(merge from 3.0)

Changes all over the shop, but all towards:
 - NTLM2 support in the server
 - KEY_EXCH support in the server
 - variable length session keys.

In detail:

 - NTLM2 is an extension of NTLMv1, that is compatible with existing
domain controllers (unlike NTLMv2, which requires a DC upgrade).

 * This is known as 'NTLMv2 session security' *

(This is not yet implemented on the RPC pipes however, so there may
well still be issues for PDC setups, particuarly around password
changes.  We do not fully understand the sign/seal implications of
NTLM2 on RPC pipes.)

This requires modifications to our authentication subsystem, as we
must handle the 'challege' input into the challenge-response algorithm
being changed.  This also needs to be turned off for
'security=server', which does not support this.

- KEY_EXCH is another 'security' mechanism, whereby the session key
actually used by the server is sent by the client, rather than being
the shared-secret directly or indirectly.

- As both these methods change the session key, the auth subsystem
needed to be changed, to 'override' session keys provided by the
backend.

- There has also been a major overhaul of the NTLMSSP subsystem, to
merge the 'client' and 'server' functions, so they both operate on a
single structure.  This should help the SPNEGO implementation.

- The 'names blob' in NTLMSSP is always in unicode - never in ascii.
Don't make an ascii version ever.

- The other big change is to allow variable length session keys.  We
have always assumed that session keys are 16 bytes long - and padded
to this length if shorter.  However, Kerberos session keys are 8 bytes
long, when the krb5 login uses DES.

 * This fix allows SMB signging on machines not yet running MIT KRB5 1.3.1. *

- Add better DEBUG() messages to ntlm_auth, warning administrators of
misconfigurations that prevent access to the privileged pipe.  This
should help reduce some of the 'it just doesn't work' issues.

- Fix data_blob_talloc() to behave the same way data_blob() does when
passed a NULL data pointer.  (just allocate)


REMEMBER to make clean after this commit - I have changed plenty of
data structures...

Andrew Bartlett
(This used to be commit 57a895aaabacc0c9147344d097d333793b77c947)

4 files changed, 142 insertions, 30 deletions

diff --git a/source3/auth/auth.c b/source3/auth/auth.c
index 553d9a686e..20dccc6592 100644
--- a/source3/auth/auth.c
+++ b/source3/auth/auth.c
@@ -88,6 +88,8 @@ static const uint8 *get_ntlm_challenge(struct auth_context *auth_context)
 		return auth_context->challenge.data;
 	}
 
+	auth_context->challenge_may_be_modified = False;
+
 	for (auth_method = auth_context->auth_method_list; auth_method; auth_method = auth_method->next) {
 		if (auth_method->get_chal == NULL) {
 			DEBUG(5, ("auth_get_challenge: module %s did not want to specify a challenge\n", auth_method->name));
@@ -127,6 +129,7 @@ static const uint8 *get_ntlm_challenge(struct auth_context *auth_context)
 							   chal, sizeof(chal));
 		
 		challenge_set_by = "random";
+		auth_context->challenge_may_be_modified = True;
 	} 
 	
 	DEBUG(5, ("auth_context challenge created by %s\n", challenge_set_by));
diff --git a/source3/auth/auth_ntlmssp.c b/source3/auth/auth_ntlmssp.c
index 3af0cbaada..a5ce101e5e 100644
--- a/source3/auth/auth_ntlmssp.c
+++ b/source3/auth/auth_ntlmssp.c
@@ -23,13 +23,59 @@
 
 #include "includes.h"
 
-static const uint8 *auth_ntlmssp_get_challenge(struct ntlmssp_state *ntlmssp_state)
+/**
+ * Return the challenge as determined by the authentication subsystem 
+ * @return an 8 byte random challenge
+ */
+
+static const uint8 *auth_ntlmssp_get_challenge(const struct ntlmssp_state *ntlmssp_state)
 {
 	AUTH_NTLMSSP_STATE *auth_ntlmssp_state = ntlmssp_state->auth_context;
 	return auth_ntlmssp_state->auth_context->get_ntlm_challenge(auth_ntlmssp_state->auth_context);
 }
 
