2 Unix SMB/CIFS implementation.
6 Copyright (C) Andrew Tridgell <tridge@samba.org> 2008
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>.
23 #include "libcli/raw/libcliraw.h"
24 #include "libcli/smb2/smb2.h"
25 #include "libcli/smb2/smb2_calls.h"
26 #include "../lib/crypto/crypto.h"
29 sign an outgoing message
31 NTSTATUS
smb2_sign_message(struct smb2_request_buffer
*buf
, DATA_BLOB session_key
)
33 struct HMACSHA256Context m
;
38 if (buf
->size
< NBT_HDR_SIZE
+ SMB2_HDR_SIGNATURE
+ 16) {
39 /* can't sign non-SMB2 messages */
43 hdr_offset
= buf
->hdr
- buf
->buffer
;
45 session_id
= BVAL(buf
->hdr
, SMB2_HDR_SESSION_ID
);
46 if (session_id
== 0) {
47 /* we don't sign messages with a zero session_id. See
52 if (session_key
.length
== 0) {
53 DEBUG(2,("Wrong session key length %u for SMB2 signing\n",
54 (unsigned)session_key
.length
));
55 return NT_STATUS_ACCESS_DENIED
;
58 memset(buf
->hdr
+ SMB2_HDR_SIGNATURE
, 0, 16);
60 SIVAL(buf
->hdr
, SMB2_HDR_FLAGS
, IVAL(buf
->hdr
, SMB2_HDR_FLAGS
) | SMB2_HDR_FLAG_SIGNED
);
63 hmac_sha256_init(session_key
.data
, MIN(session_key
.length
, 16), &m
);
64 hmac_sha256_update(buf
->hdr
, buf
->size
-hdr_offset
, &m
);
65 hmac_sha256_final(res
, &m
);
66 DEBUG(5,("signed SMB2 message of size %u\n", (unsigned)buf
->size
- NBT_HDR_SIZE
));
68 memcpy(buf
->hdr
+ SMB2_HDR_SIGNATURE
, res
, 16);
74 check an incoming signature
76 NTSTATUS
smb2_check_signature(struct smb2_request_buffer
*buf
, DATA_BLOB session_key
)
79 struct HMACSHA256Context m
;
80 uint8_t res
[SHA256_DIGEST_LENGTH
];
84 if (buf
->size
< NBT_HDR_SIZE
+ SMB2_HDR_SIGNATURE
+ 16) {
85 /* can't check non-SMB2 messages */
89 hdr_offset
= buf
->hdr
- buf
->buffer
;
91 session_id
= BVAL(buf
->hdr
, SMB2_HDR_SESSION_ID
);
92 if (session_id
== 0) {
93 /* don't sign messages with a zero session_id. See
98 if (session_key
.length
== 0) {
99 /* we don't have the session key yet */
103 memcpy(sig
, buf
->hdr
+SMB2_HDR_SIGNATURE
, 16);
105 memset(buf
->hdr
+ SMB2_HDR_SIGNATURE
, 0, 16);
108 hmac_sha256_init(session_key
.data
, MIN(session_key
.length
, 16), &m
);
109 hmac_sha256_update(buf
->hdr
, buf
->size
-hdr_offset
, &m
);
110 hmac_sha256_final(res
, &m
);
112 memcpy(buf
->hdr
+SMB2_HDR_SIGNATURE
, sig
, 16);
114 if (memcmp_const_time(res
, sig
, 16) != 0) {
115 DEBUG(0,("Bad SMB2 signature for message of size %u\n",
116 (unsigned)buf
->size
-NBT_HDR_SIZE
));
117 dump_data(0, sig
, 16);
118 dump_data(0, res
, 16);
119 return NT_STATUS_ACCESS_DENIED
;