Prepare for encryption support (first part). Add decryption and encryption key...

Prepare for encryption support (first part). Add decryption and encryption key generation. Thanks to Metze for helping with this.

BugLink: http://bugs.launchpad.net/bugs/1670508Reviewed-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Steve French <steve.french@primarydata.com>
(backported from commit 373512ec)
Signed-off-by: Joseph Salisbury <joseph.salisbury@canonical.com>

fs/cifs/cifsglob.h

@@ -227,7 +227,7 @@ struct smb_version_operations {
 	void (*print_stats)(struct seq_file *m, struct cifs_tcon *);
 	void (*dump_share_caps)(struct seq_file *, struct cifs_tcon *);
 	/* verify the message */
-	int (*check_message)(char *, unsigned int);
+	int (*check_message)(char *, unsigned int, struct TCP_Server_Info *);
 	bool (*is_oplock_break)(char *, struct TCP_Server_Info *);
 	void (*downgrade_oplock)(struct TCP_Server_Info *,
 					struct cifsInodeInfo *, bool);
@@ -632,6 +632,7 @@ struct TCP_Server_Info {
 	unsigned int	max_write;
 	struct delayed_work reconnect; /* reconnect workqueue job */
 	struct mutex reconnect_mutex; /* prevent simultaneous reconnects */
+	__u8		preauth_hash[512];
 #endif /* CONFIG_CIFS_SMB2 */
 	unsigned long echo_interval;
 };
@@ -815,7 +816,10 @@ struct cifs_ses {
 	bool need_reconnect:1; /* connection reset, uid now invalid */
 #ifdef CONFIG_CIFS_SMB2
 	__u16 session_flags;
-	char smb3signingkey[SMB3_SIGN_KEY_SIZE]; /* for signing smb3 packets */
+	__u8 smb3signingkey[SMB3_SIGN_KEY_SIZE];
+	__u8 smb3encryptionkey[SMB3_SIGN_KEY_SIZE];
+	__u8 smb3decryptionkey[SMB3_SIGN_KEY_SIZE];
+	__u8 preauth_hash[512];
 #endif /* CONFIG_CIFS_SMB2 */
 };
 

fs/cifs/cifsproto.h

@@ -102,7 +102,7 @@ extern int SendReceiveBlockingLock(const unsigned int xid,
 			struct smb_hdr *out_buf,
 			int *bytes_returned);
 extern int cifs_reconnect(struct TCP_Server_Info *server);
-extern int checkSMB(char *buf, unsigned int length);
+extern int checkSMB(char *buf, unsigned int len, struct TCP_Server_Info *srvr);
 extern bool is_valid_oplock_break(char *, struct TCP_Server_Info *);
 extern bool backup_cred(struct cifs_sb_info *);
 extern bool is_size_safe_to_change(struct cifsInodeInfo *, __u64 eof);
@@ -442,7 +442,8 @@ extern int setup_ntlm_response(struct cifs_ses *, const struct nls_table *);
 extern int setup_ntlmv2_rsp(struct cifs_ses *, const struct nls_table *);
 extern void cifs_crypto_shash_release(struct TCP_Server_Info *);
 extern int calc_seckey(struct cifs_ses *);
-extern int generate_smb3signingkey(struct cifs_ses *);
+extern int generate_smb30signingkey(struct cifs_ses *);
+extern int generate_smb311signingkey(struct cifs_ses *);
 
 #ifdef CONFIG_CIFS_WEAK_PW_HASH
 extern int calc_lanman_hash(const char *password, const char *cryptkey,

fs/cifs/connect.c

@@ -836,7 +836,7 @@ standard_receive3(struct TCP_Server_Info *server, struct mid_q_entry *mid)
 	 * 48 bytes is enough to display the header and a little bit
 	 * into the payload for debugging purposes.
 	 */
-	length = server->ops->check_message(buf, server->total_read);
+	length = server->ops->check_message(buf, server->total_read, server);
 	if (length != 0)
 		cifs_dump_mem("Bad SMB: ", buf,
 			min_t(unsigned int, server->total_read, 48));

