Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/kernel/sys.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | */ | |
6 | ||
7 | #include <linux/config.h> | |
8 | #include <linux/module.h> | |
9 | #include <linux/mm.h> | |
10 | #include <linux/utsname.h> | |
11 | #include <linux/mman.h> | |
12 | #include <linux/smp_lock.h> | |
13 | #include <linux/notifier.h> | |
14 | #include <linux/reboot.h> | |
15 | #include <linux/prctl.h> | |
16 | #include <linux/init.h> | |
17 | #include <linux/highuid.h> | |
18 | #include <linux/fs.h> | |
dc009d92 EB |
19 | #include <linux/kernel.h> |
20 | #include <linux/kexec.h> | |
1da177e4 LT |
21 | #include <linux/workqueue.h> |
22 | #include <linux/device.h> | |
23 | #include <linux/key.h> | |
24 | #include <linux/times.h> | |
25 | #include <linux/posix-timers.h> | |
26 | #include <linux/security.h> | |
27 | #include <linux/dcookies.h> | |
28 | #include <linux/suspend.h> | |
29 | #include <linux/tty.h> | |
7ed20e1a | 30 | #include <linux/signal.h> |
9f46080c | 31 | #include <linux/cn_proc.h> |
1da177e4 LT |
32 | |
33 | #include <linux/compat.h> | |
34 | #include <linux/syscalls.h> | |
35 | ||
36 | #include <asm/uaccess.h> | |
37 | #include <asm/io.h> | |
38 | #include <asm/unistd.h> | |
39 | ||
40 | #ifndef SET_UNALIGN_CTL | |
41 | # define SET_UNALIGN_CTL(a,b) (-EINVAL) | |
42 | #endif | |
43 | #ifndef GET_UNALIGN_CTL | |
44 | # define GET_UNALIGN_CTL(a,b) (-EINVAL) | |
45 | #endif | |
46 | #ifndef SET_FPEMU_CTL | |
47 | # define SET_FPEMU_CTL(a,b) (-EINVAL) | |
48 | #endif | |
49 | #ifndef GET_FPEMU_CTL | |
50 | # define GET_FPEMU_CTL(a,b) (-EINVAL) | |
51 | #endif | |
52 | #ifndef SET_FPEXC_CTL | |
53 | # define SET_FPEXC_CTL(a,b) (-EINVAL) | |
54 | #endif | |
55 | #ifndef GET_FPEXC_CTL | |
56 | # define GET_FPEXC_CTL(a,b) (-EINVAL) | |
57 | #endif | |
58 | ||
59 | /* | |
60 | * this is where the system-wide overflow UID and GID are defined, for | |
61 | * architectures that now have 32-bit UID/GID but didn't in the past | |
62 | */ | |
63 | ||
64 | int overflowuid = DEFAULT_OVERFLOWUID; | |
65 | int overflowgid = DEFAULT_OVERFLOWGID; | |
66 | ||
67 | #ifdef CONFIG_UID16 | |
68 | EXPORT_SYMBOL(overflowuid); | |
69 | EXPORT_SYMBOL(overflowgid); | |
70 | #endif | |
71 | ||
72 | /* | |
73 | * the same as above, but for filesystems which can only store a 16-bit | |
74 | * UID and GID. as such, this is needed on all architectures | |
75 | */ | |
76 | ||
77 | int fs_overflowuid = DEFAULT_FS_OVERFLOWUID; | |
78 | int fs_overflowgid = DEFAULT_FS_OVERFLOWUID; | |
79 | ||
80 | EXPORT_SYMBOL(fs_overflowuid); | |
81 | EXPORT_SYMBOL(fs_overflowgid); | |
82 | ||
83 | /* | |
84 | * this indicates whether you can reboot with ctrl-alt-del: the default is yes | |
85 | */ | |
86 | ||
87 | int C_A_D = 1; | |
88 | int cad_pid = 1; | |
89 | ||
90 | /* | |
91 | * Notifier list for kernel code which wants to be called | |
92 | * at shutdown. This is used to stop any idling DMA operations | |
93 | * and the like. | |
94 | */ | |
95 | ||
96 | static struct notifier_block *reboot_notifier_list; | |
97 | static DEFINE_RWLOCK(notifier_lock); | |
98 | ||
99 | /** | |
100 | * notifier_chain_register - Add notifier to a notifier chain | |
101 | * @list: Pointer to root list pointer | |
102 | * @n: New entry in notifier chain | |
103 | * | |
104 | * Adds a notifier to a notifier chain. | |
105 | * | |
106 | * Currently always returns zero. | |
107 | */ | |
108 | ||
109 | int notifier_chain_register(struct notifier_block **list, struct notifier_block *n) | |
110 | { | |
111 | write_lock(¬ifier_lock); | |
112 | while(*list) | |
113 | { | |
114 | if(n->priority > (*list)->priority) | |
115 | break; | |
116 | list= &((*list)->next); | |
117 | } | |
118 | n->next = *list; | |
119 | *list=n; | |
120 | write_unlock(¬ifier_lock); | |
121 | return 0; | |
122 | } | |
123 | ||
124 | EXPORT_SYMBOL(notifier_chain_register); | |
125 | ||
126 | /** | |
