linux/fs/cifs/smb2transport.c
Aurelien Aptel a5c62f4833 CIFS: fix uninitialized ptr deref in smb2 signing
server->secmech.sdeschmacsha256 is not properly initialized before
smb2_shash_allocate(), set shash after that call.

also fix typo in error message

Fixes: 8de8c4608f ("cifs: Fix validation of signed data in smb2")

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Paulo Alcantara <palcantara@suse.com>
Reported-by: Xiaoli Feng <xifeng@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
2018-08-07 14:30:59 -05:00

739 lines
18 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 <crypto/aead.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)
{
return cifs_alloc_hash("hmac(sha256)",
&server->secmech.hmacsha256,
&server->secmech.sdeschmacsha256);
}
static int
smb3_crypto_shash_allocate(struct TCP_Server_Info *server)
{
struct cifs_secmech *p = &server->secmech;
int rc;
rc = cifs_alloc_hash("hmac(sha256)",
&p->hmacsha256,
&p->sdeschmacsha256);
if (rc)
goto err;
rc = cifs_alloc_hash("cmac(aes)", &p->cmacaes, &p->sdesccmacaes);
if (rc)
goto err;
return 0;
err:
cifs_free_hash(&p->hmacsha256, &p->sdeschmacsha256);
return rc;
}
int
smb311_crypto_shash_allocate(struct TCP_Server_Info *server)
{
struct cifs_secmech *p = &server->secmech;
int rc = 0;
rc = cifs_alloc_hash("hmac(sha256)",
&p->hmacsha256,
&p->sdeschmacsha256);
if (rc)
return rc;
rc = cifs_alloc_hash("cmac(aes)", &p->cmacaes, &p->sdesccmacaes);
if (rc)
goto err;
rc = cifs_alloc_hash("sha512", &p->sha512, &p->sdescsha512);
if (rc)
goto err;
return 0;
err:
cifs_free_hash(&p->cmacaes, &p->sdesccmacaes);
cifs_free_hash(&p->hmacsha256, &p->sdeschmacsha256);
return rc;
}
static struct cifs_ses *
smb2_find_smb_ses_unlocked(struct TCP_Server_Info *server, __u64 ses_id)
{
struct cifs_ses *ses;
list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
if (ses->Suid != ses_id)
continue;
return ses;
}
return NULL;
}
struct cifs_ses *
smb2_find_smb_ses(struct TCP_Server_Info *server, __u64 ses_id)
{
struct cifs_ses *ses;
spin_lock(&cifs_tcp_ses_lock);
ses = smb2_find_smb_ses_unlocked(server, ses_id);
spin_unlock(&cifs_tcp_ses_lock);
return ses;
}
static struct cifs_tcon *
smb2_find_smb_sess_tcon_unlocked(struct cifs_ses *ses, __u32 tid)
{
struct cifs_tcon *tcon;
list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
if (tcon->tid != tid)
continue;
++tcon->tc_count;
return tcon;
}
return NULL;
}
/*
* Obtain tcon corresponding to the tid in the given
* cifs_ses
*/
struct cifs_tcon *
smb2_find_smb_tcon(struct TCP_Server_Info *server, __u64 ses_id, __u32 tid)
{
struct cifs_ses *ses;
struct cifs_tcon *tcon;
spin_lock(&cifs_tcp_ses_lock);
ses = smb2_find_smb_ses_unlocked(server, ses_id);
if (!ses) {
spin_unlock(&cifs_tcp_ses_lock);
return NULL;
}
tcon = smb2_find_smb_sess_tcon_unlocked(ses, tid);
spin_unlock(&cifs_tcp_ses_lock);
return tcon;
}
int
smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
{
int rc;
unsigned char smb2_signature[SMB2_HMACSHA256_SIZE];
unsigned char *sigptr = smb2_signature;
struct kvec *iov = rqst->rq_iov;
struct smb2_sync_hdr *shdr = (struct smb2_sync_hdr *)iov[0].iov_base;
struct cifs_ses *ses;
struct shash_desc *shash;
struct smb_rqst drqst;
ses = smb2_find_smb_ses(server, shdr->SessionId);
if (!ses) {
cifs_dbg(VFS, "%s: Could not find session\n", __func__);
return 0;
}
memset(smb2_signature, 0x0, SMB2_HMACSHA256_SIZE);
memset(shdr->Signature, 0x0, SMB2_SIGNATURE_SIZE);
rc = smb2_crypto_shash_allocate(server);
if (rc) {
cifs_dbg(VFS, "%s: sha256 alloc failed\n", __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\n", __func__);
return rc;
}
shash = &server->secmech.sdeschmacsha256->shash;
rc = crypto_shash_init(shash);
if (rc) {
cifs_dbg(VFS, "%s: Could not init sha256", __func__);
return rc;
}
/*
* For SMB2+, __cifs_calc_signature() expects to sign only the actual
* data, that is, iov[0] should not contain a rfc1002 length.
