cifs: Cleanup and thus reduce smb session structure and fields used during authentication

Removed following fields from smb session structure
 cryptkey, ntlmv2_hash, tilen, tiblob
and ntlmssp_auth structure is allocated dynamically only if the auth mech
in NTLMSSP.

response field within a session_key structure is used to initially store the
target info (either plucked from type 2 challenge packet in case of NTLMSSP
or fabricated in case of NTLMv2 without extended security) and then to store
Message Authentication Key (mak) (session key + client response).

Server challenge or cryptkey needed during a NTLMSSP authentication
is now part of ntlmssp_auth structure which gets allocated and freed
once authenticaiton process is done.

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

4 files changed, 55 insertions, 47 deletions

diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index ef95a27..f856732 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -328,15 +328,15 @@ build_avpair_blob(struct cifsSesInfo *ses, const struct nls_table *nls_cp)
 	 * 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;
+	ses->auth_key.len = size + 2 * (2 * dlen) + 2 * (2 * wlen) + 8;
+	ses->auth_key.response = kzalloc(ses->auth_key.len, GFP_KERNEL);
+	if (!ses->auth_key.response) {
+		ses->auth_key.len = 0;
 		cERROR(1, "Challenge target info allocation failure");
 		return -ENOMEM;
 	}
 
-	blobptr = ses->tiblob;
+	blobptr = ses->auth_key.response;
 	attrptr = (struct ntlmssp2_name *) blobptr;
 
 	attrptr->type = cpu_to_le16(NTLMSSP_AV_NB_DOMAIN_NAME);
@@ -400,11 +400,11 @@ find_domain_name(struct cifsSesInfo *ses, const struct nls_table *nls_cp)
 	unsigned char *blobend;
 	struct ntlmssp2_name *attrptr;
 
-	if (!ses->tilen || !ses->tiblob)
+	if (!ses->auth_key.len || !ses->auth_key.response)
 		return 0;
 
-	blobptr = ses->tiblob;
-	blobend = ses->tiblob + ses->tilen;
+	blobptr = ses->auth_key.response;
+	blobend = blobptr + ses->auth_key.len;
 
 	while (blobptr + onesize < blobend) {
 		attrptr = (struct ntlmssp2_name *) blobptr;
@@ -436,7 +436,7 @@ find_domain_name(struct cifsSesInfo *ses, const struct nls_table *nls_cp)
 	return 0;
 }
 
-static int calc_ntlmv2_hash(struct cifsSesInfo *ses,
+static int calc_ntlmv2_hash(struct cifsSesInfo *ses, char *ntlmv2_hash,
 			    const struct nls_table *nls_cp)
 {
 	int rc = 0;
@@ -509,7 +509,7 @@ static int calc_ntlmv2_hash(struct cifsSesInfo *ses,
 	}
 
 	rc = crypto_shash_final(&ses->server->secmech.sdeschmacmd5->shash,
-					ses->ntlmv2_hash);
+					ntlmv2_hash);
 
 calc_exit_1:
 	kfree(user);
@@ -518,7 +518,7 @@ calc_exit_2:
 }
 
 static int
-CalcNTLMv2_response(const struct cifsSesInfo *ses)
+CalcNTLMv2_response(const struct cifsSesInfo *ses, char *ntlmv2_hash)
 {
 	int rc;
 	unsigned int offset = CIFS_SESS_KEY_SIZE + 8;
@@ -529,7 +529,7 @@ CalcNTLMv2_response(const struct cifsSesInfo *ses)
 	}
 
 	crypto_shash_setkey(ses->server->secmech.hmacmd5,
-				ses->ntlmv2_hash, CIFS_HMAC_MD5_HASH_SIZE);
+				ntlmv2_hash, CIFS_HMAC_MD5_HASH_SIZE);
 
 	rc = crypto_shash_init(&ses->server->secmech.sdeschmacmd5->shash);
 	if (rc) {
@@ -539,7 +539,7 @@ CalcNTLMv2_response(const struct cifsSesInfo *ses)
 
