Re: [lvc-project] [PATCH] netfilter: nfnetlink: NULL-check skb->dev in __build_packet_message()
From: Igor A. Artemiev
Date: Mon Mar 27 2023 - 11:06:27 EST
On 3/27/23 13:22, Pablo Neira Ayuso wrote:
On Mon, Mar 27, 2023 at 12:41:16PM +0300, Igor Artemiev wrote:
After having been compared to NULL value at nfnetlink_log.c:560,
pointer 'skb->dev' is dereferenced at nfnetlink_log.c:576.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Signed-off-by: Igor Artemiev <Igor.A.Artemiev@xxxxxxx>
---
net/netfilter/nfnetlink_log.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
index d97eb280cb2e..2711509eb9a5 100644
--- a/net/netfilter/nfnetlink_log.c
+++ b/net/netfilter/nfnetlink_log.c
@@ -572,7 +572,7 @@ __build_packet_message(struct nfnl_log_net *log,
}
}
- if (indev && skb_mac_header_was_set(skb)) {
+ if (indev && skb->dev && skb_mac_header_was_set(skb)) {
This cannot ever happen, we assume skb->dev is always set on.
if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) ||
nla_put_be16(inst->skb, NFULA_HWLEN,
htons(skb->dev->hard_header_len)))
--
2.30.2
If skb->dev is always set on, should the check at nfnetlink_log.c:560 be removed?
|
if (indev && skb->dev &&
skb_mac_header_was_set(skb) &&
skb_mac_header_len(skb) != 0) { |
||Thanks, Igor