*
* Sign the rfc1002 length prior to passing the data (iov[1-N]) down to
* __cifs_calc_signature().
*/
drqst = *rqst;
if (drqst.rq_nvec >= 2 && iov[0].iov_len == 4) {
rc = crypto_shash_update(shash, iov[0].iov_base,
iov[0].iov_len);
if (rc) {
cifs_dbg(VFS, "%s: Could not update with payload\n",
__func__);
return rc;
}
drqst.rq_iov++;
drqst.rq_nvec--;
}
rc = __cifs_calc_signature(&drqst, server, sigptr, shash);
if (!rc)
memcpy(shdr->Signature, sigptr, SMB2_SIGNATURE_SIZE);
return rc;
}
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};
__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(key, 0x0, key_size);
rc = smb3_crypto_shash_allocate(ses->server);
if (rc) {
cifs_dbg(VFS, "%s: crypto alloc failed\n", __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\n", __func__);
goto smb3signkey_ret;
}
rc = crypto_shash_init(&ses->server->secmech.sdeschmacsha256->shash);
if (rc) {
cifs_dbg(VFS, "%s: Could not init sign hmac\n", __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\n", __func__);
goto smb3signkey_ret;
}
rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
label.iov_base, label.iov_len);
if (rc) {
cifs_dbg(VFS, "%s: Could not update with label\n", __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\n", __func__);
goto smb3signkey_ret;
}
rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
context.iov_base, context.iov_len);
if (rc) {
cifs_dbg(VFS, "%s: Could not update with context\n", __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\n", __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\n", __func__);
goto smb3signkey_ret;
}
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;
rc = generate_key(ses, ptriplet->decryption.label,
ptriplet->decryption.context,
ses->smb3decryptionkey, SMB3_SIGN_KEY_SIZE);
if (rc)
return rc;
#ifdef CONFIG_CIFS_DEBUG_DUMP_KEYS
cifs_dbg(VFS, "%s: dumping generated AES session keys\n", __func__);
/*
* The session id is opaque in terms of endianness, so we can't
* print it as a long long. we dump it as we got it on the wire
*/
cifs_dbg(VFS, "Session Id %*ph\n", (int)sizeof(ses->Suid),
&ses->Suid);
cifs_dbg(VFS, "Session Key %*ph\n",
SMB2_NTLMV2_SESSKEY_SIZE, ses->auth_key.response);
cifs_dbg(VFS, "Signing Key %*ph\n",
SMB3_SIGN_KEY_SIZE, ses->smb3signingkey);
cifs_dbg(VFS, "ServerIn Key %*ph\n",
SMB3_SIGN_KEY_SIZE, ses->smb3encryptionkey);
cifs_dbg(VFS, "ServerOut Key %*ph\n",
SMB3_SIGN_KEY_SIZE, ses->smb3decryptionkey);
#endif
return rc;
}
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 = "SMBSigningKey";
d->label.iov_len = 14;
d->context.iov_base = ses->preauth_sha_hash;
d->context.iov_len = 64;
d = &triplet.encryption;
d->label.iov_base = "SMBC2SCipherKey";
d->label.iov_len = 16;
d->context.iov_base = ses->preauth_sha_hash;
d->context.iov_len = 64;
d = &triplet.decryption;
d->label.iov_base = "SMBS2CCipherKey";
d->label.iov_len = 16;
d->context.iov_base = ses->preauth_sha_hash;
d->context.iov_len = 64;
return generate_smb3signingkey(ses, &triplet);
}
int
smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
{
int rc;
unsigned char smb3_signature[SMB2_CMACAES_SIZE];
unsigned char *sigptr = smb3_signature;
struct kvec *iov = rqst->rq_iov;
struct smb2_sync_hdr *shdr = (struct smb2_sync_hdr *)iov[0].iov_base;
struct cifs_ses *ses;
struct shash_desc *shash = &server->secmech.sdesccmacaes->shash;
struct smb_rqst drqst;
ses = smb2_find_smb_ses(server, shdr->SessionId);
if (!ses) {
cifs_dbg(VFS, "%s: Could not find session\n", __func__);
return 0;
}
memset(smb3_signature, 0x0, SMB2_CMACAES_SIZE);
memset(shdr->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\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(shash);
if (rc) {
cifs_dbg(VFS, "%s: Could not init cmac aes\n", __func__);
return rc;
}
/*
* For SMB2+, __cifs_calc_signature() expects to sign only the actual
* data, that is, iov[0] should not contain a rfc1002 length.
