Commit 21e73393 authored by Shirish Pargaonkar's avatar Shirish Pargaonkar Committed by Steve French
Browse files

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: default avatarJeff Layton <jlayton@samba.org>
Signed-off-by: default avatarShirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: default avatarSteve French <sfrench@us.ibm.com>
parent 6573e9b7

fs/cifs/cifsencrypt.c

+65 −48
Original line number Diff line number Diff line
@@ -43,15 +43,16 @@ extern void SMBencrypt(unsigned char *passwd, const unsigned char *c8, 
		       unsigned char *p24);



static int cifs_calculate_signature(const struct smb_hdr *cifs_pdu,

				const struct session_key *key, char *signature)

				struct TCP_Server_Info *server, char *signature)

{

	struct	MD5Context context;



	if ((cifs_pdu == NULL) || (signature == NULL) || (key == NULL))

	if (cifs_pdu == NULL || signature == NULL || server == NULL)

		return -EINVAL;



	cifs_MD5_init(&context);

	cifs_MD5_update(&context, (char *)&key->data, key->len);

	cifs_MD5_update(&context, server->session_key.response,

			server->session_key.len);

	cifs_MD5_update(&context, cifs_pdu->Protocol, cifs_pdu->smb_buf_length);



	cifs_MD5_final(signature, &context);
@@ -79,8 +80,7 @@ int cifs_sign_smb(struct smb_hdr *cifs_pdu, struct TCP_Server_Info *server, 
	server->sequence_number++;

	spin_unlock(&GlobalMid_Lock);



	rc = cifs_calculate_signature(cifs_pdu, &server->session_key,

				      smb_signature);

	rc = cifs_calculate_signature(cifs_pdu, server, smb_signature);

	if (rc)

		memset(cifs_pdu->Signature.SecuritySignature, 0, 8);

	else
@@ -90,16 +90,17 @@ int cifs_sign_smb(struct smb_hdr *cifs_pdu, struct TCP_Server_Info *server, 
}



static int cifs_calc_signature2(const struct kvec *iov, int n_vec,

				const struct session_key *key, char *signature)

				struct TCP_Server_Info *server, char *signature)

{

	struct  MD5Context context;

	int i;



	if ((iov == NULL) || (signature == NULL) || (key == NULL))

	if (iov == NULL || signature == NULL || server == NULL)

		return -EINVAL;



	cifs_MD5_init(&context);

	cifs_MD5_update(&context, (char *)&key->data, key->len);

	cifs_MD5_update(&context, server->session_key.response,

				server->session_key.len);

	for (i = 0; i < n_vec; i++) {

		if (iov[i].iov_len == 0)

			continue;
@@ -146,8 +147,7 @@ int cifs_sign_smb2(struct kvec *iov, int n_vec, struct TCP_Server_Info *server, 
	server->sequence_number++;

	spin_unlock(&GlobalMid_Lock);



	rc = cifs_calc_signature2(iov, n_vec, &server->session_key,

				      smb_signature);

	rc = cifs_calc_signature2(iov, n_vec, server, smb_signature);

	if (rc)

		memset(cifs_pdu->Signature.SecuritySignature, 0, 8);

	else
@@ -157,14 +157,14 @@ int cifs_sign_smb2(struct kvec *iov, int n_vec, struct TCP_Server_Info *server, 
}



int cifs_verify_signature(struct smb_hdr *cifs_pdu,

			  const struct session_key *session_key,

			  struct TCP_Server_Info *server,

			  __u32 expected_sequence_number)

{

	unsigned int rc;

	char server_response_sig[8];

	char what_we_think_sig_should_be[20];



	if (cifs_pdu == NULL || session_key == NULL)

	if (cifs_pdu == NULL || server == NULL)

		return -EINVAL;



	if (cifs_pdu->Command == SMB_COM_NEGOTIATE)
@@ -193,7 +193,7 @@ int cifs_verify_signature(struct smb_hdr *cifs_pdu, 
					cpu_to_le32(expected_sequence_number);

	cifs_pdu->Signature.Sequence.Reserved = 0;



	rc = cifs_calculate_signature(cifs_pdu, session_key,

	rc = cifs_calculate_signature(cifs_pdu, server,

		what_we_think_sig_should_be);



	if (rc)
@@ -209,18 +209,28 @@ int cifs_verify_signature(struct smb_hdr *cifs_pdu, 


}



/* We fill in key by putting in 40 byte array which was allocated by caller */

int cifs_calculate_session_key(struct session_key *key, const char *rn,

			   const char *password)

/* first calculate 24 bytes ntlm response and then 16 byte session key */

int setup_ntlm_response(struct cifsSesInfo *ses)