-static NTSTATUS auth_ntlmssp_check_password(struct ntlmssp_state *ntlmssp_state) 
+/**
+ * Some authentication methods 'fix' the challenge, so we may not be able to set it
+ *
+ * @return If the effective challenge used by the auth subsystem may be modified
+ */
+static BOOL auth_ntlmssp_may_set_challenge(const struct ntlmssp_state *ntlmssp_state)
+{
+	AUTH_NTLMSSP_STATE *auth_ntlmssp_state = ntlmssp_state->auth_context;
+	struct auth_context *auth_context = auth_ntlmssp_state->auth_context;
+
+	return auth_context->challenge_may_be_modified;
+}
+
+/**
+ * NTLM2 authentication modifies the effective challange, 
+ * @param challenge The new challenge value
+ */
+static NTSTATUS auth_ntlmssp_set_challenge(struct ntlmssp_state *ntlmssp_state, DATA_BLOB *challenge)
+{
+	AUTH_NTLMSSP_STATE *auth_ntlmssp_state = ntlmssp_state->auth_context;
+	struct auth_context *auth_context = auth_ntlmssp_state->auth_context;
+
+	SMB_ASSERT(challenge->length == 8);
+
+	auth_context->challenge = data_blob_talloc(auth_context->mem_ctx, 
+						   challenge->data, challenge->length);
+
+	auth_context->challenge_set_by = "NTLMSSP callback (NTLM2)";
+
+	DEBUG(5, ("auth_context challenge set by %s\n", auth_context->challenge_set_by));
+	DEBUG(5, ("challenge is: \n"));
+	dump_data(5, (const char *)auth_context->challenge.data, auth_context->challenge.length);
+	return NT_STATUS_OK;
+}
+
+/**
+ * Check the password on an NTLMSSP login.  
+ *
+ * Return the session keys used on the connection.
+ */
+
+static NTSTATUS auth_ntlmssp_check_password(struct ntlmssp_state *ntlmssp_state, DATA_BLOB *nt_session_key, DATA_BLOB *lm_session_key) 
 {
 	AUTH_NTLMSSP_STATE *auth_ntlmssp_state = ntlmssp_state->auth_context;
 	uint32 auth_flags = AUTH_FLAG_NONE;
@@ -45,7 +91,7 @@ static NTSTATUS auth_ntlmssp_check_password(struct ntlmssp_state *ntlmssp_state)
 		auth_flags |= AUTH_FLAG_NTLM_RESP;
 	} else 	if (auth_ntlmssp_state->ntlmssp_state->nt_resp.length > 24) {
 		auth_flags |= AUTH_FLAG_NTLMv2_RESP;
-	};
+	}
 
 	/* the client has given us its machine name (which we otherwise would not get on port 445).
 	   we need to possibly reload smb.conf if smb.conf includes depend on the machine name */
@@ -71,10 +117,26 @@ static NTSTATUS auth_ntlmssp_check_password(struct ntlmssp_state *ntlmssp_state)
 		return nt_status;
 	}
 
-	nt_status = auth_ntlmssp_state->auth_context->check_ntlm_password(auth_ntlmssp_state->auth_context, user_info, &auth_ntlmssp_state->server_info); 
-			
+	nt_status = auth_ntlmssp_state->auth_context->check_ntlm_password(auth_ntlmssp_state->auth_context, 
+									  user_info, &auth_ntlmssp_state->server_info); 
+
 	free_user_info(&user_info);
 
+	if (!NT_STATUS_IS_OK(nt_status)) {
+		return nt_status;
+	}
+	if (auth_ntlmssp_state->server_info->nt_session_key.length) {
+		DEBUG(10, ("Got NT session key of length %u\n", auth_ntlmssp_state->server_info->nt_session_key.length));
+		*nt_session_key = data_blob_talloc(auth_ntlmssp_state->mem_ctx, 
+						   auth_ntlmssp_state->server_info->nt_session_key.data,
+						   auth_ntlmssp_state->server_info->nt_session_key.length);
+	}
+	if (auth_ntlmssp_state->server_info->lm_session_key.length) {
+		DEBUG(10, ("Got LM session key of length %u\n", auth_ntlmssp_state->server_info->lm_session_key.length));
+		*lm_session_key = data_blob_talloc(auth_ntlmssp_state->mem_ctx, 
+						   auth_ntlmssp_state->server_info->lm_session_key.data,
+						   auth_ntlmssp_state->server_info->lm_session_key.length);
+	}
 	return nt_status;
 }
 
@@ -106,18 +168,20 @@ NTSTATUS auth_ntlmssp_start(AUTH_NTLMSSP_STATE **auth_ntlmssp_state)
 
