/*
   *   fs/cifs/smb2transport.c
   *
   *   Copyright (C) International Business Machines  Corp., 2002, 2011
   *                 Etersoft, 2012
   *   Author(s): Steve French (sfrench@us.ibm.com)
   *              Jeremy Allison (jra@samba.org) 2006
   *              Pavel Shilovsky (pshilovsky@samba.org) 2012
   *
   *   This library is free software; you can redistribute it and/or modify
   *   it under the terms of the GNU Lesser General Public License as published
   *   by the Free Software Foundation; either version 2.1 of the License, or
   *   (at your option) any later version.
   *
   *   This library is distributed in the hope that it will be useful,
   *   but WITHOUT ANY WARRANTY; without even the implied warranty of
   *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
   *   the GNU Lesser General Public License for more details.
   *
   *   You should have received a copy of the GNU Lesser General Public License
   *   along with this library; if not, write to the Free Software
   *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
   */
  
  #include <linux/fs.h>
  #include <linux/list.h>
  #include <linux/wait.h>
  #include <linux/net.h>
  #include <linux/delay.h>
  #include <linux/uaccess.h>
  #include <asm/processor.h>
  #include <linux/mempool.h>
  #include <linux/highmem.h>
  #include "smb2pdu.h"
  #include "cifsglob.h"
  #include "cifsproto.h"
  #include "smb2proto.h"
  #include "cifs_debug.h"
  #include "smb2status.h"
  #include "smb2glob.h"
  
  static int
  smb2_crypto_shash_allocate(struct TCP_Server_Info *server)
  {
  	int rc;
  	unsigned int size;
  
  	if (server->secmech.sdeschmacsha256 != NULL)
  		return 0; /* already allocated */
  
  	server->secmech.hmacsha256 = crypto_alloc_shash("hmac(sha256)", 0, 0);
  	if (IS_ERR(server->secmech.hmacsha256)) {
  		cifs_dbg(VFS, "could not allocate crypto hmacsha256
  ");
  		rc = PTR_ERR(server->secmech.hmacsha256);
  		server->secmech.hmacsha256 = NULL;
  		return rc;
  	}
  
  	size = sizeof(struct shash_desc) +
  			crypto_shash_descsize(server->secmech.hmacsha256);
  	server->secmech.sdeschmacsha256 = kmalloc(size, GFP_KERNEL);
  	if (!server->secmech.sdeschmacsha256) {
  		crypto_free_shash(server->secmech.hmacsha256);
  		server->secmech.hmacsha256 = NULL;
  		return -ENOMEM;
  	}
  	server->secmech.sdeschmacsha256->shash.tfm = server->secmech.hmacsha256;
  	server->secmech.sdeschmacsha256->shash.flags = 0x0;
  
  	return 0;
  }
  
  static int
  smb3_crypto_shash_allocate(struct TCP_Server_Info *server)
  {
  	unsigned int size;
  	int rc;
  
  	if (server->secmech.sdesccmacaes != NULL)
  		return 0;  /* already allocated */
  
  	rc = smb2_crypto_shash_allocate(server);
  	if (rc)
  		return rc;
  
  	server->secmech.cmacaes = crypto_alloc_shash("cmac(aes)", 0, 0);
  	if (IS_ERR(server->secmech.cmacaes)) {
  		cifs_dbg(VFS, "could not allocate crypto cmac-aes");
  		kfree(server->secmech.sdeschmacsha256);
  		server->secmech.sdeschmacsha256 = NULL;
  		crypto_free_shash(server->secmech.hmacsha256);
  		server->secmech.hmacsha256 = NULL;
  		rc = PTR_ERR(server->secmech.cmacaes);
  		server->secmech.cmacaes = NULL;
  		return rc;
  	}
  
