linux-hardened/fs/cifs/smb2transport.c
Aurélien Aptel d38de3c615 CIFS: add CONFIG_CIFS_DEBUG_KEYS to dump encryption keys
Add new config option that dumps AES keys to the console when they are
generated. This is obviously for debugging purposes only, and should not
be enabled otherwise.

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <smfrench@gmail.com>
2017-07-05 19:51:04 -05:00

716 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)
{
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\n");
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\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;
}
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[1].iov_base;
struct cifs_ses *ses;
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: shah256 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;
}
rc = crypto_shash_init(&server->secmech.sdeschmacsha256->shash);
if (rc) {
cifs_dbg(VFS, "%s: Could not init sha256", __func__);
return rc;
}
rc = __cifs_calc_signature(rqst, server, sigptr,
&server->secmech.sdeschmacsha256->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 = "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)
{
int rc = 0;
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[1].iov_base;
struct cifs_ses *ses;
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(&server->secmech.sdesccmacaes->shash);
if (rc) {
cifs_dbg(VFS, "%s: Could not init cmac aes\n", __func__);
return rc;
}
rc = __cifs_calc_signature(rqst, server, sigptr,
&server->secmech.sdesccmacaes->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[1].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[1].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));
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 = get_rfc1002_length(mid->resp_buf);
struct kvec iov[2];
struct smb_rqst rqst = { .rq_iov = iov,
.rq_nvec = 2 };
iov[0].iov_base = (char *)mid->resp_buf;
iov[0].iov_len = 4;
iov[1].iov_base = (char *)mid->resp_buf + 4;
iov[1].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[1].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[1].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;
}