[patch 32/54] buildid: add API to parse build ID out of buffer
From: Andrew Morton <akpm@linux-foundation.org>
Date: 2021-07-08 01:09:13
Also in:
mm-commits
From: Stephen Boyd <redacted> Subject: buildid: add API to parse build ID out of buffer Add an API that can parse the build ID out of a buffer, instead of a vma, to support printing a kernel module's build ID for stack traces. Link: https://lkml.kernel.org/r/20210511003845.2429846-3-swboyd@chromium.org Signed-off-by: Stephen Boyd <redacted> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Jessica Yu <jeyu@kernel.org> Cc: Evan Green <redacted> Cc: Hsin-Yi Wang <redacted> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Baoquan He <redacted> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Young <redacted> Cc: Ingo Molnar <mingo@redhat.com> Cc: Konstantin Khlebnikov <redacted> Cc: Matthew Wilcox <willy@infradead.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Sasha Levin <sashal@kernel.org> Cc: Sergey Senozhatsky <redacted> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <redacted> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> --- include/linux/buildid.h | 1 lib/buildid.c | 50 ++++++++++++++++++++++++++++---------- 2 files changed, 38 insertions(+), 13 deletions(-)
--- a/include/linux/buildid.h~buildid-add-api-to-parse-build-id-out-of-buffer
+++ a/include/linux/buildid.h@@ -8,5 +8,6 @@ int build_id_parse(struct vm_area_struct *vma, unsigned char *build_id, __u32 *size); +int build_id_parse_buf(const void *buf, unsigned char *build_id, u32 buf_size); #endif --- a/lib/buildid.c~buildid-add-api-to-parse-build-id-out-of-buffer +++ a/lib/buildid.c
@@ -2,30 +2,23 @@ #include <linux/buildid.h> #include <linux/elf.h> +#include <linux/kernel.h> #include <linux/pagemap.h> #define BUILD_ID 3 + /* * Parse build id from the note segment. This logic can be shared between * 32-bit and 64-bit system, because Elf32_Nhdr and Elf64_Nhdr are * identical. */ -static inline int parse_build_id(void *page_addr, - unsigned char *build_id, - __u32 *size, - void *note_start, - Elf32_Word note_size) +static int parse_build_id_buf(unsigned char *build_id, + __u32 *size, + const void *note_start, + Elf32_Word note_size) { Elf32_Word note_offs = 0, new_offs; - /* check for overflow */ - if (note_start < page_addr || note_start + note_size < note_start) - return -EINVAL; - - /* only supports note that fits in the first page */ - if (note_start + note_size > page_addr + PAGE_SIZE) - return -EINVAL; - while (note_offs + sizeof(Elf32_Nhdr) < note_size) { Elf32_Nhdr *nhdr = (Elf32_Nhdr *)(note_start + note_offs);
@@ -50,9 +43,27 @@ static inline int parse_build_id(void *p break; note_offs = new_offs; } + return -EINVAL; } +static inline int parse_build_id(void *page_addr, + unsigned char *build_id, + __u32 *size, + void *note_start, + Elf32_Word note_size) +{ + /* check for overflow */ + if (note_start < page_addr || note_start + note_size < note_start) + return -EINVAL; + + /* only supports note that fits in the first page */ + if (note_start + note_size > page_addr + PAGE_SIZE) + return -EINVAL; + + return parse_build_id_buf(build_id, size, note_start, note_size); +} + /* Parse build ID from 32-bit ELF */ static int get_build_id_32(void *page_addr, unsigned char *build_id, __u32 *size)
@@ -148,3 +159,16 @@ out: put_page(page); return ret; } + +/** + * build_id_parse_buf - Get build ID from a buffer + * @buf: Elf note section(s) to parse + * @buf_size: Size of @buf in bytes + * @build_id: Build ID parsed from @buf, at least BUILD_ID_SIZE_MAX long + * + * Return: 0 on success, -EINVAL otherwise + */ +int build_id_parse_buf(const void *buf, unsigned char *build_id, u32 buf_size) +{ + return parse_build_id_buf(build_id, NULL, buf, buf_size); +}
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