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smb2pdu.c
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smb2pdu.c
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/*
* fs/cifs/smb2pdu.c
*
* Copyright (C) International Business Machines Corp., 2009, 2013
* Etersoft, 2012
* Author(s): Steve French ([email protected])
* Pavel Shilovsky ([email protected]) 2012
*
* Contains the routines for constructing the SMB2 PDUs themselves
*
* 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
*/
/* SMB2 PDU handling routines here - except for leftovers (eg session setup) */
/* Note that there are handle based routines which must be */
/* treated slightly differently for reconnection purposes since we never */
/* want to reuse a stale file handle and only the caller knows the file info */
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/vfs.h>
#include <linux/task_io_accounting_ops.h>
#include <linux/uaccess.h>
#include <linux/uuid.h>
#include <linux/pagemap.h>
#include <linux/xattr.h>
#include "smb2pdu.h"
#include "cifsglob.h"
#include "cifsacl.h"
#include "cifsproto.h"
#include "smb2proto.h"
#include "cifs_unicode.h"
#include "cifs_debug.h"
#include "ntlmssp.h"
#include "smb2status.h"
#include "smb2glob.h"
#include "cifspdu.h"
#include "cifs_spnego.h"
/*
* The following table defines the expected "StructureSize" of SMB2 requests
* in order by SMB2 command. This is similar to "wct" in SMB/CIFS requests.
*
* Note that commands are defined in smb2pdu.h in le16 but the array below is
* indexed by command in host byte order.
*/
static const int smb2_req_struct_sizes[NUMBER_OF_SMB2_COMMANDS] = {
/* SMB2_NEGOTIATE */ 36,
/* SMB2_SESSION_SETUP */ 25,
/* SMB2_LOGOFF */ 4,
/* SMB2_TREE_CONNECT */ 9,
/* SMB2_TREE_DISCONNECT */ 4,
/* SMB2_CREATE */ 57,
/* SMB2_CLOSE */ 24,
/* SMB2_FLUSH */ 24,
/* SMB2_READ */ 49,
/* SMB2_WRITE */ 49,
/* SMB2_LOCK */ 48,
/* SMB2_IOCTL */ 57,
/* SMB2_CANCEL */ 4,
/* SMB2_ECHO */ 4,
/* SMB2_QUERY_DIRECTORY */ 33,
/* SMB2_CHANGE_NOTIFY */ 32,
/* SMB2_QUERY_INFO */ 41,
/* SMB2_SET_INFO */ 33,
/* SMB2_OPLOCK_BREAK */ 24 /* BB this is 36 for LEASE_BREAK variant */
};
static int encryption_required(const struct cifs_tcon *tcon)
{
if (!tcon)
return 0;
if ((tcon->ses->session_flags & SMB2_SESSION_FLAG_ENCRYPT_DATA) ||
(tcon->share_flags & SHI1005_FLAGS_ENCRYPT_DATA))
return 1;
if (tcon->seal &&
(tcon->ses->server->capabilities & SMB2_GLOBAL_CAP_ENCRYPTION))
return 1;
return 0;
}
static void
smb2_hdr_assemble(struct smb2_sync_hdr *shdr, __le16 smb2_cmd,
const struct cifs_tcon *tcon)
{
shdr->ProtocolId = SMB2_PROTO_NUMBER;
shdr->StructureSize = cpu_to_le16(64);
shdr->Command = smb2_cmd;
if (tcon && tcon->ses && tcon->ses->server) {
struct TCP_Server_Info *server = tcon->ses->server;
spin_lock(&server->req_lock);
/* Request up to 2 credits but don't go over the limit. */
if (server->credits >= server->max_credits)
shdr->CreditRequest = cpu_to_le16(0);
else
shdr->CreditRequest = cpu_to_le16(
min_t(int, server->max_credits -
server->credits, 2));
spin_unlock(&server->req_lock);
} else {
shdr->CreditRequest = cpu_to_le16(2);
}
shdr->ProcessId = cpu_to_le32((__u16)current->tgid);
if (!tcon)
goto out;
/* GLOBAL_CAP_LARGE_MTU will only be set if dialect > SMB2.02 */
/* See sections 2.2.4 and 3.2.4.1.5 of MS-SMB2 */
if ((tcon->ses) && (tcon->ses->server) &&
(tcon->ses->server->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU))
shdr->CreditCharge = cpu_to_le16(1);
/* else CreditCharge MBZ */
shdr->TreeId = tcon->tid;
/* Uid is not converted */
if (tcon->ses)
shdr->SessionId = tcon->ses->Suid;
/*
* If we would set SMB2_FLAGS_DFS_OPERATIONS on open we also would have
* to pass the path on the Open SMB prefixed by \\server\share.
