From 86cdadd9646ce34993cf06d54d491a86183324ab Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E5=88=98=E7=BA=AF?= Date: Tue, 24 Dec 2024 21:16:24 -0800 Subject: [PATCH] ipv6: fix possible UAF in ip6_finish_output2() [CVE-2024-44986] MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [修复]提交信息描述如下 [ Upstream commit e891b36de161fcd96f12ff83667473e5067b9037 ] If skb_expand_head() returns NULL, skb has been freed and associated dst/idev could also have been freed. We need to hold rcu_read_lock() to make sure the dst and associated idev are alive. Fixes: 5796015fa968 ("ipv6: allocate enough headroom in ip6_finish_output2()") Change-Id: I0acc882bf4d446c512740f6c4e28c476024f4731 Signed-off-by: Eric Dumazet Cc: Vasily Averin Reviewed-by: David Ahern Link: https://patch.msgid.link/20240820160859.3786976-3-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin (cherry picked from commit e891b36de161fcd96f12ff83667473e5067b9037) Signed-off-by: Harshvardhan Jha Signed-off-by: Sasha Levin --- net/ipv6/ip6_output.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index dbe220029..5f1a71b1a 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -69,11 +69,15 @@ static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff * /* Be paranoid, rather than too clever. */ if (unlikely(hh_len > skb_headroom(skb)) && dev->header_ops) { + /* Make sure idev stays alive */ + rcu_read_lock(); skb = skb_expand_head(skb, hh_len); if (!skb) { IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS); + rcu_read_unlock(); return -ENOMEM; } + rcu_read_unlock(); } hdr = ipv6_hdr(skb); -- Gitee