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authorStefan Metzmacher <metze@samba.org>2009-05-22 22:58:39 +0200
committerStefan Metzmacher <metze@samba.org>2009-05-26 09:53:06 +0200
commit31c6679bf12bbcd6626bfd5066bb2e751314e9c2 (patch)
treeef6447a14a449bbdfc0cccdd4df51886b1655a39
parentbd8a38b60e933bcffd90ea8bed75898a421cbdad (diff)
downloadsamba-31c6679bf12bbcd6626bfd5066bb2e751314e9c2.tar.gz
samba-31c6679bf12bbcd6626bfd5066bb2e751314e9c2.tar.bz2
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s3:smbd: add support for SMB2 signing
metze
-rw-r--r--source3/Makefile.in5
-rw-r--r--source3/smbd/globals.h11
-rw-r--r--source3/smbd/smb2_server.c114
-rw-r--r--source3/smbd/smb2_sesssetup.c70
-rw-r--r--source3/smbd/smb2_signing.c135
5 files changed, 280 insertions, 55 deletions
diff --git a/source3/Makefile.in b/source3/Makefile.in
index 1120092f90..2b30b4a5bd 100644
--- a/source3/Makefile.in
+++ b/source3/Makefile.in
@@ -359,7 +359,8 @@ UTIL_OBJ = ../lib/util/rbtree.o ../lib/util/signal.o ../lib/util/time.o \
CRYPTO_OBJ = ../lib/crypto/crc32.o ../lib/crypto/md5.o \
../lib/crypto/hmacmd5.o ../lib/crypto/arcfour.o \
- ../lib/crypto/md4.o
+ ../lib/crypto/md4.o \
+ ../lib/crypto/sha256.o ../lib/crypto/hmacsha256.o
LIB_OBJ = $(LIBSAMBAUTIL_OBJ) $(UTIL_OBJ) $(CRYPTO_OBJ) \
lib/messages.o librpc/gen_ndr/ndr_messaging.o lib/messages_local.o \
@@ -750,7 +751,7 @@ SMBD_OBJ_SRV = smbd/files.o smbd/chgpasswd.o smbd/connection.o \
smbd/dnsregister.o smbd/globals.o \
smbd/smb2_server.o smbd/smb2_negprot.o \
smbd/smb2_sesssetup.o smbd/smb2_tcon.o \
- smbd/smb2_keepalive.o \
+ smbd/smb2_keepalive.o smbd/smb2_signing.o \
$(MANGLE_OBJ) @VFS_STATIC@
SMBD_OBJ_BASE = $(PARAM_WITHOUT_REG_OBJ) $(SMBD_OBJ_SRV) $(LIBSMB_OBJ) \
diff --git a/source3/smbd/globals.h b/source3/smbd/globals.h
index 9d5eead939..c6ab31dc36 100644
--- a/source3/smbd/globals.h
+++ b/source3/smbd/globals.h
@@ -206,6 +206,13 @@ struct smbd_smb2_tcon;
DATA_BLOB negprot_spnego(void);
+NTSTATUS smb2_signing_sign_pdu(DATA_BLOB session_key,
+ struct iovec *vector,
+ int count);
+NTSTATUS smb2_signing_check_pdu(DATA_BLOB session_key,
+ const struct iovec *vector,
+ int count);
+
bool smbd_is_smb2_header(const uint8_t *inbuf, size_t size);
void reply_smb2002(struct smb_request *req, uint16_t choice);
@@ -244,6 +251,7 @@ struct smbd_smb2_request {
struct smbd_smb2_tcon *tcon;
int current_idx;
+ bool do_signing;
struct {
/* the NBT header is not allocated */
@@ -299,6 +307,9 @@ struct smbd_smb2_session {
NTSTATUS status;
uint64_t vuid;
AUTH_NTLMSSP_STATE *auth_ntlmssp_state;
+ struct auth_serversupplied_info *server_info;
+ DATA_BLOB session_key;
+ bool do_signing;
struct {
/* an id tree used to allocate tids */
diff --git a/source3/smbd/smb2_server.c b/source3/smbd/smb2_server.c
index 32bb5543ae..562fc567cc 100644
--- a/source3/smbd/smb2_server.c
+++ b/source3/smbd/smb2_server.c
@@ -288,14 +288,45 @@ static NTSTATUS smbd_smb2_request_dispatch(struct smbd_smb2_request *req)
const uint8_t *inhdr;
int i = req->current_idx;
uint16_t opcode;
+ uint32_t flags;
NTSTATUS status;
+ NTSTATUS session_status;
inhdr = (const uint8_t *)req->in.vector[i].iov_base;
/* TODO: verify more things */
+ flags = IVAL(inhdr, SMB2_HDR_FLAGS);
opcode = IVAL(inhdr, SMB2_HDR_OPCODE);