* Not sure when we would need to do the augmented path (if ever) and
* setting this flag breaks the SMB2 open operation since it is
* illegal to send an empty path name (without \\server\share prefix)
* when the DFS flag is set in the SMB open header. We could
* consider setting the flag on all operations other than open
* but it is safer to net set it for now.
*/
/* if (tcon->share_flags & SHI1005_FLAGS_DFS)
shdr->Flags |= SMB2_FLAGS_DFS_OPERATIONS; */
if (tcon->ses && tcon->ses->server && tcon->ses->server->sign &&
!encryption_required(tcon))
shdr->Flags |= SMB2_FLAGS_SIGNED;
out:
return;
}
static int
smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon)
{
int rc;
struct nls_table *nls_codepage;
struct cifs_ses *ses;
struct TCP_Server_Info *server;
/*
* SMB2s NegProt, SessSetup, Logoff do not have tcon yet so
* check for tcp and smb session status done differently
* for those three - in the calling routine.
*/
if (tcon == NULL)
return 0;
if (smb2_command == SMB2_TREE_CONNECT || smb2_command == SMB2_IOCTL)
return 0;
if (tcon->tidStatus == CifsExiting) {
/*
* only tree disconnect, open, and write,
* (and ulogoff which does not have tcon)
* are allowed as we start force umount.
*/
if ((smb2_command != SMB2_WRITE) &&
(smb2_command != SMB2_CREATE) &&
(smb2_command != SMB2_TREE_DISCONNECT)) {
cifs_dbg(FYI, "can not send cmd %d while umounting\n",
smb2_command);
return -ENODEV;
}
}
if ((!tcon->ses) || (tcon->ses->status == CifsExiting) ||
(!tcon->ses->server))
return -EIO;
ses = tcon->ses;
server = ses->server;
/*
* Give demultiplex thread up to 10 seconds to reconnect, should be
* greater than cifs socket timeout which is 7 seconds
*/
while (server->tcpStatus == CifsNeedReconnect) {
/*
* Return to caller for TREE_DISCONNECT and LOGOFF and CLOSE
* here since they are implicitly done when session drops.
*/
switch (smb2_command) {
/*
* BB Should we keep oplock break and add flush to exceptions?
*/
case SMB2_TREE_DISCONNECT:
case SMB2_CANCEL:
case SMB2_CLOSE:
case SMB2_OPLOCK_BREAK:
return -EAGAIN;
}
rc = wait_event_interruptible_timeout(server->response_q,
(server->tcpStatus != CifsNeedReconnect),
10 * HZ);
if (rc < 0) {
cifs_dbg(FYI, "%s: aborting reconnect due to a received"
" signal by the process\n", __func__);
return -ERESTARTSYS;
}
/* are we still trying to reconnect? */
if (server->tcpStatus != CifsNeedReconnect)
break;
/*
* on "soft" mounts we wait once. Hard mounts keep
* retrying until process is killed or server comes
* back on-line
*/
if (!tcon->retry) {
cifs_dbg(FYI, "gave up waiting on reconnect in smb_init\n");
return -EHOSTDOWN;
}
}
if (!tcon->ses->need_reconnect && !tcon->need_reconnect)
return 0;
nls_codepage = load_nls_default();
/*
* need to prevent multiple threads trying to simultaneously reconnect
* the same SMB session
*/
mutex_lock(&tcon->ses->session_mutex);
/*
* Recheck after acquire mutex. If another thread is negotiating
* and the server never sends an answer the socket will be closed
* and tcpStatus set to reconnect.
*/
if (server->tcpStatus == CifsNeedReconnect) {
rc = -EHOSTDOWN;
mutex_unlock(&tcon->ses->session_mutex);
goto out;
}
rc = cifs_negotiate_protocol(0, tcon->ses);
if (!rc && tcon->ses->need_reconnect) {
rc = cifs_setup_session(0, tcon->ses, nls_codepage);
if ((rc == -EACCES) && !tcon->retry) {
rc = -EHOSTDOWN;
mutex_unlock(&tcon->ses->session_mutex);
goto failed;
}
}
if (rc || !tcon->need_reconnect) {
mutex_unlock(&tcon->ses->session_mutex);
goto out;
}
cifs_mark_open_files_invalid(tcon);
if (tcon->use_persistent)
tcon->need_reopen_files = true;
rc = SMB2_tcon(0, tcon->ses, tcon->treeName, tcon, nls_codepage);
mutex_unlock(&tcon->ses->session_mutex);
cifs_dbg(FYI, "reconnect tcon rc = %d\n", rc);
if (rc)
goto out;
if (smb2_command != SMB2_INTERNAL_CMD)
queue_delayed_work(cifsiod_wq, &server->reconnect, 0);
atomic_inc(&tconInfoReconnectCount);
out:
/*
* Check if handle based operation so we know whether we can continue
* or not without returning to caller to reset file handle.