{

	char temp_key[16];

	if ((key == NULL) || (rn == NULL))

	unsigned int temp_len = CIFS_SESS_KEY_SIZE + CIFS_AUTH_RESP_SIZE;

	char temp_key[CIFS_SESS_KEY_SIZE];



	if (!ses)

		return -EINVAL;



	E_md4hash(password, temp_key);

	mdfour(key->data.ntlm, temp_key, 16);

	memcpy(key->data.ntlm+16, rn, CIFS_SESS_KEY_SIZE);

	key->len = 40;

	ses->auth_key.response = kmalloc(temp_len, GFP_KERNEL);

	if (!ses->auth_key.response) {

		cERROR(1, "NTLM can't allocate (%u bytes) memory", temp_len);

		return -ENOMEM;

	}

	ses->auth_key.len = temp_len;



	SMBNTencrypt(ses->password, ses->cryptKey,

			ses->auth_key.response + CIFS_SESS_KEY_SIZE);



	E_md4hash(ses->password, temp_key);

	mdfour(ses->auth_key.response, temp_key, CIFS_SESS_KEY_SIZE);



	return 0;

}
@@ -465,19 +475,13 @@ calc_exit_2: 
}



int

setup_ntlmv2_rsp(struct cifsSesInfo *ses, char *resp_buf,

		      const struct nls_table *nls_cp)

setup_ntlmv2_rsp(struct cifsSesInfo *ses, const struct nls_table *nls_cp)

{

	int rc;

	struct ntlmv2_resp *buf = (struct ntlmv2_resp *)resp_buf;

	int baselen;

	struct ntlmv2_resp *buf;

	struct HMACMD5Context context;



	buf->blob_signature = cpu_to_le32(0x00000101);

	buf->reserved = 0;

	buf->time = cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME));

	get_random_bytes(&buf->client_chal, sizeof(buf->client_chal));

	buf->reserved2 = 0;



	if (ses->server->secType == RawNTLMSSP) {

		if (!ses->domainName) {

			rc = find_domain_name(ses);
@@ -494,22 +498,38 @@ setup_ntlmv2_rsp(struct cifsSesInfo *ses, char *resp_buf, 
		}

	}



	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);

	if (!ses->auth_key.response) {

		rc = ENOMEM;

		cERROR(1, "%s: Can't allocate auth blob", __func__);

		goto setup_ntlmv2_rsp_ret;

	}



	buf = (struct ntlmv2_resp *)

			(ses->auth_key.response + CIFS_SESS_KEY_SIZE);

	buf->blob_signature = cpu_to_le32(0x00000101);

	buf->reserved = 0;

	buf->time = cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME));

	get_random_bytes(&buf->client_chal, sizeof(buf->client_chal));

	buf->reserved2 = 0;



	memcpy(ses->auth_key.response + baselen, ses->tiblob, ses->tilen);



	/* calculate buf->ntlmv2_hash */

	rc = calc_ntlmv2_hash(ses, nls_cp);

	if (rc) {

		cERROR(1, "could not get v2 hash rc %d", rc);

		goto setup_ntlmv2_rsp_ret;

	}

	CalcNTLMv2_response(ses, resp_buf);

	CalcNTLMv2_response(ses);



	/* now calculate the session key for NTLMv2 */

	hmac_md5_init_limK_to_64(ses->ntlmv2_hash, 16, &context);

	hmac_md5_update(resp_buf, 16, &context);

	hmac_md5_final(ses->auth_key.data.ntlmv2.key, &context);



	memcpy(&ses->auth_key.data.ntlmv2.resp, resp_buf,

	       sizeof(struct ntlmv2_resp));

	ses->auth_key.len = 16 + sizeof(struct ntlmv2_resp);

	hmac_md5_update(ses->auth_key.response + CIFS_SESS_KEY_SIZE,

				16, &context);

	hmac_md5_final(ses->auth_key.response, &context);



	return 0;
@@ -521,20 +541,17 @@ setup_ntlmv2_rsp_ret: 
	return rc;

}



void CalcNTLMv2_response(const struct cifsSesInfo *ses,

			 char *v2_session_response)

void CalcNTLMv2_response(const struct cifsSesInfo *ses)

{

	unsigned int offset = CIFS_SESS_KEY_SIZE + 8;

	struct HMACMD5Context context;



	/* rest of v2 struct already generated */

	memcpy(v2_session_response + 8, ses->cryptKey, 8);

	memcpy(ses->auth_key.response + offset, ses->cryptKey, 8);

	hmac_md5_init_limK_to_64(ses->ntlmv2_hash, 16, &context);



	hmac_md5_update(v2_session_response+8,

			sizeof(struct ntlmv2_resp) - 8, &context);



	if (ses->tilen)

		hmac_md5_update(ses->tiblob, ses->tilen, &context);

	hmac_md5_update(ses->auth_key.response + offset,

			ses->auth_key.len - offset, &context);



	hmac_md5_final(v2_session_response, &context);

