cifs: Fix broken sec=ntlmv2/i sec option (try #2)

Fix sec=ntlmv2/i authentication option during mount of Samba shares.

cifs client was coding ntlmv2 response incorrectly.
All that is needed in temp as specified in MS-NLMP seciton 3.3.2

"Define ComputeResponse(NegFlg, ResponseKeyNT, ResponseKeyLM,
CHALLENGE_MESSAGE.ServerChallenge, ClientChallenge, Time, ServerName)

as
Set temp to ConcatenationOf(Responserversion, HiResponserversion,
Z(6), Time, ClientChallenge, Z(4), ServerName, Z(4)"

is MsvAvNbDomainName.

For sec=ntlmsspi, build_av_pair is not used, a blob is plucked from
type 2 response sent by the server to use in authentication.

I tested sec=ntlmv2/i and sec=ntlmssp/i mount options against
Samba (3.6) and Windows - XP, 2003 Server and 7.
They all worked.

Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 11 insertions, 43 deletions

diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index e76bfeb68267..30acd22147e1 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -351,9 +351,7 @@ static int
 build_avpair_blob(struct cifs_ses *ses, const struct nls_table *nls_cp)
 {
         unsigned int dlen;
-        unsigned int wlen;
-        unsigned int size = 6 * sizeof(struct ntlmssp2_name);
-        __le64  curtime;
+        unsigned int size = 2 * sizeof(struct ntlmssp2_name);
         char *defdmname = "WORKGROUP";
         unsigned char *blobptr;
         struct ntlmssp2_name *attrptr;
@@ -365,15 +363,14 @@ build_avpair_blob(struct cifs_ses *ses, const struct nls_table *nls_cp)
         }
 
         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).
+        /*
+         * The length of this blob is two times the size of a
+         * structure (av pair) which holds name/size
+         * ( for NTLMSSP_AV_NB_DOMAIN_NAME followed by NTLMSSP_AV_EOL ) +
+         * unicode length of a netbios domain name
          */
-        ses->auth_key.len = size + 2 * (2 * dlen) + 2 * (2 * wlen) + 8;
+        ses->auth_key.len = size + 2 * dlen;
         ses->auth_key.response = kzalloc(ses->auth_key.len, GFP_KERNEL);
         if (!ses->auth_key.response) {
                 ses->auth_key.len = 0;
@@ -384,44 +381,15 @@ build_avpair_blob(struct cifs_ses *ses, const struct nls_table *nls_cp)
         blobptr = ses->auth_key.response;
         attrptr = (struct ntlmssp2_name *) blobptr;
 
+        /*
+         * As defined in MS-NTLM 3.3.2, just this av pair field
+         * is sufficient as part of the temp
+         */
         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;
 }