*/
/*
* BB Is flush done by server on drop of tcp session? Should we special
* case it and skip above?
*/
switch (smb2_command) {
case SMB2_FLUSH:
case SMB2_READ:
case SMB2_WRITE:
case SMB2_LOCK:
case SMB2_IOCTL:
case SMB2_QUERY_DIRECTORY:
case SMB2_CHANGE_NOTIFY:
case SMB2_QUERY_INFO:
case SMB2_SET_INFO:
rc = -EAGAIN;
}
failed:
unload_nls(nls_codepage);
return rc;
}
static void
fill_small_buf(__le16 smb2_command, struct cifs_tcon *tcon, void *buf,
unsigned int *total_len)
{
struct smb2_sync_pdu *spdu = (struct smb2_sync_pdu *)buf;
/* lookup word count ie StructureSize from table */
__u16 parmsize = smb2_req_struct_sizes[le16_to_cpu(smb2_command)];
/*
* smaller than SMALL_BUFFER_SIZE but bigger than fixed area of
* largest operations (Create)
*/
memset(buf, 0, 256);
smb2_hdr_assemble(&spdu->sync_hdr, smb2_command, tcon);
spdu->StructureSize2 = cpu_to_le16(parmsize);
*total_len = parmsize + sizeof(struct smb2_sync_hdr);
}
/* init request without RFC1001 length at the beginning */
static int
smb2_plain_req_init(__le16 smb2_command, struct cifs_tcon *tcon,
void **request_buf, unsigned int *total_len)
{
int rc;
struct smb2_sync_hdr *shdr;
rc = smb2_reconnect(smb2_command, tcon);
if (rc)
return rc;
/* BB eventually switch this to SMB2 specific small buf size */
*request_buf = cifs_small_buf_get();
if (*request_buf == NULL) {
/* BB should we add a retry in here if not a writepage? */
return -ENOMEM;
}
shdr = (struct smb2_sync_hdr *)(*request_buf);
fill_small_buf(smb2_command, tcon, shdr, total_len);
if (tcon != NULL) {
#ifdef CONFIG_CIFS_STATS2
uint16_t com_code = le16_to_cpu(smb2_command);
cifs_stats_inc(&tcon->stats.smb2_stats.smb2_com_sent[com_code]);
#endif
cifs_stats_inc(&tcon->num_smbs_sent);
}
return rc;
}
/*
* Allocate and return pointer to an SMB request hdr, and set basic
* SMB information in the SMB header. If the return code is zero, this
* function must have filled in request_buf pointer. The returned buffer
* has RFC1001 length at the beginning.
*/
static int
small_smb2_init(__le16 smb2_command, struct cifs_tcon *tcon,
void **request_buf)
{
int rc;
unsigned int total_len;
struct smb2_pdu *pdu;
rc = smb2_reconnect(smb2_command, tcon);
if (rc)
return rc;
/* BB eventually switch this to SMB2 specific small buf size */
*request_buf = cifs_small_buf_get();
if (*request_buf == NULL) {
/* BB should we add a retry in here if not a writepage? */
return -ENOMEM;
}
pdu = (struct smb2_pdu *)(*request_buf);
fill_small_buf(smb2_command, tcon, get_sync_hdr(pdu), &total_len);
/* Note this is only network field converted to big endian */
pdu->hdr.smb2_buf_length = cpu_to_be32(total_len);
if (tcon != NULL) {
#ifdef CONFIG_CIFS_STATS
uint16_t com_code = le16_to_cpu(smb2_command);
cifs_stats_inc(&tcon->stats.smb2_stats.smb2_com_sent[com_code]);
#endif
cifs_stats_inc(&tcon->num_smbs_sent);
}
return rc;
}
#ifdef CONFIG_CIFS_SMB311
/* offset is sizeof smb2_negotiate_req - 4 but rounded up to 8 bytes */
#define OFFSET_OF_NEG_CONTEXT 0x68 /* sizeof(struct smb2_negotiate_req) - 4 */
#define SMB2_PREAUTH_INTEGRITY_CAPABILITIES cpu_to_le16(1)
#define SMB2_ENCRYPTION_CAPABILITIES cpu_to_le16(2)
static void
build_preauth_ctxt(struct smb2_preauth_neg_context *pneg_ctxt)
{
pneg_ctxt->ContextType = SMB2_PREAUTH_INTEGRITY_CAPABILITIES;
pneg_ctxt->DataLength = cpu_to_le16(38);
pneg_ctxt->HashAlgorithmCount = cpu_to_le16(1);
pneg_ctxt->SaltLength = cpu_to_le16(SMB311_SALT_SIZE);
get_random_bytes(pneg_ctxt->Salt, SMB311_SALT_SIZE);