DEBUG(10,("smbd_smb2_request_dispatch: opcode[%u]\n", opcode));
+
+#define TMP_SMB2_ALLOWED_FLAGS ( \
+ SMB2_HDR_FLAG_CHAINED | \
+ SMB2_HDR_FLAG_SIGNED | \
+ SMB2_HDR_FLAG_DFS)
+ if ((flags & ~TMP_SMB2_ALLOWED_FLAGS) != 0) {
+ return smbd_smb2_request_error(req, NT_STATUS_INVALID_PARAMETER);
+ }
+#undef TMP_SMB2_ALLOWED_FLAGS
+
+ session_status = smbd_smb2_request_check_session(req);
+
+ req->do_signing = false;
+ if (flags & SMB2_HDR_FLAG_SIGNED) {
+ if (!NT_STATUS_IS_OK(session_status)) {
+ return smbd_smb2_request_error(req, session_status);
+ }
+
+ req->do_signing = true;
+ status = smb2_signing_check_pdu(req->session->session_key,
+ &req->in.vector[i], 3);
+ if (!NT_STATUS_IS_OK(status)) {
+ return smbd_smb2_request_error(req, status);
+ }
+ } else if (req->session && req->session->do_signing) {
+ return smbd_smb2_request_error(req, NT_STATUS_ACCESS_DENIED);
+ }
+
switch (opcode) {
case SMB2_OP_NEGPROT:
return smbd_smb2_request_process_negprot(req);
@@ -304,13 +335,15 @@ static NTSTATUS smbd_smb2_request_dispatch(struct smbd_smb2_request *req)
return smbd_smb2_request_process_sesssetup(req);
case SMB2_OP_LOGOFF:
- status = smbd_smb2_request_check_session(req);
- if (!NT_STATUS_IS_OK(status)) {
- return smbd_smb2_request_error(req, status);
+ if (!NT_STATUS_IS_OK(session_status)) {
+ return smbd_smb2_request_error(req, session_status);
}
return smbd_smb2_request_process_logoff(req);
case SMB2_OP_TCON:
+ if (!NT_STATUS_IS_OK(session_status)) {
+ return smbd_smb2_request_error(req, session_status);
+ }
status = smbd_smb2_request_check_session(req);
if (!NT_STATUS_IS_OK(status)) {
return smbd_smb2_request_error(req, status);
@@ -318,9 +351,8 @@ static NTSTATUS smbd_smb2_request_dispatch(struct smbd_smb2_request *req)
return smbd_smb2_request_process_tcon(req);
case SMB2_OP_TDIS:
- status = smbd_smb2_request_check_session(req);
- if (!NT_STATUS_IS_OK(status)) {
- return smbd_smb2_request_error(req, status);
+ if (!NT_STATUS_IS_OK(session_status)) {
+ return smbd_smb2_request_error(req, session_status);
}
status = smbd_smb2_request_check_tcon(req);
if (!NT_STATUS_IS_OK(status)) {
@@ -329,9 +361,8 @@ static NTSTATUS smbd_smb2_request_dispatch(struct smbd_smb2_request *req)
return smbd_smb2_request_process_tdis(req);
case SMB2_OP_CREATE:
- status = smbd_smb2_request_check_session(req);
- if (!NT_STATUS_IS_OK(status)) {
- return smbd_smb2_request_error(req, status);
+ if (!NT_STATUS_IS_OK(session_status)) {
+ return smbd_smb2_request_error(req, session_status);
}
status = smbd_smb2_request_check_tcon(req);
if (!NT_STATUS_IS_OK(status)) {
@@ -340,9 +371,8 @@ static NTSTATUS smbd_smb2_request_dispatch(struct smbd_smb2_request *req)
return smbd_smb2_request_error(req, NT_STATUS_NOT_IMPLEMENTED);
case SMB2_OP_CLOSE:
- status = smbd_smb2_request_check_session(req);
- if (!NT_STATUS_IS_OK(status)) {
- return smbd_smb2_request_error(req, status);
+ if (!NT_STATUS_IS_OK(session_status)) {
+ return smbd_smb2_request_error(req, session_status);
}
status = smbd_smb2_request_check_tcon(req);
if (!NT_STATUS_IS_OK(status)) {
@@ -351,9 +381,8 @@ static NTSTATUS smbd_smb2_request_dispatch(struct smbd_smb2_request *req)
return smbd_smb2_request_error(req, NT_STATUS_NOT_IMPLEMENTED);
