* [PATCH bpf-next] libbpf: Validate ELF symbol table entry size
@ 2026-09-16 21:23 Luis Vieira
2026-09-16 22:00 ` bot+bpf-ci
0 siblings, 1 reply; 2+ messages in thread
From: Luis Vieira @ 2026-09-16 21:23 UTC (permalink / raw)
To: Andrii Nakryiko, Eduard Zingerman, Ihor Solodrai,
Alexei Starovoitov, Daniel Borkmann, Kumar Kartikeya Dwivedi,
Martin KaFai Lau, Song Liu, Yonghong Song, Jiri Olsa,
Emil Tsalapatis
Cc: bpf, linux-kernel, Luis Vieira
elf_sym_iter_new() calculates the number of symbols by dividing the
symbol table data size by sh_entsize. A malformed ELF file with a zero
sh_entsize causes a division by zero.
Reject symbol table sections with a zero entry size before calculating
the number of symbols.
Signed-off-by: Luis Vieira <luisflavieira@gmail.com>
---
tools/lib/bpf/elf.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/tools/lib/bpf/elf.c b/tools/lib/bpf/elf.c
index fe136d025967..ba0b3df37a59 100644
--- a/tools/lib/bpf/elf.c
+++ b/tools/lib/bpf/elf.c
@@ -118,6 +118,11 @@ static int elf_sym_iter_new(struct elf_sym_iter *iter,
if (!gelf_getshdr(scn, &sh))
return -EINVAL;
+ if (!sh.sh_entsize) {
+ pr_warn("elf: symbol table section has zero entry size in '%s'\n", binary_path);
+ return -EINVAL;
+ }
+
iter->strtabidx = sh.sh_link;
iter->syms = elf_getdata(scn, 0);
if (!iter->syms) {
---
base-commit: 10c4f610b215bf961235141161992f010cf7e451
change-id: 20260916-libbpf-elf-entsize-fix-a0f9440e79c7
Best regards,
--
Luis Vieira <luisflavieira@gmail.com>
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH bpf-next] libbpf: Validate ELF symbol table entry size
2026-09-16 21:23 [PATCH bpf-next] libbpf: Validate ELF symbol table entry size Luis Vieira
@ 2026-09-16 22:00 ` bot+bpf-ci
0 siblings, 0 replies; 2+ messages in thread
From: bot+bpf-ci @ 2026-09-16 22:00 UTC (permalink / raw)
To: luisflavieira, andrii, eddyz87, ihor.solodrai, ast, daniel,
memxor, martin.lau, song, yonghong.song, jolsa, emil
Cc: bpf, linux-kernel, luisflavieira, ast, andrii, daniel,
martin.lau, eddyz87, yonghong.song, mason, ihor.solodrai
[-- Attachment #1: Type: text/plain, Size: 794 bytes --]
> libbpf: Validate ELF symbol table entry size
>
> elf_sym_iter_new() calculates the number of symbols by dividing the
> symbol table data size by sh_entsize. A malformed ELF file with a zero
> sh_entsize causes a division by zero.
>
> Reject symbol table sections with a zero entry size before calculating
> the number of symbols.
>
> Signed-off-by: Luis Vieira <luisflavieira@gmail.com>
This looks like a bug fix for the elf symbol iterator. Should this include:
Fixes: 3774705db171 ("libbpf: Add elf symbol iterator")
---
AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md
CI run summary: https://github.com/kernel-patches/bpf/actions/runs/35154126900
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2026-09-16 22:00 ` bot+bpf-ci
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