NTLM auth and sign - Allocate session key/client response dynamically

Start calculating auth response within a session.  Move/Add pertinet
data structures like session key, server challenge and ntlmv2_hash in
a session structure.  We should do the calculations within a session
before copying session key and response over to server data
structures because a session setup can fail.

Only after a very first smb session succeeds, it copy/make its
session key, session key of smb connection.  This key stays with
the smb connection throughout its life.
sequence_number within server is set to 0x2.

The authentication Message Authentication Key (mak) which consists
of session key followed by client response within structure session_key
is now dynamic.  Every authentication type allocates the key + response
sized memory within its session structure and later either assigns or
frees it once the client response is sent and if session's session key
becomes connetion's session key.

ntlm/ntlmi authentication functions are rearranged.  A function
named setup_ntlm_resp(), similar to setup_ntlmv2_resp(), replaces
function cifs_calculate_session_key().

size of CIFS_SESS_KEY_SIZE is changed to 16, to reflect the byte size
of the key it holds.

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

1 files changed, 39 insertions, 68 deletions

diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index 2a11efd96592..b2934683bd08 100644
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -32,9 +32,6 @@
 #include <linux/slab.h>
 #include "cifs_spnego.h"
 
-extern void SMBNTencrypt(unsigned char *passwd, unsigned char *c8,
-                         unsigned char *p24);
-
 /*
  * Checks if this is the first smb session to be reconnected after
  * the socket has been reestablished (so we know whether to use vc 0).
@@ -469,11 +466,9 @@ static int build_ntlmssp_auth_blob(unsigned char *pbuffer,
                                    const struct nls_table *nls_cp)
 {
         int rc;
-        unsigned int size;
         AUTHENTICATE_MESSAGE *sec_blob = (AUTHENTICATE_MESSAGE *)pbuffer;
         __u32 flags;
         unsigned char *tmp;
-        struct ntlmv2_resp ntlmv2_response = {};
 
         memcpy(sec_blob->Signature, NTLMSSP_SIGNATURE, 8);
         sec_blob->MessageType = NtLmAuthenticate;
@@ -497,25 +492,19 @@ static int build_ntlmssp_auth_blob(unsigned char *pbuffer,
         sec_blob->LmChallengeResponse.MaximumLength = 0;
 
         sec_blob->NtChallengeResponse.BufferOffset = cpu_to_le32(tmp - pbuffer);
-        rc = setup_ntlmv2_rsp(ses, (char *)&ntlmv2_response, nls_cp);
+        rc = setup_ntlmv2_rsp(ses, nls_cp);
         if (rc) {
                 cERROR(1, "Error %d during NTLMSSP authentication", rc);
                 goto setup_ntlmv2_ret;
         }
-        size =  sizeof(struct ntlmv2_resp);
-        memcpy(tmp, (char *)&ntlmv2_response, size);
-        tmp += size;
-        if (ses->tilen > 0) {
-                memcpy(tmp, ses->tiblob, ses->tilen);
-                tmp += ses->tilen;
-        }
+        memcpy(tmp, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
+                        ses->auth_key.len - CIFS_SESS_KEY_SIZE);
+        tmp += ses->auth_key.len - CIFS_SESS_KEY_SIZE;
 
-        sec_blob->NtChallengeResponse.Length = cpu_to_le16(size + ses->tilen);
+        sec_blob->NtChallengeResponse.Length =
+                        cpu_to_le16(ses->auth_key.len - CIFS_SESS_KEY_SIZE);
         sec_blob->NtChallengeResponse.MaximumLength =
-                                cpu_to_le16(size + ses->tilen);
-        kfree(ses->tiblob);
-        ses->tiblob = NULL;
-        ses->tilen = 0;
+                        cpu_to_le16(ses->auth_key.len - CIFS_SESS_KEY_SIZE);
 
         if (ses->domainName == NULL) {
                 sec_blob->DomainName.BufferOffset = cpu_to_le32(tmp - pbuffer);
@@ -687,24 +676,27 @@ ssetup_ntlmssp_authenticate:
                 ascii_ssetup_strings(&bcc_ptr, ses, nls_cp);
 #endif
         } else if (type == NTLM) {
-                char ntlm_session_key[CIFS_SESS_KEY_SIZE];
-
                 pSMB->req_no_secext.Capabilities = cpu_to_le32(capabilities);
                 pSMB->req_no_secext.CaseInsensitivePasswordLength =
-                        cpu_to_le16(CIFS_SESS_KEY_SIZE);
+                        cpu_to_le16(CIFS_AUTH_RESP_SIZE);
                 pSMB->req_no_secext.CaseSensitivePasswordLength =
-                        cpu_to_le16(CIFS_SESS_KEY_SIZE);
+                        cpu_to_le16(CIFS_AUTH_RESP_SIZE);
+
+                /* calculate ntlm response and session key */
+                rc = setup_ntlm_response(ses);
+                if (rc) {
+                        cERROR(1, "Error %d during NTLM authentication", rc);
+                        goto ssetup_exit;
+                }
 
-                /* calculate session key */
-                SMBNTencrypt(ses->password, ses->cryptKey, ntlm_session_key);
+                /* copy ntlm response */
+                memcpy(bcc_ptr, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
+                                CIFS_AUTH_RESP_SIZE);
+                bcc_ptr += CIFS_AUTH_RESP_SIZE;
+                memcpy(bcc_ptr, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
+                                CIFS_AUTH_RESP_SIZE);
+                bcc_ptr += CIFS_AUTH_RESP_SIZE;
 
