CIFS ntlm authentication and signing - Build a proper av/ti pair blob for ntlmv2...

Build an av pair blob as part of ntlmv2 (without extended security) auth
request.  Include netbios and dns names for domain and server and
a timestamp in the blob.

Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Reviewed-by: Jeff Layton <jlayton@samba.org>
Signed-off-by: Steve French <sfrench@us.ibm.com>

diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index 89fb94fac4b5cd3409f0d34fae77bfcc42fd004b..e3edd8a6840b665b27850600ee7007658216b7c6 100644 (file)
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -263,27 +263,85 @@ 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
+/* Build a proper attribute value/target info pairs blob.
+ * Fill in netbios and dns domain name and workstation name
+ * and client time (total five av pairs and + one end of fields indicator.
+ * Allocate domain name which gets freed when session struct is deallocated.
  */
 static int
-build_avpair_blob(struct cifsSesInfo *ses)
+build_avpair_blob(struct cifsSesInfo *ses, const struct nls_table *nls_cp)
 {
+       unsigned int dlen;
+       unsigned int wlen;
+       unsigned int size = 6 * sizeof(struct ntlmssp2_name);
+       __le64  curtime;
+       char *defdmname = "WORKGROUP";
+       unsigned char *blobptr;
        struct ntlmssp2_name *attrptr;
 
-       ses->tilen = 2 * sizeof(struct ntlmssp2_name);
+       if (!ses->domainName) {
+               ses->domainName = kstrdup(defdmname, GFP_KERNEL);
+               if (!ses->domainName)
+                       return -ENOMEM;
+       }
+
+       dlen = strlen(ses->domainName);
+       wlen = strlen(ses->server->hostname);
+
+       /* The length of this blob is a size which is
+        * six times the size of a structure which holds name/size +
+        * two times the unicode length of a domain name +
+        * two times the unicode length of a server name +
+        * size of a timestamp (which is 8 bytes).
+        */
+       ses->tilen = size + 2 * (2 * dlen) + 2 * (2 * wlen) + 8;
        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);
+
+       blobptr = ses->tiblob;
+       attrptr = (struct ntlmssp2_name *) blobptr;
+
+       attrptr->type = cpu_to_le16(NTLMSSP_AV_NB_DOMAIN_NAME);
+       attrptr->length = cpu_to_le16(2 * dlen);
+       blobptr = (unsigned char *)attrptr + sizeof(struct ntlmssp2_name);
+       cifs_strtoUCS((__le16 *)blobptr, ses->domainName, dlen, nls_cp);
+
+       blobptr += 2 * dlen;
+       attrptr = (struct ntlmssp2_name *) blobptr;
+
+       attrptr->type = cpu_to_le16(NTLMSSP_AV_NB_COMPUTER_NAME);
+       attrptr->length = cpu_to_le16(2 * wlen);
+       blobptr = (unsigned char *)attrptr + sizeof(struct ntlmssp2_name);
+       cifs_strtoUCS((__le16 *)blobptr, ses->server->hostname, wlen, nls_cp);
+
+       blobptr += 2 * wlen;
+       attrptr = (struct ntlmssp2_name *) blobptr;
+
+       attrptr->type = cpu_to_le16(NTLMSSP_AV_DNS_DOMAIN_NAME);
+       attrptr->length = cpu_to_le16(2 * dlen);
+       blobptr = (unsigned char *)attrptr + sizeof(struct ntlmssp2_name);
+       cifs_strtoUCS((__le16 *)blobptr, ses->domainName, dlen, nls_cp);
+
+       blobptr += 2 * dlen;
+       attrptr = (struct ntlmssp2_name *) blobptr;
+
+       attrptr->type = cpu_to_le16(NTLMSSP_AV_DNS_COMPUTER_NAME);
+       attrptr->length = cpu_to_le16(2 * wlen);
+       blobptr = (unsigned char *)attrptr + sizeof(struct ntlmssp2_name);
+       cifs_strtoUCS((__le16 *)blobptr, ses->server->hostname, wlen, nls_cp);
+
+       blobptr += 2 * wlen;
+       attrptr = (struct ntlmssp2_name *) blobptr;
+
+       attrptr->type = cpu_to_le16(NTLMSSP_AV_TIMESTAMP);
+       attrptr->length = cpu_to_le16(sizeof(__le64));
+       blobptr = (unsigned char *)attrptr + sizeof(struct ntlmssp2_name);
+       curtime = cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME));
+       memcpy(blobptr, &curtime, sizeof(__le64));
 
        return 0;
 }
@@ -429,7 +487,7 @@ setup_ntlmv2_rsp(struct cifsSesInfo *ses, char *resp_buf,
                        }
                }
        } else {
-               rc = build_avpair_blob(ses);
+               rc = build_avpair_blob(ses, nls_cp);
                if (rc) {
                        cERROR(1, "error %d building av pair blob", rc);
                        return rc;