/*	cifs_dump_mem("v2_sess_rsp: ", v2_session_response, 32); */

	hmac_md5_final(ses->auth_key.response + CIFS_SESS_KEY_SIZE, &context);

}

fs/cifs/cifsglob.h

+1 −8
Original line number Diff line number Diff line
@@ -99,14 +99,7 @@ enum protocolEnum { 


struct session_key {

	unsigned int len;

	union {

		char ntlm[CIFS_SESS_KEY_SIZE + 16];

		char krb5[CIFS_SESS_KEY_SIZE + 16]; /* BB: length correct? */

		struct {

			char key[16];

			struct ntlmv2_resp resp;

		} ntlmv2;

	} data;

	char *response;

};



struct cifs_cred {

fs/cifs/cifspdu.h

+6 −1
Original line number Diff line number Diff line
@@ -130,10 +130,15 @@ 
 */

#define CIFS_CRYPTO_KEY_SIZE (8)



/*

 * Size of the ntlm client response

 */

#define CIFS_AUTH_RESP_SIZE (24)



/*

 * Size of the session key (crypto key encrypted with the password

 */

#define CIFS_SESS_KEY_SIZE (24)

#define CIFS_SESS_KEY_SIZE (16)



/*

 * Maximum user name length

fs/cifs/cifsproto.h

+5 −6
Original line number Diff line number Diff line
@@ -362,13 +362,12 @@ extern int cifs_sign_smb(struct smb_hdr *, struct TCP_Server_Info *, __u32 *); 
extern int cifs_sign_smb2(struct kvec *iov, int n_vec, struct TCP_Server_Info *,

			  __u32 *);

extern int cifs_verify_signature(struct smb_hdr *,

				 const struct session_key *session_key,

				 struct TCP_Server_Info *server,

				__u32 expected_sequence_number);

extern int cifs_calculate_session_key(struct session_key *key, const char *rn,

				 const char *pass);

extern void CalcNTLMv2_response(const struct cifsSesInfo *, char *);

extern int setup_ntlmv2_rsp(struct cifsSesInfo *, char *,

			     const struct nls_table *);

extern void SMBNTencrypt(unsigned char *, unsigned char *, unsigned char *);

extern int setup_ntlm_response(struct cifsSesInfo *);

extern void CalcNTLMv2_response(const struct cifsSesInfo *);

extern int setup_ntlmv2_rsp(struct cifsSesInfo *, const struct nls_table *);

#ifdef CONFIG_CIFS_WEAK_PW_HASH

extern void calc_lanman_hash(const char *password, const char *cryptkey,

				bool encrypt, char *lnm_session_key);

fs/cifs/connect.c

+15 −3
Original line number Diff line number Diff line
@@ -175,6 +175,9 @@ cifs_reconnect(struct TCP_Server_Info *server) 
	}

	server->sequence_number = 0;

	server->session_estab = false;

	kfree(server->session_key.response);

	server->session_key.response = NULL;

	server->session_key.len = 0;



	spin_lock(&GlobalMid_Lock);

	list_for_each(tmp, &server->pending_mid_q) {
@@ -1562,6 +1565,10 @@ cifs_put_tcp_session(struct TCP_Server_Info *server) 


	cifs_fscache_release_client_cookie(server);



	kfree(server->session_key.response);

	server->session_key.response = NULL;

	server->session_key.len = 0;



	task = xchg(&server->tsk, NULL);

	if (task)

		force_sig(SIGKILL, task);
@@ -3178,10 +3185,11 @@ int cifs_setup_session(unsigned int xid, struct cifsSesInfo *ses, 
	} else {

		mutex_lock(&ses->server->srv_mutex);

		if (!server->session_estab) {

			memcpy(&server->session_key.data,

				&ses->auth_key.data, ses->auth_key.len);

			server->session_key.response = ses->auth_key.response;

			server->session_key.len = ses->auth_key.len;

			ses->server->session_estab = true;

			server->sequence_number = 0x2;

			server->session_estab = true;

			ses->auth_key.response = NULL;

		}

		mutex_unlock(&server->srv_mutex);
@@ -3192,6 +3200,10 @@ int cifs_setup_session(unsigned int xid, struct cifsSesInfo *ses, 
		spin_unlock(&GlobalMid_Lock);

	}



	kfree(ses->auth_key.response);

	ses->auth_key.response = NULL;

	ses->auth_key.len = 0;



	return rc;

}

CRA Git | Maintained and supported by SUSTech CRA and CCSE