source: trunk/src/sh_prelink.c@ 136

Last change on this file since 136 was 133, checked in by rainer, 17 years ago

Reentrant checksum/hash functions.
File size: 7.5 KB
Line 
1/* SAMHAIN file system integrity testing */
2/* Copyright (C) 2004 Rainer Wichmann */
3/* */
4/* This program is free software; you can redistribute it */
5/* and/or modify */
6/* it under the terms of the GNU General Public License as */
7/* published by */
8/* the Free Software Foundation; either version 2 of the License, or */
9/* (at your option) any later version. */
10/* */
11/* This program is distributed in the hope that it will be useful, */
12/* but WITHOUT ANY WARRANTY; without even the implied warranty of */
13/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */
14/* GNU General Public License for more details. */
15/* */
16/* You should have received a copy of the GNU General Public License */
17/* along with this program; if not, write to the Free Software */
18/* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
19
20#include "config_xor.h"
21
22#include <string.h>
23#include <sys/types.h>
24#include <signal.h>
25
26#if defined(SH_WITH_CLIENT) || defined(SH_STANDALONE)
27
28#include "samhain.h"
29#include "sh_tiger.h"
30#include "sh_extern.h"
31#include "sh_utils.h"
32#include "sh_unix.h"
33
34#undef FIL__
35#define FIL__ _("sh_prelink.c")
36
37static char * prelink_path = NULL;
38static char * prelink_hash = NULL;
39
40int sh_prelink_set_path (const char * str)
41{
42 SL_ENTER(_("sh_prelink_set_path"));
43 if (prelink_path != NULL)
44 SH_FREE(prelink_path);
45 if (str[0] != '/')
46 {
47 prelink_path = NULL;
48 SL_RETURN((-1), _("sh_prelink_set_path"));
49 }
50
51 prelink_path = sh_util_strdup(str);
52
53 SL_RETURN(0, _("sh_prelink_set_path"));
54}
55
56int sh_prelink_set_hash (const char * str)
57{
58 size_t len;
59 SL_ENTER(_("sh_prelink_set_hash"));
60 if (prelink_hash != NULL)
61 SH_FREE(prelink_hash);
62 len = sl_strlen (str);
63 if (len != KEY_LEN)
64 {
65 prelink_hash = NULL;
66 SL_RETURN((-1), _("sh_prelink_set_hash"));
67 }
68 prelink_hash = SH_ALLOC(len+1);
69 (void) sl_strlcpy(prelink_hash, str, len+1);
70 SL_RETURN(0, _("sh_prelink_set_hash"));
71}
72
73int sh_prelink_iself (SL_TICKET fd, off_t size, int alert_timeout, char * path)
74{
75 long status;
76 char magic[4];
77 char * tmp;
78
79 /* 42 bytes is about the minimum an ELF binary might have
80 * (with plenty of hacks to reduce the size, such as interleaving
81 * the code with the header...)
82 */
83 if (size < 42)
84 return S_FALSE;
85
86 status = sl_read_timeout (fd, magic, 4, alert_timeout, SL_FALSE);
87 (void) sl_rewind(fd);
88 if (status == 4)
89 {
90 /*@-usedef@*/
91 if (magic[0] == (char) 0x7f &&
92 magic[1] == 'E' &&
93 magic[2] == 'L' &&
94 magic[3] == 'F')
95 return S_TRUE;
96 /*@+usedef@*/
97 }
98 else
99 {
100 tmp = sh_util_safe_name (path);
101 sh_error_handle(SH_ERR_ERR, FIL__, __LINE__, status, MSG_E_SUBGPATH,
102 _("Error reading file"), _("sh_prelink_iself"), tmp);
103 SH_FREE(path);
104 }
105 return S_FALSE;
106}
107
108extern int get_the_fd (SL_TICKET ticket);
109
110static void sh_prelink_fd(sh_tas_t * task)
111{
112 SL_TICKET ticket;
113 char * tmp;
114 char hashbuf[KEYBUF_SIZE];
115
116 if (task->com_ti != (-1))
117 {
118 (void) sl_close(task->com_ti);
119 task->com_fd = -1;
120 task->com_ti = -1;
121 }
122 ticket = sl_open_read(task->command,
123 task->privileged == 0 ? SL_NOPRIV : SL_YESPRIV);
124 if (SL_ISERROR(ticket))
125 {
126 tmp = sh_util_safe_name (task->command);
127 sh_error_handle(SH_ERR_ERR, FIL__, __LINE__, ticket, MSG_E_READ, tmp);
128 SH_FREE(tmp);
129 return;
130 }
131
132 if (*(task->checksum) == '\0' ||
133 0 == sl_strcmp(task->checksum,