fs/cifs/misc.c

@@ -311,7 +311,7 @@ check_smb_hdr(struct smb_hdr *smb)
 }
 
 int
-checkSMB(char *buf, unsigned int total_read)
+checkSMB(char *buf, unsigned int total_read, struct TCP_Server_Info *server)
 {
 	struct smb_hdr *smb = (struct smb_hdr *)buf;
 	__u32 rfclen = be32_to_cpu(smb->smb_buf_length);

fs/cifs/smb2misc.c

@@ -38,7 +38,7 @@ check_smb2_hdr(struct smb2_hdr *hdr, __u64 mid)
 	 * Make sure that this really is an SMB, that it is a response,
 	 * and that the message ids match.
 	 */
-	if ((*(__le32 *)hdr->ProtocolId == SMB2_PROTO_NUMBER) &&
+	if ((hdr->ProtocolId == SMB2_PROTO_NUMBER) &&
 	    (mid == wire_mid)) {
 		if (hdr->Flags & SMB2_FLAGS_SERVER_TO_REDIR)
 			return 0;
@@ -50,9 +50,9 @@ check_smb2_hdr(struct smb2_hdr *hdr, __u64 mid)
 				cifs_dbg(VFS, "Received Request not response\n");
 		}
 	} else { /* bad signature or mid */
-		if (*(__le32 *)hdr->ProtocolId != SMB2_PROTO_NUMBER)
+		if (hdr->ProtocolId != SMB2_PROTO_NUMBER)
 			cifs_dbg(VFS, "Bad protocol string signature header %x\n",
-				 *(unsigned int *) hdr->ProtocolId);
+				 le32_to_cpu(hdr->ProtocolId));
 		if (mid != wire_mid)
 			cifs_dbg(VFS, "Mids do not match: %llu and %llu\n",
 				 mid, wire_mid);
@@ -93,11 +93,11 @@ static const __le16 smb2_rsp_struct_sizes[NUMBER_OF_SMB2_COMMANDS] = {
 };
 
 int
-smb2_check_message(char *buf, unsigned int length)
+smb2_check_message(char *buf, unsigned int length, struct TCP_Server_Info *srvr)
 {
 	struct smb2_hdr *hdr = (struct smb2_hdr *)buf;
 	struct smb2_pdu *pdu = (struct smb2_pdu *)hdr;
-	__u64 mid = le64_to_cpu(hdr->MessageId);
+	__u64 mid;
 	__u32 len = get_rfc1002_length(buf);
 	__u32 clc_len;  /* calculated length */
 	int command;
@@ -111,6 +111,30 @@ smb2_check_message(char *buf, unsigned int length)
 	 * ie Validate the wct via smb2_struct_sizes table above
 	 */
 
+	if (hdr->ProtocolId == SMB2_TRANSFORM_PROTO_NUM) {
+		struct smb2_transform_hdr *thdr =
+			(struct smb2_transform_hdr *)buf;
+		struct cifs_ses *ses = NULL;
+		struct list_head *tmp;
+
+		/* decrypt frame now that it is completely read in */
+		spin_lock(&cifs_tcp_ses_lock);
+		list_for_each(tmp, &srvr->smb_ses_list) {
+			ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
+			if (ses->Suid == thdr->SessionId)
+				break;
+
+			ses = NULL;
+		}
+		spin_unlock(&cifs_tcp_ses_lock);
+		if (ses == NULL) {
+			cifs_dbg(VFS, "no decryption - session id not found\n");
+			return 1;
+		}
+	}
+
+
+	mid = le64_to_cpu(hdr->MessageId);
 	if (length < sizeof(struct smb2_pdu)) {
 		if ((length >= sizeof(struct smb2_hdr)) && (hdr->Status != 0)) {
 			pdu->StructureSize2 = 0;
@@ -322,7 +346,7 @@ smb2_get_data_area_len(int *off, int *len, struct smb2_hdr *hdr)
 
 	/* return pointer to beginning of data area, ie offset from SMB start */
 	if ((*off != 0) && (*len != 0))
-		return (char *)(&hdr->ProtocolId[0]) + *off;
+		return (char *)(&hdr->ProtocolId) + *off;
 	else
 		return NULL;
 }

fs/cifs/smb2ops.c

@@ -182,6 +182,11 @@ smb2_find_mid(struct TCP_Server_Info *server, char *buf)
 	struct smb2_hdr *hdr = (struct smb2_hdr *)buf;
 	__u64 wire_mid = le64_to_cpu(hdr->MessageId);
 
