netdev - [PATCH bpf 1/2] bpf: allow empty module BTFs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20210110070341.1380086-1-andrii@kernel.org>
Date:   Sat, 9 Jan 2021 23:03:40 -0800
From:   Andrii Nakryiko <andrii@...nel.org>
To:     <bpf@...r.kernel.org>, <netdev@...r.kernel.org>, <ast@...com>,
        <daniel@...earbox.net>
CC:     <andrii@...nel.org>, <kernel-team@...com>,
        Christopher William Snowhill <chris@...e54.net>
Subject: [PATCH bpf 1/2] bpf: allow empty module BTFs

Some modules don't declare any new types and end up with an empty BTF,
containing only valid BTF header and no types or strings sections. This
currently causes BTF validation error. There is nothing wrong with such BTF,
so fix the issue by allowing module BTFs with no types or strings.

Reported-by: Christopher William Snowhill <chris@...e54.net>
Fixes: 36e68442d1af ("bpf: Load and verify kernel module BTFs")
Signed-off-by: Andrii Nakryiko <andrii@...nel.org>
---
 kernel/bpf/btf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 8d6bdb4f4d61..84a36ee4a4c2 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -4172,7 +4172,7 @@ static int btf_parse_hdr(struct btf_verifier_env *env)
 		return -ENOTSUPP;
 	}
 
-	if (btf_data_size == hdr->hdr_len) {
+	if (!btf->base_btf && btf_data_size == hdr->hdr_len) {
 		btf_verifier_log(env, "No data");
 		return -EINVAL;
 	}
-- 
2.24.1