 	if (ses->server->secType == RawNTLMSSP)
 		memcpy(ses->auth_key.response + offset,
-			ses->cryptkey, CIFS_SERVER_CHALLENGE_SIZE);
+			ses->ntlmssp->cryptkey, CIFS_SERVER_CHALLENGE_SIZE);
 	else
 		memcpy(ses->auth_key.response + offset,
 			ses->server->cryptkey, CIFS_SERVER_CHALLENGE_SIZE);
@@ -558,7 +558,10 @@ setup_ntlmv2_rsp(struct cifsSesInfo *ses, const struct nls_table *nls_cp)
 {
 	int rc;
 	int baselen;
+	unsigned int tilen;
 	struct ntlmv2_resp *buf;
+	char ntlmv2_hash[16];
+	unsigned char *tiblob = NULL; /* target info blob */
 
 	if (ses->server->secType == RawNTLMSSP) {
 		if (!ses->domainName) {
@@ -572,18 +575,22 @@ setup_ntlmv2_rsp(struct cifsSesInfo *ses, const struct nls_table *nls_cp)
 		rc = build_avpair_blob(ses, nls_cp);
 		if (rc) {
 			cERROR(1, "error %d building av pair blob", rc);
-			return rc;
+			goto setup_ntlmv2_rsp_ret;
 		}
 	}
 
 	baselen = CIFS_SESS_KEY_SIZE + sizeof(struct ntlmv2_resp);
-	ses->auth_key.len = baselen + ses->tilen;
-	ses->auth_key.response = kmalloc(ses->auth_key.len, GFP_KERNEL);
+	tilen = ses->auth_key.len;
+	tiblob = ses->auth_key.response;
+
+	ses->auth_key.response = kmalloc(baselen + tilen, GFP_KERNEL);
 	if (!ses->auth_key.response) {
 		rc = ENOMEM;
+		ses->auth_key.len = 0;
 		cERROR(1, "%s: Can't allocate auth blob", __func__);
 		goto setup_ntlmv2_rsp_ret;
 	}
+	ses->auth_key.len += baselen;
 
 	buf = (struct ntlmv2_resp *)
 			(ses->auth_key.response + CIFS_SESS_KEY_SIZE);
@@ -593,17 +600,17 @@ setup_ntlmv2_rsp(struct cifsSesInfo *ses, const struct nls_table *nls_cp)
 	get_random_bytes(&buf->client_chal, sizeof(buf->client_chal));
 	buf->reserved2 = 0;
 
-	memcpy(ses->auth_key.response + baselen, ses->tiblob, ses->tilen);
+	memcpy(ses->auth_key.response + baselen, tiblob, tilen);
 
 	/* calculate ntlmv2_hash */
-	rc = calc_ntlmv2_hash(ses, nls_cp);
+	rc = calc_ntlmv2_hash(ses, ntlmv2_hash, nls_cp);
 	if (rc) {
 		cERROR(1, "could not get v2 hash rc %d", rc);
 		goto setup_ntlmv2_rsp_ret;
 	}
 
 	/* calculate first part of the client response (CR1) */
-	rc = CalcNTLMv2_response(ses);
+	rc = CalcNTLMv2_response(ses, ntlmv2_hash);
 	if (rc) {
 		cERROR(1, "Could not calculate CR1  rc: %d", rc);
 		goto setup_ntlmv2_rsp_ret;
@@ -611,7 +618,7 @@ setup_ntlmv2_rsp(struct cifsSesInfo *ses, const struct nls_table *nls_cp)
 