pneg_ctxt->HashAlgorithms = SMB2_PREAUTH_INTEGRITY_SHA512;
}
static void
build_encrypt_ctxt(struct smb2_encryption_neg_context *pneg_ctxt)
{
pneg_ctxt->ContextType = SMB2_ENCRYPTION_CAPABILITIES;
pneg_ctxt->DataLength = cpu_to_le16(6);
pneg_ctxt->CipherCount = cpu_to_le16(2);
pneg_ctxt->Ciphers[0] = SMB2_ENCRYPTION_AES128_GCM;
pneg_ctxt->Ciphers[1] = SMB2_ENCRYPTION_AES128_CCM;
}
static void
assemble_neg_contexts(struct smb2_negotiate_req *req)
{
/* +4 is to account for the RFC1001 len field */
char *pneg_ctxt = (char *)req + OFFSET_OF_NEG_CONTEXT + 4;
build_preauth_ctxt((struct smb2_preauth_neg_context *)pneg_ctxt);
/* Add 2 to size to round to 8 byte boundary */
pneg_ctxt += 2 + sizeof(struct smb2_preauth_neg_context);
build_encrypt_ctxt((struct smb2_encryption_neg_context *)pneg_ctxt);
req->NegotiateContextOffset = cpu_to_le32(OFFSET_OF_NEG_CONTEXT);
req->NegotiateContextCount = cpu_to_le16(2);
inc_rfc1001_len(req, 4 + sizeof(struct smb2_preauth_neg_context)
+ sizeof(struct smb2_encryption_neg_context)); /* calculate hash */
}
#else
static void assemble_neg_contexts(struct smb2_negotiate_req *req)
{
return;
}
#endif /* SMB311 */
/*
*
* SMB2 Worker functions follow:
*
* The general structure of the worker functions is:
* 1) Call smb2_init (assembles SMB2 header)
* 2) Initialize SMB2 command specific fields in fixed length area of SMB
* 3) Call smb_sendrcv2 (sends request on socket and waits for response)
* 4) Decode SMB2 command specific fields in the fixed length area
* 5) Decode variable length data area (if any for this SMB2 command type)
* 6) Call free smb buffer
* 7) return
*
*/
int
SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
{
struct smb2_negotiate_req *req;
struct smb2_negotiate_rsp *rsp;
struct kvec iov[1];
struct kvec rsp_iov;
int rc = 0;
int resp_buftype;
struct TCP_Server_Info *server = ses->server;
int blob_offset, blob_length;
char *security_blob;
int flags = CIFS_NEG_OP;
cifs_dbg(FYI, "Negotiate protocol\n");
if (!server) {
WARN(1, "%s: server is NULL!\n", __func__);
return -EIO;
}
rc = small_smb2_init(SMB2_NEGOTIATE, NULL, (void **) &req);
if (rc)
return rc;
req->hdr.sync_hdr.SessionId = 0;
if (strcmp(ses->server->vals->version_string,
SMB3ANY_VERSION_STRING) == 0) {
req->Dialects[0] = cpu_to_le16(SMB30_PROT_ID);
req->Dialects[1] = cpu_to_le16(SMB302_PROT_ID);
req->DialectCount = cpu_to_le16(2);
inc_rfc1001_len(req, 4);
} else if (strcmp(ses->server->vals->version_string,
SMBDEFAULT_VERSION_STRING) == 0) {
req->Dialects[0] = cpu_to_le16(SMB21_PROT_ID);
req->Dialects[1] = cpu_to_le16(SMB30_PROT_ID);
req->Dialects[2] = cpu_to_le16(SMB302_PROT_ID);
req->DialectCount = cpu_to_le16(3);
inc_rfc1001_len(req, 6);
} else {
/* otherwise send specific dialect */
req->Dialects[0] = cpu_to_le16(ses->server->vals->protocol_id);
req->DialectCount = cpu_to_le16(1);
inc_rfc1001_len(req, 2);
}
/* only one of SMB2 signing flags may be set in SMB2 request */
if (ses->sign)
req->SecurityMode = cpu_to_le16(SMB2_NEGOTIATE_SIGNING_REQUIRED);
else if (global_secflags & CIFSSEC_MAY_SIGN)
req->SecurityMode = cpu_to_le16(SMB2_NEGOTIATE_SIGNING_ENABLED);
else
req->SecurityMode = 0;
req->Capabilities = cpu_to_le32(ses->server->vals->req_capabilities);
/* ClientGUID must be zero for SMB2.02 dialect */
if (ses->server->vals->protocol_id == SMB20_PROT_ID)
memset(req->ClientGUID, 0, SMB2_CLIENT_GUID_SIZE);
else {
memcpy(req->ClientGUID, server->client_guid,
