From: Jakub Kicinski Date: Mon, 18 Dec 2023 23:19:04 +0000 (-0800) Subject: bpf: Use nla_ok() instead of checking nla_len directly X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=2130c519a401e576647040043cb46d6fdc361dcc;p=linux.git bpf: Use nla_ok() instead of checking nla_len directly nla_len may also be too short to be sane, in which case after recent changes nla_len() will return a wrapped value. Fixes: 172db56d90d2 ("netlink: Return unsigned value for nla_len()") Reported-by: syzbot+f43a23b6e622797c7a28@syzkaller.appspotmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Daniel Borkmann Reviewed-by: Simon Horman Link: https://lore.kernel.org/bpf/20231218231904.260440-1-kuba@kernel.org --- diff --git a/net/core/filter.c b/net/core/filter.c index 4ff6100c6a273..3cc52b82bab8a 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -203,7 +203,7 @@ BPF_CALL_3(bpf_skb_get_nlattr_nest, struct sk_buff *, skb, u32, a, u32, x) return 0; nla = (struct nlattr *) &skb->data[a]; - if (nla->nla_len > skb->len - a) + if (!nla_ok(nla, skb->len - a)) return 0; nla = nla_find_nested(nla, x);