*
* Sign the rfc1002 length prior to passing the data (iov[1-N]) down to
* __cifs_calc_signature().
*/
drqst = *rqst;
if (drqst.rq_nvec >= 2 && iov[0].iov_len == 4) {
rc = crypto_shash_update(shash, iov[0].iov_base,
iov[0].iov_len);
if (rc) {
cifs_dbg(VFS, "%s: Could not update with payload\n",
__func__);
return rc;
}
drqst.rq_iov++;
drqst.rq_nvec--;
}
rc = __cifs_calc_signature(&drqst, server, sigptr, shash);
if (!rc)
memcpy(shdr->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_sync_hdr *shdr =
(struct smb2_sync_hdr *)rqst->rq_iov[0].iov_base;
if (!(shdr->Flags & SMB2_FLAGS_SIGNED) ||
server->tcpStatus == CifsNeedNegotiate)
return rc;
if (!server->session_estab) {
strncpy(shdr->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_sync_hdr *shdr =
(struct smb2_sync_hdr *)rqst->rq_iov[0].iov_base;
if ((shdr->Command == SMB2_NEGOTIATE) ||
(shdr->Command == SMB2_SESSION_SETUP) ||
(shdr->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(shdr->Signature, "BSRSPYL ", 8) == 0)
cifs_dbg(FYI, "dummy signature received for smb command 0x%x\n",
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, shdr->Signature, SMB2_SIGNATURE_SIZE);
memset(shdr->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, shdr->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_sync_hdr *shdr)
{
unsigned int i, num = le16_to_cpu(shdr->CreditCharge);
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_sync_hdr *shdr,
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);
memset(temp, 0, sizeof(struct mid_q_entry));
kref_init(&temp->refcount);
temp->mid = le64_to_cpu(shdr->MessageId);
temp->pid = current->pid;
temp->command = shdr->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_sync_hdr *shdr,
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 == CifsNew) {
if ((shdr->Command != SMB2_SESSION_SETUP) &&
(shdr->Command != SMB2_NEGOTIATE))
return -EAGAIN;
/* else ok - we are setting up session */
}
if (ses->status == CifsExiting) {
if (shdr->Command != SMB2_LOGOFF)
return -EAGAIN;
/* else ok - we are shutting down the session */
}
*mid = smb2_mid_entry_alloc(shdr, 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 = mid->resp_buf_size;
struct kvec iov[1];
struct smb_rqst rqst = { .rq_iov = iov,
.rq_nvec = 1 };
iov[0].iov_base = (char *)mid->resp_buf;
iov[0].iov_len = len;
dump_smb(mid->resp_buf, min_t(u32, 80, len));
/* convert the length into a more usable form */
if (len > 24 && server->sign && !mid->decrypted) {
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_sync_hdr *shdr =
(struct smb2_sync_hdr *)rqst->rq_iov[0].iov_base;
struct mid_q_entry *mid;
smb2_seq_num_into_buf(ses->server, shdr);
rc = smb2_get_mid_entry(ses, shdr, &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_sync_hdr *shdr =
(struct smb2_sync_hdr *)rqst->rq_iov[0].iov_base;
struct mid_q_entry *mid;
smb2_seq_num_into_buf(server, shdr);
mid = smb2_mid_entry_alloc(shdr, server);
if (mid == NULL)
return ERR_PTR(-ENOMEM);
rc = smb2_sign_rqst(rqst, server);
if (rc) {
DeleteMidQEntry(mid);
return ERR_PTR(rc);
}
return mid;
}
int
smb3_crypto_aead_allocate(struct TCP_Server_Info *server)
{
struct crypto_aead *tfm;
if (!server->secmech.ccmaesencrypt) {
tfm = crypto_alloc_aead("ccm(aes)", 0, 0);
if (IS_ERR(tfm)) {
cifs_dbg(VFS, "%s: Failed to alloc encrypt aead\n",
__func__);
return PTR_ERR(tfm);
}
server->secmech.ccmaesencrypt = tfm;
}
if (!server->secmech.ccmaesdecrypt) {
tfm = crypto_alloc_aead("ccm(aes)", 0, 0);
if (IS_ERR(tfm)) {
crypto_free_aead(server->secmech.ccmaesencrypt);
server->secmech.ccmaesencrypt = NULL;
cifs_dbg(VFS, "%s: Failed to alloc decrypt aead\n",
__func__);
return PTR_ERR(tfm);
}
server->secmech.ccmaesdecrypt = tfm;
}
return 0;
}