127 | * notifier_chain_unregister - Remove notifier from a notifier chain | |
128 | * @nl: Pointer to root list pointer | |
129 | * @n: New entry in notifier chain | |
130 | * | |
131 | * Removes a notifier from a notifier chain. | |
132 | * | |
133 | * Returns zero on success, or %-ENOENT on failure. | |
134 | */ | |
135 | ||
136 | int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n) | |
137 | { | |
138 | write_lock(¬ifier_lock); | |
139 | while((*nl)!=NULL) | |
140 | { | |
141 | if((*nl)==n) | |
142 | { | |
143 | *nl=n->next; | |
144 | write_unlock(¬ifier_lock); | |
145 | return 0; | |
146 | } | |
147 | nl=&((*nl)->next); | |
148 | } | |
149 | write_unlock(¬ifier_lock); | |
150 | return -ENOENT; | |
151 | } | |
152 | ||
153 | EXPORT_SYMBOL(notifier_chain_unregister); | |
154 | ||
155 | /** | |
156 | * notifier_call_chain - Call functions in a notifier chain | |
157 | * @n: Pointer to root pointer of notifier chain | |
158 | * @val: Value passed unmodified to notifier function | |
159 | * @v: Pointer passed unmodified to notifier function | |
160 | * | |
161 | * Calls each function in a notifier chain in turn. | |
162 | * | |
163 | * If the return value of the notifier can be and'd | |
164 | * with %NOTIFY_STOP_MASK, then notifier_call_chain | |
165 | * will return immediately, with the return value of | |
166 | * the notifier function which halted execution. | |
167 | * Otherwise, the return value is the return value | |
168 | * of the last notifier function called. | |
169 | */ | |
170 | ||
171 | int notifier_call_chain(struct notifier_block **n, unsigned long val, void *v) | |
172 | { | |
173 | int ret=NOTIFY_DONE; | |
174 | struct notifier_block *nb = *n; | |
175 | ||
176 | while(nb) | |
177 | { | |
178 | ret=nb->notifier_call(nb,val,v); | |
179 | if(ret&NOTIFY_STOP_MASK) | |
180 | { | |
181 | return ret; | |
182 | } | |
183 | nb=nb->next; | |
184 | } | |
185 | return ret; | |
186 | } | |
187 | ||
188 | EXPORT_SYMBOL(notifier_call_chain); | |
189 | ||
190 | /** | |
191 | * register_reboot_notifier - Register function to be called at reboot time | |
192 | * @nb: Info about notifier function to be called | |
193 | * | |
194 | * Registers a function with the list of functions | |
195 | * to be called at reboot time. | |
196 | * | |
197 | * Currently always returns zero, as notifier_chain_register | |
198 | * always returns zero. | |
199 | */ | |
200 | ||
201 | int register_reboot_notifier(struct notifier_block * nb) | |
202 | { | |
203 | return notifier_chain_register(&reboot_notifier_list, nb); | |
204 | } | |
205 | ||
206 | EXPORT_SYMBOL(register_reboot_notifier); | |
207 | ||
208 | /** | |
209 | * unregister_reboot_notifier - Unregister previously registered reboot notifier | |
210 | * @nb: Hook to be unregistered | |
211 | * | |
212 | * Unregisters a previously registered reboot | |
213 | * notifier function. | |
214 | * | |
215 | * Returns zero on success, or %-ENOENT on failure. | |
216 | */ | |
217 | ||
218 | int unregister_reboot_notifier(struct notifier_block * nb) | |
219 | { | |
220 | return notifier_chain_unregister(&reboot_notifier_list, nb); | |
221 | } | |
222 | ||
223 | EXPORT_SYMBOL(unregister_reboot_notifier); | |
224 | ||
225 | static int set_one_prio(struct task_struct *p, int niceval, int error) | |
226 | { | |
227 | int no_nice; | |
228 | ||
229 | if (p->uid != current->euid && | |
230 | p->euid != current->euid && !capable(CAP_SYS_NICE)) { | |
231 | error = -EPERM; | |
232 | goto out; | |
233 | } | |
e43379f1 | 234 | if (niceval < task_nice(p) && !can_nice(p, niceval)) { |
1da177e4 LT |
235 | error = -EACCES; |
236 | goto out; | |
237 | } | |
238 | no_nice = security_task_setnice(p, niceval); | |
239 | if (no_nice) { | |
240 | error = no_nice; | |
241 | goto out; | |
242 | } | |
243 | if (error == -ESRCH) | |
244 | error = 0; | |
245 | set_user_nice(p, niceval); | |
246 | out: | |
247 | return error; | |
248 | } | |
