linux-stable/fs/cifs/smb2transport.c
Steve French 95dc8dd14e Limit allocation of crypto mechanisms to dialect which requires
Updated patch to try to prevent allocation of cifs, smb2 or smb3 crypto
secmech structures unless needed.  Currently cifs allocates all crypto
mechanisms when the first session is established (4 functions and
4 contexts), rather than only allocating these when needed (smb3 needs
two, the rest of the dialects only need one).

Acked-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Steve French <smfrench@gmail.com>
2013-07-04 14:38:08 -05:00

562 lines
15 KiB
C

/*
* 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)
{
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\n");
return PTR_ERR(server->secmech.hmacsha256);
}
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;
return PTR_ERR(server->secmech.cmacaes);
}
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\n", __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;
}
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;
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\n", __func__);
return rc;
}
rc = crypto_shash_setkey(server->secmech.hmacsha256,
server->session_key.response, SMB2_NTLMV2_SESSKEY_SIZE);
if (rc) {
cifs_dbg(VFS, "%s: Could not update with response\n", __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\n");
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\n",
__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\n", __func__);
memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
return rc;
}
void
generate_smb3signingkey(struct TCP_Server_Info *server)
{
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(server->smb3signingkey, 0x0, SMB3_SIGNKEY_SIZE);
rc = smb3_crypto_shash_allocate(server);
if (rc) {
cifs_dbg(VFS, "%s: crypto alloc failed\n", __func__);
goto smb3signkey_ret;
}
rc = crypto_shash_setkey(server->secmech.hmacsha256,
server->session_key.response, SMB2_NTLMV2_SESSKEY_SIZE);
if (rc) {
cifs_dbg(VFS, "%s: Could not set with session key\n", __func__);
goto smb3signkey_ret;
}
rc = crypto_shash_init(&server->secmech.sdeschmacsha256->shash);
if (rc) {
cifs_dbg(VFS, "%s: Could not init sign hmac\n", __func__);
goto smb3signkey_ret;
}
rc = crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
i, 4);
if (rc) {
cifs_dbg(VFS, "%s: Could not update with n\n", __func__);
goto smb3signkey_ret;
}
rc = crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
"SMB2AESCMAC", 12);
if (rc) {
cifs_dbg(VFS, "%s: Could not update with label\n", __func__);
goto smb3signkey_ret;
}
rc = crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
&zero, 1);
if (rc) {
cifs_dbg(VFS, "%s: Could not update with zero\n", __func__);
goto smb3signkey_ret;
}
rc = crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
"SmbSign", 8);
if (rc) {
cifs_dbg(VFS, "%s: Could not update with context\n", __func__);
goto smb3signkey_ret;
}
rc = crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
L, 4);
if (rc) {
cifs_dbg(VFS, "%s: Could not update with L\n", __func__);
goto smb3signkey_ret;
}
rc = crypto_shash_final(&server->secmech.sdeschmacsha256->shash,
hashptr);
if (rc) {
cifs_dbg(VFS, "%s: Could not generate sha256 hash\n", __func__);
goto smb3signkey_ret;
}
memcpy(server->smb3signingkey, hashptr, SMB3_SIGNKEY_SIZE);
smb3signkey_ret:
return;
}
int
smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
{
int i, rc;
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;
memset(smb3_signature, 0x0, SMB2_CMACAES_SIZE);
memset(smb2_pdu->Signature, 0x0, SMB2_SIGNATURE_SIZE);
rc = crypto_shash_setkey(server->secmech.cmacaes,
server->smb3signingkey, SMB2_CMACAES_SIZE);
if (rc) {
cifs_dbg(VFS, "%s: Could not set key for cmac aes\n", __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\n", __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\n",
__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\n", __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_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\n",
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_mid(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\n");
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\n");
return -EAGAIN;
}
if (ses->status != CifsGood) {
/* check if SMB2 session is bad because we are setting it up */
if ((buf->Command != SMB2_SESSION_SETUP) &&
(buf->Command != SMB2_NEGOTIATE))
return -EAGAIN;
/* else ok - we are setting up 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\n",
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;
}