 	/* now calculate the session key for NTLMv2 */
 	crypto_shash_setkey(ses->server->secmech.hmacmd5,
-		ses->ntlmv2_hash, CIFS_HMAC_MD5_HASH_SIZE);
+		ntlmv2_hash, CIFS_HMAC_MD5_HASH_SIZE);
 
 	rc = crypto_shash_init(&ses->server->secmech.sdeschmacmd5->shash);
 	if (rc) {
@@ -627,9 +634,7 @@ setup_ntlmv2_rsp(struct cifsSesInfo *ses, const struct nls_table *nls_cp)
 		ses->auth_key.response);
 
 setup_ntlmv2_rsp_ret:
-	kfree(ses->tiblob);
-	ses->tiblob = NULL;
-	ses->tilen = 0;
+	kfree(tiblob);
 
 	return rc;
 }
@@ -657,7 +662,7 @@ calc_seckey(struct cifsSesInfo *ses)
 					CIFS_SESS_KEY_SIZE);
 
 	sg_init_one(&sgin, sec_key, CIFS_SESS_KEY_SIZE);
-	sg_init_one(&sgout, ses->ntlmssp.ciphertext, CIFS_CPHTXT_SIZE);
+	sg_init_one(&sgout, ses->ntlmssp->ciphertext, CIFS_CPHTXT_SIZE);
 
 	rc = crypto_blkcipher_encrypt(&desc, &sgout, &sgin, CIFS_CPHTXT_SIZE);
 	if (rc) {
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index b736951..f259e4d 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -119,11 +119,12 @@ struct cifs_secmech {
 	struct sdesc *sdescmd5; /* ctxt to generate cifs/smb signature */
 };
 
-/* per smb connection structure/fields */
+/* per smb session structure/fields */
 struct ntlmssp_auth {
 	__u32 client_flags; /* sent by client in type 1 ntlmsssp exchange */
 	__u32 server_flags; /* sent by server in type 2 ntlmssp exchange */
 	unsigned char ciphertext[CIFS_CPHTXT_SIZE]; /* sent to server */
+	char cryptkey[CIFS_CRYPTO_KEY_SIZE]; /* used by ntlmssp */
 };
 
 struct cifs_cred {
@@ -241,12 +242,8 @@ struct cifsSesInfo {
 	char userName[MAX_USERNAME_SIZE + 1];
 	char *domainName;
 	char *password;
-	char cryptkey[CIFS_CRYPTO_KEY_SIZE]; /* used by ntlmssp */
 	struct session_key auth_key;
-	char ntlmv2_hash[16];
-	unsigned int tilen; /* length of the target info blob */
-	unsigned char *tiblob; /* target info blob in challenge response */
-	struct ntlmssp_auth ntlmssp; /* ciphertext, flags */
+	struct ntlmssp_auth *ntlmssp; /* ciphertext, flags, server challenge */
 	bool need_reconnect:1; /* connection reset, uid now invalid */
 };
 /* no more than one of the following three session flags may be set */
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 4d8004c..9eb327d 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1818,8 +1818,6 @@ cifs_get_smb_ses(struct TCP_Server_Info *server, struct smb_vol *volume_info)
 	if (ses == NULL)
 		goto get_ses_fail;
 
-	ses->tilen = 0;
-	ses->tiblob = NULL;
 	/* new SMB session uses our server ref */
 	ses->server = server;
 	if (server->addr.sockAddr6.sin6_family == AF_INET6)
@@ -1840,10 +1838,9 @@ cifs_get_smb_ses(struct TCP_Server_Info *server, struct smb_vol *volume_info)
 			goto get_ses_fail;
 	}
 	if (volume_info->domainname) {
-		int len = strlen(volume_info->domainname);
-		ses->domainName = kmalloc(len + 1, GFP_KERNEL);
-		if (ses->domainName)
-			strcpy(ses->domainName, volume_info->domainname);
+		ses->domainName = kstrdup(volume_info->domainname, GFP_KERNEL);
+		if (!ses->domainName)
+			goto get_ses_fail;
 	}
 	ses->cred_uid = volume_info->cred_uid;
 	ses->linux_uid = volume_info->linux_uid;
@@ -3213,6 +3210,8 @@ int cifs_setup_session(unsigned int xid, struct cifsSesInfo *ses,
 	kfree(ses->auth_key.response);
 	ses->auth_key.response = NULL;
 	ses->auth_key.len = 0;
+	kfree(ses->ntlmssp);
+	ses->ntlmssp = NULL;
 
 	return rc;
 }
diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index f74c5a8..7b01d3f 100644
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -399,23 +399,22 @@ static int decode_ntlmssp_challenge(char *bcc_ptr, int blob_len,
 		return -EINVAL;
 	}
 