249 | ||
250 | asmlinkage long sys_setpriority(int which, int who, int niceval) | |
251 | { | |
252 | struct task_struct *g, *p; | |
253 | struct user_struct *user; | |
254 | int error = -EINVAL; | |
255 | ||
256 | if (which > 2 || which < 0) | |
257 | goto out; | |
258 | ||
259 | /* normalize: avoid signed division (rounding problems) */ | |
260 | error = -ESRCH; | |
261 | if (niceval < -20) | |
262 | niceval = -20; | |
263 | if (niceval > 19) | |
264 | niceval = 19; | |
265 | ||
266 | read_lock(&tasklist_lock); | |
267 | switch (which) { | |
268 | case PRIO_PROCESS: | |
269 | if (!who) | |
270 | who = current->pid; | |
271 | p = find_task_by_pid(who); | |
272 | if (p) | |
273 | error = set_one_prio(p, niceval, error); | |
274 | break; | |
275 | case PRIO_PGRP: | |
276 | if (!who) | |
277 | who = process_group(current); | |
278 | do_each_task_pid(who, PIDTYPE_PGID, p) { | |
279 | error = set_one_prio(p, niceval, error); | |
280 | } while_each_task_pid(who, PIDTYPE_PGID, p); | |
281 | break; | |
282 | case PRIO_USER: | |
283 | user = current->user; | |
284 | if (!who) | |
285 | who = current->uid; | |
286 | else | |
287 | if ((who != current->uid) && !(user = find_user(who))) | |
288 | goto out_unlock; /* No processes for this user */ | |
289 | ||
290 | do_each_thread(g, p) | |
291 | if (p->uid == who) | |
292 | error = set_one_prio(p, niceval, error); | |
293 | while_each_thread(g, p); | |
294 | if (who != current->uid) | |
295 | free_uid(user); /* For find_user() */ | |
296 | break; | |
297 | } | |
298 | out_unlock: | |
299 | read_unlock(&tasklist_lock); | |
300 | out: | |
301 | return error; | |
302 | } | |
303 | ||
304 | /* | |
305 | * Ugh. To avoid negative return values, "getpriority()" will | |
306 | * not return the normal nice-value, but a negated value that | |
307 | * has been offset by 20 (ie it returns 40..1 instead of -20..19) | |
308 | * to stay compatible. | |
309 | */ | |
310 | asmlinkage long sys_getpriority(int which, int who) | |
311 | { | |
312 | struct task_struct *g, *p; | |
313 | struct user_struct *user; | |
314 | long niceval, retval = -ESRCH; | |
315 | ||
316 | if (which > 2 || which < 0) | |
317 | return -EINVAL; | |
318 | ||
319 | read_lock(&tasklist_lock); | |
320 | switch (which) { | |
321 | case PRIO_PROCESS: | |
322 | if (!who) | |
323 | who = current->pid; | |
324 | p = find_task_by_pid(who); | |
325 | if (p) { | |
326 | niceval = 20 - task_nice(p); | |
327 | if (niceval > retval) | |
328 | retval = niceval; | |
329 | } | |
330 | break; | |
331 | case PRIO_PGRP: | |
332 | if (!who) | |
333 | who = process_group(current); | |
334 | do_each_task_pid(who, PIDTYPE_PGID, p) { | |
335 | niceval = 20 - task_nice(p); | |
336 | if (niceval > retval) | |
337 | retval = niceval; | |
338 | } while_each_task_pid(who, PIDTYPE_PGID, p); | |
339 | break; | |
340 | case PRIO_USER: | |
341 | user = current->user; | |
342 | if (!who) | |
343 | who = current->uid; | |
344 | else | |
345 | if ((who != current->uid) && !(user = find_user(who))) | |
346 | goto out_unlock; /* No processes for this user */ | |
347 | ||
348 | do_each_thread(g, p) | |
349 | if (p->uid == who) { | |
350 | niceval = 20 - task_nice(p); | |
351 | if (niceval > retval) | |
352 | retval = niceval; | |
353 | } | |
354 | while_each_thread(g, p); | |
355 | if (who != current->uid) | |
356 | free_uid(user); /* for find_user() */ | |
357 | break; | |
358 | } | |
359 | out_unlock: | |
360 | read_unlock(&tasklist_lock); | |
361 | ||
362 | return retval; | |
363 | } | |
364 | ||
e4c94330 EB |
365 | /** |
366 | * emergency_restart - reboot the system | |
367 | * | |
368 | * Without shutting down any hardware or taking any locks | |
369 | * reboot the system. This is called when we know we are in | |
370 | * trouble so this is our best effort to reboot. This is | |
371 | * safe to call in interrupt context. | |
372 | */ | |
7c903473 EB |
373 | void emergency_restart(void) |
