CIFS: Separate SMB2 header structure

In order to support compounding and encryption we need to separate
RFC1001 length field and SMB2 header structure because the protocol
treats them differently. This change will allow to simplify parsing
of such complex SMB2 packets further.

Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>

1 files changed, 40 insertions, 41 deletions

diff --git a/fs/cifs/smb2transport.c b/fs/cifs/smb2transport.c
index bc9a7b634643..52ff937fd1ed 100644
--- a/fs/cifs/smb2transport.c
+++ b/fs/cifs/smb2transport.c
@@ -115,13 +115,13 @@ smb3_crypto_shash_allocate(struct TCP_Server_Info *server)
 }
 
 static struct cifs_ses *
-smb2_find_smb_ses(struct smb2_hdr *smb2hdr, struct TCP_Server_Info *server)
+smb2_find_smb_ses(struct smb2_sync_hdr *shdr, struct TCP_Server_Info *server)
 {
 	struct cifs_ses *ses;
 
 	spin_lock(&cifs_tcp_ses_lock);
 	list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
-		if (ses->Suid != smb2hdr->SessionId)
+		if (ses->Suid != shdr->SessionId)
 			continue;
 		spin_unlock(&cifs_tcp_ses_lock);
 		return ses;
@@ -131,7 +131,6 @@ smb2_find_smb_ses(struct smb2_hdr *smb2hdr, struct TCP_Server_Info *server)
 	return NULL;
 }
 
-
 int
 smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 {
@@ -139,17 +138,17 @@ smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 	unsigned char smb2_signature[SMB2_HMACSHA256_SIZE];
 	unsigned char *sigptr = smb2_signature;
 	struct kvec *iov = rqst->rq_iov;
-	struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
+	struct smb2_sync_hdr *shdr = get_sync_hdr(iov[0].iov_base);
 	struct cifs_ses *ses;
 
-	ses = smb2_find_smb_ses(smb2_pdu, server);
+	ses = smb2_find_smb_ses(shdr, server);
 	if (!ses) {
 		cifs_dbg(VFS, "%s: Could not find session\n", __func__);
 		return 0;
 	}
 
 	memset(smb2_signature, 0x0, SMB2_HMACSHA256_SIZE);
-	memset(smb2_pdu->Signature, 0x0, SMB2_SIGNATURE_SIZE);
+	memset(shdr->Signature, 0x0, SMB2_SIGNATURE_SIZE);
 
 	rc = smb2_crypto_shash_allocate(server);
 	if (rc) {
@@ -174,7 +173,7 @@ smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 		&server->secmech.sdeschmacsha256->shash);
 
 	if (!rc)
-		memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
+		memcpy(shdr->Signature, sigptr, SMB2_SIGNATURE_SIZE);
 
 	return rc;
 }
@@ -356,17 +355,17 @@ smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 	unsigned char smb3_signature[SMB2_CMACAES_SIZE];
 	unsigned char *sigptr = smb3_signature;
 	struct kvec *iov = rqst->rq_iov;
-	struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
+	struct smb2_sync_hdr *shdr = get_sync_hdr(iov[0].iov_base);
 	struct cifs_ses *ses;
 
-	ses = smb2_find_smb_ses(smb2_pdu, server);
+	ses = smb2_find_smb_ses(shdr, server);
 	if (!ses) {
 		cifs_dbg(VFS, "%s: Could not find session\n", __func__);
 		return 0;
 	}
 
 	memset(smb3_signature, 0x0, SMB2_CMACAES_SIZE);
-	memset(smb2_pdu->Signature, 0x0, SMB2_SIGNATURE_SIZE);
+	memset(shdr->Signature, 0x0, SMB2_SIGNATURE_SIZE);
 
 	rc = crypto_shash_setkey(server->secmech.cmacaes,
 		ses->smb3signingkey, SMB2_CMACAES_SIZE);
@@ -391,7 +390,7 @@ smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 				   &server->secmech.sdesccmacaes->shash);
 
 	if (!rc)
-		memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
+		memcpy(shdr->Signature, sigptr, SMB2_SIGNATURE_SIZE);
 
 	return rc;
 }
@@ -401,14 +400,14 @@ static int
 smb2_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 {
 	int rc = 0;
-	struct smb2_hdr *smb2_pdu = rqst->rq_iov[0].iov_base;
+	struct smb2_sync_hdr *shdr = get_sync_hdr(rqst->rq_iov[0].iov_base);
 