  	size = sizeof(struct shash_desc) +
  			crypto_shash_descsize(server->secmech.cmacaes);
  	server->secmech.sdesccmacaes = kmalloc(size, GFP_KERNEL);
  	if (!server->secmech.sdesccmacaes) {
  		cifs_dbg(VFS, "%s: Can't alloc cmacaes
  ", __func__);
  		kfree(server->secmech.sdeschmacsha256);
  		server->secmech.sdeschmacsha256 = NULL;
  		crypto_free_shash(server->secmech.hmacsha256);
  		crypto_free_shash(server->secmech.cmacaes);
  		server->secmech.hmacsha256 = NULL;
  		server->secmech.cmacaes = NULL;
  		return -ENOMEM;
  	}
  	server->secmech.sdesccmacaes->shash.tfm = server->secmech.cmacaes;
  	server->secmech.sdesccmacaes->shash.flags = 0x0;
  
  	return 0;
  }
  
  static struct cifs_ses *
  smb2_find_smb_ses(struct smb2_hdr *smb2hdr, 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)
  			continue;
  		spin_unlock(&cifs_tcp_ses_lock);
  		return ses;
  	}
  	spin_unlock(&cifs_tcp_ses_lock);
  
  	return NULL;
  }
  
  
  int
  smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
  {
  	int i, rc;
  	unsigned char smb2_signature[SMB2_HMACSHA256_SIZE];
  	unsigned char *sigptr = smb2_signature;
  	struct kvec *iov = rqst->rq_iov;
  	int n_vec = rqst->rq_nvec;
  	struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
  	struct cifs_ses *ses;
  
  	ses = smb2_find_smb_ses(smb2_pdu, server);
  	if (!ses) {
  		cifs_dbg(VFS, "%s: Could not find session
  ", __func__);
  		return 0;
  	}
  
  	memset(smb2_signature, 0x0, SMB2_HMACSHA256_SIZE);
  	memset(smb2_pdu->Signature, 0x0, SMB2_SIGNATURE_SIZE);
  
  	rc = smb2_crypto_shash_allocate(server);
  	if (rc) {
  		cifs_dbg(VFS, "%s: shah256 alloc failed
  ", __func__);
  		return rc;
  	}
  
  	rc = crypto_shash_setkey(server->secmech.hmacsha256,
  		ses->auth_key.response, SMB2_NTLMV2_SESSKEY_SIZE);
  	if (rc) {
  		cifs_dbg(VFS, "%s: Could not update with response
  ", __func__);
  		return rc;
  	}
  
  	rc = crypto_shash_init(&server->secmech.sdeschmacsha256->shash);
  	if (rc) {
  		cifs_dbg(VFS, "%s: Could not init sha256", __func__);
  		return rc;
  	}
  
  	for (i = 0; i < n_vec; i++) {
  		if (iov[i].iov_len == 0)
  			continue;
  		if (iov[i].iov_base == NULL) {
  			cifs_dbg(VFS, "null iovec entry
  ");
  			return -EIO;
  		}
  		/*
  		 * The first entry includes a length field (which does not get
  		 * signed that occupies the first 4 bytes before the header).
  		 */
  		if (i == 0) {
  			if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
  				break; /* nothing to sign or corrupt header */
  			rc =
  			crypto_shash_update(
  				&server->secmech.sdeschmacsha256->shash,
  				iov[i].iov_base + 4, iov[i].iov_len - 4);
  		} else {
  			rc =
  			crypto_shash_update(
  				&server->secmech.sdeschmacsha256->shash,
  				iov[i].iov_base, iov[i].iov_len);
  		}
  		if (rc) {
  			cifs_dbg(VFS, "%s: Could not update with payload
  ",
  				 __func__);
  			return rc;
  		}
  	}
  
  	/* now hash over the rq_pages array */
  	for (i = 0; i < rqst->rq_npages; i++) {
  		struct kvec p_iov;
  
  		cifs_rqst_page_to_kvec(rqst, i, &p_iov);
  		crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
  					p_iov.iov_base, p_iov.iov_len);
  		kunmap(rqst->rq_pages[i]);
  	}
  
  	rc = crypto_shash_final(&server->secmech.sdeschmacsha256->shash,
  				sigptr);
  	if (rc)
  		cifs_dbg(VFS, "%s: Could not generate sha256 hash
  ", __func__);
  