374 | { | |
375 | machine_emergency_restart(); | |
376 | } | |
377 | EXPORT_SYMBOL_GPL(emergency_restart); | |
378 | ||
e4c94330 EB |
379 | /** |
380 | * kernel_restart - reboot the system | |
381 | * | |
382 | * Shutdown everything and perform a clean reboot. | |
383 | * This is not safe to call in interrupt context. | |
384 | */ | |
385 | void kernel_restart_prepare(char *cmd) | |
4a00ea1e EB |
386 | { |
387 | notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd); | |
388 | system_state = SYSTEM_RESTART; | |
4a00ea1e | 389 | device_shutdown(); |
e4c94330 EB |
390 | } |
391 | void kernel_restart(char *cmd) | |
392 | { | |
393 | kernel_restart_prepare(cmd); | |
4a00ea1e EB |
394 | if (!cmd) { |
395 | printk(KERN_EMERG "Restarting system.\n"); | |
396 | } else { | |
397 | printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd); | |
398 | } | |
399 | printk(".\n"); | |
400 | machine_restart(cmd); | |
401 | } | |
402 | EXPORT_SYMBOL_GPL(kernel_restart); | |
403 | ||
e4c94330 EB |
404 | /** |
405 | * kernel_kexec - reboot the system | |
406 | * | |
407 | * Move into place and start executing a preloaded standalone | |
408 | * executable. If nothing was preloaded return an error. | |
409 | */ | |
4a00ea1e EB |
410 | void kernel_kexec(void) |
411 | { | |
412 | #ifdef CONFIG_KEXEC | |
413 | struct kimage *image; | |
414 | image = xchg(&kexec_image, 0); | |
415 | if (!image) { | |
416 | return; | |
417 | } | |
e4c94330 | 418 | kernel_restart_prepare(NULL); |
4a00ea1e EB |
419 | printk(KERN_EMERG "Starting new kernel\n"); |
420 | machine_shutdown(); | |
421 | machine_kexec(image); | |
422 | #endif | |
423 | } | |
424 | EXPORT_SYMBOL_GPL(kernel_kexec); | |
425 | ||
e4c94330 EB |
426 | /** |
427 | * kernel_halt - halt the system | |
428 | * | |
429 | * Shutdown everything and perform a clean system halt. | |
430 | */ | |
431 | void kernel_halt_prepare(void) | |
4a00ea1e EB |
432 | { |
433 | notifier_call_chain(&reboot_notifier_list, SYS_HALT, NULL); | |
434 | system_state = SYSTEM_HALT; | |
4a00ea1e | 435 | device_shutdown(); |
e4c94330 EB |
436 | } |
437 | void kernel_halt(void) | |
438 | { | |
439 | kernel_halt_prepare(); | |
4a00ea1e EB |
440 | printk(KERN_EMERG "System halted.\n"); |
441 | machine_halt(); | |
442 | } | |
443 | EXPORT_SYMBOL_GPL(kernel_halt); | |
444 | ||
e4c94330 EB |
445 | /** |
446 | * kernel_power_off - power_off the system | |
447 | * | |
448 | * Shutdown everything and perform a clean system power_off. | |
449 | */ | |
450 | void kernel_power_off_prepare(void) | |
4a00ea1e EB |
451 | { |
452 | notifier_call_chain(&reboot_notifier_list, SYS_POWER_OFF, NULL); | |
453 | system_state = SYSTEM_POWER_OFF; | |
4a00ea1e | 454 | device_shutdown(); |
e4c94330 EB |
455 | } |
456 | void kernel_power_off(void) | |
457 | { | |
458 | kernel_power_off_prepare(); | |
4a00ea1e EB |
459 | printk(KERN_EMERG "Power down.\n"); |
460 | machine_power_off(); | |
461 | } | |
462 | EXPORT_SYMBOL_GPL(kernel_power_off); | |
1da177e4 LT |
463 | |
464 | /* | |
465 | * Reboot system call: for obvious reasons only root may call it, | |
466 | * and even root needs to set up some magic numbers in the registers | |
467 | * so that some mistake won't make this reboot the whole machine. | |
468 | * You can also set the meaning of the ctrl-alt-del-key here. | |
469 | * | |
470 | * reboot doesn't sync: do that yourself before calling this. | |
471 | */ | |
472 | asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg) | |
473 | { | |
474 | char buffer[256]; | |
475 | ||
476 | /* We only trust the superuser with rebooting the system. */ | |
477 | if (!capable(CAP_SYS_BOOT)) | |
478 | return -EPERM; | |
479 | ||
480 | /* For safety, we require "magic" arguments. */ | |
481 | if (magic1 != LINUX_REBOOT_MAGIC1 || | |
482 | (magic2 != LINUX_REBOOT_MAGIC2 && | |
483 | magic2 != LINUX_REBOOT_MAGIC2A && | |
484 | magic2 != LINUX_REBOOT_MAGIC2B && | |
485 | magic2 != LINUX_REBOOT_MAGIC2C)) | |