+	if (hdr->ProtocolId == SMB2_TRANSFORM_PROTO_NUM) {
+		cifs_dbg(VFS, "encrypted frame parsing not supported yet");
+		return NULL;
+	}
+
 	spin_lock(&GlobalMid_Lock);
 	list_for_each_entry(mid, &server->pending_mid_q, qhead) {
 		if ((mid->mid == wire_mid) &&
@@ -1720,7 +1725,7 @@ struct smb_version_operations smb30_operations = {
 	.get_lease_key = smb2_get_lease_key,
 	.set_lease_key = smb2_set_lease_key,
 	.new_lease_key = smb2_new_lease_key,
-	.generate_signingkey = generate_smb3signingkey,
+	.generate_signingkey = generate_smb30signingkey,
 	.calc_signature = smb3_calc_signature,
 	.set_integrity  = smb3_set_integrity,
 	.is_read_op = smb21_is_read_op,
@@ -1807,7 +1812,7 @@ struct smb_version_operations smb311_operations = {
 	.get_lease_key = smb2_get_lease_key,
 	.set_lease_key = smb2_set_lease_key,
 	.new_lease_key = smb2_new_lease_key,
-	.generate_signingkey = generate_smb3signingkey,
+	.generate_signingkey = generate_smb311signingkey,
 	.calc_signature = smb3_calc_signature,
 	.set_integrity  = smb3_set_integrity,
 	.is_read_op = smb21_is_read_op,
@@ -1866,7 +1871,7 @@ struct smb_version_values smb21_values = {
 struct smb_version_values smb30_values = {
 	.version_string = SMB30_VERSION_STRING,
 	.protocol_id = SMB30_PROT_ID,
-	.req_capabilities = SMB2_GLOBAL_CAP_DFS | SMB2_GLOBAL_CAP_LEASING | SMB2_GLOBAL_CAP_LARGE_MTU | SMB2_GLOBAL_CAP_PERSISTENT_HANDLES,
+	.req_capabilities = SMB2_GLOBAL_CAP_DFS | SMB2_GLOBAL_CAP_LEASING | SMB2_GLOBAL_CAP_LARGE_MTU | SMB2_GLOBAL_CAP_PERSISTENT_HANDLES | SMB2_GLOBAL_CAP_ENCRYPTION,
 	.large_lock_type = 0,
 	.exclusive_lock_type = SMB2_LOCKFLAG_EXCLUSIVE_LOCK,
 	.shared_lock_type = SMB2_LOCKFLAG_SHARED_LOCK,
@@ -1886,7 +1891,7 @@ struct smb_version_values smb30_values = {
 struct smb_version_values smb302_values = {
 	.version_string = SMB302_VERSION_STRING,
 	.protocol_id = SMB302_PROT_ID,
-	.req_capabilities = SMB2_GLOBAL_CAP_DFS | SMB2_GLOBAL_CAP_LEASING | SMB2_GLOBAL_CAP_LARGE_MTU | SMB2_GLOBAL_CAP_PERSISTENT_HANDLES,
+	.req_capabilities = SMB2_GLOBAL_CAP_DFS | SMB2_GLOBAL_CAP_LEASING | SMB2_GLOBAL_CAP_LARGE_MTU | SMB2_GLOBAL_CAP_PERSISTENT_HANDLES | SMB2_GLOBAL_CAP_ENCRYPTION,
 	.large_lock_type = 0,
 	.exclusive_lock_type = SMB2_LOCKFLAG_EXCLUSIVE_LOCK,
 	.shared_lock_type = SMB2_LOCKFLAG_SHARED_LOCK,

fs/cifs/smb2pdu.c

@@ -97,10 +97,7 @@ smb2_hdr_assemble(struct smb2_hdr *hdr, __le16 smb2_cmd /* command */ ,
 	hdr->smb2_buf_length = cpu_to_be32(parmsize + sizeof(struct smb2_hdr)
 			- 4 /*  RFC 1001 length field itself not counted */);
 