 	(*auth_ntlmssp_state)->ntlmssp_state->auth_context = (*auth_ntlmssp_state);
 	(*auth_ntlmssp_state)->ntlmssp_state->get_challenge = auth_ntlmssp_get_challenge;
+	(*auth_ntlmssp_state)->ntlmssp_state->may_set_challenge = auth_ntlmssp_may_set_challenge;
+	(*auth_ntlmssp_state)->ntlmssp_state->set_challenge = auth_ntlmssp_set_challenge;
 	(*auth_ntlmssp_state)->ntlmssp_state->check_password = auth_ntlmssp_check_password;
 	(*auth_ntlmssp_state)->ntlmssp_state->server_role = lp_server_role();
 
 	return NT_STATUS_OK;
 }
 
-NTSTATUS auth_ntlmssp_end(AUTH_NTLMSSP_STATE **auth_ntlmssp_state)
+void auth_ntlmssp_end(AUTH_NTLMSSP_STATE **auth_ntlmssp_state)
 {
 	TALLOC_CTX *mem_ctx = (*auth_ntlmssp_state)->mem_ctx;
 
 	if ((*auth_ntlmssp_state)->ntlmssp_state) {
-		ntlmssp_server_end(&(*auth_ntlmssp_state)->ntlmssp_state);
+		ntlmssp_end(&(*auth_ntlmssp_state)->ntlmssp_state);
 	}
 	if ((*auth_ntlmssp_state)->auth_context) {
 		((*auth_ntlmssp_state)->auth_context->free)(&(*auth_ntlmssp_state)->auth_context);
@@ -127,11 +191,10 @@ NTSTATUS auth_ntlmssp_end(AUTH_NTLMSSP_STATE **auth_ntlmssp_state)
 	}
 	talloc_destroy(mem_ctx);
 	*auth_ntlmssp_state = NULL;
-	return NT_STATUS_OK;
 }
 
 NTSTATUS auth_ntlmssp_update(AUTH_NTLMSSP_STATE *auth_ntlmssp_state, 
 			     const DATA_BLOB request, DATA_BLOB *reply) 
 {
-	return ntlmssp_server_update(auth_ntlmssp_state->ntlmssp_state, request, reply);
+	return ntlmssp_update(auth_ntlmssp_state->ntlmssp_state, request, reply);
 }
diff --git a/source3/auth/auth_sam.c b/source3/auth/auth_sam.c
index 2a00b6fb80..7352a9685b 100644
--- a/source3/auth/auth_sam.c
+++ b/source3/auth/auth_sam.c
@@ -33,7 +33,7 @@
 static BOOL smb_pwd_check_ntlmv1(const DATA_BLOB *nt_response,
 				 const uchar *part_passwd,
 				 const DATA_BLOB *sec_blob,
-				 uint8 user_sess_key[16])
+				 DATA_BLOB *user_sess_key)
 {
 	/* Finish the encryption of part_passwd. */
 	uchar p24[24];
@@ -56,7 +56,8 @@ static BOOL smb_pwd_check_ntlmv1(const DATA_BLOB *nt_response,
 
 	SMBOWFencrypt(part_passwd, sec_blob->data, p24);
 	if (user_sess_key != NULL) {
-		SMBsesskeygen_ntv1(part_passwd, NULL, user_sess_key);
+		*user_sess_key = data_blob(NULL, 16);
+		SMBsesskeygen_ntv1(part_passwd, NULL, user_sess_key->data);
 	}
 	
 	
@@ -83,7 +84,7 @@ static BOOL smb_pwd_check_ntlmv2(const DATA_BLOB *ntv2_response,
 				 const uchar *part_passwd,
 				 const DATA_BLOB *sec_blob,
 				 const char *user, const char *domain,
-				 uint8 user_sess_key[16])
+				 DATA_BLOB *user_sess_key)
 {
 	/* Finish the encryption of part_passwd. */
 	uchar kr[16];
@@ -120,7 +121,8 @@ static BOOL smb_pwd_check_ntlmv2(const DATA_BLOB *ntv2_response,
 
 	SMBOWFencrypt_ntv2(kr, sec_blob, &client_key_data, value_from_encryption);
 	if (user_sess_key != NULL) {
-		SMBsesskeygen_ntv2(kr, value_from_encryption, user_sess_key);
+		*user_sess_key = data_blob(NULL, 16);
+		SMBsesskeygen_ntv2(kr, value_from_encryption, user_sess_key->data);
 	}
 