486 | return -EINVAL; | |
487 | ||
488 | lock_kernel(); | |
489 | switch (cmd) { | |
490 | case LINUX_REBOOT_CMD_RESTART: | |
4a00ea1e | 491 | kernel_restart(NULL); |
1da177e4 LT |
492 | break; |
493 | ||
494 | case LINUX_REBOOT_CMD_CAD_ON: | |
495 | C_A_D = 1; | |
496 | break; | |
497 | ||
498 | case LINUX_REBOOT_CMD_CAD_OFF: | |
499 | C_A_D = 0; | |
500 | break; | |
501 | ||
502 | case LINUX_REBOOT_CMD_HALT: | |
4a00ea1e | 503 | kernel_halt(); |
1da177e4 LT |
504 | unlock_kernel(); |
505 | do_exit(0); | |
506 | break; | |
507 | ||
508 | case LINUX_REBOOT_CMD_POWER_OFF: | |
4a00ea1e | 509 | kernel_power_off(); |
1da177e4 LT |
510 | unlock_kernel(); |
511 | do_exit(0); | |
512 | break; | |
513 | ||
514 | case LINUX_REBOOT_CMD_RESTART2: | |
515 | if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) { | |
516 | unlock_kernel(); | |
517 | return -EFAULT; | |
518 | } | |
519 | buffer[sizeof(buffer) - 1] = '\0'; | |
520 | ||
4a00ea1e | 521 | kernel_restart(buffer); |
1da177e4 LT |
522 | break; |
523 | ||
dc009d92 | 524 | case LINUX_REBOOT_CMD_KEXEC: |
4a00ea1e EB |
525 | kernel_kexec(); |
526 | unlock_kernel(); | |
527 | return -EINVAL; | |
528 | ||
1da177e4 LT |
529 | #ifdef CONFIG_SOFTWARE_SUSPEND |
530 | case LINUX_REBOOT_CMD_SW_SUSPEND: | |
531 | { | |
532 | int ret = software_suspend(); | |
533 | unlock_kernel(); | |
534 | return ret; | |
535 | } | |
536 | #endif | |
537 | ||
538 | default: | |
539 | unlock_kernel(); | |
540 | return -EINVAL; | |
541 | } | |
542 | unlock_kernel(); | |
543 | return 0; | |
544 | } | |
545 | ||
546 | static void deferred_cad(void *dummy) | |
547 | { | |
abcd9e51 | 548 | kernel_restart(NULL); |
1da177e4 LT |
549 | } |
550 | ||
551 | /* | |
552 | * This function gets called by ctrl-alt-del - ie the keyboard interrupt. | |
553 | * As it's called within an interrupt, it may NOT sync: the only choice | |
554 | * is whether to reboot at once, or just ignore the ctrl-alt-del. | |
555 | */ | |
556 | void ctrl_alt_del(void) | |
557 | { | |
558 | static DECLARE_WORK(cad_work, deferred_cad, NULL); | |
559 | ||
560 | if (C_A_D) | |
561 | schedule_work(&cad_work); | |
562 | else | |
563 | kill_proc(cad_pid, SIGINT, 1); | |
564 | } | |
565 | ||
566 | ||
567 | /* | |
568 | * Unprivileged users may change the real gid to the effective gid | |
569 | * or vice versa. (BSD-style) | |
570 | * | |
571 | * If you set the real gid at all, or set the effective gid to a value not | |
572 | * equal to the real gid, then the saved gid is set to the new effective gid. | |
573 | * | |
574 | * This makes it possible for a setgid program to completely drop its | |
575 | * privileges, which is often a useful assertion to make when you are doing | |
576 | * a security audit over a program. | |
577 | * | |
578 | * The general idea is that a program which uses just setregid() will be | |
579 | * 100% compatible with BSD. A program which uses just setgid() will be | |
580 | * 100% compatible with POSIX with saved IDs. | |
581 | * | |
582 | * SMP: There are not races, the GIDs are checked only by filesystem | |
583 | * operations (as far as semantic preservation is concerned). | |
584 | */ | |
585 | asmlinkage long sys_setregid(gid_t rgid, gid_t egid) | |
586 | { | |
587 | int old_rgid = current->gid; | |
588 | int old_egid = current->egid; | |
589 | int new_rgid = old_rgid; | |
590 | int new_egid = old_egid; | |
591 | int retval; | |
592 | ||
593 | retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE); | |
594 | if (retval) | |
595 | return retval; | |
596 | ||
597 | if (rgid != (gid_t) -1) { | |
598 | if ((old_rgid == rgid) || | |
599 | (current->egid==rgid) || | |
600 | capable(CAP_SETGID)) | |
601 | new_rgid = rgid; | |
602 | else | |
603 | return -EPERM; | |
604 | } | |
605 | if (egid != (gid_t) -1) { | |
606 | if ((old_rgid == egid) || | |
607 | (current->egid == egid) || | |
608 | (current->sgid == egid) || | |
