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| author | HanQuan <eilaimemedsnaimel@gmail.com> | 2026-06-23 01:52:08 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-07-04 13:45:09 +0200 |
| commit | 7ddc29a094d96e9b3aa280433c6dc443df9eabf2 (patch) | |
| tree | 72d5f73c435ff820e8d6fce00d3f50a66143acdd | |
| parent | e36e35660adb9b8ef1435ac359151dda5f094c55 (diff) | |
| download | linux-7ddc29a094d96e9b3aa280433c6dc443df9eabf2.tar.gz linux-7ddc29a094d96e9b3aa280433c6dc443df9eabf2.zip | |
net/tcp-ao: fix use-after-free of key in del_async path
commit 5ba9950bc9078e19b69cca1e56d1553b125c6857 upstream.
In tcp_ao_delete_key(), the del_async path skips the current_key
and rnext_key validity checks present in the synchronous path,
assuming these pointers are always NULL on LISTEN sockets. However,
if a key was added with set_current=1/set_rnext=1 while the socket
was in CLOSE state, current_key and rnext_key will be non-NULL
after listen() transitions the socket to LISTEN.
When such a key is deleted with del_async=1, hlist_del_rcu() and
call_rcu() free the key without clearing the dangling pointers.
After the RCU grace period, getsockopt(TCP_AO_INFO) dereferences
current_key->sndid and rnext_key->rcvid from freed slab memory.
Clear current_key and rnext_key in the del_async path when they
reference the key being deleted.
Fixes: d6732b95b6fb ("net/tcp: Allow asynchronous delete for TCP-AO keys (MKTs)")
Signed-off-by: HanQuan <eilaimemedsnaimel@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260623015208.1191687-1-eilaimemedsnaimel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/ipv4/tcp_ao.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c index 0a4b38b315fe..36984e905070 100644 --- a/net/ipv4/tcp_ao.c +++ b/net/ipv4/tcp_ao.c @@ -1776,6 +1776,10 @@ static int tcp_ao_delete_key(struct sock *sk, struct tcp_ao_info *ao_info, * them and we can just free all resources in RCU fashion. */ if (del_async) { + if (ao_info->current_key == key) + WRITE_ONCE(ao_info->current_key, NULL); + if (ao_info->rnext_key == key) + WRITE_ONCE(ao_info->rnext_key, NULL); atomic_sub(tcp_ao_sizeof_key(key), &sk->sk_omem_alloc); call_rcu(&key->rcu, tcp_ao_key_free_rcu); return 0; |