case SMB2_OP_FLUSH:
- status = smbd_smb2_request_check_session(req);
- if (!NT_STATUS_IS_OK(status)) {
- return smbd_smb2_request_error(req, status);
+ if (!NT_STATUS_IS_OK(session_status)) {
+ return smbd_smb2_request_error(req, session_status);
}
status = smbd_smb2_request_check_tcon(req);
if (!NT_STATUS_IS_OK(status)) {
@@ -362,9 +391,8 @@ static NTSTATUS smbd_smb2_request_dispatch(struct smbd_smb2_request *req)
return smbd_smb2_request_error(req, NT_STATUS_NOT_IMPLEMENTED);
case SMB2_OP_READ:
- status = smbd_smb2_request_check_session(req);
- if (!NT_STATUS_IS_OK(status)) {
- return smbd_smb2_request_error(req, status);
+ if (!NT_STATUS_IS_OK(session_status)) {
+ return smbd_smb2_request_error(req, session_status);
}
status = smbd_smb2_request_check_tcon(req);
if (!NT_STATUS_IS_OK(status)) {
@@ -373,9 +401,8 @@ static NTSTATUS smbd_smb2_request_dispatch(struct smbd_smb2_request *req)
return smbd_smb2_request_error(req, NT_STATUS_NOT_IMPLEMENTED);
case SMB2_OP_WRITE:
- status = smbd_smb2_request_check_session(req);
- if (!NT_STATUS_IS_OK(status)) {
- return smbd_smb2_request_error(req, status);
+ if (!NT_STATUS_IS_OK(session_status)) {
+ return smbd_smb2_request_error(req, session_status);
}
status = smbd_smb2_request_check_tcon(req);
if (!NT_STATUS_IS_OK(status)) {
@@ -384,9 +411,8 @@ static NTSTATUS smbd_smb2_request_dispatch(struct smbd_smb2_request *req)
return smbd_smb2_request_error(req, NT_STATUS_NOT_IMPLEMENTED);
case SMB2_OP_LOCK:
- status = smbd_smb2_request_check_session(req);
- if (!NT_STATUS_IS_OK(status)) {
- return smbd_smb2_request_error(req, status);
+ if (!NT_STATUS_IS_OK(session_status)) {
+ return smbd_smb2_request_error(req, session_status);
}
status = smbd_smb2_request_check_tcon(req);
if (!NT_STATUS_IS_OK(status)) {
@@ -395,9 +421,8 @@ static NTSTATUS smbd_smb2_request_dispatch(struct smbd_smb2_request *req)
return smbd_smb2_request_error(req, NT_STATUS_NOT_IMPLEMENTED);
case SMB2_OP_IOCTL:
- status = smbd_smb2_request_check_session(req);
- if (!NT_STATUS_IS_OK(status)) {
- return smbd_smb2_request_error(req, status);
+ if (!NT_STATUS_IS_OK(session_status)) {
+ return smbd_smb2_request_error(req, session_status);
}
status = smbd_smb2_request_check_tcon(req);
if (!NT_STATUS_IS_OK(status)) {
@@ -412,9 +437,8 @@ static NTSTATUS smbd_smb2_request_dispatch(struct smbd_smb2_request *req)
return smbd_smb2_request_process_keepalive(req);
case SMB2_OP_FIND:
- status = smbd_smb2_request_check_session(req);
- if (!NT_STATUS_IS_OK(status)) {
- return smbd_smb2_request_error(req, status);
+ if (!NT_STATUS_IS_OK(session_status)) {
+ return smbd_smb2_request_error(req, session_status);
}
status = smbd_smb2_request_check_tcon(req);
if (!NT_STATUS_IS_OK(status)) {
@@ -423,9 +447,8 @@ static NTSTATUS smbd_smb2_request_dispatch(struct smbd_smb2_request *req)
return smbd_smb2_request_error(req, NT_STATUS_NOT_IMPLEMENTED);
case SMB2_OP_NOTIFY:
- status = smbd_smb2_request_check_session(req);
- if (!NT_STATUS_IS_OK(status)) {
- return smbd_smb2_request_error(req, status);
+ if (!NT_STATUS_IS_OK(session_status)) {
+ return smbd_smb2_request_error(req, session_status);
}
status = smbd_smb2_request_check_tcon(req);
if (!NT_STATUS_IS_OK(status)) {
