[PATCH 5.12 238/700] smb3: fix possible access to uninitialized pointer to DACL

[Greg Kroah-Hartman]

From: Steve French <stfrench@xxxxxxxxxxxxx>

[ Upstream commit a5628263a9f8d47d9a1548fe9d5d75ba4423a735 ]

dacl_ptr can be null so we must check for it everywhere it is
used in build_sec_desc.

Addresses-Coverity: 1475598 ("Explicit null dereference")
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 fs/cifs/cifsacl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c
index d178cf85e926..b80b6ba232aa 100644
--- a/fs/cifs/cifsacl.c
+++ b/fs/cifs/cifsacl.c
@@ -1310,7 +1310,7 @@ static int build_sec_desc(struct cifs_ntsd *pntsd, struct cifs_ntsd *pnntsd,
 		ndacl_ptr = (struct cifs_acl *)((char *)pnntsd + ndacloffset);
 		ndacl_ptr->revision =
 			dacloffset ? dacl_ptr->revision : cpu_to_le16(ACL_REVISION);
-		ndacl_ptr->num_aces = dacl_ptr->num_aces;
+		ndacl_ptr->num_aces = dacl_ptr ? dacl_ptr->num_aces : 0;
 
 		if (uid_valid(uid)) { /* chown */
 			uid_t id;
-- 
2.30.2