From: Steve French <stfrench@microsoft.com>
Date: Tue, 22 Jun 2021 22:54:50 +0000 (-0500)
Subject: smb3: fix possible access to uninitialized pointer to DACL
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=a5628263a9f8d47d9a1548fe9d5d75ba4423a735;p=linux.git

smb3: fix possible access to uninitialized pointer to DACL

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@microsoft.com>
---

diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c
index 5ec5d9d24032b..388eb536cff15 100644
--- a/fs/cifs/cifsacl.c
+++ b/fs/cifs/cifsacl.c
@@ -1294,7 +1294,7 @@ 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;