Patch "sock_diag: annotate data-races around sock_diag_handlers[family]" 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

    sock_diag: annotate data-races around sock_diag_handlers[family]

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:
     sock_diag-annotate-data-races-around-sock_diag_handl.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 902b1287101a653fd4e31b2a5b5391ff93bdba35
Author: Eric Dumazet <edumazet@xxxxxxxxxx>
Date:   Mon Jan 22 11:25:55 2024 +0000

    sock_diag: annotate data-races around sock_diag_handlers[family]
    
    [ Upstream commit efd402537673f9951992aea4ef0f5ff51d858f4b ]
    
    __sock_diag_cmd() and sock_diag_bind() read sock_diag_handlers[family]
    without a lock held.
    
    Use READ_ONCE()/WRITE_ONCE() annotations to avoid potential issues.
    
    Fixes: 8ef874bfc729 ("sock_diag: Move the sock_ code to net/core/")
    Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
    Reviewed-by: Guillaume Nault <gnault@xxxxxxxxxx>
    Reviewed-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
    Reviewed-by: Willem de Bruijn <willemb@xxxxxxxxxx>
    Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/core/sock_diag.c b/net/core/sock_diag.c
index f7cf74cdd3db1..e6ea6764d10ab 100644
--- a/net/core/sock_diag.c
+++ b/net/core/sock_diag.c
@@ -190,7 +190,7 @@ int sock_diag_register(const struct sock_diag_handler *hndl)
 	if (sock_diag_handlers[hndl->family])
 		err = -EBUSY;
 	else
-		sock_diag_handlers[hndl->family] = hndl;
+		WRITE_ONCE(sock_diag_handlers[hndl->family], hndl);
 	mutex_unlock(&sock_diag_table_mutex);
 
 	return err;
@@ -206,7 +206,7 @@ void sock_diag_unregister(const struct sock_diag_handler *hnld)
 
 	mutex_lock(&sock_diag_table_mutex);
 	BUG_ON(sock_diag_handlers[family] != hnld);
-	sock_diag_handlers[family] = NULL;
+	WRITE_ONCE(sock_diag_handlers[family], NULL);
 	mutex_unlock(&sock_diag_table_mutex);
 }
 EXPORT_SYMBOL_GPL(sock_diag_unregister);
@@ -224,7 +224,7 @@ static int __sock_diag_cmd(struct sk_buff *skb, struct nlmsghdr *nlh)
 		return -EINVAL;
 	req->sdiag_family = array_index_nospec(req->sdiag_family, AF_MAX);
 
-	if (sock_diag_handlers[req->sdiag_family] == NULL)
+	if (READ_ONCE(sock_diag_handlers[req->sdiag_family]) == NULL)
 		sock_load_diag_module(req->sdiag_family, 0);
 
 	mutex_lock(&sock_diag_table_mutex);
@@ -283,12 +283,12 @@ static int sock_diag_bind(struct net *net, int group)
 	switch (group) {
 	case SKNLGRP_INET_TCP_DESTROY:
 	case SKNLGRP_INET_UDP_DESTROY:
-		if (!sock_diag_handlers[AF_INET])
+		if (!READ_ONCE(sock_diag_handlers[AF_INET]))
 			sock_load_diag_module(AF_INET, 0);
 		break;
 	case SKNLGRP_INET6_TCP_DESTROY:
 	case SKNLGRP_INET6_UDP_DESTROY:
-		if (!sock_diag_handlers[AF_INET6])
+		if (!READ_ONCE(sock_diag_handlers[AF_INET6]))
 			sock_load_diag_module(AF_INET6, 0);
 		break;
 	}