From: Eric Dumazet <edumazet@google.com> stable inclusion from stable-v6.6.96 commit 3c709dce16999bf6a1d2ce377deb5dd6fdd8cb08 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/ICL7Y8 CVE: CVE-2025-38251 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit b993ea46b3b601915ceaaf3c802adf11e7d6bac6 ] 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... 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> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com> --- net/atm/clip.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/net/atm/clip.c b/net/atm/clip.c index 294cb9efe3d3..511467bb7fe4 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) { -- 2.34.1