Patch "net: Return error from sk_stream_wait_connect() if sk_wait_event() fails" has been added to the 6.1-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    net: Return error from sk_stream_wait_connect() if sk_wait_event() fails

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     net-return-error-from-sk_stream_wait_connect-if-sk_w.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit c949678dfd745d62e2a9442d6b05a4549b8b50e1
Author: Shigeru Yoshida <syoshida@xxxxxxxxxx>
Date:   Thu Dec 14 14:09:22 2023 +0900

    net: Return error from sk_stream_wait_connect() if sk_wait_event() fails
    
    [ Upstream commit cac23b7d7627915d967ce25436d7aae26e88ed06 ]
    
    The following NULL pointer dereference issue occurred:
    
    BUG: kernel NULL pointer dereference, address: 0000000000000000
    <...>
    RIP: 0010:ccid_hc_tx_send_packet net/dccp/ccid.h:166 [inline]
    RIP: 0010:dccp_write_xmit+0x49/0x140 net/dccp/output.c:356
    <...>
    Call Trace:
     <TASK>
     dccp_sendmsg+0x642/0x7e0 net/dccp/proto.c:801
     inet_sendmsg+0x63/0x90 net/ipv4/af_inet.c:846
     sock_sendmsg_nosec net/socket.c:730 [inline]
     __sock_sendmsg+0x83/0xe0 net/socket.c:745
     ____sys_sendmsg+0x443/0x510 net/socket.c:2558
     ___sys_sendmsg+0xe5/0x150 net/socket.c:2612
     __sys_sendmsg+0xa6/0x120 net/socket.c:2641
     __do_sys_sendmsg net/socket.c:2650 [inline]
     __se_sys_sendmsg net/socket.c:2648 [inline]
     __x64_sys_sendmsg+0x45/0x50 net/socket.c:2648
     do_syscall_x64 arch/x86/entry/common.c:51 [inline]
     do_syscall_64+0x43/0x110 arch/x86/entry/common.c:82
     entry_SYSCALL_64_after_hwframe+0x63/0x6b
    
    sk_wait_event() returns an error (-EPIPE) if disconnect() is called on the
    socket waiting for the event. However, sk_stream_wait_connect() returns
    success, i.e. zero, even if sk_wait_event() returns -EPIPE, so a function
    that waits for a connection with sk_stream_wait_connect() may misbehave.
    
    In the case of the above DCCP issue, dccp_sendmsg() is waiting for the
    connection. If disconnect() is called in concurrently, the above issue
    occurs.
    
    This patch fixes the issue by returning error from sk_stream_wait_connect()
    if sk_wait_event() fails.
    
    Fixes: 419ce133ab92 ("tcp: allow again tcp_disconnect() when threads are waiting")
    Signed-off-by: Shigeru Yoshida <syoshida@xxxxxxxxxx>
    Reviewed-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
    Reported-by: syzbot+c71bc336c5061153b502@xxxxxxxxxxxxxxxxxxxxxxxxx
    Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx>
    Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
    Reported-by: syzkaller <syzkaller@xxxxxxxxxxxxxxxx>
    Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/core/stream.c b/net/core/stream.c
index 051aa71a8ad0f..30e7deff4c551 100644
--- a/net/core/stream.c
+++ b/net/core/stream.c
@@ -79,7 +79,7 @@ int sk_stream_wait_connect(struct sock *sk, long *timeo_p)
 		remove_wait_queue(sk_sleep(sk), &wait);
 		sk->sk_write_pending--;
 	} while (!done);
-	return 0;
+	return done < 0 ? done : 0;
 }
 EXPORT_SYMBOL(sk_stream_wait_connect);