mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-25 02:09:42 +00:00
![Stephen Boyd](/assets/img/avatar_default.png)
We can use the vmlinux_build_id array here now instead of open coding it. This mostly consolidates code. Link: https://lkml.kernel.org/r/20210511003845.2429846-14-swboyd@chromium.org Signed-off-by: Stephen Boyd <swboyd@chromium.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Jessica Yu <jeyu@kernel.org> Cc: Evan Green <evgreen@chromium.org> Cc: Hsin-Yi Wang <hsinyi@chromium.org> Cc: Dave Young <dyoung@redhat.com> Cc: Baoquan He <bhe@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> 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 <sergey.senozhatsky@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
191 lines
5 KiB
C
191 lines
5 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
|
|
#include <linux/buildid.h>
|
|
#include <linux/cache.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 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;
|
|
|
|
while (note_offs + sizeof(Elf32_Nhdr) < note_size) {
|
|
Elf32_Nhdr *nhdr = (Elf32_Nhdr *)(note_start + note_offs);
|
|
|
|
if (nhdr->n_type == BUILD_ID &&
|
|
nhdr->n_namesz == sizeof("GNU") &&
|
|
!strcmp((char *)(nhdr + 1), "GNU") &&
|
|
nhdr->n_descsz > 0 &&
|
|
nhdr->n_descsz <= BUILD_ID_SIZE_MAX) {
|
|
memcpy(build_id,
|
|
note_start + note_offs +
|
|
ALIGN(sizeof("GNU"), 4) + sizeof(Elf32_Nhdr),
|
|
nhdr->n_descsz);
|
|
memset(build_id + nhdr->n_descsz, 0,
|
|
BUILD_ID_SIZE_MAX - nhdr->n_descsz);
|
|
if (size)
|
|
*size = nhdr->n_descsz;
|
|
return 0;
|
|
}
|
|
new_offs = note_offs + sizeof(Elf32_Nhdr) +
|
|
ALIGN(nhdr->n_namesz, 4) + ALIGN(nhdr->n_descsz, 4);
|
|
if (new_offs <= note_offs) /* overflow */
|
|
break;
|
|
note_offs = new_offs;
|
|
}
|
|
|
|
return -EINVAL;
|
|
}
|
|
|
|
static inline int parse_build_id(const void *page_addr,
|
|
unsigned char *build_id,
|
|
__u32 *size,
|
|
const 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(const void *page_addr, unsigned char *build_id,
|
|
__u32 *size)
|
|
{
|
|
Elf32_Ehdr *ehdr = (Elf32_Ehdr *)page_addr;
|
|
Elf32_Phdr *phdr;
|
|
int i;
|
|
|
|
/* only supports phdr that fits in one page */
|
|
if (ehdr->e_phnum >
|
|
(PAGE_SIZE - sizeof(Elf32_Ehdr)) / sizeof(Elf32_Phdr))
|
|
return -EINVAL;
|
|
|
|
phdr = (Elf32_Phdr *)(page_addr + sizeof(Elf32_Ehdr));
|
|
|
|
for (i = 0; i < ehdr->e_phnum; ++i) {
|
|
if (phdr[i].p_type == PT_NOTE &&
|
|
!parse_build_id(page_addr, build_id, size,
|
|
page_addr + phdr[i].p_offset,
|
|
phdr[i].p_filesz))
|
|
return 0;
|
|
}
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Parse build ID from 64-bit ELF */
|
|
static int get_build_id_64(const void *page_addr, unsigned char *build_id,
|
|
__u32 *size)
|
|
{
|
|
Elf64_Ehdr *ehdr = (Elf64_Ehdr *)page_addr;
|
|
Elf64_Phdr *phdr;
|
|
int i;
|
|
|
|
/* only supports phdr that fits in one page */
|
|
if (ehdr->e_phnum >
|
|
(PAGE_SIZE - sizeof(Elf64_Ehdr)) / sizeof(Elf64_Phdr))
|
|
return -EINVAL;
|
|
|
|
phdr = (Elf64_Phdr *)(page_addr + sizeof(Elf64_Ehdr));
|
|
|
|
for (i = 0; i < ehdr->e_phnum; ++i) {
|
|
if (phdr[i].p_type == PT_NOTE &&
|
|
!parse_build_id(page_addr, build_id, size,
|
|
page_addr + phdr[i].p_offset,
|
|
phdr[i].p_filesz))
|
|
return 0;
|
|
}
|
|
return -EINVAL;
|
|
}
|
|
|
|
/*
|
|
* Parse build ID of ELF file mapped to vma
|
|
* @vma: vma object
|
|
* @build_id: buffer to store build id, at least BUILD_ID_SIZE long
|
|
* @size: returns actual build id size in case of success
|
|
*
|
|
* Return: 0 on success, -EINVAL otherwise
|
|
*/
|
|
int build_id_parse(struct vm_area_struct *vma, unsigned char *build_id,
|
|
__u32 *size)
|
|
{
|
|
Elf32_Ehdr *ehdr;
|
|
struct page *page;
|
|
void *page_addr;
|
|
int ret;
|
|
|
|
/* only works for page backed storage */
|
|
if (!vma->vm_file)
|
|
return -EINVAL;
|
|
|
|
page = find_get_page(vma->vm_file->f_mapping, 0);
|
|
if (!page)
|
|
return -EFAULT; /* page not mapped */
|
|
|
|
ret = -EINVAL;
|
|
page_addr = kmap_atomic(page);
|
|
ehdr = (Elf32_Ehdr *)page_addr;
|
|
|
|
/* compare magic x7f "ELF" */
|
|
if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) != 0)
|
|
goto out;
|
|
|
|
/* only support executable file and shared object file */
|
|
if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN)
|
|
goto out;
|
|
|
|
if (ehdr->e_ident[EI_CLASS] == ELFCLASS32)
|
|
ret = get_build_id_32(page_addr, build_id, size);
|
|
else if (ehdr->e_ident[EI_CLASS] == ELFCLASS64)
|
|
ret = get_build_id_64(page_addr, build_id, size);
|
|
out:
|
|
kunmap_atomic(page_addr);
|
|
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);
|
|
}
|
|
|
|
#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID) || IS_ENABLED(CONFIG_CRASH_CORE)
|
|
unsigned char vmlinux_build_id[BUILD_ID_SIZE_MAX] __ro_after_init;
|
|
|
|
/**
|
|
* init_vmlinux_build_id - Compute and stash the running kernel's build ID
|
|
*/
|
|
void __init init_vmlinux_build_id(void)
|
|
{
|
|
extern const void __start_notes __weak;
|
|
extern const void __stop_notes __weak;
|
|
unsigned int size = &__stop_notes - &__start_notes;
|
|
|
|
build_id_parse_buf(&__start_notes, vmlinux_build_id, size);
|
|
}
|
|
#endif
|