@@ -434,9 +457,8 @@ static NTSTATUS smbd_smb2_request_dispatch(struct smbd_smb2_request *req)
return smbd_smb2_request_error(req, NT_STATUS_NOT_IMPLEMENTED);
case SMB2_OP_GETINFO:
- status = smbd_smb2_request_check_session(req);
- if (!NT_STATUS_IS_OK(status)) {
- return smbd_smb2_request_error(req, status);
+ if (!NT_STATUS_IS_OK(session_status)) {
+ return smbd_smb2_request_error(req, session_status);
}
status = smbd_smb2_request_check_tcon(req);
if (!NT_STATUS_IS_OK(status)) {
@@ -445,9 +467,8 @@ static NTSTATUS smbd_smb2_request_dispatch(struct smbd_smb2_request *req)
return smbd_smb2_request_error(req, NT_STATUS_NOT_IMPLEMENTED);
case SMB2_OP_SETINFO:
- status = smbd_smb2_request_check_session(req);
- if (!NT_STATUS_IS_OK(status)) {
- return smbd_smb2_request_error(req, status);
+ if (!NT_STATUS_IS_OK(session_status)) {
+ return smbd_smb2_request_error(req, session_status);
}
status = smbd_smb2_request_check_tcon(req);
if (!NT_STATUS_IS_OK(status)) {
@@ -456,9 +477,8 @@ static NTSTATUS smbd_smb2_request_dispatch(struct smbd_smb2_request *req)
return smbd_smb2_request_error(req, NT_STATUS_NOT_IMPLEMENTED);
case SMB2_OP_BREAK:
- status = smbd_smb2_request_check_session(req);
- if (!NT_STATUS_IS_OK(status)) {
- return smbd_smb2_request_error(req, status);
+ if (!NT_STATUS_IS_OK(session_status)) {
+ return smbd_smb2_request_error(req, session_status);
}
status = smbd_smb2_request_check_tcon(req);
if (!NT_STATUS_IS_OK(status)) {
@@ -481,6 +501,16 @@ static NTSTATUS smbd_smb2_request_reply(struct smbd_smb2_request *req)
smb2_setup_nbt_length(req->out.vector, req->out.vector_count);
+ if (req->do_signing) {
+ int i = req->current_idx;
+ NTSTATUS status;
+ status = smb2_signing_sign_pdu(req->session->session_key,
+ &req->out.vector[i], 3);
+ if (!NT_STATUS_IS_OK(status)) {
+ return status;
+ }
+ }
+
req->current_idx += 3;
if (req->current_idx > req->in.vector_count) {
diff --git a/source3/smbd/smb2_sesssetup.c b/source3/smbd/smb2_sesssetup.c
index fafda24ca4..be37aec04d 100644
--- a/source3/smbd/smb2_sesssetup.c
+++ b/source3/smbd/smb2_sesssetup.c
@@ -24,7 +24,9 @@
static NTSTATUS smbd_smb2_session_setup(struct smbd_smb2_request *req,
uint64_t in_session_id,
+ uint8_t in_security_mode,
DATA_BLOB in_security_buffer,
+ uint16_t *out_session_flags,
DATA_BLOB *out_security_buffer,
uint64_t *out_session_id);
@@ -39,9 +41,11 @@ NTSTATUS smbd_smb2_request_process_sesssetup(struct smbd_smb2_request *req)
size_t expected_body_size = 0x19;
size_t body_size;
uint64_t in_session_id;
+ uint8_t in_security_mode;
uint16_t in_security_offset;
uint16_t in_security_length;
DATA_BLOB in_security_buffer;
+ uint16_t out_session_flags;
uint64_t out_session_id;
uint16_t out_security_offset;
DATA_BLOB out_security_buffer;
@@ -72,12 +76,15 @@ NTSTATUS smbd_smb2_request_process_sesssetup(struct smbd_smb2_request *req)
}
in_session_id = BVAL(inhdr, SMB2_HDR_SESSION_ID);
+ in_security_mode = CVAL(inbody, 0x03);
in_security_buffer.data = (uint8_t *)req->in.vector[i+2].iov_base;
in_security_buffer.length = in_security_length;
status = smbd_smb2_session_setup(req,
in_session_id,
+ in_security_mode,
in_security_buffer,
+ &out_session_flags,
&out_security_buffer,
&out_session_id);
if (!NT_STATUS_IS_OK(status) &&
