Commit | Line | Data |
---|---|---|
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> | |
00d7c05a | 35 | #include <linux/kprobes.h> |
1da177e4 LT |
36 | |
37 | #include <asm/uaccess.h> | |
38 | #include <asm/io.h> | |
39 | #include <asm/unistd.h> | |
40 | ||
41 | #ifndef SET_UNALIGN_CTL | |
42 | # define SET_UNALIGN_CTL(a,b) (-EINVAL) | |
43 | #endif | |
44 | #ifndef GET_UNALIGN_CTL | |
45 | # define GET_UNALIGN_CTL(a,b) (-EINVAL) | |
46 | #endif | |
47 | #ifndef SET_FPEMU_CTL | |
48 | # define SET_FPEMU_CTL(a,b) (-EINVAL) | |
49 | #endif | |
50 | #ifndef GET_FPEMU_CTL | |
51 | # define GET_FPEMU_CTL(a,b) (-EINVAL) | |
52 | #endif | |
53 | #ifndef SET_FPEXC_CTL | |
54 | # define SET_FPEXC_CTL(a,b) (-EINVAL) | |
55 | #endif | |
56 | #ifndef GET_FPEXC_CTL | |
57 | # define GET_FPEXC_CTL(a,b) (-EINVAL) | |
58 | #endif | |
59 | ||
60 | /* | |
61 | * this is where the system-wide overflow UID and GID are defined, for | |
62 | * architectures that now have 32-bit UID/GID but didn't in the past | |
63 | */ | |
64 | ||
65 | int overflowuid = DEFAULT_OVERFLOWUID; | |
66 | int overflowgid = DEFAULT_OVERFLOWGID; | |
67 | ||
68 | #ifdef CONFIG_UID16 | |
69 | EXPORT_SYMBOL(overflowuid); | |
70 | EXPORT_SYMBOL(overflowgid); | |
71 | #endif | |
72 | ||
73 | /* | |
74 | * the same as above, but for filesystems which can only store a 16-bit | |
75 | * UID and GID. as such, this is needed on all architectures | |
76 | */ | |
77 | ||
78 | int fs_overflowuid = DEFAULT_FS_OVERFLOWUID; | |
79 | int fs_overflowgid = DEFAULT_FS_OVERFLOWUID; | |
80 | ||
81 | EXPORT_SYMBOL(fs_overflowuid); | |
82 | EXPORT_SYMBOL(fs_overflowgid); | |
83 | ||
84 | /* | |
85 | * this indicates whether you can reboot with ctrl-alt-del: the default is yes | |
86 | */ | |
87 | ||
88 | int C_A_D = 1; | |
89 | int cad_pid = 1; | |
90 | ||
91 | /* | |
92 | * Notifier list for kernel code which wants to be called | |
93 | * at shutdown. This is used to stop any idling DMA operations | |
94 | * and the like. | |
95 | */ | |
96 | ||
97 | static struct notifier_block *reboot_notifier_list; | |
98 | static DEFINE_RWLOCK(notifier_lock); | |
99 | ||
100 | /** | |
101 | * notifier_chain_register - Add notifier to a notifier chain | |
102 | * @list: Pointer to root list pointer | |
103 | * @n: New entry in notifier chain | |
104 | * | |
105 | * Adds a notifier to a notifier chain. | |
106 | * | |
107 | * Currently always returns zero. | |
108 | */ | |
109 | ||
110 | int notifier_chain_register(struct notifier_block **list, struct notifier_block *n) | |
111 | { | |
112 | write_lock(¬ifier_lock); | |
113 | while(*list) | |
114 | { | |
115 | if(n->priority > (*list)->priority) | |
116 | break; | |
117 | list= &((*list)->next); | |
118 | } | |
119 | n->next = *list; | |
120 | *list=n; | |
121 | write_unlock(¬ifier_lock); | |
122 | return 0; | |
123 | } | |
124 | ||
125 | EXPORT_SYMBOL(notifier_chain_register); | |
126 | ||
127 | /** | |
128 | * notifier_chain_unregister - Remove notifier from a notifier chain | |
129 | * @nl: Pointer to root list pointer | |
130 | * @n: New entry in notifier chain | |
131 | * | |
132 | * Removes a notifier from a notifier chain. | |
133 | * | |
134 | * Returns zero on success, or %-ENOENT on failure. | |
135 | */ | |
136 | ||
137 | int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n) | |
138 | { | |
139 | write_lock(¬ifier_lock); | |
140 | while((*nl)!=NULL) | |
141 | { | |
142 | if((*nl)==n) | |
143 | { | |
144 | *nl=n->next; | |
145 | write_unlock(¬ifier_lock); | |
146 | return 0; | |
147 | } | |
148 | nl=&((*nl)->next); | |
149 | } | |
150 | write_unlock(¬ifier_lock); | |
151 | return -ENOENT; | |
152 | } | |
153 | ||
154 | EXPORT_SYMBOL(notifier_chain_unregister); | |
155 | ||
156 | /** | |
157 | * notifier_call_chain - Call functions in a notifier chain | |
