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authorEric Dumazet <edumazet@google.com>2025-06-20 17:28:44 +0300
committerDavid S. Miller <davem@davemloft.net>2025-06-22 21:31:14 +0300
commitb993ea46b3b601915ceaaf3c802adf11e7d6bac6 (patch)
tree185e77ce5547f20aa42fee8c5fbeb76536c93c70
parent302251f1fdfd302ce99a619aac1a5164d0bb7c4b (diff)
downloadlinux-b993ea46b3b601915ceaaf3c802adf11e7d6bac6.tar.xz
atm: clip: prevent NULL deref in clip_push()
Blamed commit missed that vcc_destroy_socket() calls clip_push() with a NULL skb. If clip_devs is NULL, clip_push() then crashes when reading skb->truesize. Fixes: 93a2014afbac ("atm: fix a UAF in lec_arp_clear_vccs()") Reported-by: syzbot+1316233c4c6803382a8b@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/68556f59.a00a0220.137b3.004e.GAE@google.com/T/#u Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: Gengming Liu <l.dmxcsnsbh@gmail.com> Reviewed-by: Simon Horman <horms@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/atm/clip.c11
1 files changed, 5 insertions, 6 deletions
diff --git a/net/atm/clip.c b/net/atm/clip.c
index 61b5b700817d..b234dc3bcb0d 100644
--- a/net/atm/clip.c
+++ b/net/atm/clip.c
@@ -193,12 +193,6 @@ static void clip_push(struct atm_vcc *vcc, struct sk_buff *skb)
pr_debug("\n");
- if (!clip_devs) {
- atm_return(vcc, skb->truesize);
- kfree_skb(skb);
- return;
- }
-
if (!skb) {
pr_debug("removing VCC %p\n", clip_vcc);
if (clip_vcc->entry)
@@ -208,6 +202,11 @@ static void clip_push(struct atm_vcc *vcc, struct sk_buff *skb)
return;
}
atm_return(vcc, skb->truesize);
+ if (!clip_devs) {
+ kfree_skb(skb);
+ return;
+ }
+
skb->dev = clip_vcc->entry ? clip_vcc->entry->neigh->dev : clip_devs;
/* clip_vcc->entry == NULL if we don't have an IP address yet */
if (!skb->dev) {