@@ -98,7 +105,8 @@ NTSTATUS smbd_smb2_request_process_sesssetup(struct smbd_smb2_request *req)
SBVAL(outhdr, SMB2_HDR_SESSION_ID, out_session_id);
SSVAL(outbody.data, 0x00, 0x08 + 1); /* struct size */
- SSVAL(outbody.data, 0x02, 0); /* session flags */
+ SSVAL(outbody.data, 0x02,
+ out_session_flags); /* session flags */
SSVAL(outbody.data, 0x04,
out_security_offset); /* security buffer offset */
SSVAL(outbody.data, 0x06,
@@ -132,13 +140,17 @@ static int smbd_smb2_session_destructor(struct smbd_smb2_session *session)
static NTSTATUS smbd_smb2_session_setup(struct smbd_smb2_request *req,
uint64_t in_session_id,
+ uint8_t in_security_mode,
DATA_BLOB in_security_buffer,
+ uint16_t *out_session_flags,
DATA_BLOB *out_security_buffer,
uint64_t *out_session_id)
{
struct smbd_smb2_session *session;
NTSTATUS status;
+ *out_session_flags = 0;
+
if (in_session_id == 0) {
int id;
@@ -185,6 +197,7 @@ static NTSTATUS smbd_smb2_session_setup(struct smbd_smb2_request *req,
if (session->auth_ntlmssp_state == NULL) {
status = auth_ntlmssp_start(&session->auth_ntlmssp_state);
if (!NT_STATUS_IS_OK(status)) {
+ TALLOC_FREE(session);
return status;
}
}
@@ -193,19 +206,54 @@ static NTSTATUS smbd_smb2_session_setup(struct smbd_smb2_request *req,
in_security_buffer,
out_security_buffer);
if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
- /* nothing to do */
- } else if (NT_STATUS_IS_OK(status)) {
- /* TODO: setup session key for signing */
- session->status = NT_STATUS_OK;
- /*
- * we attach the session to the request
- * so that the response can be signed
- */
- req->session = session;
- } else {
+ *out_session_id = session->vuid;
+ return status;
+ } else if (!NT_STATUS_IS_OK(status)) {
+ TALLOC_FREE(session);
return status;
}
+ /* TODO: setup session key for signing */
+
+ if ((in_security_mode & SMB2_NEGOTIATE_SIGNING_REQUIRED) ||
+ lp_server_signing() == Required) {
+ session->do_signing = true;
+ }
+
+ if (session->auth_ntlmssp_state->server_info->guest) {
+ /* we map anonymous to guest internally */
+ *out_session_flags |= SMB2_SESSION_FLAG_IS_GUEST;
+ *out_session_flags |= SMB2_SESSION_FLAG_IS_NULL;
+ /* force no signing */
+ session->do_signing = false;
+ }
+
+ session->server_info = session->auth_ntlmssp_state->server_info;
+ data_blob_free(&session->server_info->user_session_key);
+ session->server_info->user_session_key =
+ data_blob_talloc(
+ session->server_info,
+ session->auth_ntlmssp_state->ntlmssp_state->session_key.data,
+ session->auth_ntlmssp_state->ntlmssp_state->session_key.length);
+ if (session->auth_ntlmssp_state->ntlmssp_state->session_key.length > 0) {
+ if (session->server_info->user_session_key.data == NULL) {
+ TALLOC_FREE(session);
+ return NT_STATUS_NO_MEMORY;
+ }
+ }
+ session->session_key = session->server_info->user_session_key;
+
+ session->status = NT_STATUS_OK;
+
+ /*
+ * we attach the session to the request
+ * so that the response can be signed
+ */
+ req->session = session;
+ if (session->do_signing) {
+ req->do_signing = true;
+ }
+
*out_session_id = session->vuid;
return status;
}
diff --git a/source3/smbd/smb2_signing.c b/source3/smbd/smb2_signing.c
new file mode 100644
index 0000000000..55ed4f6d1c
--- /dev/null
+++ b/source3/smbd/smb2_signing.c
@@ -0,0 +1,135 @@
+/*
+ Unix SMB/CIFS implementation.
