diff options
| author | Eric Dumazet <edumazet@google.com> | 2026-05-05 15:39:27 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-05-06 18:11:33 -0700 |
| commit | c8f7244c8cccaaed4e6c9fe4b8a07e101d0423e5 (patch) | |
| tree | 410de56141b25893ef9a03f0c23982d512c9eabd | |
| parent | 770b136ff9bf3e319d19875da59c4f7f4853da3a (diff) | |
tcp: tcp_child_process() related UAF
tcp_child_process( .. child ...) currently calls sock_put(child).
Unfortunately @child (named @nsk in callers) can be used after
this point to send a RST packet.
To fix this UAF, I remove the sock_put() from tcp_child_process()
and let the callers handle this after it is safe.
Remove @rsk variable in tcp_v4_do_rcv() and change tcp_v6_do_rcv()
so that both functions look the same.
Fixes: cfb6eeb4c860 ("[TCP]: MD5 Signature Option (RFC2385) support.")
Reported-by: Damiano Melotti <melotti@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260505153927.3435532-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 14 | ||||
| -rw-r--r-- | net/ipv4/tcp_minisocks.c | 2 | ||||
| -rw-r--r-- | net/ipv6/tcp_ipv6.c | 13 |
3 files changed, 15 insertions, 14 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 8fc24c3743c5..c0526cc03980 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1827,7 +1827,6 @@ INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *, int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb) { enum skb_drop_reason reason; - struct sock *rsk; reason = psp_sk_rx_policy_check(sk, skb); if (reason) @@ -1863,24 +1862,21 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb) return 0; if (nsk != sk) { reason = tcp_child_process(sk, nsk, skb); - if (reason) { - rsk = nsk; + sock_put(nsk); + if (reason) goto reset; - } return 0; } } else sock_rps_save_rxhash(sk, skb); reason = tcp_rcv_state_process(sk, skb); - if (reason) { - rsk = sk; + if (reason) goto reset; - } return 0; reset: - tcp_v4_send_reset(rsk, skb, sk_rst_convert_drop_reason(reason)); + tcp_v4_send_reset(sk, skb, sk_rst_convert_drop_reason(reason)); discard: sk_skb_reason_drop(sk, skb, reason); /* Be careful here. If this function gets more complicated and @@ -2193,8 +2189,10 @@ lookup: rst_reason = sk_rst_convert_drop_reason(drop_reason); tcp_v4_send_reset(nsk, skb, rst_reason); + sock_put(nsk); goto discard_and_relse; } + sock_put(nsk); sock_put(sk); return 0; } diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index 199f0b579e89..e6092c3ac840 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -1012,6 +1012,6 @@ enum skb_drop_reason tcp_child_process(struct sock *parent, struct sock *child, } bh_unlock_sock(child); - sock_put(child); + return reason; } diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 2c3f7a739709..51583aef0643 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1617,12 +1617,13 @@ int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb) if (sk->sk_state == TCP_LISTEN) { struct sock *nsk = tcp_v6_cookie_check(sk, skb); + if (!nsk) + return 0; if (nsk != sk) { - if (nsk) { - reason = tcp_child_process(sk, nsk, skb); - if (reason) - goto reset; - } + reason = tcp_child_process(sk, nsk, skb); + sock_put(nsk); + if (reason) + goto reset; return 0; } } else @@ -1827,8 +1828,10 @@ lookup: rst_reason = sk_rst_convert_drop_reason(drop_reason); tcp_v6_send_reset(nsk, skb, rst_reason); + sock_put(nsk); goto discard_and_relse; } + sock_put(nsk); sock_put(sk); return 0; } |