158 | * @n: Pointer to root pointer of notifier chain | |
159 | * @val: Value passed unmodified to notifier function | |
160 | * @v: Pointer passed unmodified to notifier function | |
161 | * | |
162 | * Calls each function in a notifier chain in turn. | |
163 | * | |
164 | * If the return value of the notifier can be and'd | |
165 | * with %NOTIFY_STOP_MASK, then notifier_call_chain | |
166 | * will return immediately, with the return value of | |
167 | * the notifier function which halted execution. | |
168 | * Otherwise, the return value is the return value | |
169 | * of the last notifier function called. | |
170 | */ | |
171 | ||
00d7c05a | 172 | int __kprobes notifier_call_chain(struct notifier_block **n, unsigned long val, void *v) |
1da177e4 LT |
173 | { |
174 | int ret=NOTIFY_DONE; | |
175 | struct notifier_block *nb = *n; | |
176 | ||
177 | while(nb) | |
178 | { | |
179 | ret=nb->notifier_call(nb,val,v); | |
180 | if(ret&NOTIFY_STOP_MASK) | |
181 | { | |
182 | return ret; | |
183 | } | |
184 | nb=nb->next; | |
185 | } | |
186 | return ret; | |
187 | } | |
188 | ||
189 | EXPORT_SYMBOL(notifier_call_chain); | |
190 | ||
191 | /** | |
192 | * register_reboot_notifier - Register function to be called at reboot time | |
193 | * @nb: Info about notifier function to be called | |
194 | * | |
195 | * Registers a function with the list of functions | |
196 | * to be called at reboot time. | |
197 | * | |
198 | * Currently always returns zero, as notifier_chain_register | |
199 | * always returns zero. | |
200 | */ | |
201 | ||
202 | int register_reboot_notifier(struct notifier_block * nb) | |
203 | { | |
204 | return notifier_chain_register(&reboot_notifier_list, nb); | |
205 | } | |
206 | ||
207 | EXPORT_SYMBOL(register_reboot_notifier); | |
208 | ||
209 | /** | |
210 | * unregister_reboot_notifier - Unregister previously registered reboot notifier | |
211 | * @nb: Hook to be unregistered | |
212 | * | |
213 | * Unregisters a previously registered reboot | |
214 | * notifier function. | |
215 | * | |
216 | * Returns zero on success, or %-ENOENT on failure. | |
217 | */ | |
218 | ||
219 | int unregister_reboot_notifier(struct notifier_block * nb) | |
220 | { | |
221 | return notifier_chain_unregister(&reboot_notifier_list, nb); | |
222 | } | |
223 | ||
224 | EXPORT_SYMBOL(unregister_reboot_notifier); | |
225 | ||
e16885c5 IM |
226 | #ifndef CONFIG_SECURITY |
227 | int capable(int cap) | |
228 | { | |
229 | if (cap_raised(current->cap_effective, cap)) { | |
230 | current->flags |= PF_SUPERPRIV; | |
231 | return 1; | |
232 | } | |
233 | return 0; | |
234 | } | |
235 | EXPORT_SYMBOL(capable); | |
236 | #endif | |
237 | ||
1da177e4 LT |
238 | static int set_one_prio(struct task_struct *p, int niceval, int error) |
239 | { | |
240 | int no_nice; | |
241 | ||
242 | if (p->uid != current->euid && | |
243 | p->euid != current->euid && !capable(CAP_SYS_NICE)) { | |
244 | error = -EPERM; | |
245 | goto out; | |
246 | } | |
e43379f1 | 247 | if (niceval < task_nice(p) && !can_nice(p, niceval)) { |
1da177e4 LT |
248 | error = -EACCES; |
249 | goto out; | |
250 | } | |
251 | no_nice = security_task_setnice(p, niceval); | |
252 | if (no_nice) { | |
253 | error = no_nice; | |
254 | goto out; | |
255 | } | |
256 | if (error == -ESRCH) | |
257 | error = 0; | |
258 | set_user_nice(p, niceval); | |
259 | out: | |
260 | return error; | |
261 | } | |
262 | ||
263 | asmlinkage long sys_setpriority(int which, int who, int niceval) | |
264 | { | |
265 | struct task_struct *g, *p; | |
266 | struct user_struct *user; | |
267 | int error = -EINVAL; | |
268 | ||
269 | if (which > 2 || which < 0) | |
270 | goto out; | |
271 | ||
272 | /* normalize: avoid signed division (rounding problems) */ | |
273 | error = -ESRCH; | |
274 | if (niceval < -20) | |
275 | niceval = -20; | |