+ SMB2 signing
+
+ Copyright (C) Stefan Metzmacher 2009
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program 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 General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "includes.h"
+#include "smbd/globals.h"
+#include "../source4/libcli/smb2/smb2_constants.h"
+#include "../lib/crypto/crypto.h"
+
+NTSTATUS smb2_signing_sign_pdu(DATA_BLOB session_key,
+ struct iovec *vector,
+ int count)
+{
+ uint8_t *hdr;
+ uint64_t session_id;
+ struct HMACSHA256Context m;
+ uint8_t res[SHA256_DIGEST_LENGTH];
+ int i;
+
+ if (count < 2) {
+ return NT_STATUS_INVALID_PARAMETER;
+ }
+
+ if (vector[0].iov_len != SMB2_HDR_BODY) {
+ return NT_STATUS_INVALID_PARAMETER;
+ }
+
+ hdr = (uint8_t *)vector[0].iov_base;
+
+ session_id = BVAL(hdr, SMB2_HDR_SESSION_ID);
+ if (session_id == 0) {
+ /*
+ * do not sign messages with a zero session_id.
+ * See MS-SMB2 3.2.4.1.1
+ */
+ return NT_STATUS_OK;
+ }
+
+ if (session_key.length == 0) {
+ DEBUG(2,("Wrong session key length %u for SMB2 signing\n",
+ (unsigned)session_key.length));
+ return NT_STATUS_ACCESS_DENIED;
+ }
+
+ memset(hdr + SMB2_HDR_SIGNATURE, 0, 16);
+
+ SIVAL(hdr, SMB2_HDR_FLAGS, IVAL(hdr, SMB2_HDR_FLAGS) | SMB2_HDR_FLAG_SIGNED);
+
+ ZERO_STRUCT(m);
+ hmac_sha256_init(session_key.data, MIN(session_key.length, 16), &m);
+ for (i=0; i < count; i++) {
+ hmac_sha256_update((const uint8_t *)vector[i].iov_base,
+ vector[i].iov_len, &m);
+ }
+ hmac_sha256_final(res, &m);
+ DEBUG(5,("signed SMB2 message\n"));
+
+ memcpy(hdr + SMB2_HDR_SIGNATURE, res, 16);
+
+ return NT_STATUS_OK;
+}
+
+NTSTATUS smb2_signing_check_pdu(DATA_BLOB session_key,
+ const struct iovec *vector,
+ int count)
+{
+ const uint8_t *hdr;
+ const uint8_t *sig;
+ uint64_t session_id;
+ struct HMACSHA256Context m;
+ uint8_t res[SHA256_DIGEST_LENGTH];
+ static const uint8_t zero_sig[16];
+ int i;
+
+ if (count < 2) {
+ return NT_STATUS_INVALID_PARAMETER;
+ }
+
+ if (vector[0].iov_len != SMB2_HDR_BODY) {
+ return NT_STATUS_INVALID_PARAMETER;
+ }
+
+ hdr = (const uint8_t *)vector[0].iov_base;
+
+ session_id = BVAL(hdr, SMB2_HDR_SESSION_ID);
+ if (session_id == 0) {
+ /*
+ * do not sign messages with a zero session_id.
+ * See MS-SMB2 3.2.4.1.1
+ */
+ return NT_STATUS_OK;
+ }
+
+ if (session_key.length == 0) {
+ /* we don't have the session key yet */
+ return NT_STATUS_OK;
+ }
+
+ sig = hdr+SMB2_HDR_SIGNATURE;
+
+ ZERO_STRUCT(m);
+ hmac_sha256_init(session_key.data, MIN(session_key.length, 16), &m);
+ hmac_sha256_update(hdr, SMB2_HDR_SIGNATURE, &m);
+ hmac_sha256_update(zero_sig, 16, &m);
+ for (i=1; i < count; i++) {
+ hmac_sha256_update((const uint8_t *)vector[i].iov_base,
+ vector[i].iov_len, &m);
+ }
+ hmac_sha256_final(res, &m);
+
+ if (memcmp(res, sig, 16) != 0) {
+ DEBUG(0,("Bad SMB2 signature for message\n"));
+ dump_data(0, sig, 16);
+ dump_data(0, res, 16);
+ return NT_STATUS_ACCESS_DENIED;
+ }
+
+ return NT_STATUS_OK;
+}