  	memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
  
  	return rc;
  }
  
  int
  generate_smb3signingkey(struct cifs_ses *ses)
  {
  	unsigned char zero = 0x0;
  	__u8 i[4] = {0, 0, 0, 1};
  	__u8 L[4] = {0, 0, 0, 128};
  	int rc = 0;
  	unsigned char prfhash[SMB2_HMACSHA256_SIZE];
  	unsigned char *hashptr = prfhash;
  
  	memset(prfhash, 0x0, SMB2_HMACSHA256_SIZE);
  	memset(ses->smb3signingkey, 0x0, SMB3_SIGNKEY_SIZE);
  
  	rc = smb3_crypto_shash_allocate(ses->server);
  	if (rc) {
  		cifs_dbg(VFS, "%s: crypto alloc failed
  ", __func__);
  		goto smb3signkey_ret;
  	}
  
  	rc = crypto_shash_setkey(ses->server->secmech.hmacsha256,
  		ses->auth_key.response, SMB2_NTLMV2_SESSKEY_SIZE);
  	if (rc) {
  		cifs_dbg(VFS, "%s: Could not set with session key
  ", __func__);
  		goto smb3signkey_ret;
  	}
  
  	rc = crypto_shash_init(&ses->server->secmech.sdeschmacsha256->shash);
  	if (rc) {
  		cifs_dbg(VFS, "%s: Could not init sign hmac
  ", __func__);
  		goto smb3signkey_ret;
  	}
  
  	rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
  				i, 4);
  	if (rc) {
  		cifs_dbg(VFS, "%s: Could not update with n
  ", __func__);
  		goto smb3signkey_ret;
  	}
  
  	rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
  				"SMB2AESCMAC", 12);
  	if (rc) {
  		cifs_dbg(VFS, "%s: Could not update with label
  ", __func__);
  		goto smb3signkey_ret;
  	}
  
  	rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
  				&zero, 1);
  	if (rc) {
  		cifs_dbg(VFS, "%s: Could not update with zero
  ", __func__);
  		goto smb3signkey_ret;
  	}
  
  	rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
  				"SmbSign", 8);
  	if (rc) {
  		cifs_dbg(VFS, "%s: Could not update with context
  ", __func__);
  		goto smb3signkey_ret;
  	}
  
  	rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
  				L, 4);
  	if (rc) {
  		cifs_dbg(VFS, "%s: Could not update with L
  ", __func__);
  		goto smb3signkey_ret;
  	}
  
  	rc = crypto_shash_final(&ses->server->secmech.sdeschmacsha256->shash,
  				hashptr);
  	if (rc) {
  		cifs_dbg(VFS, "%s: Could not generate sha256 hash
  ", __func__);
  		goto smb3signkey_ret;
  	}
  
  	memcpy(ses->smb3signingkey, hashptr, SMB3_SIGNKEY_SIZE);
  
  smb3signkey_ret:
  	return rc;
  }
  
  int
  smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
  {
  	int i;
  	int rc = 0;
  	unsigned char smb3_signature[SMB2_CMACAES_SIZE];
  	unsigned char *sigptr = smb3_signature;
  	struct kvec *iov = rqst->rq_iov;
  	int n_vec = rqst->rq_nvec;
  	struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
  	struct cifs_ses *ses;
  
  	ses = smb2_find_smb_ses(smb2_pdu, server);
  	if (!ses) {
  		cifs_dbg(VFS, "%s: Could not find session
  ", __func__);
  		return 0;
  	}
  
  	memset(smb3_signature, 0x0, SMB2_CMACAES_SIZE);
  	memset(smb2_pdu->Signature, 0x0, SMB2_SIGNATURE_SIZE);
  
  	rc = crypto_shash_setkey(server->secmech.cmacaes,
  		ses->smb3signingkey, SMB2_CMACAES_SIZE);
  
  	if (rc) {
  		cifs_dbg(VFS, "%s: Could not set key for cmac aes
  ", __func__);
  		return rc;
  	}
  
