diff options
| author | Eric Dumazet <edumazet@google.com> | 2024-08-20 16:08:59 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2024-08-21 17:35:49 -0700 |
| commit | 2d5ff7e339d04622d8282661df36151906d0e1c7 (patch) | |
| tree | 7c555df7e6e3d2e51519885f279a1e6c41a080fe /net | |
| parent | da273b377ae0d9bd255281ed3c2adb228321687b (diff) | |
| download | lwn-2d5ff7e339d04622d8282661df36151906d0e1c7.tar.gz lwn-2d5ff7e339d04622d8282661df36151906d0e1c7.zip | |
ipv6: prevent possible UAF in ip6_xmit()
If skb_expand_head() returns NULL, skb has been freed
and the associated dst/idev could also have been freed.
We must use rcu_read_lock() to prevent a possible UAF.
Fixes: 0c9f227bee11 ("ipv6: use skb_expand_head in ip6_xmit")
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/20240820160859.3786976-4-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
| -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 1b9ebee7308f..f26841f1490f 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -287,11 +287,15 @@ int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6, head_room += opt->opt_nflen + opt->opt_flen; if (unlikely(head_room > skb_headroom(skb))) { + /* Make sure idev stays alive */ + rcu_read_lock(); skb = skb_expand_head(skb, head_room); if (!skb) { IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS); + rcu_read_unlock(); return -ENOBUFS; } + rcu_read_unlock(); } if (opt) { |