609 | capable(CAP_SETGID)) | |
610 | new_egid = egid; | |
611 | else { | |
612 | return -EPERM; | |
613 | } | |
614 | } | |
615 | if (new_egid != old_egid) | |
616 | { | |
d6e71144 | 617 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 618 | smp_wmb(); |
1da177e4 LT |
619 | } |
620 | if (rgid != (gid_t) -1 || | |
621 | (egid != (gid_t) -1 && egid != old_rgid)) | |
622 | current->sgid = new_egid; | |
623 | current->fsgid = new_egid; | |
624 | current->egid = new_egid; | |
625 | current->gid = new_rgid; | |
626 | key_fsgid_changed(current); | |
9f46080c | 627 | proc_id_connector(current, PROC_EVENT_GID); |
1da177e4 LT |
628 | return 0; |
629 | } | |
630 | ||
631 | /* | |
632 | * setgid() is implemented like SysV w/ SAVED_IDS | |
633 | * | |
634 | * SMP: Same implicit races as above. | |
635 | */ | |
636 | asmlinkage long sys_setgid(gid_t gid) | |
637 | { | |
638 | int old_egid = current->egid; | |
639 | int retval; | |
640 | ||
641 | retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID); | |
642 | if (retval) | |
643 | return retval; | |
644 | ||
645 | if (capable(CAP_SETGID)) | |
646 | { | |
647 | if(old_egid != gid) | |
648 | { | |
d6e71144 | 649 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 650 | smp_wmb(); |
1da177e4 LT |
651 | } |
652 | current->gid = current->egid = current->sgid = current->fsgid = gid; | |
653 | } | |
654 | else if ((gid == current->gid) || (gid == current->sgid)) | |
655 | { | |
656 | if(old_egid != gid) | |
657 | { | |
d6e71144 | 658 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 659 | smp_wmb(); |
1da177e4 LT |
660 | } |
661 | current->egid = current->fsgid = gid; | |
662 | } | |
663 | else | |
664 | return -EPERM; | |
665 | ||
666 | key_fsgid_changed(current); | |
9f46080c | 667 | proc_id_connector(current, PROC_EVENT_GID); |
1da177e4 LT |
668 | return 0; |
669 | } | |
670 | ||
671 | static int set_user(uid_t new_ruid, int dumpclear) | |
672 | { | |
673 | struct user_struct *new_user; | |
674 | ||
675 | new_user = alloc_uid(new_ruid); | |
676 | if (!new_user) | |
677 | return -EAGAIN; | |
678 | ||
679 | if (atomic_read(&new_user->processes) >= | |
680 | current->signal->rlim[RLIMIT_NPROC].rlim_cur && | |
681 | new_user != &root_user) { | |
682 | free_uid(new_user); | |
683 | return -EAGAIN; | |
684 | } | |
685 | ||
686 | switch_uid(new_user); | |
687 | ||
688 | if(dumpclear) | |
689 | { | |
d6e71144 | 690 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 691 | smp_wmb(); |
1da177e4 LT |
692 | } |
693 | current->uid = new_ruid; | |
694 | return 0; | |
695 | } | |
696 | ||
697 | /* | |
698 | * Unprivileged users may change the real uid to the effective uid | |
699 | * or vice versa. (BSD-style) | |
700 | * | |
701 | * If you set the real uid at all, or set the effective uid to a value not | |
702 | * equal to the real uid, then the saved uid is set to the new effective uid. | |
703 | * | |
704 | * This makes it possible for a setuid program to completely drop its | |
705 | * privileges, which is often a useful assertion to make when you are doing | |
706 | * a security audit over a program. | |
707 | * | |
708 | * The general idea is that a program which uses just setreuid() will be | |
709 | * 100% compatible with BSD. A program which uses just setuid() will be | |
710 | * 100% compatible with POSIX with saved IDs. | |
711 | */ | |
712 | asmlinkage long sys_setreuid(uid_t ruid, uid_t euid) | |
713 | { | |
714 | int old_ruid, old_euid, old_suid, new_ruid, new_euid; | |
715 | int retval; | |
716 | ||
717 | retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE); | |
718 | if (retval) | |
719 | return retval; | |
720 | ||
721 | new_ruid = old_ruid = current->uid; | |
722 | new_euid = old_euid = current->euid; | |
723 | old_suid = current->suid; | |
724 | ||
725 | if (ruid != (uid_t) -1) { | |
726 | new_ruid = ruid; | |
727 | if ((old_ruid != ruid) && | |
728 | (current->euid != ruid) && | |
