrew Jones" <drjones@redhat.com>, "Kees Cook" <keescook@chromium.org>, "Arnd Bergmann" <arnd@arndb.de>, "Jann Horn" <jannh@google.com>, "Richard Henderson" <richard.henderson@linaro.org>, "Kristina Martšenko" <kristina.martsenko@arm.com>, "Thomas Gleixner" <tglx@linutronix.de>, "Florian Weimer" <fweimer@redhat.com>, "Sudakshina Das" <sudi.das@arm.com>, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-fsdevel@vger.kernel.org, "Dave Martin" <Dave.Martin@arm.com>, "Mark Brown" <broonie@kernel.org> Subject: [PATCH v6 02/11] ELF: Add ELF program property parsing support Date: Wed, 12 Feb 2020 19:28:57 +0000 Message-ID: <20200212192906.53366-3-broonie@kernel.org> (raw) In-Reply-To: <20200212192906.53366-1-broonie@kernel.org> From: Dave Martin <Dave.Martin@arm.com> ELF program properties will be needed for detecting whether to enable optional architecture or ABI features for a new ELF process. For now, there are no generic properties that we care about, so do nothing unless CONFIG_ARCH_USE_GNU_PROPERTY=y. Otherwise, the presence of properties using the PT_PROGRAM_PROPERTY phdrs entry (if any), and notify each property to the arch code. For now, the added code is not used. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Signed-off-by: Mark Brown <broonie@kernel.org> --- fs/binfmt_elf.c | 127 +++++++++++++++++++++++++++++++++++++++ fs/compat_binfmt_elf.c | 4 ++ include/linux/elf.h | 19 ++++++ include/uapi/linux/elf.h | 4 ++ 4 files changed, 154 insertions(+) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index f4713ea76e82..1fb67e506b68 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -39,12 +39,18 @@ #include <linux/sched/coredump.h> #include <linux/sched/task_stack.h> #include <linux/sched/cputime.h> +#include <linux/sizes.h> +#include <linux/types.h> #include <linux/cred.h> #include <linux/dax.h> #include <linux/uaccess.h> #include <asm/param.h> #include <asm/page.h> +#ifndef ELF_COMPAT +#define ELF_COMPAT 0 +#endif + #ifndef user_long_t #define user_long_t long #endif @@ -681,6 +687,111 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex, * libraries. There is no binary dependent code anywhere else. */ +static int parse_elf_property(const char *data, size_t *off, size_t datasz, + struct arch_elf_state *arch, + bool have_prev_type, u32 *prev_type) +{ + size_t o, step; + const struct gnu_property *pr; + int ret; + + if (*off == datasz) + return -ENOENT; + + if (WARN_ON_ONCE(*off > datasz || *off % ELF_GNU_PROPERTY_ALIGN)) + return -EIO; + o = *off; + datasz -= *off; + + if (datasz < sizeof(*pr)) + return -ENOEXEC; + pr = (const struct gnu_property *)(data + o); + o += sizeof(*pr); + datasz -= sizeof(*pr); + + if (pr->pr_datasz > datasz) + return -ENOEXEC; + + WARN_ON_ONCE(o % ELF_GNU_PROPERTY_ALIGN); + step = round_up(pr->pr_datasz, ELF_GNU_PROPERTY_ALIGN); + if (step > datasz) + return -ENOEXEC; + + /* Properties are supposed to be unique and sorted on pr_type: */ + if (have_prev_type && pr->pr_type <= *prev_type) + return -ENOEXEC; + *prev_type = pr->pr_type; + + ret = arch_parse_elf_property(pr->pr_type, data + o, + pr->pr_datasz, ELF_COMPAT, arch); + if (ret) + return ret; + + *off = o + step; + return 0; +} + +#define NOTE_DATA_SZ SZ_1K +#define GNU_PROPERTY_TYPE_0_NAME "GNU" +#define NOTE_NAME_SZ (sizeof(GNU_PROPERTY_TYPE_0_NAME)) + +static int parse_elf_properties(struct file *f, const struct elf_phdr *phdr, + struct arch_elf_state *arch) +{ + union { + struct