1 /*
2 * md5 based hashtab
3 *
4 * Copyright (C) 2013-2022 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
5 * Copyright (C) 2008-2013 Sourcefire, Inc.
6 *
7 * Authors: aCaB <acab@clamav.net>
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 version 2 as
11 * published by the Free Software Foundation.
12 *
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.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
21 * MA 02110-1301, USA.
22 */
23
24 #if HAVE_CONFIG_H
25 #include "clamav-config.h"
26 #endif
27
28 #include <stdlib.h>
29 #if HAVE_STRING_H
30 #include <string.h>
31 #endif
32
33 #include "clamav.h"
34 #include "uniq.h"
35 #include "others.h"
36
uniq_init(uint32_t count)37 struct uniq *uniq_init(uint32_t count)
38 {
39 struct uniq *U;
40
41 if (!count) return NULL;
42 U = cli_calloc(1, sizeof(*U));
43 if (!U) return NULL;
44
45 U->md5s = cli_malloc(count * sizeof(*U->md5s));
46 if (!U->md5s) {
47 uniq_free(U);
48 return NULL;
49 }
50 U->max_unique_items = count;
51
52 return U;
53 }
54
uniq_free(struct uniq * U)55 void uniq_free(struct uniq *U)
56 {
57 free(U->md5s);
58 free(U);
59 }
60
uniq_add(struct uniq * U,const char * item,uint32_t item_len,char ** rhash,uint32_t * count)61 cl_error_t uniq_add(struct uniq *U, const char *item, uint32_t item_len, char **rhash, uint32_t *count)
62 {
63 cl_error_t status = CL_EARG;
64 unsigned int i;
65 uint8_t digest[16];
66 struct UNIQMD5 *m = NULL;
67
68 if (!U) {
69 /* Invalid args */
70 goto done;
71 }
72
73 /* Uniq adds are limited by the maximum allocated in uniq_init(). */
74 if (U->cur_unique_items >= U->max_unique_items) {
75 /* Attempted to add more uniq items than may be stored. */
76 status = CL_EMAXSIZE;
77 goto done;
78 }
79
80 /* Make a hash of the item string */
81 if (NULL == cl_hash_data("md5", item, item_len, digest, NULL)) {
82 /* Failed to create hash of item. */
83 status = CL_EFORMAT;
84 goto done;
85 }
86
87 /* Check for md5 digest match in md5 collection */
88 if (U->items && U->md5s[U->idx[*digest]].md5[0] == *digest)
89 for (m = &U->md5s[U->idx[*digest]]; m; m = m->next)
90 if (!memcmp(&digest[1], &m->md5[1], 15)) break;
91
92 if (!m) {
93 /* No match. Add new md5 to list */
94 const char HEX[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
95
96 m = &U->md5s[U->items];
97 m->count = 0;
98
99 if (U->items && U->md5s[U->idx[*digest]].md5[0] == *digest)
100 m->next = &U->md5s[U->idx[*digest]];
101 else
102 m->next = NULL;
103
104 U->idx[*digest] = U->items;
105
106 for (i = 0; i < 16; i++) {
107 m->name[i * 2] = HEX[digest[i] >> 4 & 0xf];
108 m->name[i * 2 + 1] = HEX[digest[i] & 0xf];
109 m->md5[i] = digest[i];
110 }
111 m->name[32] = '\0';
112
113 /* Increment # of unique items. */
114 U->cur_unique_items++;
115 }
116
117 /* Increment total # of items. */
118 U->items++;
119
120 /* Increment # items matching this md5 digest (probably just this 1). */
121 m->count++;
122
123 /* Pass back the ascii hash, if requested. */
124 if (rhash) *rhash = m->name;
125
126 /* Pass back the count, if requested. */
127 if (count) *count = m->count;
128
129 status = CL_SUCCESS;
130
131 done:
132 return status;
133 }
134
uniq_get(struct uniq * U,const char * item,uint32_t item_len,char ** rhash,uint32_t * count)135 cl_error_t uniq_get(struct uniq *U, const char *item, uint32_t item_len, char **rhash, uint32_t *count)
136 {
137 cl_error_t status = CL_EARG;
138 uint8_t digest[16];
139 struct UNIQMD5 *m = NULL;
140 uint32_t idx = 0;
141
142 if (!U || !count) {
143 /* Invalid args */
144 goto done;
145 }
146
147 *count = 0;
148
149 if (!U->items) {
150 goto not_found;
151 }
152
153 /* Make a hash of the item string */
154 if (NULL == cl_hash_data("md5", item, item_len, digest, NULL)) {
155 /* Failed to create hash of item. */
156 status = CL_EFORMAT;
157 goto done;
158 }
159
160 /* Get the md5s array index for the bucket list head. */
161 idx = U->idx[*digest];
162 m = &U->md5s[idx];
163
164 if (m->md5[0] != *digest) {
165 /*
166 * If the first two bytes in the digest doesn't actually match,
167 * then the item has never been added.
168 * This is a common scenario because the idx table is initialized
169 * to 0's.
170 */
171 goto not_found;
172 }
173
174 do {
175 if (0 == memcmp(&digest[1], &m->md5[1], 15)) {
176 /* The item-hash matched.
177 * Pass back the ascii hash value (if requested).
178 * Return the count of matching items (will be 1+).
179 */
180 if (rhash)
181 *rhash = m->name;
182 *count = m->count;
183 break;
184 }
185 m = m->next;
186 } while (NULL != m);
187
188 not_found:
189 status = CL_SUCCESS;
190
191 done:
192 return status;
193 }
194