729 | !capable(CAP_SETUID)) | |
730 | return -EPERM; | |
731 | } | |
732 | ||
733 | if (euid != (uid_t) -1) { | |
734 | new_euid = euid; | |
735 | if ((old_ruid != euid) && | |
736 | (current->euid != euid) && | |
737 | (current->suid != euid) && | |
738 | !capable(CAP_SETUID)) | |
739 | return -EPERM; | |
740 | } | |
741 | ||
742 | if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0) | |
743 | return -EAGAIN; | |
744 | ||
745 | if (new_euid != old_euid) | |
746 | { | |
d6e71144 | 747 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 748 | smp_wmb(); |
1da177e4 LT |
749 | } |
750 | current->fsuid = current->euid = new_euid; | |
751 | if (ruid != (uid_t) -1 || | |
752 | (euid != (uid_t) -1 && euid != old_ruid)) | |
753 | current->suid = current->euid; | |
754 | current->fsuid = current->euid; | |
755 | ||
756 | key_fsuid_changed(current); | |
9f46080c | 757 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
758 | |
759 | return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE); | |
760 | } | |
761 | ||
762 | ||
763 | ||
764 | /* | |
765 | * setuid() is implemented like SysV with SAVED_IDS | |
766 | * | |
767 | * Note that SAVED_ID's is deficient in that a setuid root program | |
768 | * like sendmail, for example, cannot set its uid to be a normal | |
769 | * user and then switch back, because if you're root, setuid() sets | |
770 | * the saved uid too. If you don't like this, blame the bright people | |
771 | * in the POSIX committee and/or USG. Note that the BSD-style setreuid() | |
772 | * will allow a root program to temporarily drop privileges and be able to | |
773 | * regain them by swapping the real and effective uid. | |
774 | */ | |
775 | asmlinkage long sys_setuid(uid_t uid) | |
776 | { | |
777 | int old_euid = current->euid; | |
778 | int old_ruid, old_suid, new_ruid, new_suid; | |
779 | int retval; | |
780 | ||
781 | retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID); | |
782 | if (retval) | |
783 | return retval; | |
784 | ||
785 | old_ruid = new_ruid = current->uid; | |
786 | old_suid = current->suid; | |
787 | new_suid = old_suid; | |
788 | ||
789 | if (capable(CAP_SETUID)) { | |
790 | if (uid != old_ruid && set_user(uid, old_euid != uid) < 0) | |
791 | return -EAGAIN; | |
792 | new_suid = uid; | |
793 | } else if ((uid != current->uid) && (uid != new_suid)) | |
794 | return -EPERM; | |
795 | ||
796 | if (old_euid != uid) | |
797 | { | |
d6e71144 | 798 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 799 | smp_wmb(); |
1da177e4 LT |
800 | } |
801 | current->fsuid = current->euid = uid; | |
802 | current->suid = new_suid; | |
803 | ||
804 | key_fsuid_changed(current); | |
9f46080c | 805 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
806 | |
807 | return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID); | |
808 | } | |
809 | ||
810 | ||
811 | /* | |
812 | * This function implements a generic ability to update ruid, euid, | |
813 | * and suid. This allows you to implement the 4.4 compatible seteuid(). | |
814 | */ | |
815 | asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid) | |
816 | { | |
817 | int old_ruid = current->uid; | |
818 | int old_euid = current->euid; | |
819 | int old_suid = current->suid; | |
820 | int retval; | |
821 | ||
822 | retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES); | |
823 | if (retval) | |
824 | return retval; | |
825 | ||
826 | if (!capable(CAP_SETUID)) { | |
827 | if ((ruid != (uid_t) -1) && (ruid != current->uid) && | |
828 | (ruid != current->euid) && (ruid != current->suid)) | |
829 | return -EPERM; | |
830 | if ((euid != (uid_t) -1) && (euid != current->uid) && | |
831 | (euid != current->euid) && (euid != current->suid)) | |
832 | return -EPERM; | |
833 | if ((suid != (uid_t) -1) && (suid != current->uid) && | |
834 | (suid != current->euid) && (suid != current->suid)) | |
835 | return -EPERM; | |
836 | } | |
837 | if (ruid != (uid_t) -1) { | |