 #if DEBUG_PASSWORD
@@ -148,7 +150,8 @@ static NTSTATUS sam_password_ok(const struct auth_context *auth_context,
 				TALLOC_CTX *mem_ctx,
 				SAM_ACCOUNT *sampass, 
 				const auth_usersupplied_info *user_info, 
-				uint8 user_sess_key[16])
+				DATA_BLOB *user_sess_key, 
+				DATA_BLOB *lm_sess_key)
 {
 	uint16 acct_ctrl;
 	const uint8 *nt_pw, *lm_pw;
@@ -225,6 +228,16 @@ static NTSTATUS sam_password_ok(const struct auth_context *auth_context,
 			if (smb_pwd_check_ntlmv1(&user_info->nt_resp, 
 						 nt_pw, &auth_context->challenge,
 						 user_sess_key)) {
+				/* The LM session key for this response is not very secure, 
+				   so use it only if we otherwise allow LM authentication */
+				lm_pw = pdb_get_lanman_passwd(sampass);
+
+				if (lp_lanman_auth() && lm_pw) {
+					uint8 first_8_lm_hash[16];
+					memcpy(first_8_lm_hash, lm_pw, 8);
+					memset(first_8_lm_hash + 8, '\0', 8);
+					*lm_sess_key = data_blob(first_8_lm_hash, 16);
+				}
 				return NT_STATUS_OK;
 			} else {
 				DEBUG(3,("sam_password_ok: NT MD4 password check failed for user %s\n",pdb_get_username(sampass)));
@@ -252,7 +265,12 @@ static NTSTATUS sam_password_ok(const struct auth_context *auth_context,
 			DEBUG(4,("sam_password_ok: Checking LM password\n"));
 			if (smb_pwd_check_ntlmv1(&user_info->lm_resp, 
 						 lm_pw, &auth_context->challenge,
-						 user_sess_key)) {
+						 NULL)) {
+				uint8 first_8_lm_hash[16];
+				memcpy(first_8_lm_hash, lm_pw, 8);
+				memset(first_8_lm_hash + 8, '\0', 8);
+				*user_sess_key = data_blob(first_8_lm_hash, 16);
+				*lm_sess_key = data_blob(first_8_lm_hash, 16);
 				return NT_STATUS_OK;
 			}
 		}
@@ -272,7 +290,7 @@ static NTSTATUS sam_password_ok(const struct auth_context *auth_context,
 					  nt_pw, &auth_context->challenge, 
 					  user_info->smb_name.str, 
 					  user_info->client_domain.str,
-					  user_sess_key)) {
+					  NULL)) {
 			return NT_STATUS_OK;
 		}
 
@@ -281,7 +299,7 @@ static NTSTATUS sam_password_ok(const struct auth_context *auth_context,
 					  nt_pw, &auth_context->challenge, 
 					  user_info->smb_name.str, 
 					  "",
-					  user_sess_key)) {
+					  NULL)) {
 			return NT_STATUS_OK;
 		}
 
@@ -292,7 +310,19 @@ static NTSTATUS sam_password_ok(const struct auth_context *auth_context,
 		if (lp_ntlm_auth()) {
 			if (smb_pwd_check_ntlmv1(&user_info->lm_resp, 
 						 nt_pw, &auth_context->challenge,
-						 user_sess_key)) {
+						 NULL)) {
+				/* The session key for this response is still very odd.  
+				   It not very secure, so use it only if we otherwise 
+				   allow LM authentication */
+				lm_pw = pdb_get_lanman_passwd(sampass);
+			
+				if (lp_lanman_auth() && lm_pw) {
+					uint8 first_8_lm_hash[16];
+					memcpy(first_8_lm_hash, lm_pw, 8);
+					memset(first_8_lm_hash + 8, '\0', 8);
+					*user_sess_key = data_blob(first_8_lm_hash, 16);
+					*lm_sess_key = data_blob(first_8_lm_hash, 16);
+				}
 				return NT_STATUS_OK;
 			}
 			DEBUG(3,("sam_password_ok: LM password, NT MD4 password in LM field and LMv2 failed for user %s\n",pdb_get_username(sampass)));
@@ -301,7 +331,6 @@ static NTSTATUS sam_password_ok(const struct auth_context *auth_context,
 			DEBUG(3,("sam_password_ok: LM password and LMv2 failed for user %s, and NT MD4 password in LM field not permitted\n",pdb_get_username(sampass)));
 			return NT_STATUS_WRONG_PASSWORD;
 		}
-			
 	}
 		
