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Grant Edwards8a082772011-04-07 20:25:40 +00001/*
2 * Copyright (c) 2011, Comtrol Corp.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 *
27 */
28
29#include "defs.h"
Dmitry V. Levinb038a432011-08-30 16:05:26 +000030#include <sys/param.h>
Dmitry V. Levin80d5e012015-07-30 16:23:58 +000031#include <poll.h>
Grant Edwards8a082772011-04-07 20:25:40 +000032
33#include "syscall.h"
34
Denys Vlasenko38cfe7c2013-03-05 16:01:53 +010035const char **paths_selected = NULL;
Denys Vlasenko7239dbc2013-03-05 15:46:34 +010036static unsigned num_selected = 0;
Grant Edwards8a082772011-04-07 20:25:40 +000037
38/*
39 * Return true if specified path matches one that we're tracing.
40 */
41static int
42pathmatch(const char *path)
43{
Denys Vlasenko7239dbc2013-03-05 15:46:34 +010044 unsigned i;
Grant Edwards8a082772011-04-07 20:25:40 +000045
Denys Vlasenko7239dbc2013-03-05 15:46:34 +010046 for (i = 0; i < num_selected; ++i) {
Denys Vlasenko38cfe7c2013-03-05 16:01:53 +010047 if (strcmp(path, paths_selected[i]) == 0)
Grant Edwards8a082772011-04-07 20:25:40 +000048 return 1;
49 }
50 return 0;
51}
52
53/*
54 * Return true if specified path (in user-space) matches.
55 */
56static int
57upathmatch(struct tcb *tcp, unsigned long upath)
58{
Denys Vlasenko7b609d52011-06-22 14:32:43 +020059 char path[PATH_MAX + 1];
Grant Edwards8a082772011-04-07 20:25:40 +000060
Dmitry V. Levin1a880cf2013-02-26 19:23:27 +000061 return umovestr(tcp, upath, sizeof path, path) > 0 &&
Grant Edwards8a082772011-04-07 20:25:40 +000062 pathmatch(path);
63}
64
65/*
66 * Return true if specified fd maps to a path we're tracing.
67 */
68static int
69fdmatch(struct tcb *tcp, int fd)
70{
Denys Vlasenko61ad0a42013-03-06 18:24:34 +010071 char path[PATH_MAX + 1];
72 int n = getfdpath(tcp, fd, path, sizeof(path));
Grant Edwards8a082772011-04-07 20:25:40 +000073
Denys Vlasenko61ad0a42013-03-06 18:24:34 +010074 return n >= 0 && pathmatch(path);
Grant Edwards8a082772011-04-07 20:25:40 +000075}
76
77/*
78 * Add a path to the set we're tracing.
Philippe Ombredanne894c7e32014-02-01 09:57:45 -080079 * Specifying NULL will delete all paths.
Grant Edwards8a082772011-04-07 20:25:40 +000080 */
Denys Vlasenko7239dbc2013-03-05 15:46:34 +010081static void
Grant Edwards8a082772011-04-07 20:25:40 +000082storepath(const char *path)
83{
Denys Vlasenko7239dbc2013-03-05 15:46:34 +010084 unsigned i;
Grant Edwards8a082772011-04-07 20:25:40 +000085
Denys Vlasenko7239dbc2013-03-05 15:46:34 +010086 if (pathmatch(path))
87 return; /* already in table */
Grant Edwards8a082772011-04-07 20:25:40 +000088
Denys Vlasenko7239dbc2013-03-05 15:46:34 +010089 i = num_selected++;
Dmitry V. Levin3e9d71f2015-05-25 20:41:02 +000090 paths_selected = xreallocarray(paths_selected, num_selected,
91 sizeof(paths_selected[0]));
Denys Vlasenko38cfe7c2013-03-05 16:01:53 +010092 paths_selected[i] = path;
Grant Edwards8a082772011-04-07 20:25:40 +000093}
94
95/*
96 * Get path associated with fd.
97 */
Denys Vlasenko61ad0a42013-03-06 18:24:34 +010098int
99getfdpath(struct tcb *tcp, int fd, char *buf, unsigned bufsize)
Grant Edwards8a082772011-04-07 20:25:40 +0000100{
Denys Vlasenko384b0ad2012-03-15 18:11:51 +0100101 char linkpath[sizeof("/proc/%u/fd/%u") + 2 * sizeof(int)*3];
Grant Edwards8a082772011-04-07 20:25:40 +0000102 ssize_t n;
103
104 if (fd < 0)
Denys Vlasenko61ad0a42013-03-06 18:24:34 +0100105 return -1;
Grant Edwards8a082772011-04-07 20:25:40 +0000106
Denys Vlasenko29865e72012-03-15 18:03:56 +0100107 sprintf(linkpath, "/proc/%u/fd/%u", tcp->pid, fd);
Denys Vlasenko61ad0a42013-03-06 18:24:34 +0100108 n = readlink(linkpath, buf, bufsize - 1);
109 /*
110 * NB: if buf is too small, readlink doesn't fail,
111 * it returns truncated result (IOW: n == bufsize - 1).
112 */
113 if (n >= 0)
114 buf[n] = '\0';
115 return n;
Grant Edwards8a082772011-04-07 20:25:40 +0000116}
117
118/*
119 * Add a path to the set we're tracing. Also add the canonicalized
120 * version of the path. Secifying NULL will delete all paths.
121 */
Denys Vlasenko7239dbc2013-03-05 15:46:34 +0100122void
Grant Edwards8a082772011-04-07 20:25:40 +0000123pathtrace_select(const char *path)
124{
Denys Vlasenko29865e72012-03-15 18:03:56 +0100125 char *rpath;
Grant Edwards8a082772011-04-07 20:25:40 +0000126
Denys Vlasenko7239dbc2013-03-05 15:46:34 +0100127 storepath(path);
Grant Edwards8a082772011-04-07 20:25:40 +0000128
129 rpath = realpath(path, NULL);
130
131 if (rpath == NULL)
Denys Vlasenko7239dbc2013-03-05 15:46:34 +0100132 return;
Grant Edwards8a082772011-04-07 20:25:40 +0000133
134 /* if realpath and specified path are same, we're done */
Denys Vlasenko29865e72012-03-15 18:03:56 +0100135 if (strcmp(path, rpath) == 0) {
Grant Edwards8a082772011-04-07 20:25:40 +0000136 free(rpath);
Denys Vlasenko7239dbc2013-03-05 15:46:34 +0100137 return;
Grant Edwards8a082772011-04-07 20:25:40 +0000138 }
139
Dmitry V. Levin6c8ef052015-05-25 22:51:19 +0000140 error_msg("Requested path '%s' resolved into '%s'", path, rpath);
Denys Vlasenko7239dbc2013-03-05 15:46:34 +0100141 storepath(rpath);
Grant Edwards8a082772011-04-07 20:25:40 +0000142}
143
144/*
145 * Return true if syscall accesses a selected path
146 * (or if no paths have been specified for tracing).
147 */
148int
149pathtrace_match(struct tcb *tcp)
150{
Denys Vlasenkoa9fe13c2013-02-22 13:26:10 +0100151 const struct_sysent *s;
Grant Edwards8a082772011-04-07 20:25:40 +0000152
Denys Vlasenko74ec14f2013-02-21 16:13:47 +0100153 s = tcp->s_ent;
Grant Edwards8a082772011-04-07 20:25:40 +0000154
Philippe Ombredanne894c7e32014-02-01 09:57:45 -0800155 if (!(s->sys_flags & (TRACE_FILE | TRACE_DESC | TRACE_NETWORK)))
Grant Edwards8a082772011-04-07 20:25:40 +0000156 return 0;
157
158 /*
159 * Check for special cases where we need to do something
160 * other than test arg[0].
161 */
162
Elvira Khabirova483c15f2015-07-10 22:24:58 +0300163 switch (s->sen) {
164 case SEN_dup2:
165 case SEN_dup3:
Dmitry V. Levinea197052015-11-22 18:51:05 +0000166 case SEN_kexec_file_load:
Elvira Khabirova483c15f2015-07-10 22:24:58 +0300167 case SEN_sendfile:
168 case SEN_sendfile64:
169 case SEN_tee:
Grant Edwards8a082772011-04-07 20:25:40 +0000170 /* fd, fd */
171 return fdmatch(tcp, tcp->u_arg[0]) ||
172 fdmatch(tcp, tcp->u_arg[1]);
Grant Edwards8a082772011-04-07 20:25:40 +0000173
Elvira Khabirova483c15f2015-07-10 22:24:58 +0300174 case SEN_faccessat:
175 case SEN_fchmodat:
176 case SEN_fchownat:
177 case SEN_futimesat:
178 case SEN_inotify_add_watch:
179 case SEN_mkdirat:
180 case SEN_mknodat:
Dmitry V. Levin4b3a1702015-11-22 21:29:32 +0000181 case SEN_name_to_handle_at:
Elvira Khabirova483c15f2015-07-10 22:24:58 +0300182 case SEN_newfstatat:
183 case SEN_openat:
184 case SEN_pipe2:
185 case SEN_readlinkat:
186 case SEN_unlinkat:
187 case SEN_utimensat:
Grant Edwards8a082772011-04-07 20:25:40 +0000188 /* fd, path */
189 return fdmatch(tcp, tcp->u_arg[0]) ||
190 upathmatch(tcp, tcp->u_arg[1]);
Grant Edwards8a082772011-04-07 20:25:40 +0000191
Elvira Khabirova483c15f2015-07-10 22:24:58 +0300192 case SEN_link:
193 case SEN_mount:
194 case SEN_pivotroot:
Grant Edwards8a082772011-04-07 20:25:40 +0000195 /* path, path */
196 return upathmatch(tcp, tcp->u_arg[0]) ||
197 upathmatch(tcp, tcp->u_arg[1]);
Grant Edwards8a082772011-04-07 20:25:40 +0000198
Elvira Khabirova483c15f2015-07-10 22:24:58 +0300199 case SEN_quotactl:
Dmitry V. Levin79439662012-10-26 23:43:13 +0000200 /* x, path */
201 return upathmatch(tcp, tcp->u_arg[1]);
Dmitry V. Levin79439662012-10-26 23:43:13 +0000202
Elvira Khabirova483c15f2015-07-10 22:24:58 +0300203 case SEN_linkat:
204 case SEN_renameat2:
205 case SEN_renameat:
Grant Edwards8a082772011-04-07 20:25:40 +0000206 /* fd, path, fd, path */
207 return fdmatch(tcp, tcp->u_arg[0]) ||
208 fdmatch(tcp, tcp->u_arg[2]) ||
209 upathmatch(tcp, tcp->u_arg[1]) ||
210 upathmatch(tcp, tcp->u_arg[3]);
Grant Edwards8a082772011-04-07 20:25:40 +0000211
Elvira Khabirova483c15f2015-07-10 22:24:58 +0300212 case SEN_old_mmap:
Denys Vlasenko1ba85432013-02-19 11:28:20 +0100213#if defined(S390)
Elvira Khabirova483c15f2015-07-10 22:24:58 +0300214 case SEN_old_mmap_pgoff:
Denys Vlasenko1ba85432013-02-19 11:28:20 +0100215#endif
Elvira Khabirova483c15f2015-07-10 22:24:58 +0300216 case SEN_mmap:
217 case SEN_mmap_4koff:
218 case SEN_mmap_pgoff:
Dmitry V. Levindd1a80c2015-12-24 15:40:55 +0000219 case SEN_ARCH_mmap:
Grant Edwards8a082772011-04-07 20:25:40 +0000220 /* x, x, x, x, fd */
221 return fdmatch(tcp, tcp->u_arg[4]);
Grant Edwards8a082772011-04-07 20:25:40 +0000222
Elvira Khabirova483c15f2015-07-10 22:24:58 +0300223 case SEN_symlinkat:
Grant Edwards8a082772011-04-07 20:25:40 +0000224 /* path, fd, path */
225 return fdmatch(tcp, tcp->u_arg[1]) ||
226 upathmatch(tcp, tcp->u_arg[0]) ||
Denys Vlasenkob63256e2011-06-07 12:13:24 +0200227 upathmatch(tcp, tcp->u_arg[2]);
Grant Edwards8a082772011-04-07 20:25:40 +0000228
Elvira Khabirova483c15f2015-07-10 22:24:58 +0300229 case SEN_splice:
Grant Edwards8a082772011-04-07 20:25:40 +0000230 /* fd, x, fd, x, x */
231 return fdmatch(tcp, tcp->u_arg[0]) ||
232 fdmatch(tcp, tcp->u_arg[2]);
Grant Edwards8a082772011-04-07 20:25:40 +0000233
Elvira Khabirova483c15f2015-07-10 22:24:58 +0300234 case SEN_epoll_ctl:
Grant Edwards8a082772011-04-07 20:25:40 +0000235 /* x, x, fd, x */
236 return fdmatch(tcp, tcp->u_arg[2]);
Grant Edwards8a082772011-04-07 20:25:40 +0000237
Elvira Khabirova483c15f2015-07-10 22:24:58 +0300238
239 case SEN_fanotify_mark:
Dmitry V. Levin99db95d2014-02-05 04:13:18 +0000240 /* x, x, x, fd, path */
241 return fdmatch(tcp, tcp->u_arg[3]) ||
242 upathmatch(tcp, tcp->u_arg[4]);
Dmitry V. Levin99db95d2014-02-05 04:13:18 +0000243
Elvira Khabirova483c15f2015-07-10 22:24:58 +0300244 case SEN_oldselect:
245 case SEN_pselect6:
246 case SEN_select:
Grant Edwards8a082772011-04-07 20:25:40 +0000247 {
Denys Vlasenko79a79ea2011-09-01 16:35:44 +0200248 int i, j;
Denys Vlasenko64778cb2013-11-09 20:46:55 +0100249 int nfds;
Grant Edwards8a082772011-04-07 20:25:40 +0000250 long *args, oldargs[5];
251 unsigned fdsize;
252 fd_set *fds;
253
Denys Vlasenko64778cb2013-11-09 20:46:55 +0100254 args = tcp->u_arg;
Elvira Khabirova483c15f2015-07-10 22:24:58 +0300255 if (SEN_oldselect == s->sen) {
Grant Edwards8a082772011-04-07 20:25:40 +0000256 if (umoven(tcp, tcp->u_arg[0], sizeof oldargs,
Denys Vlasenko7e69ed92015-03-21 19:50:53 +0100257 oldargs) < 0)
Grant Edwards8a082772011-04-07 20:25:40 +0000258 {
Dmitry V. Levin6c8ef052015-05-25 22:51:19 +0000259 error_msg("umoven() failed");
Grant Edwards8a082772011-04-07 20:25:40 +0000260 return 0;
261 }
262 args = oldargs;
Denys Vlasenko64778cb2013-11-09 20:46:55 +0100263 }
Grant Edwards8a082772011-04-07 20:25:40 +0000264
Denys Vlasenko64778cb2013-11-09 20:46:55 +0100265 /* Kernel truncates arg[0] to int, we do the same. */
266 nfds = (int) args[0];
267 /* Kernel rejects negative nfds, so we don't parse it either. */
268 if (nfds <= 0)
269 return 0;
Denys Vlasenko79a79ea2011-09-01 16:35:44 +0200270 /* Beware of select(2^31-1, NULL, NULL, NULL) and similar... */
Denys Vlasenko64778cb2013-11-09 20:46:55 +0100271 if (nfds > 1024*1024)
Denys Vlasenko79a79ea2011-09-01 16:35:44 +0200272 nfds = 1024*1024;
Denys Vlasenko64778cb2013-11-09 20:46:55 +0100273 fdsize = (((nfds + 7) / 8) + current_wordsize-1) & -current_wordsize;
Dmitry V. Levin3e9d71f2015-05-25 20:41:02 +0000274 fds = xmalloc(fdsize);
Grant Edwards8a082772011-04-07 20:25:40 +0000275
Denys Vlasenko7b609d52011-06-22 14:32:43 +0200276 for (i = 1; i <= 3; ++i) {
