diff options
| author | Eric Dumazet <edumazet@google.com> | 2024-08-20 16:08:58 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2024-08-21 17:35:49 -0700 |
| commit | da273b377ae0d9bd255281ed3c2adb228321687b (patch) | |
| tree | 93eb1d8a41e18154d4ca37d010815fe762e98fe0 | |
| parent | faa389b2fbaaec7fd27a390b4896139f9da662e3 (diff) | |
ipv6: fix possible UAF in ip6_finish_output2()
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()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Vasily Averin <vasily.averin@linux.dev>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20240820160859.3786976-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/ipv6/ip6_output.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index f7b53effc80f..1b9ebee7308f 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -70,11 +70,15 @@ 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); |