 	/* Should not be reached, but if they send nothing... */
@@ -421,8 +450,8 @@ static NTSTATUS check_sam_security(const struct auth_context *auth_context,
 	SAM_ACCOUNT *sampass=NULL;
 	BOOL ret;
 	NTSTATUS nt_status;
-	uint8 user_sess_key[16];
-	const uint8* lm_hash;
+	DATA_BLOB user_sess_key = data_blob(NULL, 0);
+	DATA_BLOB lm_sess_key = data_blob(NULL, 0);
 
 	if (!user_info || !auth_context) {
 		return NT_STATUS_UNSUCCESSFUL;
@@ -446,7 +475,8 @@ static NTSTATUS check_sam_security(const struct auth_context *auth_context,
 		return NT_STATUS_NO_SUCH_USER;
 	}
 
-	nt_status = sam_password_ok(auth_context, mem_ctx, sampass, user_info, user_sess_key);
+	nt_status = sam_password_ok(auth_context, mem_ctx, sampass, 
+				    user_info, &user_sess_key, &lm_sess_key);
 	
 	if (!NT_STATUS_IS_OK(nt_status)) {
 		pdb_free_sam(&sampass);
@@ -465,12 +495,8 @@ static NTSTATUS check_sam_security(const struct auth_context *auth_context,
 		return nt_status;
 	}
 
-	lm_hash = pdb_get_lanman_passwd((*server_info)->sam_account);
-	if (lm_hash) {
-		memcpy((*server_info)->first_8_lm_hash, lm_hash, 8);
-	}
-	
-	memcpy((*server_info)->session_key, user_sess_key, sizeof(user_sess_key));
+	(*server_info)->nt_session_key = user_sess_key;
+	(*server_info)->lm_session_key = lm_sess_key;
 
 	return nt_status;
 }
diff --git a/source3/auth/auth_util.c b/source3/auth/auth_util.c
index d7d7f53e2d..5d3f8f0277 100644
--- a/source3/auth/auth_util.c
+++ b/source3/auth/auth_util.c
@@ -900,7 +900,13 @@ NTSTATUS make_server_info_guest(auth_serversupplied_info **server_info)
 	nt_status = make_server_info_sam(server_info, sampass);
 
 	if (NT_STATUS_IS_OK(nt_status)) {
+		static const char zeros[16];
 		(*server_info)->guest = True;
+		
+		/* annoying, but the Guest really does have a session key, 
+		   and it is all zeros! */
+		(*server_info)->nt_session_key = data_blob(zeros, sizeof(zeros));
+		(*server_info)->lm_session_key = data_blob(zeros, sizeof(zeros));
 	}
 
 	return nt_status;
@@ -992,6 +998,8 @@ NTSTATUS make_server_info_info3(TALLOC_CTX *mem_ctx,
 				auth_serversupplied_info **server_info, 
 				NET_USER_INFO_3 *info3) 
 {
+	static const char zeros[16];
+
 	NTSTATUS nt_status = NT_STATUS_OK;
 	char *found_username;
 	const char *nt_domain;
@@ -1210,10 +1218,20 @@ NTSTATUS make_server_info_info3(TALLOC_CTX *mem_ctx,
 	(*server_info)->ptok = token; 
 
 	SAFE_FREE(all_group_SIDs);
+
+	/* ensure we are never given NULL session keys */
 	
-	memcpy((*server_info)->session_key, info3->user_sess_key, sizeof((*server_info)->session_key)/* 16 */);
-	memcpy((*server_info)->first_8_lm_hash, info3->padding, 8);
+	if (memcmp(info3->user_sess_key, zeros, sizeof(zeros)) == 0) {
+		(*server_info)->nt_session_key = data_blob(NULL, 0);
+	} else {
+		(*server_info)->nt_session_key = data_blob(info3->user_sess_key, sizeof(info3->user_sess_key));
+	}
 
+	if (memcmp(info3->padding, zeros, sizeof(zeros)) == 0) {
+		(*server_info)->lm_session_key = data_blob(NULL, 0);
+	} else {
+		(*server_info)->lm_session_key = data_blob(info3->padding, 16);
+	}
 	return NT_STATUS_OK;
 }
 
@@ -1256,6 +1274,8 @@ void free_server_info(auth_serversupplied_info **server_info)
 		delete_nt_token( &(*server_info)->ptok );
 		SAFE_FREE((*server_info)->groups);
 		SAFE_FREE((*server_info)->unix_name);
+		data_blob_free(&(*server_info)->lm_session_key);
+		data_blob_free(&(*server_info)->nt_session_key);
 		ZERO_STRUCT(**server_info);
 	}
 	SAFE_FREE(*server_info);