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authorFangrui Song <maskray@google.com>2023-05-12 05:25:28 +0300
committerKees Cook <keescook@chromium.org>2023-05-17 00:32:00 +0300
commit60592fb6b67c653beaa2e7acad9a9d7aa0b71dff (patch)
tree27f14ecfcbf21dd70c09f2b27764a0c38a1eacd0
parentf1fcbaa18b28dec10281551dfe6ed3a3ed80e3d6 (diff)
downloadlinux-60592fb6b67c653beaa2e7acad9a9d7aa0b71dff.tar.xz
coredump, vmcore: Set p_align to 4 for PT_NOTE
Tools like readelf/llvm-readelf use p_align to parse a PT_NOTE program header as an array of 4-byte entries or 8-byte entries. Currently, there are workarounds[1] in place for Linux to treat p_align==0 as 4. However, it would be more appropriate to set the correct alignment so that tools do not have to rely on guesswork. FreeBSD coredumps set p_align to 4 as well. [1]: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=82ed9683ec099d8205dc499ac84febc975235af6 [2]: https://reviews.llvm.org/D150022 Signed-off-by: Fangrui Song <maskray@google.com> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20230512022528.3430327-1-maskray@google.com
-rw-r--r--fs/binfmt_elf.c2
-rw-r--r--fs/binfmt_elf_fdpic.c2
-rw-r--r--fs/proc/vmcore.c4
3 files changed, 4 insertions, 4 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 1033fbdfdbec..44b4c42ab8e8 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1517,7 +1517,7 @@ static void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
phdr->p_filesz = sz;
phdr->p_memsz = 0;
phdr->p_flags = 0;
- phdr->p_align = 0;
+ phdr->p_align = 4;
}
static void fill_note(struct memelfnote *note, const char *name, int type,
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 05a1471d5283..d76ad3d4f676 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -1269,7 +1269,7 @@ static inline void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offs
phdr->p_filesz = sz;
phdr->p_memsz = 0;
phdr->p_flags = 0;
- phdr->p_align = 0;
+ phdr->p_align = 4;
return;
}
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index 03f5963914a1..cb80a7703d58 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -877,7 +877,7 @@ static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
phdr.p_offset = roundup(note_off, PAGE_SIZE);
phdr.p_vaddr = phdr.p_paddr = 0;
phdr.p_filesz = phdr.p_memsz = phdr_sz;
- phdr.p_align = 0;
+ phdr.p_align = 4;
/* Add merged PT_NOTE program header*/
tmp = elfptr + sizeof(Elf64_Ehdr);
@@ -1068,7 +1068,7 @@ static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
phdr.p_offset = roundup(note_off, PAGE_SIZE);
phdr.p_vaddr = phdr.p_paddr = 0;
phdr.p_filesz = phdr.p_memsz = phdr_sz;
- phdr.p_align = 0;
+ phdr.p_align = 4;
/* Add merged PT_NOTE program header*/
tmp = elfptr + sizeof(Elf32_Ehdr);