-	hdr->ProtocolId[0] = 0xFE;
-	hdr->ProtocolId[1] = 'S';
-	hdr->ProtocolId[2] = 'M';
-	hdr->ProtocolId[3] = 'B';
+	hdr->ProtocolId = SMB2_PROTO_NUMBER;
 	hdr->StructureSize = cpu_to_le16(64);
 	hdr->Command = smb2_cmd;
 	if (tcon && tcon->ses && tcon->ses->server) {
@@ -1597,7 +1594,8 @@ SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
 		goto ioctl_exit;
 	}
 
-	memcpy(*out_data, rsp->hdr.ProtocolId + le32_to_cpu(rsp->OutputOffset),
+	memcpy(*out_data,
+	       (char *)&rsp->hdr.ProtocolId + le32_to_cpu(rsp->OutputOffset),
 	       *plen);
 ioctl_exit:
 	free_rsp_buf(resp_buftype, rsp);
@@ -2172,7 +2170,7 @@ SMB2_read(const unsigned int xid, struct cifs_io_parms *io_parms,
 	}
 
 	if (*buf) {
-		memcpy(*buf, (char *)rsp->hdr.ProtocolId + rsp->DataOffset,
+		memcpy(*buf, (char *)&rsp->hdr.ProtocolId + rsp->DataOffset,
 		       *nbytes);
 		free_rsp_buf(resp_buftype, iov[0].iov_base);
 	} else if (resp_buftype != CIFS_NO_BUFFER) {

fs/cifs/smb2pdu.h

@@ -86,6 +86,7 @@
 #define MAX_SMB2_HDR_SIZE 0x78 /* 4 len + 64 hdr + (2*24 wct) + 2 bct + 2 pad */
 
 #define SMB2_PROTO_NUMBER cpu_to_le32(0x424d53fe)
+#define SMB2_TRANSFORM_PROTO_NUM cpu_to_le32(0x424d53fd)
 
 /*
  * SMB2 Header Definition
@@ -102,7 +103,7 @@ struct smb2_hdr {
 	__be32 smb2_buf_length;	/* big endian on wire */
 				/* length is only two or three bytes - with
 				 one or two byte type preceding it that MBZ */
-	__u8   ProtocolId[4];	/* 0xFE 'S' 'M' 'B' */
+	__le32 ProtocolId;	/* 0xFE 'S' 'M' 'B' */
 	__le16 StructureSize;	/* 64 */
 	__le16 CreditCharge;	/* MBZ */
 	__le32 Status;		/* Error from server */
@@ -128,11 +129,10 @@ struct smb2_transform_hdr {
 				 one or two byte type preceding it that MBZ */
 	__u8   ProtocolId[4];	/* 0xFD 'S' 'M' 'B' */
 	__u8   Signature[16];
-	__u8   Nonce[11];
-	__u8   Reserved[5];
+	__u8   Nonce[16];
 	__le32 OriginalMessageSize;
 	__u16  Reserved1;
-	__le16 EncryptionAlgorithm;
+	__le16 Flags; /* EncryptionAlgorithm */
 	__u64  SessionId;
 } __packed;
 

fs/cifs/smb2proto.h

@@ -34,7 +34,8 @@ struct smb_rqst;
  *****************************************************************
  */
 extern int map_smb2_to_linux_error(char *buf, bool log_err);
-extern int smb2_check_message(char *buf, unsigned int length);
+extern int smb2_check_message(char *buf, unsigned int length,
+			      struct TCP_Server_Info *server);
 extern unsigned int smb2_calc_size(void *buf);
 extern char *smb2_get_data_area_len(int *off, int *len, struct smb2_hdr *hdr);
 extern __le16 *cifs_convert_path_to_utf16(const char *from,

fs/cifs/smb2transport.c

@@ -222,8 +222,8 @@ smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 	return rc;
 }
 
