diff --git a/fs/smb/server/smbacl.c b/fs/smb/server/smbacl.c
index 340ea98fa494..fc9937cedb01 100644
--- a/fs/smb/server/smbacl.c
+++ b/fs/smb/server/smbacl.c
@@ -374,6 +374,7 @@ static void parse_dacl(struct mnt_idmap *idmap,
 {
 	int i, ret;
 	u16 num_aces = 0;
+	u16 dacl_size;
 	unsigned int acl_size;
 	char *acl_base;
 	struct smb_ace **ppace;
@@ -403,7 +404,11 @@ static void parse_dacl(struct mnt_idmap *idmap,
 	if (num_aces <= 0)
 		return;
 
-	if (num_aces > (le16_to_cpu(pdacl->size) - sizeof(struct smb_acl)) /
+	dacl_size = le16_to_cpu(pdacl->size);
+	if (dacl_size < sizeof(struct smb_acl))
+		return;
+
+	if (num_aces > (dacl_size - sizeof(struct smb_acl)) /
 			(offsetof(struct smb_ace, sid) +
 			 offsetof(struct smb_sid, sub_auth) + sizeof(__le16)))
 		return;