1 files changed, 115 insertions, 6 deletions

diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index eed70cae1275..730038a12982 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -27,6 +27,7 @@
 #include "md5.h"
 #include "cifs_unicode.h"
 #include "cifsproto.h"
+#include "ntlmssp.h"
 #include <linux/ctype.h>
 #include <linux/random.h>
 
@@ -262,6 +263,87 @@ void calc_lanman_hash(const char *password, const char *cryptkey, bool encrypt,
 }
 #endif /* CIFS_WEAK_PW_HASH */
 
+/* This is just a filler for ntlmv2 type of security mechanisms.
+ * Older servers are not very particular about the contents of av pairs
+ * in the blob and for sec mechs like ntlmv2, there is no negotiation
+ * as in ntlmssp, so unless domain and server  netbios and dns names
+ * are specified, there is no way to obtain name.  In case of ntlmssp,
+ * server provides that info in type 2 challenge packet
+ */
+static int
+build_avpair_blob(struct cifsSesInfo *ses)
+{
+	struct ntlmssp2_name *attrptr;
+
+	ses->tilen = 2 * sizeof(struct ntlmssp2_name);
+	ses->tiblob = kzalloc(ses->tilen, GFP_KERNEL);
+	if (!ses->tiblob) {
+		ses->tilen = 0;
+		cERROR(1, "Challenge target info allocation failure");
+		return -ENOMEM;
+	}
+	attrptr = (struct ntlmssp2_name *) ses->tiblob;
+	attrptr->type = cpu_to_le16(NTLMSSP_DOMAIN_TYPE);
+
+	return 0;
+}
+
+/* Server has provided av pairs/target info in the type 2 challenge
+ * packet and we have plucked it and stored within smb session.
+ * We parse that blob here to find netbios domain name to be used
+ * as part of ntlmv2 authentication (in Target String), if not already
+ * specified on the command line.
+ * If this function returns without any error but without fetching
+ * domain name, authentication may fail against some server but
+ * may not fail against other (those who are not very particular
+ * about target string i.e. for some, just user name might suffice.
+ */
+static int
+find_domain_name(struct cifsSesInfo *ses)
+{
+	unsigned int attrsize;
+	unsigned int type;
+	unsigned int onesize = sizeof(struct ntlmssp2_name);
+	unsigned char *blobptr;
+	unsigned char *blobend;
+	struct ntlmssp2_name *attrptr;
+
+	if (!ses->tilen || !ses->tiblob)
+		return 0;
+
+	blobptr = ses->tiblob;
+	blobend = ses->tiblob + ses->tilen;
+
+	while (blobptr + onesize < blobend) {
+		attrptr = (struct ntlmssp2_name *) blobptr;
+		type = le16_to_cpu(attrptr->type);
+		if (type == NTLMSSP_AV_EOL)
+			break;
+		blobptr += 2; /* advance attr type */
+		attrsize = le16_to_cpu(attrptr->length);
+		blobptr += 2; /* advance attr size */
+		if (blobptr + attrsize > blobend)
+			break;
+		if (type == NTLMSSP_AV_NB_DOMAIN_NAME) {
+			if (!attrsize)
+				break;
+			if (!ses->domainName) {
+				ses->domainName =
+					kmalloc(attrsize + 1, GFP_KERNEL);
+				if (!ses->domainName)
+						return -ENOMEM;
+				cifs_from_ucs2(ses->domainName,
+					(__le16 *)blobptr, attrsize, attrsize,
+					load_nls_default(), false);
+				break;
+			}
+		}
+		blobptr += attrsize; /* advance attr  value */
+	}
+
+	return 0;
+}
+
 static int calc_ntlmv2_hash(struct cifsSesInfo *ses,
 			    const struct nls_table *nls_cp)
 {
@@ -321,7 +403,8 @@ calc_exit_2:
 	return rc;
 }
 
-void setup_ntlmv2_rsp(struct cifsSesInfo *ses, char *resp_buf,
+int
+setup_ntlmv2_rsp(struct cifsSesInfo *ses, char *resp_buf,
 		      const struct nls_table *nls_cp)
 {
 	int rc;
@@ -333,15 +416,29 @@ void setup_ntlmv2_rsp(struct cifsSesInfo *ses, char *resp_buf,
 	buf->time = cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME));
 	get_random_bytes(&buf->client_chal, sizeof(buf->client_chal));
 	buf->reserved2 = 0;
-	buf->names[0].type = cpu_to_le16(NTLMSSP_DOMAIN_TYPE);
-	buf->names[0].length = 0;
-	buf->names[1].type = 0;
-	buf->names[1].length = 0;
+
+	if (ses->server->secType == RawNTLMSSP) {
+		if (!ses->domainName) {
+			rc = find_domain_name(ses);
+			if (rc) {
+				cERROR(1, "error %d finding domain name", rc);
+				goto setup_ntlmv2_rsp_ret;
+			}
+		}
+	} else {
+		rc = build_avpair_blob(ses);
+		if (rc) {
+			cERROR(1, "error %d building av pair blob", rc);
+			return rc;
+		}
+	}
 
 	/* calculate buf->ntlmv2_hash */
 	rc = calc_ntlmv2_hash(ses, nls_cp);
-	if (rc)
+	if (rc) {
 		cERROR(1, "could not get v2 hash rc %d", rc);
+		goto setup_ntlmv2_rsp_ret;
+	}
 	CalcNTLMv2_response(ses, resp_buf);
 
 	/* now calculate the MAC key for NTLMv2 */
@@ -352,6 +449,15 @@ void setup_ntlmv2_rsp(struct cifsSesInfo *ses, char *resp_buf,
 	memcpy(&ses->server->session_key.data.ntlmv2.resp, resp_buf,
 	       sizeof(struct ntlmv2_resp));
 	ses->server->session_key.len = 16 + sizeof(struct ntlmv2_resp);
+
+	return 0;
+
+setup_ntlmv2_rsp_ret:
+	kfree(ses->tiblob);
+	ses->tiblob = NULL;
+	ses->tilen = 0;
+
+	return rc;
 }
 
 void CalcNTLMv2_response(const struct cifsSesInfo *ses,
@@ -365,6 +471,9 @@ void CalcNTLMv2_response(const struct cifsSesInfo *ses,
 	hmac_md5_update(v2_session_response+8,
 			sizeof(struct ntlmv2_resp) - 8, &context);
 
+	if (ses->tilen)
+		hmac_md5_update(ses->tiblob, ses->tilen, &context);
+
 	hmac_md5_final(v2_session_response, &context);
 /*	cifs_dump_mem("v2_sess_rsp: ", v2_session_response, 32); */
 }