134 sh_tiger_hash (task->command, ticket, 0, hashbuf, sizeof(hashbuf))))
135 {
136 task->com_fd = get_the_fd(ticket);
137 task->com_ti = ticket;
138 }
139 else
140 {
141 tmp = sh_util_safe_name (task->command);
142 sh_error_handle(SH_ERR_ERR, FIL__, __LINE__, ticket, MSG_E_HASH, tmp);
143 SH_FREE(tmp);
144 (void) sl_close(ticket);
145 }
146 return;
147}
148
149/* returns static storage
150 */
151int sh_prelink_run (char * path, char * file_hash, int alert_timeout)
152{
153 static int init = S_FALSE;
154 static int args_filled = 0;
155 static sh_tas_t task;
156
157 int status = 0;
158 char * p;
159 struct sigaction new_act;
160 struct sigaction old_act;
161
162 SL_ENTER(_("sh_prelink_run"));
163
164 /* reset if path == NULL
165 */
166 if (path == NULL)
167 {
168 if (init == S_FALSE)
169 {
170 SL_RETURN (0, _("sh_prelink_run"));
171 }
172 sh_ext_tas_free(&task);
173 init = S_FALSE;
174 args_filled = 0;
175 SL_RETURN (0, _("sh_prelink_run"));
176 }
177
178 /* initialize task structure
179 */
180 if (init == S_FALSE)
181 {
182 char dir[SH_PATHBUF];
183
184 sh_ext_tas_init(&task);
185 p = sh_unix_getUIDdir (SH_ERR_ERR, task.run_user_uid, dir, sizeof(dir));
186 if (p)
187 {
188 (void) sh_ext_tas_add_envv (&task, _("HOME"), p);
189 }
190 (void) sh_ext_tas_add_envv (&task, _("SHELL"),
191 _("/bin/sh"));
192 (void) sh_ext_tas_add_envv (&task, _("PATH"),
193 _("/sbin:/usr/sbin:/bin:/usr/bin"));
194 if (sh.timezone != NULL)
195 {
196 (void) sh_ext_tas_add_envv(&task, "TZ", sh.timezone);
197 }
198 if (prelink_path == NULL)
199 {
200 sh_ext_tas_command(&task, _("/usr/sbin/prelink"));
201 (void) sh_ext_tas_add_argv(&task, _("/usr/sbin/prelink"));
202 }
203 else
204 {
205 sh_ext_tas_command(&task, prelink_path);
206 (void) sh_ext_tas_add_argv(&task, prelink_path);
207 }
208 args_filled = sh_ext_tas_add_argv(&task, _("--verify"));
209
210 if (prelink_hash != NULL)
211 {
212 (void) sl_strlcpy(task.checksum, prelink_hash, KEY_LEN+1);
213 }
214 task.rw = 'r';
215 task.fork_twice = S_FALSE;
216
217 sh_prelink_fd(&task);
218
219 init = S_TRUE;
220 }
221
222 /* rm filename arg if set; fill in filename
223 */
224 if (args_filled == 3)
225 args_filled = sh_ext_tas_rm_argv(&task);
226 if (args_filled == 2)
227 args_filled = sh_ext_tas_add_argv(&task, path);
228 else
229 {
230 sh_error_handle(SH_ERR_ERR, FIL__, __LINE__, args_filled, MSG_E_SUBGEN,
231 _("Bad argument count"), _("sh_prelink_run"));
232 SL_RETURN ((-1), _("sh_prelink_run"));
233 }
234
235 /* open pipe
236 */
237 status = sh_ext_popen(&task);
238 if (status != 0)
239 {
240 sh_error_handle(SH_ERR_ALL, FIL__, __LINE__, status, MSG_E_SUBGEN,
241 _("Could not open pipe"), _("sh_prelink_run"));
242 SL_RETURN ((-1), _("sh_prelink_run"));
243 }
244
245 if (SL_ISERROR(task.pipeTI))
246 {
247 sh_error_handle(SH_ERR_ALL, FIL__, __LINE__, task.pipeTI, MSG_E_SUBGEN,
248 _("No valid ticket"), _("sh_prelink_run"));
249 SL_RETURN ((-1), _("sh_prelink_run"));
250 }
251
252 /* ignore SIGPIPE (instead get EPIPE if connection is closed)
253 */
254 new_act.sa_handler = SIG_IGN;
255 (void) retry_sigaction (FIL__, __LINE__, SIGPIPE, &new_act, &old_act);
256
257 /* read from pipe
258 */
259 sl_read_timeout_prep (task.pipeTI);
260
261 {
262 char hashbuf[KEYBUF_SIZE];
263 sl_strlcpy(file_hash,
264 sh_tiger_generic_hash (path, task.pipeTI, TIGER_NOLIM, alert_timeout,
265 hashbuf, sizeof(hashbuf)),
266 KEY_LEN+1);
267 }
268
269 /* restore old signal handler
270 */
271 (void) retry_sigaction (FIL__, __LINE__, SIGPIPE, &old_act, NULL);
272
273 /* close pipe and return exit status
274 */
275 status = sh_ext_pclose(&task);
276 SL_RETURN ((status), _("sh_prelink_run"));
277}
278/* defined(SH_WITH_CLIENT) || defined(SH_STANDALONE)
279 */
280#endif
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