elf_note nhdr; + char data[NOTE_DATA_SZ]; + } note; + loff_t pos; + ssize_t n; + size_t off, datasz; + int ret; + bool have_prev_type; + u32 prev_type; + + if (!IS_ENABLED(CONFIG_ARCH_USE_GNU_PROPERTY) || !phdr) + return 0; + + /* load_elf_binary() shouldn't call us unless this is true... */ + if (WARN_ON_ONCE(phdr->p_type != PT_GNU_PROPERTY)) + return -ENOEXEC; + + /* If the properties are crazy large, that's too bad (for now): */ + if (phdr->p_filesz > sizeof(note)) + return -ENOEXEC; + + pos = phdr->p_offset; + n = kernel_read(f, ¬e, phdr->p_filesz, &pos); + + BUILD_BUG_ON(sizeof(note) < sizeof(note.nhdr) + NOTE_NAME_SZ); + if (n < 0 || n < sizeof(note.nhdr) + NOTE_NAME_SZ) + return -EIO; + + if (note.nhdr.n_type != NT_GNU_PROPERTY_TYPE_0 || + note.nhdr.n_namesz != NOTE_NAME_SZ || + strncmp(note.data + sizeof(note.nhdr), + GNU_PROPERTY_TYPE_0_NAME, n - sizeof(note.nhdr))) + return -ENOEXEC; + + off = round_up(sizeof(note.nhdr) + NOTE_NAME_SZ, + ELF_GNU_PROPERTY_ALIGN); + if (off > n) + return -ENOEXEC; + + if (note.nhdr.n_descsz > n - off) + return -ENOEXEC; + datasz = off + note.nhdr.n_descsz; + + have_prev_type = false; + do { + ret = parse_elf_property(note.data, &off, datasz, arch, + have_prev_type, &prev_type); + have_prev_type = true; + } while (!ret); + + return ret == -ENOENT ? 0 : ret; +} + static int load_elf_binary(struct linux_binprm *bprm) { struct file *interpreter = NULL; /* to shut gcc up */ @@ -688,6 +799,7 @@ static int load_elf_binary(struct linux_binprm *bprm) int load_addr_set = 0; unsigned long error; struct elf_phdr *elf_ppnt, *elf_phdata, *interp_elf_phdata = NULL; + struct elf_phdr *elf_property_phdata = NULL; unsigned long elf_bss, elf_brk; int bss_prot = 0; int retval, i; @@ -733,6 +845,11 @@ static int load_elf_binary(struct linux_binprm *bprm) for (i = 0; i < elf_ex->e_phnum; i++, elf_ppnt++) { char *elf_interpreter; + if (elf_ppnt->p_type == PT_GNU_PROPERTY) { + elf_property_phdata = elf_ppnt; + continue; + } + if (elf_ppnt->p_type != PT_INTERP) continue; @@ -820,9 +937,14 @@ static int load_elf_binary(struct linux_binprm *bprm) goto out_free_dentry; /* Pass PT_LOPROC..PT_HIPROC headers to arch code */ + elf_property_phdata = NULL; elf_ppnt = interp_elf_phdata; for (i = 0; i < loc->interp_elf_ex.e_phnum; i++, elf_ppnt++) switch (elf_ppnt->p_type) { + case PT_GNU_PROPERTY: + elf_property_phdata = elf_ppnt; + break; + case PT_LOPROC ... PT_HIPROC: retval = arch_elf_pt_proc(&loc->interp_elf_ex, elf_ppnt, interpreter, @@ -833,6 +955,11 @@ static int load_elf_binary(struct linux_binprm *bprm) } } + retval = parse_elf_properties(interpreter ?: bprm->file, + elf_property_phdata, &arch_state); + if (retval) + goto out_free_dentry; + /* * Allow arch code to reject the ELF at this point, whilst it's * still possible to return an error to the code that invoked diff --git a/fs/compat_binfmt_elf.c b/fs/compat_binfmt_elf.c index aaad4ca1217e..13a087bc816b 100644 --- a/fs/compat_binfmt_elf.c +++ b/fs/compat_binfmt_elf.c @@ -17,6 +17,8 @@ #include <linux/elfcore-compat.h> #include <linux/time.h> +#define ELF_COMPAT 1 + /* * Rename the basic ELF layout types to refer to the 32-bit class of files. */ @@ -28,11 +30,13 @@ #undef elf_shdr #undef elf_note #undef elf_addr_t +#undef ELF_GNU_PROPERTY_ALIGN #define elfhdr elf32_hdr #define elf_phdr elf32_phdr #define elf_shdr elf32_shdr #define elf_note elf32_note #define elf_addr_t Elf32_Addr +#define ELF_GNU_PROPERTY_ALIGN