-	if (!(smb2_pdu->Flags & SMB2_FLAGS_SIGNED) ||
+	if (!(shdr->Flags & SMB2_FLAGS_SIGNED) ||
 	    server->tcpStatus == CifsNeedNegotiate)
 		return rc;
 
 	if (!server->session_estab) {
-		strncpy(smb2_pdu->Signature, "BSRSPYL", 8);
+		strncpy(shdr->Signature, "BSRSPYL", 8);
 		return rc;
 	}
 
@@ -422,11 +421,11 @@ smb2_verify_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 {
 	unsigned int rc;
 	char server_response_sig[16];
-	struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
+	struct smb2_sync_hdr *shdr = get_sync_hdr(rqst->rq_iov[0].iov_base);
 
-	if ((smb2_pdu->Command == SMB2_NEGOTIATE) ||
-	    (smb2_pdu->Command == SMB2_SESSION_SETUP) ||
-	    (smb2_pdu->Command == SMB2_OPLOCK_BREAK) ||
+	if ((shdr->Command == SMB2_NEGOTIATE) ||
+	    (shdr->Command == SMB2_SESSION_SETUP) ||
+	    (shdr->Command == SMB2_OPLOCK_BREAK) ||
 	    (!server->session_estab))
 		return 0;
 
@@ -436,17 +435,17 @@ smb2_verify_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 	 */
 
 	/* Do not need to verify session setups with signature "BSRSPYL " */
-	if (memcmp(smb2_pdu->Signature, "BSRSPYL ", 8) == 0)
+	if (memcmp(shdr->Signature, "BSRSPYL ", 8) == 0)
 		cifs_dbg(FYI, "dummy signature received for smb command 0x%x\n",
-			 smb2_pdu->Command);
+			 shdr->Command);
 
 	/*
 	 * Save off the origiginal signature so we can modify the smb and check
 	 * our calculated signature against what the server sent.
 	 */
-	memcpy(server_response_sig, smb2_pdu->Signature, SMB2_SIGNATURE_SIZE);
+	memcpy(server_response_sig, shdr->Signature, SMB2_SIGNATURE_SIZE);
 
-	memset(smb2_pdu->Signature, 0, SMB2_SIGNATURE_SIZE);
+	memset(shdr->Signature, 0, SMB2_SIGNATURE_SIZE);
 
 	mutex_lock(&server->srv_mutex);
 	rc = server->ops->calc_signature(rqst, server);
@@ -455,8 +454,7 @@ smb2_verify_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 	if (rc)
 		return rc;
 
-	if (memcmp(server_response_sig, smb2_pdu->Signature,
-		   SMB2_SIGNATURE_SIZE))
+	if (memcmp(server_response_sig, shdr->Signature, SMB2_SIGNATURE_SIZE))
 		return -EACCES;
 	else
 		return 0;
@@ -467,18 +465,19 @@ smb2_verify_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
  * and when srv_mutex is held.
  */
 static inline void
-smb2_seq_num_into_buf(struct TCP_Server_Info *server, struct smb2_hdr *hdr)
+smb2_seq_num_into_buf(struct TCP_Server_Info *server,
+		      struct smb2_sync_hdr *shdr)
 {
-	unsigned int i, num = le16_to_cpu(hdr->CreditCharge);
+	unsigned int i, num = le16_to_cpu(shdr->CreditCharge);
 