SMB2_CLIENT_GUID_SIZE);
if (ses->server->vals->protocol_id == SMB311_PROT_ID)
assemble_neg_contexts(req);
}
iov[0].iov_base = (char *)req;
/* 4 for rfc1002 length field */
iov[0].iov_len = get_rfc1002_length(req) + 4;
rc = SendReceive2(xid, ses, iov, 1, &resp_buftype, flags, &rsp_iov);
cifs_small_buf_release(req);
rsp = (struct smb2_negotiate_rsp *)rsp_iov.iov_base;
/*
* No tcon so can't do
* cifs_stats_inc(&tcon->stats.smb2_stats.smb2_com_fail[SMB2...]);
*/
if (rc == -EOPNOTSUPP) {
cifs_dbg(VFS, "Dialect not supported by server. Consider "
"specifying vers=1.0 or vers=2.0 on mount for accessing"
" older servers\n");
goto neg_exit;
} else if (rc != 0)
goto neg_exit;
if (strcmp(ses->server->vals->version_string,
SMB3ANY_VERSION_STRING) == 0) {
if (rsp->DialectRevision == cpu_to_le16(SMB20_PROT_ID)) {
cifs_dbg(VFS,
"SMB2 dialect returned but not requested\n");
return -EIO;
} else if (rsp->DialectRevision == cpu_to_le16(SMB21_PROT_ID)) {
cifs_dbg(VFS,
"SMB2.1 dialect returned but not requested\n");
return -EIO;
}
} else if (strcmp(ses->server->vals->version_string,
SMBDEFAULT_VERSION_STRING) == 0) {
if (rsp->DialectRevision == cpu_to_le16(SMB20_PROT_ID)) {
cifs_dbg(VFS,
"SMB2 dialect returned but not requested\n");
return -EIO;
} else if (rsp->DialectRevision == cpu_to_le16(SMB21_PROT_ID)) {
/* ops set to 3.0 by default for default so update */
ses->server->ops = &smb21_operations;
ses->server->vals = &smb21_values;
}
} else if (le16_to_cpu(rsp->DialectRevision) !=
ses->server->vals->protocol_id) {
/* if requested single dialect ensure returned dialect matched */
cifs_dbg(VFS, "Illegal 0x%x dialect returned: not requested\n",
le16_to_cpu(rsp->DialectRevision));
return -EIO;
}
cifs_dbg(FYI, "mode 0x%x\n", rsp->SecurityMode);
if (rsp->DialectRevision == cpu_to_le16(SMB20_PROT_ID))
cifs_dbg(FYI, "negotiated smb2.0 dialect\n");
else if (rsp->DialectRevision == cpu_to_le16(SMB21_PROT_ID))
cifs_dbg(FYI, "negotiated smb2.1 dialect\n");
else if (rsp->DialectRevision == cpu_to_le16(SMB30_PROT_ID))
cifs_dbg(FYI, "negotiated smb3.0 dialect\n");
else if (rsp->DialectRevision == cpu_to_le16(SMB302_PROT_ID))
cifs_dbg(FYI, "negotiated smb3.02 dialect\n");
#ifdef CONFIG_CIFS_SMB311
else if (rsp->DialectRevision == cpu_to_le16(SMB311_PROT_ID))
cifs_dbg(FYI, "negotiated smb3.1.1 dialect\n");
#endif /* SMB311 */
else {
cifs_dbg(VFS, "Illegal dialect returned by server 0x%x\n",
le16_to_cpu(rsp->DialectRevision));
rc = -EIO;
goto neg_exit;
}
server->dialect = le16_to_cpu(rsp->DialectRevision);
/* BB: add check that dialect was valid given dialect(s) we asked for */
/* SMB2 only has an extended negflavor */
server->negflavor = CIFS_NEGFLAVOR_EXTENDED;
/* set it to the maximum buffer size value we can send with 1 credit */
server->maxBuf = min_t(unsigned int, le32_to_cpu(rsp->MaxTransactSize),
SMB2_MAX_BUFFER_SIZE);
server->max_read = le32_to_cpu(rsp->MaxReadSize);
server->max_write = le32_to_cpu(rsp->MaxWriteSize);
/* BB Do we need to validate the SecurityMode? */
server->sec_mode = le16_to_cpu(rsp->SecurityMode);
server->capabilities = le32_to_cpu(rsp->Capabilities);
/* Internal types */
server->capabilities |= SMB2_NT_FIND | SMB2_LARGE_FILES;
security_blob = smb2_get_data_area_len(&blob_offset, &blob_length,
&rsp->hdr);
/*
* See MS-SMB2 section 2.2.4: if no blob, client picks default which
* for us will be
* ses->sectype = RawNTLMSSP;
* but for time being this is our only auth choice so doesn't matter.
