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

Reviewed-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Steve French <steve.french@primarydata.com>

10 files changed, 156 insertions, 33 deletions

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 9d14926..a25b251 100644
--- a/fs/cifs/cifsglob.h
+++ b/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);
@@ -630,6 +630,7 @@ struct TCP_Server_Info {
 #ifdef CONFIG_CIFS_SMB2
 	unsigned int	max_read;
 	unsigned int	max_write;
+	__u8		preauth_hash[512];
 #endif /* CONFIG_CIFS_SMB2 */
 	unsigned long echo_interval;
 };
@@ -813,7 +814,10 @@ 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 */
 };
 
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index c63fd1d..eed7ff5 100644
--- a/fs/cifs/cifsproto.h
+++ b/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);
@@ -439,7 +439,8 @@ 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,
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index de53c55..6ab9e83 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -831,7 +831,7 @@ 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));
diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index 8442b8b..813fe13 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -310,7 +310,7 @@ 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);
diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
index 1c59070..389fb9f 100644
--- a/fs/cifs/smb2misc.c
+++ b/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;
 }
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 53ccdde..3525ed7 100644
--- a/fs/cifs/smb2ops.c
+++ b/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) &&
@@ -1692,7 +1697,7 @@ 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,
@@ -1779,7 +1784,7 @@ 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,
@@ -1838,7 +1843,7 @@ 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,
@@ -1858,7 +1863,7 @@ 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,
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 7675555..10f8d5c 100644
--- a/fs/cifs/smb2pdu.c
+++ b/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;
 	hdr->CreditRequest = cpu_to_le16(2); /* BB make this dynamic */
@@ -1573,7 +1570,8 @@ 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);
@@ -2093,7 +2091,7 @@ 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) {
diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h
index 4af5278..ff88d9f 100644
--- a/fs/cifs/smb2pdu.h
+++ b/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;
 
diff --git a/fs/cifs/smb2proto.h b/fs/cifs/smb2proto.h
index 79dc650..4f07dc9 100644
--- a/fs/cifs/smb2proto.h
+++ b/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,
diff --git a/fs/cifs/smb2transport.c b/fs/cifs/smb2transport.c
index d4c5b6f..8732a43 100644
--- a/fs/cifs/smb2transport.c
+++ b/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)
 {