ELF32_GNU_PROPERTY_ALIGN /* * Some data types as stored in coredump. diff --git a/include/linux/elf.h b/include/linux/elf.h index 459cddcceaac..7bdc6da160c7 100644 --- a/include/linux/elf.h +++ b/include/linux/elf.h @@ -22,6 +22,9 @@ SET_PERSONALITY(ex) #endif +#define ELF32_GNU_PROPERTY_ALIGN 4 +#define ELF64_GNU_PROPERTY_ALIGN 8 + #if ELF_CLASS == ELFCLASS32 extern Elf32_Dyn _DYNAMIC []; @@ -32,6 +35,7 @@ extern Elf32_Dyn _DYNAMIC []; #define elf_addr_t Elf32_Off #define Elf_Half Elf32_Half #define Elf_Word Elf32_Word +#define ELF_GNU_PROPERTY_ALIGN ELF32_GNU_PROPERTY_ALIGN #else @@ -43,6 +47,7 @@ extern Elf64_Dyn _DYNAMIC []; #define elf_addr_t Elf64_Off #define Elf_Half Elf64_Half #define Elf_Word Elf64_Word +#define ELF_GNU_PROPERTY_ALIGN ELF64_GNU_PROPERTY_ALIGN #endif @@ -64,4 +69,18 @@ struct gnu_property { u32 pr_datasz; }; +struct arch_elf_state; + +#ifndef CONFIG_ARCH_USE_GNU_PROPERTY +static inline int arch_parse_elf_property(u32 type, const void *data, + size_t datasz, bool compat, + struct arch_elf_state *arch) +{ + return 0; +} +#else +extern int arch_parse_elf_property(u32 type, const void *data, size_t datasz, + bool compat, struct arch_elf_state *arch); +#endif + #endif /* _LINUX_ELF_H */ diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h index c37731407074..20900f4496b7 100644 --- a/include/uapi/linux/elf.h +++ b/include/uapi/linux/elf.h @@ -368,6 +368,7 @@ typedef struct elf64_shdr { * Notes used in ET_CORE. Architectures export some of the arch register sets * using the corresponding note types via the PTRACE_GETREGSET and * PTRACE_SETREGSET requests. + * The note name for all these is "LINUX". */ #define NT_PRSTATUS 1 #define NT_PRFPREG 2 @@ -430,6 +431,9 @@ typedef struct elf64_shdr { #define NT_MIPS_FP_MODE 0x801 /* MIPS floating-point mode */ #define NT_MIPS_MSA 0x802 /* MIPS SIMD registers */ +/* Note types with note name "GNU" */ +#define NT_GNU_PROPERTY_TYPE_0 5 + /* Note header in a PT_NOTE section */ typedef struct elf32_note { Elf32_Word n_namesz; /* Name size */ -- 2.20.1
next prev parent reply index Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-02-12 19:28 [PATCH v6 00/11] arm64: Branch Target Identification support Mark Brown 2020-02-12 19:28 ` [PATCH v6 01/11] ELF: UAPI and Kconfig additions for ELF program properties Mark Brown 2020-02-26 5:49 ` Kees Cook 2020-02-26 11:20 ` Mark Brown 2020-02-12 19:28 ` Mark Brown [this message] 2020-02-12 19:28 ` [PATCH v6 03/11] arm64: Basic Branch Target Identification support Mark Brown 2020-02-12 19:28 ` [PATCH v6 04/11] elf: Allow arch to tweak initial mmap prot flags Mark Brown 2020-02-12 19:29 ` [PATCH v6 05/11] arm64: elf: Enable BTI at exec based on ELF program properties Mark Brown 2020-02-25 13:28 ` Amit Kachhap 2020-02-25 17:27 ` Mark Brown 2020-02-26 5:47 ` Kees Cook 2020-02-12 19:29 ` [PATCH v6 06/11] arm64: BTI: Decode BTYPE bits when printing PSTATE Mark Brown 2020-02-12 19:29 ` [PATCH v6 07/11] arm64: unify native/compat instruction skipping Mark Brown 2020-02-12 19:29 ` [PATCH v6 08/11] arm64: traps: Shuffle code to eliminate forward declarations Mark Brown 2020-02-12 19:29 ` [PATCH v6 09/11] arm64: BTI: Reset BTYPE when skipping emulated instructions Mark Brown 2020-02-12 19:29 ` [PATCH v6 10/11] KVM: " Mark Brown 2020-02-15 11:56 ` Marc Zyngier 2020-02-12 19:29 ` [PATCH v6 11/11] arm64: mm: Display guarded pages in ptdump Mark Brown
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