276 | if (niceval > 19) | |
277 | niceval = 19; | |
278 | ||
279 | read_lock(&tasklist_lock); | |
280 | switch (which) { | |
281 | case PRIO_PROCESS: | |
282 | if (!who) | |
283 | who = current->pid; | |
284 | p = find_task_by_pid(who); | |
285 | if (p) | |
286 | error = set_one_prio(p, niceval, error); | |
287 | break; | |
288 | case PRIO_PGRP: | |
289 | if (!who) | |
290 | who = process_group(current); | |
291 | do_each_task_pid(who, PIDTYPE_PGID, p) { | |
292 | error = set_one_prio(p, niceval, error); | |
293 | } while_each_task_pid(who, PIDTYPE_PGID, p); | |
294 | break; | |
295 | case PRIO_USER: | |
296 | user = current->user; | |
297 | if (!who) | |
298 | who = current->uid; | |
299 | else | |
300 | if ((who != current->uid) && !(user = find_user(who))) | |
301 | goto out_unlock; /* No processes for this user */ | |
302 | ||
303 | do_each_thread(g, p) | |
304 | if (p->uid == who) | |
305 | error = set_one_prio(p, niceval, error); | |
306 | while_each_thread(g, p); | |
307 | if (who != current->uid) | |
308 | free_uid(user); /* For find_user() */ | |
309 | break; | |
310 | } | |
311 | out_unlock: | |
312 | read_unlock(&tasklist_lock); | |
313 | out: | |
314 | return error; | |
315 | } | |
316 | ||
317 | /* | |
318 | * Ugh. To avoid negative return values, "getpriority()" will | |
319 | * not return the normal nice-value, but a negated value that | |
320 | * has been offset by 20 (ie it returns 40..1 instead of -20..19) | |
321 | * to stay compatible. | |
322 | */ | |
323 | asmlinkage long sys_getpriority(int which, int who) | |
324 | { | |
325 | struct task_struct *g, *p; | |
326 | struct user_struct *user; | |
327 | long niceval, retval = -ESRCH; | |
328 | ||
329 | if (which > 2 || which < 0) | |
330 | return -EINVAL; | |
331 | ||
332 | read_lock(&tasklist_lock); | |
333 | switch (which) { | |
334 | case PRIO_PROCESS: | |
335 | if (!who) | |
336 | who = current->pid; | |
337 | p = find_task_by_pid(who); | |
338 | if (p) { | |
339 | niceval = 20 - task_nice(p); | |
340 | if (niceval > retval) | |
341 | retval = niceval; | |
342 | } | |
343 | break; | |
344 | case PRIO_PGRP: | |
345 | if (!who) | |
346 | who = process_group(current); | |
347 | do_each_task_pid(who, PIDTYPE_PGID, p) { | |
348 | niceval = 20 - task_nice(p); | |
349 | if (niceval > retval) | |
350 | retval = niceval; | |
351 | } while_each_task_pid(who, PIDTYPE_PGID, p); | |
352 | break; | |
353 | case PRIO_USER: | |
354 | user = current->user; | |
355 | if (!who) | |
356 | who = current->uid; | |
357 | else | |
358 | if ((who != current->uid) && !(user = find_user(who))) | |
359 | goto out_unlock; /* No processes for this user */ | |
360 | ||
361 | do_each_thread(g, p) | |
362 | if (p->uid == who) { | |
363 | niceval = 20 - task_nice(p); | |
364 | if (niceval > retval) | |
365 | retval = niceval; | |
366 | } | |
367 | while_each_thread(g, p); | |
368 | if (who != current->uid) | |
369 | free_uid(user); /* for find_user() */ | |
370 | break; | |
371 | } | |
372 | out_unlock: | |
373 | read_unlock(&tasklist_lock); | |
374 | ||
375 | return retval; | |
376 | } | |
377 | ||
e4c94330 EB |
378 | /** |
379 | * emergency_restart - reboot the system | |
380 | * | |
381 | * Without shutting down any hardware or taking any locks | |
382 | * reboot the system. This is called when we know we are in | |
383 | * trouble so this is our best effort to reboot. This is | |
384 | * safe to call in interrupt context. | |
385 | */ | |
7c903473 EB |
386 | void emergency_restart(void) |
387 | { | |
388 | machine_emergency_restart(); | |
389 | } | |
390 | EXPORT_SYMBOL_GPL(emergency_restart); | |
391 | ||
e4c94330 | 392 | void kernel_restart_prepare(char *cmd) |
4a00ea1e EB |
393 | { |
394 | notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd); | |
395 | system_state = SYSTEM_RESTART; | |
