tipc: fix a possible memleak in tipc_buf_append

Origin: https://git.kernel.org/linus/97bf6f81b29a8efaf5d0983251a7450e5794370d

__skb_linearize() doesn't free the skb when it fails, so move
'*buf = NULL' after __skb_linearize(), so that the skb can be
freed on the err path.

Fixes: b7df21cf1b79 ("tipc: skb_linearize the head skb when reassembling msgs")
Reported-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Tung Nguyen <tung.q.nguyen@dektech.com.au>
Link: https://lore.kernel.org/r/90710748c29a1521efac4f75ea01b3b7e61414cf.1714485818.git.lucien.xin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Gbp-Pq: Topic bugfix/all
Gbp-Pq: Name tipc-fix-a-possible-memleak-in-tipc_buf_append.patch

diff --git a/net/tipc/msg.c b/net/tipc/msg.c
index 9a6e9bcbf694021fc7c21aab23ce3ad3d9b7951e..76284fc538ebdd38d52c879bd4fc58c84abc6371 100644 (file)
--- a/net/tipc/msg.c
+++ b/net/tipc/msg.c
@@ -142,9 +142,9 @@ int tipc_buf_append(struct sk_buff **headbuf, struct sk_buff **buf)
        if (fragid == FIRST_FRAGMENT) {
                if (unlikely(head))
                        goto err;
-               *buf = NULL;
                if (skb_has_frag_list(frag) && __skb_linearize(frag))
                        goto err;
+               *buf = NULL;
                frag = skb_unshare(frag, GFP_ATOMIC);
                if (unlikely(!frag))
                        goto err;