ksmbd: prevent memory leak on error return

BugLink: https://bugs.launchpad.net/bugs/2052406

[ Upstream commit 9004448 ]

When allocated memory for 'new' failed,just return
will cause memory leak of 'ar'.

Fixes: 1819a90 ("ksmbd: reorganize ksmbd_iov_pin_rsp()")
Reported-by: kernel test robot <[email protected]>
Reported-by: Dan Carpenter <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]/
Signed-off-by: Zongmin Zhou<[email protected]>
Acked-by: Namjae Jeon <[email protected]>
Signed-off-by: Steve French <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Portia Stephens <[email protected]>
Signed-off-by: Roxana Nicolescu <[email protected]>

Author: Zongmin Zhou

fs/ksmbd/ksmbd_work.c

@@ -106,7 +106,7 @@ static inline void __ksmbd_iov_pin(struct ksmbd_work *work, void *ib,
 static int __ksmbd_iov_pin_rsp(struct ksmbd_work *work, void *ib, int len,
 			       void *aux_buf, unsigned int aux_size)
 {
-	struct aux_read *ar;
+	struct aux_read *ar = NULL;
 	int need_iov_cnt = 1;
 
 	if (aux_size) {
@@ -123,8 +123,11 @@ static int __ksmbd_iov_pin_rsp(struct ksmbd_work *work, void *ib, int len,
 		new = krealloc(work->iov,
 			       sizeof(struct kvec) * work->iov_alloc_cnt,
 			       GFP_KERNEL | __GFP_ZERO);
-		if (!new)
+		if (!new) {
+			kfree(ar);
+			work->iov_alloc_cnt -= 4;
 			return -ENOMEM;
+		}
 		work->iov = new;
 	}