4a00ea1e | 396 | device_shutdown(); |
e4c94330 | 397 | } |
1e5d5331 RD |
398 | |
399 | /** | |
400 | * kernel_restart - reboot the system | |
401 | * @cmd: pointer to buffer containing command to execute for restart | |
b8887e6e | 402 | * or %NULL |
1e5d5331 RD |
403 | * |
404 | * Shutdown everything and perform a clean reboot. | |
405 | * This is not safe to call in interrupt context. | |
406 | */ | |
e4c94330 EB |
407 | void kernel_restart(char *cmd) |
408 | { | |
409 | kernel_restart_prepare(cmd); | |
4a00ea1e EB |
410 | if (!cmd) { |
411 | printk(KERN_EMERG "Restarting system.\n"); | |
412 | } else { | |
413 | printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd); | |
414 | } | |
415 | printk(".\n"); | |
416 | machine_restart(cmd); | |
417 | } | |
418 | EXPORT_SYMBOL_GPL(kernel_restart); | |
419 | ||
e4c94330 EB |
420 | /** |
421 | * kernel_kexec - reboot the system | |
422 | * | |
423 | * Move into place and start executing a preloaded standalone | |
424 | * executable. If nothing was preloaded return an error. | |
425 | */ | |
4a00ea1e EB |
426 | void kernel_kexec(void) |
427 | { | |
428 | #ifdef CONFIG_KEXEC | |
429 | struct kimage *image; | |
430 | image = xchg(&kexec_image, 0); | |
431 | if (!image) { | |
432 | return; | |
433 | } | |
e4c94330 | 434 | kernel_restart_prepare(NULL); |
4a00ea1e EB |
435 | printk(KERN_EMERG "Starting new kernel\n"); |
436 | machine_shutdown(); | |
437 | machine_kexec(image); | |
438 | #endif | |
439 | } | |
440 | EXPORT_SYMBOL_GPL(kernel_kexec); | |
441 | ||
e4c94330 EB |
442 | /** |
443 | * kernel_halt - halt the system | |
444 | * | |
445 | * Shutdown everything and perform a clean system halt. | |
446 | */ | |
447 | void kernel_halt_prepare(void) | |
4a00ea1e EB |
448 | { |
449 | notifier_call_chain(&reboot_notifier_list, SYS_HALT, NULL); | |
450 | system_state = SYSTEM_HALT; | |
4a00ea1e | 451 | device_shutdown(); |
e4c94330 EB |
452 | } |
453 | void kernel_halt(void) | |
454 | { | |
455 | kernel_halt_prepare(); | |
4a00ea1e EB |
456 | printk(KERN_EMERG "System halted.\n"); |
457 | machine_halt(); | |
458 | } | |
459 | EXPORT_SYMBOL_GPL(kernel_halt); | |
460 | ||
e4c94330 EB |
461 | /** |
462 | * kernel_power_off - power_off the system | |
463 | * | |
464 | * Shutdown everything and perform a clean system power_off. | |
465 | */ | |
466 | void kernel_power_off_prepare(void) | |
4a00ea1e EB |
467 | { |
468 | notifier_call_chain(&reboot_notifier_list, SYS_POWER_OFF, NULL); | |
469 | system_state = SYSTEM_POWER_OFF; | |
4a00ea1e | 470 | device_shutdown(); |
e4c94330 EB |
471 | } |
472 | void kernel_power_off(void) | |
473 | { | |
474 | kernel_power_off_prepare(); | |
4a00ea1e EB |
475 | printk(KERN_EMERG "Power down.\n"); |
476 | machine_power_off(); | |
477 | } | |
478 | EXPORT_SYMBOL_GPL(kernel_power_off); | |
1da177e4 LT |
479 | |
480 | /* | |
481 | * Reboot system call: for obvious reasons only root may call it, | |
482 | * and even root needs to set up some magic numbers in the registers | |
483 | * so that some mistake won't make this reboot the whole machine. | |
484 | * You can also set the meaning of the ctrl-alt-del-key here. | |
485 | * | |
486 | * reboot doesn't sync: do that yourself before calling this. | |
487 | */ | |
488 | asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg) | |
489 | { | |
490 | char buffer[256]; | |
491 | ||
492 | /* We only trust the superuser with rebooting the system. */ | |
493 | if (!capable(CAP_SYS_BOOT)) | |
494 | return -EPERM; | |
495 | ||
496 | /* For safety, we require "magic" arguments. */ | |
497 | if (magic1 != LINUX_REBOOT_MAGIC1 || | |
498 | (magic2 != LINUX_REBOOT_MAGIC2 && | |
499 | magic2 != LINUX_REBOOT_MAGIC2A && | |
500 | magic2 != LINUX_REBOOT_MAGIC2B && | |
501 | magic2 != LINUX_REBOOT_MAGIC2C)) | |
502 | return -EINVAL; | |
503 | ||
