* [PATCH bpf-next] libbpf: fix off-by-one error in ELF sanity check
@ 2019-10-28 23:37 Andrii Nakryiko
2019-10-29 3:29 ` Alexei Starovoitov
0 siblings, 1 reply; 2+ messages in thread
From: Andrii Nakryiko @ 2019-10-28 23:37 UTC (permalink / raw)
To: bpf, netdev, ast, daniel; +Cc: andrii.nakryiko, kernel-team, Andrii Nakryiko
libbpf's bpf_object__elf_collect() does simple sanity check after iterating
over all ELF sections, if checks that .strtab index is correct. Unfortunately,
due to section indices being 1-based, the check breaks for cases when .strtab
ends up being the very last section in ELF.
Fixes: 77ba9a5b48a7 ("tools lib bpf: Fetch map names from correct strtab")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
---
tools/lib/bpf/libbpf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index d71631a01926..5d15cc4dfcd6 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1664,7 +1664,7 @@ static int bpf_object__elf_collect(struct bpf_object *obj, bool relaxed_maps)
}
}
- if (!obj->efile.strtabidx || obj->efile.strtabidx >= idx) {
+ if (!obj->efile.strtabidx || obj->efile.strtabidx > idx) {
pr_warn("Corrupted ELF file: index of strtab invalid\n");
return -LIBBPF_ERRNO__FORMAT;
}
--
2.17.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH bpf-next] libbpf: fix off-by-one error in ELF sanity check
2019-10-28 23:37 [PATCH bpf-next] libbpf: fix off-by-one error in ELF sanity check Andrii Nakryiko
@ 2019-10-29 3:29 ` Alexei Starovoitov
0 siblings, 0 replies; 2+ messages in thread
From: Alexei Starovoitov @ 2019-10-29 3:29 UTC (permalink / raw)
To: Andrii Nakryiko, bpf, netdev, daniel; +Cc: andrii.nakryiko, Kernel Team
On 10/28/19 4:37 PM, Andrii Nakryiko wrote:
> libbpf's bpf_object__elf_collect() does simple sanity check after iterating
> over all ELF sections, if checks that .strtab index is correct. Unfortunately,
> due to section indices being 1-based, the check breaks for cases when .strtab
> ends up being the very last section in ELF.
>
> Fixes: 77ba9a5b48a7 ("tools lib bpf: Fetch map names from correct strtab")
> Signed-off-by: Andrii Nakryiko <andriin@fb.com>
4 year old bug. Nice!
Applied. Thanks.
^ permalink raw reply [flat|nested] 2+ messages in thread
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