diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index cdcd665582085bea30938a05e330f7f787625cbd..b4675bdaed995bcedb802cb43b5a4c8693b189f7 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -369,7 +369,7 @@ find_domain_name(struct cifs_ses *ses, const struct nls_table *nls_cp)
 		if (blobptr + attrsize > blobend)
 			break;
 		if (type == NTLMSSP_AV_NB_DOMAIN_NAME) {
-			if (!attrsize)
+			if (!attrsize || attrsize >= CIFS_MAX_DOMAINNAME_LEN)
 				break;
 			if (!ses->domainName) {
 				ses->domainName =
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 2f3ff59929deb7f86e3bfd670b0d45c23f5862e5..7b68088978415c8f60ccfc37b18018d49700c20f 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -38,6 +38,7 @@
 #define MAX_TREE_SIZE (2 + MAX_SERVER_SIZE + 1 + MAX_SHARE_SIZE + 1)
 #define MAX_SERVER_SIZE 15
 #define MAX_SHARE_SIZE 80
+#define CIFS_MAX_DOMAINNAME_LEN 256 /* max domain name length */
 #define MAX_USERNAME_SIZE 256	/* reasonable maximum for current servers */
 #define MAX_PASSWORD_SIZE 512	/* max for windows seems to be 256 wide chars */
 
diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index 250480917aa5019af74fb45f4132c20f05fb20d1..d36262661245f0325730eb0e1fc31356e7d89d9d 100644
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -198,7 +198,7 @@ static void unicode_domain_string(char **pbcc_area, struct cifs_ses *ses,
 		bytes_ret = 0;
 	} else
 		bytes_ret = cifs_strtoUCS((__le16 *) bcc_ptr, ses->domainName,
-					  256, nls_cp);
+					  CIFS_MAX_DOMAINNAME_LEN, nls_cp);
 	bcc_ptr += 2 * bytes_ret;
 	bcc_ptr += 2;  /* account for null terminator */
 
@@ -256,8 +256,8 @@ static void ascii_ssetup_strings(char **pbcc_area, struct cifs_ses *ses,
 
 	/* copy domain */
 	if (ses->domainName != NULL) {
-		strncpy(bcc_ptr, ses->domainName, 256);
-		bcc_ptr += strnlen(ses->domainName, 256);
+		strncpy(bcc_ptr, ses->domainName, CIFS_MAX_DOMAINNAME_LEN);
+		bcc_ptr += strnlen(ses->domainName, CIFS_MAX_DOMAINNAME_LEN);
 	} /* else we will send a null domain name
 	     so the server will default to its own domain */
 	*bcc_ptr = 0;