5e38291d EB |
504 | /* Instead of trying to make the power_off code look like |
505 | * halt when pm_power_off is not set do it the easy way. | |
506 | */ | |
507 | if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off) | |
508 | cmd = LINUX_REBOOT_CMD_HALT; | |
509 | ||
1da177e4 LT |
510 | lock_kernel(); |
511 | switch (cmd) { | |
512 | case LINUX_REBOOT_CMD_RESTART: | |
4a00ea1e | 513 | kernel_restart(NULL); |
1da177e4 LT |
514 | break; |
515 | ||
516 | case LINUX_REBOOT_CMD_CAD_ON: | |
517 | C_A_D = 1; | |
518 | break; | |
519 | ||
520 | case LINUX_REBOOT_CMD_CAD_OFF: | |
521 | C_A_D = 0; | |
522 | break; | |
523 | ||
524 | case LINUX_REBOOT_CMD_HALT: | |
4a00ea1e | 525 | kernel_halt(); |
1da177e4 LT |
526 | unlock_kernel(); |
527 | do_exit(0); | |
528 | break; | |
529 | ||
530 | case LINUX_REBOOT_CMD_POWER_OFF: | |
4a00ea1e | 531 | kernel_power_off(); |
1da177e4 LT |
532 | unlock_kernel(); |
533 | do_exit(0); | |
534 | break; | |
535 | ||
536 | case LINUX_REBOOT_CMD_RESTART2: | |
537 | if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) { | |
538 | unlock_kernel(); | |
539 | return -EFAULT; | |
540 | } | |
541 | buffer[sizeof(buffer) - 1] = '\0'; | |
542 | ||
4a00ea1e | 543 | kernel_restart(buffer); |
1da177e4 LT |
544 | break; |
545 | ||
dc009d92 | 546 | case LINUX_REBOOT_CMD_KEXEC: |
4a00ea1e EB |
547 | kernel_kexec(); |
548 | unlock_kernel(); | |
549 | return -EINVAL; | |
550 | ||
1da177e4 LT |
551 | #ifdef CONFIG_SOFTWARE_SUSPEND |
552 | case LINUX_REBOOT_CMD_SW_SUSPEND: | |
553 | { | |
554 | int ret = software_suspend(); | |
555 | unlock_kernel(); | |
556 | return ret; | |
557 | } | |
558 | #endif | |
559 | ||
560 | default: | |
561 | unlock_kernel(); | |
562 | return -EINVAL; | |
563 | } | |
564 | unlock_kernel(); | |
565 | return 0; | |
566 | } | |
567 | ||
568 | static void deferred_cad(void *dummy) | |
569 | { | |
abcd9e51 | 570 | kernel_restart(NULL); |
1da177e4 LT |
571 | } |
572 | ||
573 | /* | |
574 | * This function gets called by ctrl-alt-del - ie the keyboard interrupt. | |
575 | * As it's called within an interrupt, it may NOT sync: the only choice | |
576 | * is whether to reboot at once, or just ignore the ctrl-alt-del. | |
577 | */ | |
578 | void ctrl_alt_del(void) | |
579 | { | |
580 | static DECLARE_WORK(cad_work, deferred_cad, NULL); | |
581 | ||
582 | if (C_A_D) | |
583 | schedule_work(&cad_work); | |
584 | else | |
585 | kill_proc(cad_pid, SIGINT, 1); | |
586 | } | |
587 | ||
588 | ||
589 | /* | |
590 | * Unprivileged users may change the real gid to the effective gid | |
591 | * or vice versa. (BSD-style) | |
592 | * | |
593 | * If you set the real gid at all, or set the effective gid to a value not | |
594 | * equal to the real gid, then the saved gid is set to the new effective gid. | |
595 | * | |
596 | * This makes it possible for a setgid program to completely drop its | |
597 | * privileges, which is often a useful assertion to make when you are doing | |
598 | * a security audit over a program. | |
599 | * | |
600 | * The general idea is that a program which uses just setregid() will be | |
601 | * 100% compatible with BSD. A program which uses just setgid() will be | |
602 | * 100% compatible with POSIX with saved IDs. | |
603 | * | |
604 | * SMP: There are not races, the GIDs are checked only by filesystem | |
605 | * operations (as far as semantic preservation is concerned). | |
606 | */ | |
607 | asmlinkage long sys_setregid(gid_t rgid, gid_t egid) | |
608 | { | |
609 | int old_rgid = current->gid; | |
610 | int old_egid = current->egid; | |
611 | int new_rgid = old_rgid; | |
612 | int new_egid = old_egid; | |
613 | int retval; | |
614 | ||
615 | retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE); | |
616 | if (retval) | |
617 | return retval; | |
618 | ||
619 | if (rgid != (gid_t) -1) { | |