-	hdr->MessageId = get_next_mid64(server);
+	shdr->MessageId = get_next_mid64(server);
 	/* skip message numbers according to CreditCharge field */
 	for (i = 1; i < num; i++)
 		get_next_mid(server);
 }
 
 static struct mid_q_entry *
-smb2_mid_entry_alloc(const struct smb2_hdr *smb_buffer,
+smb2_mid_entry_alloc(const struct smb2_sync_hdr *shdr,
 		     struct TCP_Server_Info *server)
 {
 	struct mid_q_entry *temp;
@@ -493,9 +492,9 @@ smb2_mid_entry_alloc(const struct smb2_hdr *smb_buffer,
 		return temp;
 	else {
 		memset(temp, 0, sizeof(struct mid_q_entry));
-		temp->mid = le64_to_cpu(smb_buffer->MessageId);
+		temp->mid = le64_to_cpu(shdr->MessageId);
 		temp->pid = current->pid;
-		temp->command = smb_buffer->Command;	/* Always LE */
+		temp->command = shdr->Command; /* Always LE */
 		temp->when_alloc = jiffies;
 		temp->server = server;
 
@@ -513,7 +512,7 @@ smb2_mid_entry_alloc(const struct smb2_hdr *smb_buffer,
 }
 
 static int
-smb2_get_mid_entry(struct cifs_ses *ses, struct smb2_hdr *buf,
+smb2_get_mid_entry(struct cifs_ses *ses, struct smb2_sync_hdr *shdr,
 		   struct mid_q_entry **mid)
 {
 	if (ses->server->tcpStatus == CifsExiting)
@@ -525,19 +524,19 @@ smb2_get_mid_entry(struct cifs_ses *ses, struct smb2_hdr *buf,
 	}
 
 	if (ses->status == CifsNew) {
-		if ((buf->Command != SMB2_SESSION_SETUP) &&
-		    (buf->Command != SMB2_NEGOTIATE))
+		if ((shdr->Command != SMB2_SESSION_SETUP) &&
+		    (shdr->Command != SMB2_NEGOTIATE))
 			return -EAGAIN;
 		/* else ok - we are setting up session */
 	}
 
 	if (ses->status == CifsExiting) {
-		if (buf->Command != SMB2_LOGOFF)
+		if (shdr->Command != SMB2_LOGOFF)
 			return -EAGAIN;
 		/* else ok - we are shutting down the session */
 	}
 
-	*mid = smb2_mid_entry_alloc(buf, ses->server);
+	*mid = smb2_mid_entry_alloc(shdr, ses->server);
 	if (*mid == NULL)
 		return -ENOMEM;
 	spin_lock(&GlobalMid_Lock);
@@ -576,12 +575,12 @@ struct mid_q_entry *
 smb2_setup_request(struct cifs_ses *ses, struct smb_rqst *rqst)
 {
 	int rc;
-	struct smb2_hdr *hdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
+	struct smb2_sync_hdr *shdr = get_sync_hdr(rqst->rq_iov[0].iov_base);
 	struct mid_q_entry *mid;
 
-	smb2_seq_num_into_buf(ses->server, hdr);
+	smb2_seq_num_into_buf(ses->server, shdr);
 
-	rc = smb2_get_mid_entry(ses, hdr, &mid);
+	rc = smb2_get_mid_entry(ses, shdr, &mid);
 	if (rc)
 		return ERR_PTR(rc);
 	rc = smb2_sign_rqst(rqst, ses->server);
@@ -596,12 +595,12 @@ struct mid_q_entry *
 smb2_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 {
 	int rc;
-	struct smb2_hdr *hdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
+	struct smb2_sync_hdr *shdr = get_sync_hdr(rqst->rq_iov[0].iov_base);
 	struct mid_q_entry *mid;
 
-	smb2_seq_num_into_buf(server, hdr);
+	smb2_seq_num_into_buf(server, shdr);
 
-	mid = smb2_mid_entry_alloc(hdr, server);
+	mid = smb2_mid_entry_alloc(shdr, server);
 	if (mid == NULL)
 		return ERR_PTR(-ENOMEM);