  	/*
  	 * we already allocate sdesccmacaes when we init smb3 signing key,
  	 * so unlike smb2 case we do not have to check here if secmech are
  	 * initialized
  	 */
  	rc = crypto_shash_init(&server->secmech.sdesccmacaes->shash);
  	if (rc) {
  		cifs_dbg(VFS, "%s: Could not init cmac aes
  ", __func__);
  		return rc;
  	}
  
  	for (i = 0; i < n_vec; i++) {
  		if (iov[i].iov_len == 0)
  			continue;
  		if (iov[i].iov_base == NULL) {
  			cifs_dbg(VFS, "null iovec entry");
  			return -EIO;
  		}
  		/*
  		 * The first entry includes a length field (which does not get
  		 * signed that occupies the first 4 bytes before the header).
  		 */
  		if (i == 0) {
  			if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
  				break; /* nothing to sign or corrupt header */
  			rc =
  			crypto_shash_update(
  				&server->secmech.sdesccmacaes->shash,
  				iov[i].iov_base + 4, iov[i].iov_len - 4);
  		} else {
  			rc =
  			crypto_shash_update(
  				&server->secmech.sdesccmacaes->shash,
  				iov[i].iov_base, iov[i].iov_len);
  		}
  		if (rc) {
  			cifs_dbg(VFS, "%s: Couldn't update cmac aes with payload
  ",
  							__func__);
  			return rc;
  		}
  	}
  
  	/* now hash over the rq_pages array */
  	for (i = 0; i < rqst->rq_npages; i++) {
  		struct kvec p_iov;
  
  		cifs_rqst_page_to_kvec(rqst, i, &p_iov);
  		crypto_shash_update(&server->secmech.sdesccmacaes->shash,
  					p_iov.iov_base, p_iov.iov_len);
  		kunmap(rqst->rq_pages[i]);
  	}
  
  	rc = crypto_shash_final(&server->secmech.sdesccmacaes->shash,
  						sigptr);
  	if (rc)
  		cifs_dbg(VFS, "%s: Could not generate cmac aes
  ", __func__);
  
  	memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
  
  	return rc;
  }
  
  /* must be called with server->srv_mutex held */
  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;
  
  	if (!(smb2_pdu->Flags & SMB2_FLAGS_SIGNED) ||
  	    server->tcpStatus == CifsNeedNegotiate)
  		return rc;
  
  	if (!server->session_estab) {
  		strncpy(smb2_pdu->Signature, "BSRSPYL", 8);
  		return rc;
  	}
  
  	rc = server->ops->calc_signature(rqst, server);
  
  	return rc;
  }
  
  int
  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;
  
  	if ((smb2_pdu->Command == SMB2_NEGOTIATE) ||
  	    (smb2_pdu->Command == SMB2_SESSION_SETUP) ||
  	    (smb2_pdu->Command == SMB2_OPLOCK_BREAK) ||
  	    (!server->session_estab))
  		return 0;
  
  	/*
  	 * BB what if signatures are supposed to be on for session but
  	 * server does not send one? BB
  	 */
  
  	/* Do not need to verify session setups with signature "BSRSPYL " */
  	if (memcmp(smb2_pdu->Signature, "BSRSPYL ", 8) == 0)
  		cifs_dbg(FYI, "dummy signature received for smb command 0x%x
  ",
  			 smb2_pdu->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);
  
  	memset(smb2_pdu->Signature, 0, SMB2_SIGNATURE_SIZE);
  
  	mutex_lock(&server->srv_mutex);
  	rc = server->ops->calc_signature(rqst, server);
  	mutex_unlock(&server->srv_mutex);
  
  	if (rc)
  		return rc;
  
  	if (memcmp(server_response_sig, smb2_pdu->Signature,
  		   SMB2_SIGNATURE_SIZE))
  		return -EACCES;
  	else
  		return 0;
  }
  
