diff options
| author | Fourie Zhang <fouriezhang@tencent.com> | 2026-10-22 10:26:22 +0800 |
|---|---|---|
| committer | Steffen Klassert <steffen.klassert@secunet.com> | 2026-10-27 09:09:36 +0000 |
| commit | 5def91015ba7b59de62a81384572da7281b8a033 (patch) | |
| tree | c7d71331667c512c59ddc59eddc649fb062642c9 | |
| parent | 835912998ca54a76b5c57f8c8459a86b1b45de40 (diff) | |
xfrm4: use a full socket for local errors
xfrm4_local_error() passes skb->sk to inet_sk() and ip_local_error()
without ensuring it points to a full socket. TCP SYN-ACK skbs can be owned
by TCP_NEW_SYN_RECV request sockets.
xfrm4_tunnel_check_size() already checks sk_fullsock() since commit
1620c88887b1 ("xfrm: Fix the usage of skb->sk"), so iptfs_is_too_big() is
the only remaining IPv4 caller passing a request socket here: the sk it
tests is the listener, while skb->sk is the request socket.
When IP-TFS rejects such an skb because it exceeds its payload MTU, the
local error path treats the request socket as a struct inet_sock. KASAN
reports a slab-out-of-bounds read in ip_local_error() beyond the
request_sock_TCP allocation.
Resolve the skb owner with skb_to_full_sk() before accessing inet_sock
state or reporting the error. This maps a request socket to its listener
and rejects sockets that cannot be used as full sockets, matching what
commit 6973a21ee73c ("ipv6: xfrm: use full sockets in local error paths")
did for xfrm6_local_error().
Fixes: 0e4fbf013fa5 ("xfrm: iptfs: add user packet (tunnel ingress) handling")
Cc: stable@vger.kernel.org
Reported-by: TencentOS Corvus AI <corvus@tencent.com>
Link: https://lore.kernel.org/netdev/20260908224856.1591189-1-kuba@kernel.org/
Reviewed-by: Eric Dumazet <edumazet@kernel.org>
Assisted-by: tencentos-corvus-ai:hy4-preview
Signed-off-by: Fourie Zhang <fouriezhang@tencent.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
| -rw-r--r-- | net/ipv4/xfrm4_output.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/net/ipv4/xfrm4_output.c b/net/ipv4/xfrm4_output.c index 0ae67d537499..fffa3c4f456e 100644 --- a/net/ipv4/xfrm4_output.c +++ b/net/ipv4/xfrm4_output.c @@ -38,9 +38,12 @@ int xfrm4_output(struct net *net, struct sock *sk, struct sk_buff *skb) void xfrm4_local_error(struct sk_buff *skb, u32 mtu) { + struct sock *sk = skb_to_full_sk(skb); struct iphdr *hdr; + if (!sk) + return; + hdr = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb); - ip_local_error(skb->sk, EMSGSIZE, hdr->daddr, - inet_sk(skb->sk)->inet_dport, mtu); + ip_local_error(sk, EMSGSIZE, hdr->daddr, inet_sk(sk)->inet_dport, mtu); } |