[PATCH v2 1/2] Revert "smb: client: Fix netns refcount imbalance causing leaks and use-after-free"

[Kuniyuki Iwashima <kuniyu@amazon.com>]

This reverts commit 4e7f1644f2ac6d01dc584f6301c3b1d5aac4eaef.

The commit e9f2517a3e18 ("smb: client: fix TCP timers deadlock after
rmmod") is not only a bogus fix for LOCKDEP null-ptr-deref but also
introduces a real issue, TCP sockets leak, which will be explained in
detail in the next revert.

Also, CNA assigned CVE-2024-54680 to it but is rejecting it. [0]

Thus, we are reverting the commit and its follow-up commit 4e7f1644f2ac
("smb: client: Fix netns refcount imbalance causing leaks and
use-after-free").

Link: https://lore.kernel.org/all/2025040248-tummy-smilingly-4240@gregkh/ #[0]
Fixes: 4e7f1644f2ac ("smb: client: Fix netns refcount imbalance causing leaks and use-after-free")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Cc: stable@vger.kernel.org
---
 fs/smb/client/connect.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c
index 10a7c28d2d44..137a611c5ab0 100644
--- a/fs/smb/client/connect.c
+++ b/fs/smb/client/connect.c
@@ -300,7 +300,6 @@ cifs_abort_connection(struct TCP_Server_Info *server)
 			 server->ssocket->flags);
 		sock_release(server->ssocket);
 		server->ssocket = NULL;
-		put_net(cifs_net_ns(server));
 	}
 	server->sequence_number = 0;
 	server->session_estab = false;
@@ -3367,12 +3366,8 @@ generic_ip_connect(struct TCP_Server_Info *server)
 		/*
 		 * Grab netns reference for the socket.
 		 *
-		 * This reference will be released in several situations:
-		 * - In the failure path before the cifsd thread is started.
-		 * - In the all place where server->socket is released, it is
-		 *   also set to NULL.
-		 * - Ultimately in clean_demultiplex_info(), during the final
-		 *   teardown.
+		 * It'll be released here, on error, or in clean_demultiplex_info() upon server
+		 * teardown.
 		 */
 		get_net(net);
 
@@ -3388,8 +3383,10 @@ generic_ip_connect(struct TCP_Server_Info *server)
 	}
 
 	rc = bind_socket(server);
-	if (rc < 0)
+	if (rc < 0) {
+		put_net(cifs_net_ns(server));
 		return rc;
+	}
 
 	/*
 	 * Eventually check for other socket options to change from
@@ -3444,6 +3441,9 @@ generic_ip_connect(struct TCP_Server_Info *server)
 	    (server->rfc1001_sessinit == -1 && sport == htons(RFC1001_PORT)))
 		rc = ip_rfc1001_connect(server);
 
+	if (rc < 0)
+		put_net(cifs_net_ns(server));
+
 	return rc;
 }
 
-- 
2.48.1