Commit c825f5fe authored Oct 22, 2021 by Andrii Nakryiko Committed by Alexei Starovoitov Oct 22, 2021

libbpf: Fix BTF header parsing checks



Original code assumed fixed and correct BTF header length. That's not
always the case, though, so fix this bug with a proper additional check.
And use actual header length instead of sizeof(struct btf_header) in
sanity checks.

Fixes: 8a138aed ("bpf: btf: Add BTF support to libbpf")
Reported-by: Evgeny Vereshchagin <evvers@ya.ru>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211023003157.726961-2-andrii@kernel.org

parent 5245dafe

tools/lib/bpf/btf.c

+9 −3

Original line number	Diff line number	Diff line
		@@ -240,7 +240,13 @@ static int btf_parse_hdr(struct btf *btf)
		return -EINVAL;
		}

		meta_left = btf->raw_size - sizeof(*hdr);
		if (btf->raw_size < hdr->hdr_len) {
		pr_debug("BTF header len %u larger than data size %u\n",
		hdr->hdr_len, btf->raw_size);
		return -EINVAL;
		}

		meta_left = btf->raw_size - hdr->hdr_len;
		if (meta_left < (long long)hdr->str_off + hdr->str_len) {
		pr_debug("Invalid BTF total size: %u\n", btf->raw_size);
		return -EINVAL;