  /*
   * Set message id for the request. Should be called after wait_for_free_request
   * and when srv_mutex is held.
   */
  static inline void
  smb2_seq_num_into_buf(struct TCP_Server_Info *server, struct smb2_hdr *hdr)
  {
  	hdr->MessageId = get_next_mid64(server);
  }
  
  static struct mid_q_entry *
  smb2_mid_entry_alloc(const struct smb2_hdr *smb_buffer,
  		     struct TCP_Server_Info *server)
  {
  	struct mid_q_entry *temp;
  
  	if (server == NULL) {
  		cifs_dbg(VFS, "Null TCP session in smb2_mid_entry_alloc
  ");
  		return NULL;
  	}
  
  	temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
  	if (temp == NULL)
  		return temp;
  	else {
  		memset(temp, 0, sizeof(struct mid_q_entry));
  		temp->mid = smb_buffer->MessageId;	/* always LE */
  		temp->pid = current->pid;
  		temp->command = smb_buffer->Command;	/* Always LE */
  		temp->when_alloc = jiffies;
  		temp->server = server;
  
  		/*
  		 * The default is for the mid to be synchronous, so the
  		 * default callback just wakes up the current task.
  		 */
  		temp->callback = cifs_wake_up_task;
  		temp->callback_data = current;
  	}
  
  	atomic_inc(&midCount);
  	temp->mid_state = MID_REQUEST_ALLOCATED;
  	return temp;
  }
  
  static int
  smb2_get_mid_entry(struct cifs_ses *ses, struct smb2_hdr *buf,
  		   struct mid_q_entry **mid)
  {
  	if (ses->server->tcpStatus == CifsExiting)
  		return -ENOENT;
  
  	if (ses->server->tcpStatus == CifsNeedReconnect) {
  		cifs_dbg(FYI, "tcp session dead - return to caller to retry
  ");
  		return -EAGAIN;
  	}
  
  	if (ses->status == CifsNew) {
  		if ((buf->Command != SMB2_SESSION_SETUP) &&
  		    (buf->Command != SMB2_NEGOTIATE))
  			return -EAGAIN;
  		/* else ok - we are setting up session */
  	}
  
  	if (ses->status == CifsExiting) {
  		if (buf->Command != SMB2_LOGOFF)
  			return -EAGAIN;
  		/* else ok - we are shutting down the session */
  	}
  
  	*mid = smb2_mid_entry_alloc(buf, ses->server);
  	if (*mid == NULL)
  		return -ENOMEM;
  	spin_lock(&GlobalMid_Lock);
  	list_add_tail(&(*mid)->qhead, &ses->server->pending_mid_q);
  	spin_unlock(&GlobalMid_Lock);
  	return 0;
  }
  
  int
  smb2_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
  		   bool log_error)
  {
  	unsigned int len = get_rfc1002_length(mid->resp_buf);
  	struct kvec iov;
  	struct smb_rqst rqst = { .rq_iov = &iov,
  				 .rq_nvec = 1 };
  
  	iov.iov_base = (char *)mid->resp_buf;
  	iov.iov_len = get_rfc1002_length(mid->resp_buf) + 4;
  
  	dump_smb(mid->resp_buf, min_t(u32, 80, len));
  	/* convert the length into a more usable form */
  	if (len > 24 && server->sign) {
  		int rc;
  
  		rc = smb2_verify_signature(&rqst, server);
  		if (rc)
  			cifs_dbg(VFS, "SMB signature verification returned error = %d
  ",
  				 rc);
  	}
  
  	return map_smb2_to_linux_error(mid->resp_buf, log_error);
  }
  
  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 mid_q_entry *mid;
  
  	smb2_seq_num_into_buf(ses->server, hdr);
  
  	rc = smb2_get_mid_entry(ses, hdr, &mid);
  	if (rc)
  		return ERR_PTR(rc);
  	rc = smb2_sign_rqst(rqst, ses->server);
  	if (rc) {
  		cifs_delete_mid(mid);
  		return ERR_PTR(rc);
  	}
  	return mid;
  }
  
  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 mid_q_entry *mid;
  
  	smb2_seq_num_into_buf(server, hdr);
  
  	mid = smb2_mid_entry_alloc(hdr, server);
  	if (mid == NULL)
  		return ERR_PTR(-ENOMEM);
  
  	rc = smb2_sign_rqst(rqst, server);
  	if (rc) {
  		DeleteMidQEntry(mid);
  		return ERR_PTR(rc);
  	}
  
  	return mid;
  }