From: Andrii Nakryiko <andrii@kernel.org>
To: <bpf@vger.kernel.org>, <ast@kernel.org>, <daniel@iogearbox.net>
Cc: <andrii@kernel.org>, <kernel-team@fb.com>, Yonghong Song <yhs@fb.com>
Subject: [PATCH v2 bpf-next 1/5] libbpf: detect corrupted ELF symbols section
Date: Wed, 3 Nov 2021 10:32:09 -0700 [thread overview]
Message-ID: <20211103173213.1376990-2-andrii@kernel.org> (raw)
In-Reply-To: <20211103173213.1376990-1-andrii@kernel.org>
Prevent divide-by-zero if ELF is corrupted and has zero sh_entsize.
Reported by oss-fuzz project.
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
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 a1bea1953df6..71f5a009010a 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -3555,7 +3555,7 @@ static int bpf_object__collect_externs(struct bpf_object *obj)
scn = elf_sec_by_idx(obj, obj->efile.symbols_shndx);
sh = elf_sec_hdr(obj, scn);
- if (!sh)
+ if (!sh || sh->sh_entsize != sizeof(Elf64_Sym))
return -LIBBPF_ERRNO__FORMAT;
dummy_var_btf_id = add_dummy_ksym_var(obj->btf);
--
2.30.2
next prev parent reply other threads:[~2021-11-03 17:35 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-03 17:32 [PATCH v2 bpf-next 0/5] libbpf ELF sanity checking improvements Andrii Nakryiko
2021-11-03 17:32 ` Andrii Nakryiko [this message]
2021-11-03 17:32 ` [PATCH v2 bpf-next 2/5] libbpf: improve sanity checking during BTF fix up Andrii Nakryiko
2021-11-03 17:32 ` [PATCH v2 bpf-next 3/5] libbpf: validate that .BTF and .BTF.ext sections contain data Andrii Nakryiko
2021-11-03 17:32 ` [PATCH v2 bpf-next 4/5] libbpf: fix section counting logic Andrii Nakryiko
2021-11-03 17:32 ` [PATCH v2 bpf-next 5/5] libbpf: improve ELF relo sanitization Andrii Nakryiko
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