| 1 | /*
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| 2 | Unix SMB/CIFS implementation.
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| 3 | SMB2 signing
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| 4 |
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| 5 | Copyright (C) Stefan Metzmacher 2009
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| 6 |
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| 7 | This program is free software; you can redistribute it and/or modify
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| 8 | it under the terms of the GNU General Public License as published by
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| 9 | the Free Software Foundation; either version 3 of the License, or
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| 10 | (at your option) any later version.
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| 11 |
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| 12 | This program is distributed in the hope that it will be useful,
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| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 15 | GNU General Public License for more details.
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| 16 |
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| 17 | You should have received a copy of the GNU General Public License
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| 18 | along with this program. If not, see <http://www.gnu.org/licenses/>.
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| 19 | */
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| 20 |
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| 21 | #include "includes.h"
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| 22 | #include "smbd/smbd.h"
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| 23 | #include "smbd/globals.h"
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| 24 | #include "../libcli/smb/smb_common.h"
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| 25 | #include "../lib/crypto/crypto.h"
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| 26 |
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| 27 | NTSTATUS smb2_signing_sign_pdu(DATA_BLOB session_key,
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| 28 | struct iovec *vector,
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| 29 | int count)
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| 30 | {
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| 31 | uint8_t *hdr;
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| 32 | uint64_t session_id;
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| 33 | struct HMACSHA256Context m;
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| 34 | uint8_t res[SHA256_DIGEST_LENGTH];
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| 35 | int i;
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| 36 |
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| 37 | if (count < 2) {
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| 38 | return NT_STATUS_INVALID_PARAMETER;
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| 39 | }
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| 40 |
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| 41 | if (vector[0].iov_len != SMB2_HDR_BODY) {
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| 42 | return NT_STATUS_INVALID_PARAMETER;
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| 43 | }
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| 44 |
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| 45 | hdr = (uint8_t *)vector[0].iov_base;
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| 46 |
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| 47 | session_id = BVAL(hdr, SMB2_HDR_SESSION_ID);
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| 48 | if (session_id == 0) {
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| 49 | /*
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| 50 | * do not sign messages with a zero session_id.
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| 51 | * See MS-SMB2 3.2.4.1.1
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| 52 | */
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| 53 | return NT_STATUS_OK;
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| 54 | }
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| 55 |
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| 56 | if (session_key.length == 0) {
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| 57 | DEBUG(2,("Wrong session key length %u for SMB2 signing\n",
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| 58 | (unsigned)session_key.length));
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| 59 | return NT_STATUS_ACCESS_DENIED;
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| 60 | }
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| 61 |
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| 62 | memset(hdr + SMB2_HDR_SIGNATURE, 0, 16);
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| 63 |
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| 64 | SIVAL(hdr, SMB2_HDR_FLAGS, IVAL(hdr, SMB2_HDR_FLAGS) | SMB2_HDR_FLAG_SIGNED);
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| 65 |
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| 66 | ZERO_STRUCT(m);
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| 67 | hmac_sha256_init(session_key.data, MIN(session_key.length, 16), &m);
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| 68 | for (i=0; i < count; i++) {
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| 69 | hmac_sha256_update((const uint8_t *)vector[i].iov_base,
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| 70 | vector[i].iov_len, &m);
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| 71 | }
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| 72 | hmac_sha256_final(res, &m);
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| 73 | DEBUG(5,("signed SMB2 message\n"));
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| 74 |
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| 75 | memcpy(hdr + SMB2_HDR_SIGNATURE, res, 16);
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| 76 |
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| 77 | return NT_STATUS_OK;
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| 78 | }
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| 79 |
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| 80 | NTSTATUS smb2_signing_check_pdu(DATA_BLOB session_key,
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| 81 | const struct iovec *vector,
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| 82 | int count)
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| 83 | {
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| 84 | const uint8_t *hdr;
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| 85 | const uint8_t *sig;
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| 86 | uint64_t session_id;
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| 87 | struct HMACSHA256Context m;
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| 88 | uint8_t res[SHA256_DIGEST_LENGTH];
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| 89 | static const uint8_t zero_sig[16] = { 0, };
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| 90 | int i;
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| 91 |
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| 92 | if (count < 2) {
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