* We just found a server which sets blob length to zero expecting raw.
*/
if (blob_length == 0) {
cifs_dbg(FYI, "missing security blob on negprot\n");
server->sec_ntlmssp = true;
}
rc = cifs_enable_signing(server, ses->sign);
if (rc)
goto neg_exit;
if (blob_length) {
rc = decode_negTokenInit(security_blob, blob_length, server);
if (rc == 1)
rc = 0;
else if (rc == 0)
rc = -EIO;
}
neg_exit:
free_rsp_buf(resp_buftype, rsp);
return rc;
}
int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
{
int rc = 0;
struct validate_negotiate_info_req vneg_inbuf;
struct validate_negotiate_info_rsp *pneg_rsp = NULL;
u32 rsplen;
u32 inbuflen; /* max of 4 dialects */
cifs_dbg(FYI, "validate negotiate\n");
/*
* validation ioctl must be signed, so no point sending this if we
* can not sign it (ie are not known user). Even if signing is not
* required (enabled but not negotiated), in those cases we selectively
* sign just this, the first and only signed request on a connection.
* Having validation of negotiate info helps reduce attack vectors.
*/
if (tcon->ses->session_flags & SMB2_SESSION_FLAG_IS_GUEST)
return 0; /* validation requires signing */
if (tcon->ses->user_name == NULL) {
cifs_dbg(FYI, "Can't validate negotiate: null user mount\n");
return 0; /* validation requires signing */
}
if (tcon->ses->session_flags & SMB2_SESSION_FLAG_IS_NULL)
cifs_dbg(VFS, "Unexpected null user (anonymous) auth flag sent by server\n");
vneg_inbuf.Capabilities =
cpu_to_le32(tcon->ses->server->vals->req_capabilities);
memcpy(vneg_inbuf.Guid, tcon->ses->server->client_guid,
SMB2_CLIENT_GUID_SIZE);
if (tcon->ses->sign)
vneg_inbuf.SecurityMode =
cpu_to_le16(SMB2_NEGOTIATE_SIGNING_REQUIRED);
else if (global_secflags & CIFSSEC_MAY_SIGN)
vneg_inbuf.SecurityMode =
cpu_to_le16(SMB2_NEGOTIATE_SIGNING_ENABLED);
else
vneg_inbuf.SecurityMode = 0;
if (strcmp(tcon->ses->server->vals->version_string,
SMB3ANY_VERSION_STRING) == 0) {
vneg_inbuf.Dialects[0] = cpu_to_le16(SMB30_PROT_ID);
vneg_inbuf.Dialects[1] = cpu_to_le16(SMB302_PROT_ID);
vneg_inbuf.DialectCount = cpu_to_le16(2);
/* structure is big enough for 3 dialects, sending only 2 */
inbuflen = sizeof(struct validate_negotiate_info_req) - 2;
} else if (strcmp(tcon->ses->server->vals->version_string,
SMBDEFAULT_VERSION_STRING) == 0) {
vneg_inbuf.Dialects[0] = cpu_to_le16(SMB21_PROT_ID);
vneg_inbuf.Dialects[1] = cpu_to_le16(SMB30_PROT_ID);
vneg_inbuf.Dialects[2] = cpu_to_le16(SMB302_PROT_ID);
vneg_inbuf.DialectCount = cpu_to_le16(3);
/* structure is big enough for 3 dialects */
inbuflen = sizeof(struct validate_negotiate_info_req);
} else {
/* otherwise specific dialect was requested */
vneg_inbuf.Dialects[0] =
cpu_to_le16(tcon->ses->server->vals->protocol_id);
vneg_inbuf.DialectCount = cpu_to_le16(1);
/* structure is big enough for 3 dialects, sending only 1 */
inbuflen = sizeof(struct validate_negotiate_info_req) - 4;
}
rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
FSCTL_VALIDATE_NEGOTIATE_INFO, true /* is_fsctl */,
false /* use_ipc */,
(char *)&vneg_inbuf, sizeof(struct validate_negotiate_info_req),
(char **)&pneg_rsp, &rsplen);
if (rc != 0) {
cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", rc);
return -EIO;
}