-	memcpy(ses->cryptkey, pblob->Challenge, CIFS_CRYPTO_KEY_SIZE);
+	memcpy(ses->ntlmssp->cryptkey, pblob->Challenge, CIFS_CRYPTO_KEY_SIZE);
 	/* BB we could decode pblob->NegotiateFlags; some may be useful */
 	/* In particular we can examine sign flags */
 	/* BB spec says that if AvId field of MsvAvTimestamp is populated then
 		we must set the MIC field of the AUTHENTICATE_MESSAGE */
-	ses->ntlmssp.server_flags = le32_to_cpu(pblob->NegotiateFlags);
+	ses->ntlmssp->server_flags = le32_to_cpu(pblob->NegotiateFlags);
 	tioffset = cpu_to_le16(pblob->TargetInfoArray.BufferOffset);
 	tilen = cpu_to_le16(pblob->TargetInfoArray.Length);
-	ses->tilen = tilen;
-	if (ses->tilen) {
-		ses->tiblob = kmalloc(tilen, GFP_KERNEL);
-		if (!ses->tiblob) {
+	if (tilen) {
+		ses->auth_key.response = kmalloc(tilen, GFP_KERNEL);
+		if (!ses->auth_key.response) {
 			cERROR(1, "Challenge target info allocation failure");
-			ses->tilen = 0;
 			return -ENOMEM;
 		}
-		memcpy(ses->tiblob,  bcc_ptr + tioffset, ses->tilen);
+		memcpy(ses->auth_key.response, bcc_ptr + tioffset, tilen);
+		ses->auth_key.len = tilen;
 	}
 
 	return 0;
@@ -545,9 +544,9 @@ static int build_ntlmssp_auth_blob(unsigned char *pbuffer,
 	sec_blob->WorkstationName.MaximumLength = 0;
 	tmp += 2;
 
-	if ((ses->ntlmssp.server_flags & NTLMSSP_NEGOTIATE_KEY_XCH) &&
+	if ((ses->ntlmssp->server_flags & NTLMSSP_NEGOTIATE_KEY_XCH) &&
 			!calc_seckey(ses)) {
-		memcpy(tmp, ses->ntlmssp.ciphertext, CIFS_CPHTXT_SIZE);
+		memcpy(tmp, ses->ntlmssp->ciphertext, CIFS_CPHTXT_SIZE);
 		sec_blob->SessionKey.BufferOffset = cpu_to_le32(tmp - pbuffer);
 		sec_blob->SessionKey.Length = cpu_to_le16(CIFS_CPHTXT_SIZE);
 		sec_blob->SessionKey.MaximumLength =
@@ -601,8 +600,16 @@ CIFS_SessSetup(unsigned int xid, struct cifsSesInfo *ses,
 		return -EINVAL;
 
 	type = ses->server->secType;
-
 	cFYI(1, "sess setup type %d", type);
+	if (type == RawNTLMSSP) {
+		/* if memory allocation is successful, caller of this function
+		 * frees it.
+		 */
+		ses->ntlmssp = kmalloc(sizeof(struct ntlmssp_auth), GFP_KERNEL);
+		if (!ses->ntlmssp)
+			return -ENOMEM;
+	}
+
 ssetup_ntlmssp_authenticate:
 	if (phase == NtLmChallenge)
 		phase = NtLmAuthenticate; /* if ntlmssp, now final phase */