From 7ad8474990ffcb1bed869929fc89086f39dcf056 Mon Sep 17 00:00:00 2001 From: KP Singh Date: Sun, 2 Nov 2025 12:37:42 +0100 Subject: [PATCH] bpf: Check size of the signature buffer Accept only a SHA256 sized buffer. Fixes: 349271568303 ("bpf: Implement signature verification for BPF programs") Reported-by: Chris Mason Signed-off-by: KP Singh --- kernel/bpf/syscall.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 8a129746bd6cc..cc5bce20ec86c 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2826,6 +2826,9 @@ static int bpf_prog_verify_signature(struct bpf_prog *prog, union bpf_attr *attr void *sig; int err = 0; + if (attr->signature_size != SHA256_DIGEST_SIZE) + return -EINVAL; + if (system_keyring_id_check(attr->keyring_id) == 0) key = bpf_lookup_system_key(attr->keyring_id); else