From: Andrii Nakryiko andrii@kernel.org
[ 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 --- tools/lib/bpf/btf.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 99d28f04b59d4..3e3ecac43ea9b 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -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;