620 | if ((old_rgid == rgid) || | |
621 | (current->egid==rgid) || | |
622 | capable(CAP_SETGID)) | |
623 | new_rgid = rgid; | |
624 | else | |
625 | return -EPERM; | |
626 | } | |
627 | if (egid != (gid_t) -1) { | |
628 | if ((old_rgid == egid) || | |
629 | (current->egid == egid) || | |
630 | (current->sgid == egid) || | |
631 | capable(CAP_SETGID)) | |
632 | new_egid = egid; | |
633 | else { | |
634 | return -EPERM; | |
635 | } | |
636 | } | |
637 | if (new_egid != old_egid) | |
638 | { | |
d6e71144 | 639 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 640 | smp_wmb(); |
1da177e4 LT |
641 | } |
642 | if (rgid != (gid_t) -1 || | |
643 | (egid != (gid_t) -1 && egid != old_rgid)) | |
644 | current->sgid = new_egid; | |
645 | current->fsgid = new_egid; | |
646 | current->egid = new_egid; | |
647 | current->gid = new_rgid; | |
648 | key_fsgid_changed(current); | |
9f46080c | 649 | proc_id_connector(current, PROC_EVENT_GID); |
1da177e4 LT |
650 | return 0; |
651 | } | |
652 | ||
653 | /* | |
654 | * setgid() is implemented like SysV w/ SAVED_IDS | |
655 | * | |
656 | * SMP: Same implicit races as above. | |
657 | */ | |
658 | asmlinkage long sys_setgid(gid_t gid) | |
659 | { | |
660 | int old_egid = current->egid; | |
661 | int retval; | |
662 | ||
663 | retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID); | |
664 | if (retval) | |
665 | return retval; | |
666 | ||
667 | if (capable(CAP_SETGID)) | |
668 | { | |
669 | if(old_egid != gid) | |
670 | { | |
d6e71144 | 671 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 672 | smp_wmb(); |
1da177e4 LT |
673 | } |
674 | current->gid = current->egid = current->sgid = current->fsgid = gid; | |
675 | } | |
676 | else if ((gid == current->gid) || (gid == current->sgid)) | |
677 | { | |
678 | if(old_egid != gid) | |
679 | { | |
d6e71144 | 680 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 681 | smp_wmb(); |
1da177e4 LT |
682 | } |
683 | current->egid = current->fsgid = gid; | |
684 | } | |
685 | else | |
686 | return -EPERM; | |
687 | ||
688 | key_fsgid_changed(current); | |
9f46080c | 689 | proc_id_connector(current, PROC_EVENT_GID); |
1da177e4 LT |
690 | return 0; |
691 | } | |
692 | ||
693 | static int set_user(uid_t new_ruid, int dumpclear) | |
694 | { | |
695 | struct user_struct *new_user; | |
696 | ||
697 | new_user = alloc_uid(new_ruid); | |
698 | if (!new_user) | |
699 | return -EAGAIN; | |
700 | ||
701 | if (atomic_read(&new_user->processes) >= | |
702 | current->signal->rlim[RLIMIT_NPROC].rlim_cur && | |
703 | new_user != &root_user) { | |
704 | free_uid(new_user); | |
705 | return -EAGAIN; | |
706 | } | |
707 | ||
708 | switch_uid(new_user); | |
709 | ||
710 | if(dumpclear) | |
711 | { | |
d6e71144 | 712 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 713 | smp_wmb(); |
1da177e4 LT |
714 | } |
715 | current->uid = new_ruid; | |
716 | return 0; | |
717 | } | |
718 | ||
719 | /* | |
720 | * Unprivileged users may change the real uid to the effective uid | |
721 | * or vice versa. (BSD-style) | |
722 | * | |
723 | * If you set the real uid at all, or set the effective uid to a value not | |
724 | * equal to the real uid, then the saved uid is set to the new effective uid. | |
725 | * | |
726 | * This makes it possible for a setuid program to completely drop its | |
727 | * privileges, which is often a useful assertion to make when you are doing | |
728 | * a security audit over a program. | |
729 | * | |
730 | * The general idea is that a program which uses just setreuid() will be | |
731 | * 100% compatible with BSD. A program which uses just setuid() will be | |
732 | * 100% compatible with POSIX with saved IDs. | |
733 | */ | |
734 | asmlinkage long sys_setreuid(uid_t ruid, uid_t euid) | |
735 | { | |
736 | int old_ruid, old_euid, old_suid, new_ruid, new_euid; | |
