From: Namjae Jeon <linkinjeon@kernel.org>
Date: Wed, 12 Feb 2025 08:52:19 +0000 (+0900)
Subject: cifs: add validation check for the fields in smb_aces
X-Git-Tag: v6.14.9~709
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=69b1824c9630853d0d045704e62344af8ae44cc9;p=thirdparty%2Fkernel%2Fstable.git

cifs: add validation check for the fields in smb_aces

[ Upstream commit eeb827f2922eb07ffbf7d53569cc95b38272646f ]

cifs.ko is missing validation check when accessing smb_aces.
This patch add validation check for the fields in smb_aces.

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/fs/smb/client/cifsacl.c b/fs/smb/client/cifsacl.c
index 64bd68f750f84..f9d577f2d59bb 100644
--- a/fs/smb/client/cifsacl.c
+++ b/fs/smb/client/cifsacl.c
@@ -811,7 +811,23 @@ static void parse_dacl(struct smb_acl *pdacl, char *end_of_acl,
 			return;
 
 		for (i = 0; i < num_aces; ++i) {
+			if (end_of_acl - acl_base < acl_size)
+				break;
+
 			ppace[i] = (struct smb_ace *) (acl_base + acl_size);
+			acl_base = (char *)ppace[i];
+			acl_size = offsetof(struct smb_ace, sid) +
+				offsetof(struct smb_sid, sub_auth);
+
+			if (end_of_acl - acl_base < acl_size ||
+			    ppace[i]->sid.num_subauth == 0 ||
+			    ppace[i]->sid.num_subauth > SID_MAX_SUB_AUTHORITIES ||
+			    (end_of_acl - acl_base <
+			     acl_size + sizeof(__le32) * ppace[i]->sid.num_subauth) ||
+			    (le16_to_cpu(ppace[i]->size) <
+			     acl_size + sizeof(__le32) * ppace[i]->sid.num_subauth))
+				break;
+
 #ifdef CONFIG_CIFS_DEBUG2
 			dump_ace(ppace[i], end_of_acl);
 #endif
@@ -855,7 +871,6 @@ static void parse_dacl(struct smb_acl *pdacl, char *end_of_acl,
 				(void *)ppace[i],
 				sizeof(struct smb_ace)); */
 
-			acl_base = (char *)ppace[i];
 			acl_size = le16_to_cpu(ppace[i]->size);
 		}