[PATCH 5.15 041/247] ksmbd: fix reference count leak in smb_check_perm_dacl()

[Greg Kroah-Hartman]

From: Xin Xiong <xiongx18@xxxxxxxxxxxx>

[ Upstream commit d21a580dafc69aa04f46e6099616146a536b0724 ]

The issue happens in a specific path in smb_check_perm_dacl(). When
"id" and "uid" have the same value, the function simply jumps out of
the loop without decrementing the reference count of the object
"posix_acls", which is increased by get_acl() earlier. This may
result in memory leaks.

Fix it by decreasing the reference count of "posix_acls" before
jumping to label "check_access_bits".

Fixes: 777cad1604d6 ("ksmbd: remove select FS_POSIX_ACL in Kconfig")
Signed-off-by: Xin Xiong <xiongx18@xxxxxxxxxxxx>
Signed-off-by: Xin Tan <tanxin.ctf@xxxxxxxxx>
Acked-by: Namjae Jeon <linkinjeon@xxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 fs/ksmbd/smbacl.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/ksmbd/smbacl.c b/fs/ksmbd/smbacl.c
index bd792db32623..7e57ffdb4ce3 100644
--- a/fs/ksmbd/smbacl.c
+++ b/fs/ksmbd/smbacl.c
@@ -1274,6 +1274,7 @@ int smb_check_perm_dacl(struct ksmbd_conn *conn, struct path *path,
 					if (!access_bits)
 						access_bits =
 							SET_MINIMUM_RIGHTS;
+					posix_acl_release(posix_acls);
 					goto check_access_bits;
 				}
 			}
-- 
2.35.1