737 | int retval; | |
738 | ||
739 | retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE); | |
740 | if (retval) | |
741 | return retval; | |
742 | ||
743 | new_ruid = old_ruid = current->uid; | |
744 | new_euid = old_euid = current->euid; | |
745 | old_suid = current->suid; | |
746 | ||
747 | if (ruid != (uid_t) -1) { | |
748 | new_ruid = ruid; | |
749 | if ((old_ruid != ruid) && | |
750 | (current->euid != ruid) && | |
751 | !capable(CAP_SETUID)) | |
752 | return -EPERM; | |
753 | } | |
754 | ||
755 | if (euid != (uid_t) -1) { | |
756 | new_euid = euid; | |
757 | if ((old_ruid != euid) && | |
758 | (current->euid != euid) && | |
759 | (current->suid != euid) && | |
760 | !capable(CAP_SETUID)) | |
761 | return -EPERM; | |
762 | } | |
763 | ||
764 | if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0) | |
765 | return -EAGAIN; | |
766 | ||
767 | if (new_euid != old_euid) | |
768 | { | |
d6e71144 | 769 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 770 | smp_wmb(); |
1da177e4 LT |
771 | } |
772 | current->fsuid = current->euid = new_euid; | |
773 | if (ruid != (uid_t) -1 || | |
774 | (euid != (uid_t) -1 && euid != old_ruid)) | |
775 | current->suid = current->euid; | |
776 | current->fsuid = current->euid; | |
777 | ||
778 | key_fsuid_changed(current); | |
9f46080c | 779 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
780 | |
781 | return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE); | |
782 | } | |
783 | ||
784 | ||
785 | ||
786 | /* | |
787 | * setuid() is implemented like SysV with SAVED_IDS | |
788 | * | |
789 | * Note that SAVED_ID's is deficient in that a setuid root program | |
790 | * like sendmail, for example, cannot set its uid to be a normal | |
791 | * user and then switch back, because if you're root, setuid() sets | |
792 | * the saved uid too. If you don't like this, blame the bright people | |
793 | * in the POSIX committee and/or USG. Note that the BSD-style setreuid() | |
794 | * will allow a root program to temporarily drop privileges and be able to | |
795 | * regain them by swapping the real and effective uid. | |
796 | */ | |
797 | asmlinkage long sys_setuid(uid_t uid) | |
798 | { | |
799 | int old_euid = current->euid; | |
800 | int old_ruid, old_suid, new_ruid, new_suid; | |
801 | int retval; | |
802 | ||
803 | retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID); | |
804 | if (retval) | |
805 | return retval; | |
806 | ||
807 | old_ruid = new_ruid = current->uid; | |
808 | old_suid = current->suid; | |
809 | new_suid = old_suid; | |
810 | ||
811 | if (capable(CAP_SETUID)) { | |
812 | if (uid != old_ruid && set_user(uid, old_euid != uid) < 0) | |
813 | return -EAGAIN; | |
814 | new_suid = uid; | |
815 | } else if ((uid != current->uid) && (uid != new_suid)) | |
816 | return -EPERM; | |
817 | ||
818 | if (old_euid != uid) | |
819 | { | |
d6e71144 | 820 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 821 | smp_wmb(); |
1da177e4 LT |
822 | } |
823 | current->fsuid = current->euid = uid; | |
824 | current->suid = new_suid; | |
825 | ||
826 | key_fsuid_changed(current); | |
9f46080c | 827 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
828 | |
829 | return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID); | |
830 | } | |
831 | ||
832 | ||
833 | /* | |
834 | * This function implements a generic ability to update ruid, euid, | |
835 | * and suid. This allows you to implement the 4.4 compatible seteuid(). | |
836 | */ | |
837 | asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid) | |
838 | { | |
839 | int old_ruid = current->uid; | |
840 | int old_euid = current->euid; | |
841 | int old_suid = current->suid; | |
842 | int retval; | |
843 | ||
844 | retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES); | |
845 | if (retval) | |
846 | return retval; | |
847 | ||
