1/*
2   Unix SMB/CIFS implementation.
3
4   SMB2 Create Context Blob handling
5
6   Copyright (C) Andrew Tridgell 2005
7   Copyright (C) Stefan Metzmacher 2008-2009
8
9   This program is free software; you can redistribute it and/or modify
10   it under the terms of the GNU General Public License as published by
11   the Free Software Foundation; either version 3 of the License, or
12   (at your option) any later version.
13
14   This program is distributed in the hope that it will be useful,
15   but WITHOUT ANY WARRANTY; without even the implied warranty of
16   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17   GNU General Public License for more details.
18
19   You should have received a copy of the GNU General Public License
20   along with this program.  If not, see <http://www.gnu.org/licenses/>.
21*/
22
23#include "includes.h"
24#include "../libcli/smb/smb_common.h"
25
26static size_t smb2_create_blob_padding(uint32_t offset, size_t n)
27{
28	if ((offset & (n-1)) == 0) return 0;
29	return n - (offset & (n-1));
30}
31
32/*
33  parse a set of SMB2 create blobs
34*/
35NTSTATUS smb2_create_blob_parse(TALLOC_CTX *mem_ctx, const DATA_BLOB buffer,
36				struct smb2_create_blobs *blobs)
37{
38	const uint8_t *data = buffer.data;
39	uint32_t remaining = buffer.length;
40
41	while (remaining > 0) {
42		uint32_t next;
43		uint32_t name_offset, name_length;
44		uint32_t reserved, data_offset;
45		uint32_t data_length;
46		char *tag;
47		DATA_BLOB b;
48		NTSTATUS status;
49
50		if (remaining < 16) {
51			return NT_STATUS_INVALID_PARAMETER;
52		}
53		next        = IVAL(data, 0);
54		name_offset = SVAL(data, 4);
55		name_length = SVAL(data, 6);
56		reserved    = SVAL(data, 8);
57		data_offset = SVAL(data, 10);
58		data_length = IVAL(data, 12);
59
60		if ((next & 0x7) != 0 ||
61		    next > remaining ||
62		    name_offset < 16 ||
63		    name_offset > remaining ||
64		    name_length != 4 || /* windows enforces this */
65		    name_offset + name_length > remaining ||
66		    data_offset < name_offset + name_length ||
67		    data_offset > remaining ||
68		    data_offset + (uint64_t)data_length > remaining) {
69			return NT_STATUS_INVALID_PARAMETER;
70		}
71
72		tag = talloc_strndup(mem_ctx, (const char *)data + name_offset, name_length);
73		if (tag == NULL) {
74			return NT_STATUS_NO_MEMORY;
75		}
76
77		b = data_blob_const(data+data_offset, data_length);
78		status = smb2_create_blob_add(mem_ctx, blobs, tag, b);
79		if (!NT_STATUS_IS_OK(status)) {
80			return status;
81		}
82
83		talloc_free(tag);
84
85		if (next == 0) break;
86
87		remaining -= next;
88		data += next;
89
90		if (remaining < 16) {
91			return NT_STATUS_INVALID_PARAMETER;
92		}
93	}
94
95	return NT_STATUS_OK;
96}
97
98
99/*
100  add a blob to a smb2_create attribute blob
101*/
102static NTSTATUS smb2_create_blob_push_one(TALLOC_CTX *mem_ctx, DATA_BLOB *buffer,
103					  const struct smb2_create_blob *blob,
104					  bool last)
105{
106	uint32_t ofs = buffer->length;
107	size_t tag_length = strlen(blob->tag);
108	uint8_t pad = smb2_create_blob_padding(blob->data.length+tag_length, 4);
109
110	if (!data_blob_realloc(mem_ctx, buffer,
111			       buffer->length + 0x14 + tag_length + blob->data.length + pad))
112		return NT_STATUS_NO_MEMORY;
113
114	if (last) {
115		SIVAL(buffer->data, ofs+0x00, 0);
116	} else {
117		SIVAL(buffer->data, ofs+0x00, 0x14 + tag_length + blob->data.length + pad);
118	}
119	SSVAL(buffer->data, ofs+0x04, 0x10); /* offset of tag */
120	SIVAL(buffer->data, ofs+0x06, tag_length); /* tag length */
121	SSVAL(buffer->data, ofs+0x0A, 0x14 + tag_length); /* offset of data */
122	SIVAL(buffer->data, ofs+0x0C, blob->data.length);
123	memcpy(buffer->data+ofs+0x10, blob->tag, tag_length);
124	SIVAL(buffer->data, ofs+0x10+tag_length, 0); /* pad? */
125	memcpy(buffer->data+ofs+0x14+tag_length, blob->data.data, blob->data.length);
126	memset(buffer->data+ofs+0x14+tag_length+blob->data.length, 0, pad);
127
128	return NT_STATUS_OK;
129}
130
131
132/*
133  create a buffer of a set of create blobs
134*/
135NTSTATUS smb2_create_blob_push(TALLOC_CTX *mem_ctx, DATA_BLOB *buffer,
136			       const struct smb2_create_blobs blobs)
137{
138	int i;
139	NTSTATUS status;
140
141	*buffer = data_blob(NULL, 0);
142	for (i=0; i < blobs.num_blobs; i++) {
143		bool last = false;
144		const struct smb2_create_blob *c;
145
146		if ((i + 1) == blobs.num_blobs) {
147			last = true;
148		}
149
150		c = &blobs.blobs[i];
151		status = smb2_create_blob_push_one(mem_ctx, buffer, c, last);
152		if (!NT_STATUS_IS_OK(status)) {
153			return status;
154		}
155	}
156	return NT_STATUS_OK;
157}
158
159
160NTSTATUS smb2_create_blob_add(TALLOC_CTX *mem_ctx, struct smb2_create_blobs *b,
161			      const char *tag, DATA_BLOB data)
162{
163	struct smb2_create_blob *array;
164
165	array = talloc_realloc(mem_ctx, b->blobs,
166			       struct smb2_create_blob,
167			       b->num_blobs + 1);
168	NT_STATUS_HAVE_NO_MEMORY(array);
169	b->blobs = array;
170
171	b->blobs[b->num_blobs].tag = talloc_strdup(b->blobs, tag);
172	NT_STATUS_HAVE_NO_MEMORY(b->blobs[b->num_blobs].tag);
173
174	if (data.data) {
175		b->blobs[b->num_blobs].data = data_blob_talloc(b->blobs,
176							       data.data,
177							       data.length);
178		NT_STATUS_HAVE_NO_MEMORY(b->blobs[b->num_blobs].data.data);
179	} else {
180		b->blobs[b->num_blobs].data = data_blob(NULL, 0);
181	}
182
183	b->num_blobs += 1;
184
185	return NT_STATUS_OK;
186}
187
188/*
189 * return the first blob with the given tag
190 */
191struct smb2_create_blob *smb2_create_blob_find(const struct smb2_create_blobs *b,
192					       const char *tag)
193{
194	uint32_t i;
195
196	for (i=0; i < b->num_blobs; i++) {
197		if (strcmp(b->blobs[i].tag, tag) == 0) {
198			return &b->blobs[i];
199		}
200	}
201
202	return NULL;
203}
204