if (rsplen != sizeof(struct validate_negotiate_info_rsp)) {
cifs_dbg(VFS, "invalid protocol negotiate response size: %d\n",
rsplen);
/* relax check since Mac returns max bufsize allowed on ioctl */
if ((rsplen > CIFSMaxBufSize)
|| (rsplen < sizeof(struct validate_negotiate_info_rsp)))
goto err_rsp_free;
}
/* check validate negotiate info response matches what we got earlier */
if (pneg_rsp->Dialect != cpu_to_le16(tcon->ses->server->dialect))
goto vneg_out;
if (pneg_rsp->SecurityMode != cpu_to_le16(tcon->ses->server->sec_mode))
goto vneg_out;
/* do not validate server guid because not saved at negprot time yet */
if ((le32_to_cpu(pneg_rsp->Capabilities) | SMB2_NT_FIND |
SMB2_LARGE_FILES) != tcon->ses->server->capabilities)
goto vneg_out;
/* validate negotiate successful */
cifs_dbg(FYI, "validate negotiate info successful\n");
kfree(pneg_rsp);
return 0;
vneg_out:
cifs_dbg(VFS, "protocol revalidation - security settings mismatch\n");
err_rsp_free:
kfree(pneg_rsp);
return -EIO;
}
enum securityEnum
smb2_select_sectype(struct TCP_Server_Info *server, enum securityEnum requested)
{
switch (requested) {
case Kerberos:
case RawNTLMSSP:
return requested;
case NTLMv2:
return RawNTLMSSP;
case Unspecified:
if (server->sec_ntlmssp &&
(global_secflags & CIFSSEC_MAY_NTLMSSP))
return RawNTLMSSP;
if ((server->sec_kerberos || server->sec_mskerberos) &&
(global_secflags & CIFSSEC_MAY_KRB5))
return Kerberos;
/* Fallthrough */
default:
return Unspecified;
}
}
struct SMB2_sess_data {
unsigned int xid;
struct cifs_ses *ses;
struct nls_table *nls_cp;
void (*func)(struct SMB2_sess_data *);
int result;
u64 previous_session;
/* we will send the SMB in three pieces:
* a fixed length beginning part, an optional
* SPNEGO blob (which can be zero length), and a
* last part which will include the strings
* and rest of bcc area. This allows us to avoid
* a large buffer 17K allocation
*/
int buf0_type;
struct kvec iov[2];
};
static int
SMB2_sess_alloc_buffer(struct SMB2_sess_data *sess_data)
{
int rc;
struct cifs_ses *ses = sess_data->ses;
struct smb2_sess_setup_req *req;
struct TCP_Server_Info *server = ses->server;
rc = small_smb2_init(SMB2_SESSION_SETUP, NULL, (void **) &req);
if (rc)
return rc;
/* First session, not a reauthenticate */
req->hdr.sync_hdr.SessionId = 0;
/* if reconnect, we need to send previous sess id, otherwise it is 0 */
req->PreviousSessionId = sess_data->previous_session;
req->Flags = 0; /* MBZ */
/* to enable echos and oplocks */
req->hdr.sync_hdr.CreditRequest = cpu_to_le16(3);
/* only one of SMB2 signing flags may be set in SMB2 request */
if (server->sign)
req->SecurityMode = SMB2_NEGOTIATE_SIGNING_REQUIRED;
else if (global_secflags & CIFSSEC_MAY_SIGN) /* one flag unlike MUST_ */
req->SecurityMode = SMB2_NEGOTIATE_SIGNING_ENABLED;
else
req->SecurityMode = 0;
#ifdef CONFIG_CIFS_DFS_UPCALL
req->Capabilities = cpu_to_le32(SMB2_GLOBAL_CAP_DFS);
#else
req->Capabilities = 0;
#endif /* DFS_UPCALL */
req->Channel = 0; /* MBZ */
sess_data->iov[0].iov_base = (char *)req;
/* 4 for rfc1002 length field and 1 for pad */
sess_data->iov[0].iov_len = get_rfc1002_length(req) + 4 - 1;
/*
* This variable will be used to clear the buffer
* allocated above in case of any error in the calling function.