-int
-generate_smb3signingkey(struct cifs_ses *ses)
+static int generate_key(struct cifs_ses *ses, struct kvec label,
+			struct kvec context, __u8 *key, unsigned int key_size)
 {
 	unsigned char zero = 0x0;
 	__u8 i[4] = {0, 0, 0, 1};
@@ -233,7 +233,7 @@ generate_smb3signingkey(struct cifs_ses *ses)
 	unsigned char *hashptr = prfhash;
 
 	memset(prfhash, 0x0, SMB2_HMACSHA256_SIZE);
-	memset(ses->smb3signingkey, 0x0, SMB3_SIGNKEY_SIZE);
+	memset(key, 0x0, key_size);
 
 	rc = smb3_crypto_shash_allocate(ses->server);
 	if (rc) {
@@ -262,7 +262,7 @@ generate_smb3signingkey(struct cifs_ses *ses)
 	}
 
 	rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
-				"SMB2AESCMAC", 12);
+				label.iov_base, label.iov_len);
 	if (rc) {
 		cifs_dbg(VFS, "%s: Could not update with label\n", __func__);
 		goto smb3signkey_ret;
@@ -276,7 +276,7 @@ generate_smb3signingkey(struct cifs_ses *ses)
 	}
 
 	rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
-				"SmbSign", 8);
+				context.iov_base, context.iov_len);
 	if (rc) {
 		cifs_dbg(VFS, "%s: Could not update with context\n", __func__);
 		goto smb3signkey_ret;
@@ -296,12 +296,102 @@ generate_smb3signingkey(struct cifs_ses *ses)
 		goto smb3signkey_ret;
 	}
 
-	memcpy(ses->smb3signingkey, hashptr, SMB3_SIGNKEY_SIZE);
+	memcpy(key, hashptr, key_size);
 
 smb3signkey_ret:
 	return rc;
 }
 
+struct derivation {
+	struct kvec label;
+	struct kvec context;
+};
+
+struct derivation_triplet {
+	struct derivation signing;
+	struct derivation encryption;
+	struct derivation decryption;
+};
+
+static int
+generate_smb3signingkey(struct cifs_ses *ses,
+			const struct derivation_triplet *ptriplet)
+{
+	int rc;
+
+	rc = generate_key(ses, ptriplet->signing.label,
+			  ptriplet->signing.context, ses->smb3signingkey,
+			  SMB3_SIGN_KEY_SIZE);
+	if (rc)
+		return rc;
+
+	rc = generate_key(ses, ptriplet->encryption.label,
+			  ptriplet->encryption.context, ses->smb3encryptionkey,
+			  SMB3_SIGN_KEY_SIZE);
+	if (rc)
+		return rc;
+
+	return generate_key(ses, ptriplet->decryption.label,
+			    ptriplet->decryption.context,
+			    ses->smb3decryptionkey, SMB3_SIGN_KEY_SIZE);
+}
+
+int
+generate_smb30signingkey(struct cifs_ses *ses)
+
+{
+	struct derivation_triplet triplet;
+	struct derivation *d;
+
+	d = &triplet.signing;
+	d->label.iov_base = "SMB2AESCMAC";
+	d->label.iov_len = 12;
+	d->context.iov_base = "SmbSign";
+	d->context.iov_len = 8;
+
+	d = &triplet.encryption;
+	d->label.iov_base = "SMB2AESCCM";
+	d->label.iov_len = 11;
+	d->context.iov_base = "ServerIn ";
+	d->context.iov_len = 10;
+
+	d = &triplet.decryption;
+	d->label.iov_base = "SMB2AESCCM";
+	d->label.iov_len = 11;
+	d->context.iov_base = "ServerOut";
+	d->context.iov_len = 10;
+
+	return generate_smb3signingkey(ses, &triplet);
+}
+
+int
+generate_smb311signingkey(struct cifs_ses *ses)
+
+{
+	struct derivation_triplet triplet;
+	struct derivation *d;
+
+	d = &triplet.signing;
+	d->label.iov_base = "SMB2AESCMAC";
+	d->label.iov_len = 12;
+	d->context.iov_base = "SmbSign";
+	d->context.iov_len = 8;
+
+	d = &triplet.encryption;
+	d->label.iov_base = "SMB2AESCCM";
+	d->label.iov_len = 11;
+	d->context.iov_base = "ServerIn ";
+	d->context.iov_len = 10;
+
+	d = &triplet.decryption;
+	d->label.iov_base = "SMB2AESCCM";
+	d->label.iov_len = 11;
+	d->context.iov_base = "ServerOut";
+	d->context.iov_len = 10;
+
+	return generate_smb3signingkey(ses, &triplet);
+}
+
 int
 smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 {