838 | if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0) | |
839 | return -EAGAIN; | |
840 | } | |
841 | if (euid != (uid_t) -1) { | |
842 | if (euid != current->euid) | |
843 | { | |
d6e71144 | 844 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 845 | smp_wmb(); |
1da177e4 LT |
846 | } |
847 | current->euid = euid; | |
848 | } | |
849 | current->fsuid = current->euid; | |
850 | if (suid != (uid_t) -1) | |
851 | current->suid = suid; | |
852 | ||
853 | key_fsuid_changed(current); | |
9f46080c | 854 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
855 | |
856 | return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES); | |
857 | } | |
858 | ||
859 | asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid) | |
860 | { | |
861 | int retval; | |
862 | ||
863 | if (!(retval = put_user(current->uid, ruid)) && | |
864 | !(retval = put_user(current->euid, euid))) | |
865 | retval = put_user(current->suid, suid); | |
866 | ||
867 | return retval; | |
868 | } | |
869 | ||
870 | /* | |
871 | * Same as above, but for rgid, egid, sgid. | |
872 | */ | |
873 | asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid) | |
874 | { | |
875 | int retval; | |
876 | ||
877 | retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES); | |
878 | if (retval) | |
879 | return retval; | |
880 | ||
881 | if (!capable(CAP_SETGID)) { | |
882 | if ((rgid != (gid_t) -1) && (rgid != current->gid) && | |
883 | (rgid != current->egid) && (rgid != current->sgid)) | |
884 | return -EPERM; | |
885 | if ((egid != (gid_t) -1) && (egid != current->gid) && | |
886 | (egid != current->egid) && (egid != current->sgid)) | |
887 | return -EPERM; | |
888 | if ((sgid != (gid_t) -1) && (sgid != current->gid) && | |
889 | (sgid != current->egid) && (sgid != current->sgid)) | |
890 | return -EPERM; | |
891 | } | |
892 | if (egid != (gid_t) -1) { | |
893 | if (egid != current->egid) | |
894 | { | |
d6e71144 | 895 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 896 | smp_wmb(); |
1da177e4 LT |
897 | } |
898 | current->egid = egid; | |
899 | } | |
900 | current->fsgid = current->egid; | |
901 | if (rgid != (gid_t) -1) | |
902 | current->gid = rgid; | |
903 | if (sgid != (gid_t) -1) | |
904 | current->sgid = sgid; | |
905 | ||
906 | key_fsgid_changed(current); | |
9f46080c | 907 | proc_id_connector(current, PROC_EVENT_GID); |
1da177e4 LT |
908 | return 0; |
909 | } | |
910 | ||
911 | asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid) | |
912 | { | |
913 | int retval; | |
914 | ||
915 | if (!(retval = put_user(current->gid, rgid)) && | |
916 | !(retval = put_user(current->egid, egid))) | |
917 | retval = put_user(current->sgid, sgid); | |
918 | ||
919 | return retval; | |
920 | } | |
921 | ||
922 | ||
923 | /* | |
924 | * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This | |
925 | * is used for "access()" and for the NFS daemon (letting nfsd stay at | |
926 | * whatever uid it wants to). It normally shadows "euid", except when | |
927 | * explicitly set by setfsuid() or for access.. | |
928 | */ | |
929 | asmlinkage long sys_setfsuid(uid_t uid) | |
930 | { | |
931 | int old_fsuid; | |
932 | ||
933 | old_fsuid = current->fsuid; | |
934 | if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS)) | |
935 | return old_fsuid; | |
936 | ||
937 | if (uid == current->uid || uid == current->euid || | |
938 | uid == current->suid || uid == current->fsuid || | |
939 | capable(CAP_SETUID)) | |
940 | { | |
941 | if (uid != old_fsuid) | |
942 | { | |
d6e71144 | 943 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 944 | smp_wmb(); |
1da177e4 LT |
945 | } |
946 | current->fsuid = uid; | |
947 | } | |
948 | ||
949 | key_fsuid_changed(current); | |
9f46080c | 950 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
951 | |
952 | security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS); | |
953 | ||
954 | return old_fsuid; | |
955 | } | |
956 | ||
957 | /* | |
958 |