*/
sess_data->buf0_type = CIFS_SMALL_BUFFER;
return 0;
}
static void
SMB2_sess_free_buffer(struct SMB2_sess_data *sess_data)
{
free_rsp_buf(sess_data->buf0_type, sess_data->iov[0].iov_base);
sess_data->buf0_type = CIFS_NO_BUFFER;
}
static int
SMB2_sess_sendreceive(struct SMB2_sess_data *sess_data)
{
int rc;
struct smb2_sess_setup_req *req = sess_data->iov[0].iov_base;
struct kvec rsp_iov = { NULL, 0 };
/* Testing shows that buffer offset must be at location of Buffer[0] */
req->SecurityBufferOffset =
cpu_to_le16(sizeof(struct smb2_sess_setup_req) -
1 /* pad */ - 4 /* rfc1001 len */);
req->SecurityBufferLength = cpu_to_le16(sess_data->iov[1].iov_len);
inc_rfc1001_len(req, sess_data->iov[1].iov_len - 1 /* pad */);
/* BB add code to build os and lm fields */
rc = SendReceive2(sess_data->xid, sess_data->ses,
sess_data->iov, 2,
&sess_data->buf0_type,
CIFS_LOG_ERROR | CIFS_NEG_OP, &rsp_iov);
cifs_small_buf_release(sess_data->iov[0].iov_base);
memcpy(&sess_data->iov[0], &rsp_iov, sizeof(struct kvec));
return rc;
}
static int
SMB2_sess_establish_session(struct SMB2_sess_data *sess_data)
{
int rc = 0;
struct cifs_ses *ses = sess_data->ses;
mutex_lock(&ses->server->srv_mutex);
if (ses->server->ops->generate_signingkey) {
rc = ses->server->ops->generate_signingkey(ses);
if (rc) {
cifs_dbg(FYI,
"SMB3 session key generation failed\n");
mutex_unlock(&ses->server->srv_mutex);
return rc;
}
}
if (!ses->server->session_estab) {
ses->server->sequence_number = 0x2;
ses->server->session_estab = true;
}
mutex_unlock(&ses->server->srv_mutex);
cifs_dbg(FYI, "SMB2/3 session established successfully\n");
spin_lock(&GlobalMid_Lock);
ses->status = CifsGood;
ses->need_reconnect = false;
spin_unlock(&GlobalMid_Lock);
return rc;
}
#ifdef CONFIG_CIFS_UPCALL
static void
SMB2_auth_kerberos(struct SMB2_sess_data *sess_data)
{
int rc;
struct cifs_ses *ses = sess_data->ses;
struct cifs_spnego_msg *msg;
struct key *spnego_key = NULL;
struct smb2_sess_setup_rsp *rsp = NULL;
rc = SMB2_sess_alloc_buffer(sess_data);
if (rc)
goto out;
spnego_key = cifs_get_spnego_key(ses);
if (IS_ERR(spnego_key)) {
rc = PTR_ERR(spnego_key);
spnego_key = NULL;
goto out;
}
msg = spnego_key->payload.data[0];
/*
* check version field to make sure that cifs.upcall is
* sending us a response in an expected form
*/
if (msg->version != CIFS_SPNEGO_UPCALL_VERSION) {
cifs_dbg(VFS,
"bad cifs.upcall version. Expected %d got %d",
CIFS_SPNEGO_UPCALL_VERSION, msg->version);
rc = -EKEYREJECTED;
goto out_put_spnego_key;
}
ses->auth_key.response = kmemdup(msg->data, msg->sesskey_len,
GFP_KERNEL);
if (!ses->auth_key.response) {
cifs_dbg(VFS,
"Kerberos can't allocate (%u bytes) memory",
msg->sesskey_len);
rc = -ENOMEM;
goto out_put_spnego_key;
}
ses->auth_key.len = msg->sesskey_len;
sess_data->iov[1].iov_base = msg->data + msg->sesskey_len;
sess_data->iov[1].iov_len = msg->secblob_len;
rc = SMB2_sess_sendreceive(sess_data);
if (rc)
goto out_put_spnego_key;
rsp = (struct smb2_sess_setup_rsp *)sess_data->iov[0].iov_base;
ses->Suid = rsp->hdr.sync_hdr.SessionId;
ses->session_flags = le16_to_cpu(rsp->SessionFlags);
rc = SMB2_sess_establish_session(sess_data);
out_put_spnego_key:
key_invalidate(spnego_key);
key_put(spnego_key);
out:
sess_data->result = rc;
sess_data->func = NULL;
SMB2_sess_free_buffer(sess_data);
}
#else
static void
SMB2_auth_kerberos(struct SMB2_sess_data *sess_data)
{
cifs_dbg(VFS, "Kerberos negotiated but upcall support disabled!\n");
sess_data->result = -EOPNOTSUPP;
sess_data->func = NULL;