6.12-stable review patch. If anyone has any objections, please let me know.
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From: Christoph Paasch cpaasch@openai.com
[ Upstream commit fa390321aba0a54d0f7ae95ee4ecde1358bb9234 ]
When tcp_ao_copy_all_matching() fails in tcp_v6_syn_recv_sock() it just exits the function. This ends up causing a memory-leak:
unreferenced object 0xffff0000281a8200 (size 2496): comm "softirq", pid 0, jiffies 4295174684 hex dump (first 32 bytes): 7f 00 00 06 7f 00 00 06 00 00 00 00 cb a8 88 13 ................ 0a 00 03 61 00 00 00 00 00 00 00 00 00 00 00 00 ...a............ backtrace (crc 5ebdbe15): kmemleak_alloc+0x44/0xe0 kmem_cache_alloc_noprof+0x248/0x470 sk_prot_alloc+0x48/0x120 sk_clone_lock+0x38/0x3b0 inet_csk_clone_lock+0x34/0x150 tcp_create_openreq_child+0x3c/0x4a8 tcp_v6_syn_recv_sock+0x1c0/0x620 tcp_check_req+0x588/0x790 tcp_v6_rcv+0x5d0/0xc18 ip6_protocol_deliver_rcu+0x2d8/0x4c0 ip6_input_finish+0x74/0x148 ip6_input+0x50/0x118 ip6_sublist_rcv+0x2fc/0x3b0 ipv6_list_rcv+0x114/0x170 __netif_receive_skb_list_core+0x16c/0x200 netif_receive_skb_list_internal+0x1f0/0x2d0
This is because in tcp_v6_syn_recv_sock (and the IPv4 counterpart), when exiting upon error, inet_csk_prepare_forced_close() and tcp_done() need to be called. They make sure the newsk will end up being correctly free'd.
tcp_v4_syn_recv_sock() makes this very clear by having the put_and_exit label that takes care of things. So, this patch here makes sure tcp_v4_syn_recv_sock and tcp_v6_syn_recv_sock have similar error-handling and thus fixes the leak for TCP-AO.
Fixes: 06b22ef29591 ("net/tcp: Wire TCP-AO to request sockets") Signed-off-by: Christoph Paasch cpaasch@openai.com Reviewed-by: Dmitry Safonov 0x7f454c46@gmail.com Link: https://patch.msgid.link/20250830-tcpao_leak-v1-1-e5878c2c3173@openai.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/ipv6/tcp_ipv6.c | 32 +++++++++++++++----------------- 1 file changed, 15 insertions(+), 17 deletions(-)
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 59173f58ce992..882ce5444572e 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1417,17 +1417,17 @@ static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff * ireq = inet_rsk(req);
if (sk_acceptq_is_full(sk)) - goto out_overflow; + goto exit_overflow;
if (!dst) { dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_TCP); if (!dst) - goto out; + goto exit; }
newsk = tcp_create_openreq_child(sk, req, skb); if (!newsk) - goto out_nonewsk; + goto exit_nonewsk;
/* * No need to charge this sock to the relevant IPv6 refcnt debug socks @@ -1517,25 +1517,19 @@ static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff * const union tcp_md5_addr *addr;
addr = (union tcp_md5_addr *)&newsk->sk_v6_daddr; - if (tcp_md5_key_copy(newsk, addr, AF_INET6, 128, l3index, key)) { - inet_csk_prepare_forced_close(newsk); - tcp_done(newsk); - goto out; - } + if (tcp_md5_key_copy(newsk, addr, AF_INET6, 128, l3index, key)) + goto put_and_exit; } } #endif #ifdef CONFIG_TCP_AO /* Copy over tcp_ao_info if any */ if (tcp_ao_copy_all_matching(sk, newsk, req, skb, AF_INET6)) - goto out; /* OOM */ + goto put_and_exit; /* OOM */ #endif
- if (__inet_inherit_port(sk, newsk) < 0) { - inet_csk_prepare_forced_close(newsk); - tcp_done(newsk); - goto out; - } + if (__inet_inherit_port(sk, newsk) < 0) + goto put_and_exit; *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash), &found_dup_sk); if (*own_req) { @@ -1562,13 +1556,17 @@ static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *
return newsk;
-out_overflow: +exit_overflow: __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); -out_nonewsk: +exit_nonewsk: dst_release(dst); -out: +exit: tcp_listendrop(sk); return NULL; +put_and_exit: + inet_csk_prepare_forced_close(newsk); + tcp_done(newsk); + goto exit; }
INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *,