summaryrefslogtreecommitdiffstats
path: root/src/shared/clean-ipc.c
blob: 46fa68027ed9477e6abdad61fcf89a4f07360f76 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
/* SPDX-License-Identifier: LGPL-2.1+ */

#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <mqueue.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <sys/sem.h>
#include <sys/shm.h>
#include <sys/stat.h>
#include <unistd.h>

#include "clean-ipc.h"
#include "dirent-util.h"
#include "fd-util.h"
#include "fileio.h"
#include "format-util.h"
#include "log.h"
#include "macro.h"
#include "string-util.h"
#include "strv.h"
#include "user-util.h"

static bool match_uid_gid(uid_t subject_uid, gid_t subject_gid, uid_t delete_uid, gid_t delete_gid) {

        if (uid_is_valid(delete_uid) && subject_uid == delete_uid)
                return true;

        if (gid_is_valid(delete_gid) && subject_gid == delete_gid)
                return true;

        return false;
}

static int clean_sysvipc_shm(uid_t delete_uid, gid_t delete_gid, bool rm) {
        _cleanup_fclose_ FILE *f = NULL;
        bool first = true;
        int ret = 0, r;

        f = fopen("/proc/sysvipc/shm", "re");
        if (!f) {
                if (errno == ENOENT)
                        return 0;

                return log_warning_errno(errno, "Failed to open /proc/sysvipc/shm: %m");
        }

        for (;;) {
                _cleanup_free_ char *line = NULL;
                unsigned n_attached;
                pid_t cpid, lpid;
                uid_t uid, cuid;
                gid_t gid, cgid;
                int shmid;

                r = read_line(f, LONG_LINE_MAX, &line);
                if (r < 0)
                        return log_warning_errno(errno, "Failed to read /proc/sysvipc/shm: %m");
                if (r == 0)
                        break;

                if (first) {
                        first = false;
                        continue;
                }

                if (sscanf(line, "%*i %i %*o %*u " PID_FMT " " PID_FMT " %u " UID_FMT " " GID_FMT " " UID_FMT " " GID_FMT,
                           &shmid, &cpid, &lpid, &n_attached, &uid, &gid, &cuid, &cgid) != 8)
                        continue;

                if (n_attached > 0)
                        continue;

                if (!match_uid_gid(uid, gid, delete_uid, delete_gid))
                        continue;

                if (!rm)
                        return 1;

                if (shmctl(shmid, IPC_RMID, NULL) < 0) {

                        /* Ignore entries that are already deleted */
                        if (IN_SET(errno, EIDRM, EINVAL))
                                continue;

                        ret = log_warning_errno(errno,
                                                "Failed to remove SysV shared memory segment %i: %m",
                                                shmid);
                } else {
                        log_debug("Removed SysV shared memory segment %i.", shmid);
                        if (ret == 0)
                                ret = 1;
                }
        }

        return ret;
}

static int clean_sysvipc_sem(uid_t delete_uid, gid_t delete_gid, bool rm) {
        _cleanup_fclose_ FILE *f = NULL;
        bool first = true;
        int ret = 0, r;

        f = fopen("/proc/sysvipc/sem", "re");
        if (!f) {
                if (errno == ENOENT)
                        return 0;

                return log_warning_errno(errno, "Failed to open /proc/sysvipc/sem: %m");
        }

        for (;;) {
                _cleanup_free_ char *line = NULL;
                uid_t uid, cuid;
                gid_t gid, cgid;
                int semid;

                r = read_line(f, LONG_LINE_MAX, &line);
                if (r < 0)
                        return log_warning_errno(r, "Failed to read /proc/sysvipc/sem: %m");
                if (r == 0)
                        break;

                if (first) {
                        first = false;
                        continue;
                }

                if (sscanf(line, "%*i %i %*o %*u " UID_FMT " " GID_FMT " " UID_FMT " " GID_FMT,
                           &semid, &uid, &gid, &cuid, &cgid) != 5)
                        continue;

                if (!match_uid_gid(uid, gid, delete_uid, delete_gid))
                        continue;

                if (!rm)
                        return 1;

                if (semctl(semid, 0, IPC_RMID) < 0) {

                        /* Ignore entries that are already deleted */
                        if (IN_SET(errno, EIDRM, EINVAL))
                                continue;

                        ret = log_warning_errno(errno,
                                                "Failed to remove SysV semaphores object %i: %m",
                                                semid);
                } else {
                        log_debug("Removed SysV semaphore %i.", semid);
                        if (ret == 0)
                                ret = 1;
                }
        }

        return ret;
}

static int clean_sysvipc_msg(uid_t delete_uid, gid_t delete_gid, bool rm) {
        _cleanup_fclose_ FILE *f = NULL;
        bool first = true;
        int ret = 0, r;

        f = fopen("/proc/sysvipc/msg", "re");
        if (!f) {
                if (errno == ENOENT)
                        return 0;

                return log_warning_errno(errno, "Failed to open /proc/sysvipc/msg: %m");
        }

        for (;;) {
                _cleanup_free_ char *line = NULL;
                uid_t uid, cuid;
                gid_t gid, cgid;
                pid_t cpid, lpid;
                int msgid;

                r = read_line(f, LONG_LINE_MAX, &line);
                if (r < 0)
                        return log_warning_errno(r, "Failed to read /proc/sysvipc/msg: %m");
                if (r == 0)
                        break;

                if (first) {
                        first = false;
                        continue;
                }

                if (sscanf(line, "%*i %i %*o %*u %*u " PID_FMT " " PID_FMT " " UID_FMT " " GID_FMT " " UID_FMT " " GID_FMT,
                           &msgid, &cpid, &lpid, &uid, &gid, &cuid, &cgid) != 7)
                        continue;

                if (!match_uid_gid(uid, gid, delete_uid, delete_gid))
                        continue;

                if (!rm)
                        return 1;

                if (msgctl(msgid, IPC_RMID, NULL) < 0) {

                        /* Ignore entries that are already deleted */
                        if (IN_SET(errno, EIDRM, EINVAL))
                                continue;

                        ret = log_warning_errno(errno,
                                                "Failed to remove SysV message queue %i: %m",
                                                msgid);
                } else {
                        log_debug("Removed SysV message queue %i.", msgid);
                        if (ret == 0)
                                ret = 1;
                }
        }

        return ret;
}

static int clean_posix_shm_internal(DIR *dir, uid_t uid, gid_t gid, bool rm) {
        struct dirent *de;
        int ret = 0, r;

        assert(dir);

        FOREACH_DIRENT_ALL(de, dir, goto fail) {
                struct stat st;

                if (dot_or_dot_dot(de->d_name))
                        continue;

                if (fstatat(dirfd(dir), de->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0) {
                        if (errno == ENOENT)
                                continue;

                        ret = log_warning_errno(errno, "Failed to stat() POSIX shared memory segment %s: %m", de->d_name);
                        continue;
                }

                if (S_ISDIR(st.st_mode)) {
                        _cleanup_closedir_ DIR *kid;

                        kid = xopendirat(dirfd(dir), de->d_name, O_NOFOLLOW|O_NOATIME);
                        if (!kid) {
                                if (errno != ENOENT)
                                        ret = log_warning_errno(errno, "Failed to enter shared memory directory %s: %m", de->d_name);
                        } else {
                                r = clean_posix_shm_internal(kid, uid, gid, rm);
                                if (r < 0)
                                        ret = r;
                        }

                        if (!match_uid_gid(st.st_uid, st.st_gid, uid, gid))
                                continue;

                        if (!rm)
                                return 1;

                        if (unlinkat(dirfd(dir), de->d_name, AT_REMOVEDIR) < 0) {

                                if (errno == ENOENT)
                                        continue;

                                ret = log_warning_errno(errno, "Failed to remove POSIX shared memory directory %s: %m", de->d_name);
                        } else {
                                log_debug("Removed POSIX shared memory directory %s", de->d_name);
                                if (ret == 0)
                                        ret = 1;
                        }
                } else {

                        if (!match_uid_gid(st.st_uid, st.st_gid, uid, gid))
                                continue;

                        if (!rm)
                                return 1;

                        if (unlinkat(dirfd(dir), de->d_name, 0) < 0) {

                                if (errno == ENOENT)
                                        continue;

                                ret = log_warning_errno(errno, "Failed to remove POSIX shared memory segment %s: %m", de->d_name);
                        } else {
                                log_debug("Removed POSIX shared memory segment %s", de->d_name);
                                if (ret == 0)
                                        ret = 1;
                        }
                }
        }

        return ret;

fail:
        return log_warning_errno(errno, "Failed to read /dev/shm: %m");
}

static int clean_posix_shm(uid_t uid, gid_t gid, bool rm) {
        _cleanup_closedir_ DIR *dir = NULL;

        dir = opendir("/dev/shm");
        if (!dir) {
                if (errno == ENOENT)
                        return 0;

                return log_warning_errno(errno, "Failed to open /dev/shm: %m");
        }

        return clean_posix_shm_internal(dir, uid, gid, rm);
}

static int clean_posix_mq(uid_t uid, gid_t gid, bool rm) {
        _cleanup_closedir_ DIR *dir = NULL;
        struct dirent *de;
        int ret = 0;

        dir = opendir("/dev/mqueue");
        if (!dir) {
                if (errno == ENOENT)
                        return 0;

                return log_warning_errno(errno, "Failed to open /dev/mqueue: %m");
        }

        FOREACH_DIRENT_ALL(de, dir, goto fail) {
                struct stat st;
                char fn[1+strlen(de->d_name)+1];

                if (dot_or_dot_dot(de->d_name))
                        continue;

                if (fstatat(dirfd(dir), de->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0) {
                        if (errno == ENOENT)
                                continue;

                        ret = log_warning_errno(errno,
                                                "Failed to stat() MQ segment %s: %m",
                                                de->d_name);
                        continue;
                }

                if (!match_uid_gid(st.st_uid, st.st_gid, uid, gid))
                        continue;

                if (!rm)
                        return 1;

                fn[0] = '/';
                strcpy(fn+1, de->d_name);

                if (mq_unlink(fn) < 0) {
                        if (errno == ENOENT)
                                continue;

                        ret = log_warning_errno(errno,
                                                "Failed to unlink POSIX message queue %s: %m",
                                                fn);
                } else {
                        log_debug("Removed POSIX message queue %s", fn);
                        if (ret == 0)
                                ret = 1;
                }
        }

        return ret;

fail:
        return log_warning_errno(errno, "Failed to read /dev/mqueue: %m");
}

int clean_ipc_internal(uid_t uid, gid_t gid, bool rm) {
        int ret = 0, r;

        /* If 'rm' is true, clean all IPC objects owned by either the specified UID or the specified GID. Return the
         * last error encountered or == 0 if no matching IPC objects have been found or > 0 if matching IPC objects
         * have been found and have been removed.
         *
         * If 'rm' is false, just search for IPC objects owned by either the specified UID or the specified GID. In
         * this case we return < 0 on error, > 0 if we found a matching object, == 0 if we didn't.
         *
         * As special rule: if UID/GID is specified as root we'll silently not clean up things, and always claim that
         * there are IPC objects for it. */

        if (uid == 0) {
                if (!rm)
                        return 1;

                uid = UID_INVALID;
        }
        if (gid == 0) {
                if (!rm)
                        return 1;

                gid = GID_INVALID;
        }

        /* Anything to do? */
        if (!uid_is_valid(uid) && !gid_is_valid(gid))
                return 0;

        r = clean_sysvipc_shm(uid, gid, rm);
        if (r != 0) {
                if (!rm)
                        return r;
                if (ret == 0)
                        ret = r;
        }

        r = clean_sysvipc_sem(uid, gid, rm);
        if (r != 0) {
                if (!rm)
                        return r;
                if (ret == 0)
                        ret = r;
        }

        r = clean_sysvipc_msg(uid, gid, rm);
        if (r != 0) {
                if (!rm)
                        return r;
                if (ret == 0)
                        ret = r;
        }

        r = clean_posix_shm(uid, gid, rm);
        if (r != 0) {
                if (!rm)
                        return r;
                if (ret == 0)
                        ret = r;
        }

        r = clean_posix_mq(uid, gid, rm);
        if (r != 0) {
                if (!rm)
                        return r;
                if (ret == 0)
                        ret = r;
        }

        return ret;
}

int clean_ipc_by_uid(uid_t uid) {
        return clean_ipc_internal(uid, GID_INVALID, true);
}

int clean_ipc_by_gid(gid_t gid) {
        return clean_ipc_internal(UID_INVALID, gid, true);
}