Patch "net: rose: lock the socket in rose_bind()" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    net: rose: lock the socket in rose_bind()

to the 5.15-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-rose-lock-the-socket-in-rose_bind.patch
and it can be found in the queue-5.15 subdirectory.

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



commit 1ad3b7fb31bb9d898604ffed09dc6d60fb1b8b7e
Author: Eric Dumazet <edumazet@xxxxxxxxxx>
Date:   Mon Feb 3 17:08:38 2025 +0000

    net: rose: lock the socket in rose_bind()
    
    [ Upstream commit a1300691aed9ee852b0a9192e29e2bdc2411a7e6 ]
    
    syzbot reported a soft lockup in rose_loopback_timer(),
    with a repro calling bind() from multiple threads.
    
    rose_bind() must lock the socket to avoid this issue.
    
    Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
    Reported-by: syzbot+7ff41b5215f0c534534e@xxxxxxxxxxxxxxxxxxxxxxxxx
    Closes: https://lore.kernel.org/netdev/67a0f78d.050a0220.d7c5a.00a0.GAE@xxxxxxxxxx/T/#u
    Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
    Acked-by: Paolo Abeni <pabeni@xxxxxxxxxx>
    Link: https://patch.msgid.link/20250203170838.3521361-1-edumazet@xxxxxxxxxx
    Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c
index 65fd5b99f9dea..f8cd085c42345 100644
--- a/net/rose/af_rose.c
+++ b/net/rose/af_rose.c
@@ -700,11 +700,9 @@ static int rose_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 	struct net_device *dev;
 	ax25_address *source;
 	ax25_uid_assoc *user;
+	int err = -EINVAL;
 	int n;
 
-	if (!sock_flag(sk, SOCK_ZAPPED))
-		return -EINVAL;
-
 	if (addr_len != sizeof(struct sockaddr_rose) && addr_len != sizeof(struct full_sockaddr_rose))
 		return -EINVAL;
 
@@ -717,8 +715,15 @@ static int rose_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 	if ((unsigned int) addr->srose_ndigis > ROSE_MAX_DIGIS)
 		return -EINVAL;
 
-	if ((dev = rose_dev_get(&addr->srose_addr)) == NULL)
-		return -EADDRNOTAVAIL;
+	lock_sock(sk);
+
+	if (!sock_flag(sk, SOCK_ZAPPED))
+		goto out_release;
+
+	err = -EADDRNOTAVAIL;
+	dev = rose_dev_get(&addr->srose_addr);
+	if (!dev)
+		goto out_release;
 
 	source = &addr->srose_call;
 
@@ -729,7 +734,8 @@ static int rose_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 	} else {
 		if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE)) {
 			dev_put(dev);
-			return -EACCES;
+			err = -EACCES;
+			goto out_release;
 		}
 		rose->source_call   = *source;
 	}
@@ -751,8 +757,10 @@ static int rose_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 	rose_insert_socket(sk);
 
 	sock_reset_flag(sk, SOCK_ZAPPED);
-
-	return 0;
+	err = 0;
+out_release:
+	release_sock(sk);
+	return err;
 }
 
 static int rose_connect(struct socket *sock, struct sockaddr *uaddr, int addr_len, int flags)