-                cifs_calculate_session_key(&ses->auth_key,
-                                        ntlm_session_key, ses->password);
-                /* copy session key */
-                memcpy(bcc_ptr, (char *)ntlm_session_key, CIFS_SESS_KEY_SIZE);
-                bcc_ptr += CIFS_SESS_KEY_SIZE;
-                memcpy(bcc_ptr, (char *)ntlm_session_key, CIFS_SESS_KEY_SIZE);
-                bcc_ptr += CIFS_SESS_KEY_SIZE;
                 if (ses->capabilities & CAP_UNICODE) {
                         /* unicode strings must be word aligned */
                         if (iov[0].iov_len % 2) {
@@ -715,47 +707,26 @@ ssetup_ntlmssp_authenticate:
                 } else
                         ascii_ssetup_strings(&bcc_ptr, ses, nls_cp);
         } else if (type == NTLMv2) {
-                char *v2_sess_key =
-                        kmalloc(sizeof(struct ntlmv2_resp), GFP_KERNEL);
-
-                /* BB FIXME change all users of v2_sess_key to
-                   struct ntlmv2_resp */
-
-                if (v2_sess_key == NULL) {
-                        rc = -ENOMEM;
-                        goto ssetup_exit;
-                }
-
                 pSMB->req_no_secext.Capabilities = cpu_to_le32(capabilities);
 
                 /* LM2 password would be here if we supported it */
                 pSMB->req_no_secext.CaseInsensitivePasswordLength = 0;
-                /*      cpu_to_le16(LM2_SESS_KEY_SIZE); */
 
-                /* calculate session key */
-                rc = setup_ntlmv2_rsp(ses, v2_sess_key, nls_cp);
+                /* calculate nlmv2 response and session key */
+                rc = setup_ntlmv2_rsp(ses, nls_cp);
                 if (rc) {
                         cERROR(1, "Error %d during NTLMv2 authentication", rc);
-                        kfree(v2_sess_key);
                         goto ssetup_exit;
                 }
-                memcpy(bcc_ptr, (char *)v2_sess_key,
-                                sizeof(struct ntlmv2_resp));
-                bcc_ptr += sizeof(struct ntlmv2_resp);
-                kfree(v2_sess_key);
+                memcpy(bcc_ptr, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
+                                ses->auth_key.len - CIFS_SESS_KEY_SIZE);
+                bcc_ptr += ses->auth_key.len - CIFS_SESS_KEY_SIZE;
+
                 /* set case sensitive password length after tilen may get
                  * assigned, tilen is 0 otherwise.
                  */
                 pSMB->req_no_secext.CaseSensitivePasswordLength =
-                        cpu_to_le16(sizeof(struct ntlmv2_resp) + ses->tilen);
-                if (ses->tilen > 0) {
-                        memcpy(bcc_ptr, ses->tiblob, ses->tilen);
-                        bcc_ptr += ses->tilen;
-                        /* we never did allocate ses->domainName to free */
-                        kfree(ses->tiblob);
-                        ses->tiblob = NULL;
-                        ses->tilen = 0;
-                }
+                        cpu_to_le16(ses->auth_key.len);
 
                 if (ses->capabilities & CAP_UNICODE) {
                         if (iov[0].iov_len % 2) {
@@ -768,6 +739,7 @@ ssetup_ntlmssp_authenticate:
         } else if (type == Kerberos) {
 #ifdef CONFIG_CIFS_UPCALL
                 struct cifs_spnego_msg *msg;
+
                 spnego_key = cifs_get_spnego_key(ses);
                 if (IS_ERR(spnego_key)) {
                         rc = PTR_ERR(spnego_key);
@@ -785,16 +757,17 @@ ssetup_ntlmssp_authenticate:
                         rc = -EKEYREJECTED;
                         goto ssetup_exit;
                 }
-                /* bail out if key is too long */
-                if (msg->sesskey_len >
-                    sizeof(ses->auth_key.data.krb5)) {
-                        cERROR(1, "Kerberos signing key too long (%u bytes)",
-                                msg->sesskey_len);
-                        rc = -EOVERFLOW;
+
+                ses->auth_key.response = kmalloc(msg->sesskey_len, GFP_KERNEL);
+                if (!ses->auth_key.response) {
+                        cERROR(1, "Kerberos can't allocate (%u bytes) memory",
+                                        msg->sesskey_len);
+                        rc = -ENOMEM;
                         goto ssetup_exit;
                 }
+                memcpy(ses->auth_key.response, msg->data, msg->sesskey_len);
                 ses->auth_key.len = msg->sesskey_len;
-                memcpy(ses->auth_key.data.krb5, msg->data, msg->sesskey_len);
+
                 pSMB->req.hdr.Flags2 |= SMBFLG2_EXT_SEC;
                 capabilities |= CAP_EXTENDED_SECURITY;
                 pSMB->req.Capabilities = cpu_to_le32(capabilities);
@@ -897,8 +870,6 @@ ssetup_ntlmssp_authenticate:
                           CIFS_STD_OP /* not long */ | CIFS_LOG_ERROR);
         /* SMB request buf freed in SendReceive2 */
 
-        cFYI(1, "ssetup rc from sendrecv2 is %d", rc);
-
         pSMB = (SESSION_SETUP_ANDX *)iov[0].iov_base;
         smb_buf = (struct smb_hdr *)iov[0].iov_base;