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libbpf: Fix overflow in BTF sanity checks

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[ Upstream commit 5245dafe3d49efba4d3285cf27ee1cc1eeafafc6 ]

btf_header's str_off+str_len or type_off+type_len can overflow as they
are u32s. This will lead to bypassing the sanity checks during BTF
parsing, resulting in crashes afterwards. Fix by using 64-bit signed
integers for comparison.

Fixes: d8123624506c ("libbpf: Fix BTF data layout checks and allow empty BTF")
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/20211023003157.726961-1-andrii@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Andrii Nakryiko 2021-10-22 17:31:56 -07:00 committed by Greg Kroah-Hartman
parent e6c63efb0c
commit ffb5d239e7
1 changed files with 2 additions and 2 deletions
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4
tools/lib/bpf/btf.c
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@ -236,12 +236,12 @@ static int btf_parse_hdr(struct btf *btf)
}
meta_left = btf->raw_size - sizeof(*hdr);
if (meta_left < hdr->str_off + hdr->str_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;
}
if (hdr->type_off + hdr->type_len > hdr->str_off) {
if ((long long)hdr->type_off + hdr->type_len > hdr->str_off) {
pr_debug("Invalid BTF data sections layout: type data at %u + %u, strings data at %u + %u\n",
hdr->type_off, hdr->type_len, hdr->str_off, hdr->str_len);
return -EINVAL;