Grant Edwards8a082772011-04-07 20:25:40 +0000277 if (args[i] == 0)
278 continue;
Denys Vlasenko7e69ed92015-03-21 19:50:53 +0100279 if (umoven(tcp, args[i], fdsize, fds) < 0) {
Dmitry V. Levin6c8ef052015-05-25 22:51:19 +0000280 error_msg("umoven() failed");
Grant Edwards8a082772011-04-07 20:25:40 +0000281 continue;
282 }
Denys Vlasenko64778cb2013-11-09 20:46:55 +0100283 for (j = 0;; j++) {
284 j = next_set_bit(fds, j, nfds);
285 if (j < 0)
286 break;
287 if (fdmatch(tcp, j)) {
Grant Edwards8a082772011-04-07 20:25:40 +0000288 free(fds);
289 return 1;
290 }
Denys Vlasenko64778cb2013-11-09 20:46:55 +0100291 }
Grant Edwards8a082772011-04-07 20:25:40 +0000292 }
293 free(fds);
294 return 0;
295 }
296
Elvira Khabirova483c15f2015-07-10 22:24:58 +0300297 case SEN_poll:
298 case SEN_ppoll:
Grant Edwards8a082772011-04-07 20:25:40 +0000299 {
300 struct pollfd fds;
301 unsigned nfds;
302 unsigned long start, cur, end;
303
304 start = tcp->u_arg[0];
305 nfds = tcp->u_arg[1];
306
307 end = start + sizeof(fds) * nfds;
308
309 if (nfds == 0 || end < start)
310 return 0;
311
312 for (cur = start; cur < end; cur += sizeof(fds))
Denys Vlasenko7e69ed92015-03-21 19:50:53 +0100313 if ((umoven(tcp, cur, sizeof fds, &fds) == 0)
Grant Edwards8a082772011-04-07 20:25:40 +0000314 && fdmatch(tcp, fds.fd))
315 return 1;
316
317 return 0;
318 }
319
Dmitry V. Levinddb53dd2015-07-25 23:55:51 +0000320 case SEN_bpf:
Elvira Khabirova483c15f2015-07-10 22:24:58 +0300321 case SEN_epoll_create:
Dmitry V. Levin27163462015-08-01 23:07:19 +0000322 case SEN_epoll_create1:
Elvira Khabirova483c15f2015-07-10 22:24:58 +0300323 case SEN_eventfd2:
324 case SEN_eventfd:
325 case SEN_fanotify_init:
326 case SEN_inotify_init1:
Dmitry V. Levin95b84ea2015-07-28 23:03:41 +0000327 case SEN_memfd_create:
Elvira Khabirova483c15f2015-07-10 22:24:58 +0300328 case SEN_perf_event_open:
329 case SEN_pipe:
330 case SEN_printargs:
331 case SEN_socket:
332 case SEN_socketpair:
333 case SEN_timerfd_create:
334 case SEN_timerfd_gettime:
335 case SEN_timerfd_settime:
Dmitry V. Levin87d64ed2015-11-22 19:56:00 +0000336 case SEN_userfaultfd:
Grant Edwards8a082772011-04-07 20:25:40 +0000337 /*
Philippe Ombredanne894c7e32014-02-01 09:57:45 -0800338 * These have TRACE_FILE or TRACE_DESCRIPTOR or TRACE_NETWORK set,
339 * but they don't have any file descriptor or path args to test.
Grant Edwards8a082772011-04-07 20:25:40 +0000340 */
341 return 0;
342 }
Grant Edwards8a082772011-04-07 20:25:40 +0000343
344 /*
345 * Our fallback position for calls that haven't already
346 * been handled is to just check arg[0].
347 */
348
349 if (s->sys_flags & TRACE_FILE)
350 return upathmatch(tcp, tcp->u_arg[0]);
351
Philippe Ombredanne894c7e32014-02-01 09:57:45 -0800352 if (s->sys_flags & (TRACE_DESC | TRACE_NETWORK))
Grant Edwards8a082772011-04-07 20:25:40 +0000353 return fdmatch(tcp, tcp->u_arg[0]);
354
355 return 0;
356}