848 | if (!capable(CAP_SETUID)) { | |
849 | if ((ruid != (uid_t) -1) && (ruid != current->uid) && | |
850 | (ruid != current->euid) && (ruid != current->suid)) | |
851 | return -EPERM; | |
852 | if ((euid != (uid_t) -1) && (euid != current->uid) && | |
853 | (euid != current->euid) && (euid != current->suid)) | |
854 | return -EPERM; | |
855 | if ((suid != (uid_t) -1) && (suid != current->uid) && | |
856 | (suid != current->euid) && (suid != current->suid)) | |
857 | return -EPERM; | |
858 | } | |
859 | if (ruid != (uid_t) -1) { | |
860 | if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0) | |
861 | return -EAGAIN; | |
862 | } | |
863 | if (euid != (uid_t) -1) { | |
864 | if (euid != current->euid) | |
865 | { | |
d6e71144 | 866 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 867 | smp_wmb(); |
1da177e4 LT |
868 | } |
869 | current->euid = euid; | |
870 | } | |
871 | current->fsuid = current->euid; | |
872 | if (suid != (uid_t) -1) | |
873 | current->suid = suid; | |
874 | ||
875 | key_fsuid_changed(current); | |
9f46080c | 876 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
877 | |
878 | return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES); | |
879 | } | |
880 | ||
881 | asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid) | |
882 | { | |
883 | int retval; | |
884 | ||
885 | if (!(retval = put_user(current->uid, ruid)) && | |
886 | !(retval = put_user(current->euid, euid))) | |
887 | retval = put_user(current->suid, suid); | |
888 | ||
889 | return retval; | |
890 | } | |
891 | ||
892 | /* | |
893 | * Same as above, but for rgid, egid, sgid. | |
894 | */ | |
895 | asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid) | |
896 | { | |
897 | int retval; | |
898 | ||
899 | retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES); | |
900 | if (retval) | |
901 | return retval; | |
902 | ||
903 | if (!capable(CAP_SETGID)) { | |
904 | if ((rgid != (gid_t) -1) && (rgid != current->gid) && | |
905 | (rgid != current->egid) && (rgid != current->sgid)) | |
906 | return -EPERM; | |
907 | if ((egid != (gid_t) -1) && (egid != current->gid) && | |
908 | (egid != current->egid) && (egid != current->sgid)) | |
909 | return -EPERM; | |
910 | if ((sgid != (gid_t) -1) && (sgid != current->gid) && | |
911 | (sgid != current->egid) && (sgid != current->sgid)) | |
912 | return -EPERM; | |
913 | } | |
914 | if (egid != (gid_t) -1) { | |
915 | if (egid != current->egid) | |
916 | { | |
d6e71144 | 917 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 918 | smp_wmb(); |
1da177e4 LT |
919 | } |
920 | current->egid = egid; | |
921 | } | |
922 | current->fsgid = current->egid; | |
923 | if (rgid != (gid_t) -1) | |
924 | current->gid = rgid; | |
925 | if (sgid != (gid_t) -1) | |
926 | current->sgid = sgid; | |
927 | ||
928 | key_fsgid_changed(current); | |
9f46080c | 929 | proc_id_connector(current, PROC_EVENT_GID); |
1da177e4 LT |
930 | return 0; |
931 | } | |
932 | ||
933 | asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid) | |
934 | { | |
935 | int retval; | |
936 | ||
937 | if (!(retval = put_user(current->gid, rgid)) && | |
938 | !(retval = put_user(current->egid, egid))) | |
939 | retval = put_user(current->sgid, sgid); | |
940 | ||
941 | return retval; | |
942 | } | |
943 | ||
944 | ||
945 | /* | |
946 | * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This | |
947 | * is used for "access()" and for the NFS daemon (letting nfsd stay at | |
948 | * whatever uid it wants to). It normally shadows "euid", except when | |
949 | * explicitly set by setfsuid() or for access.. | |
950 | */ | |
951 | asmlinkage long sys_setfsuid(uid_t uid) | |
952 | { | |
953 | int old_fsuid; | |
954 | ||
955 | old_fsuid = current->fsuid; | |
956 | if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS)) | |
957 | return old_fsuid; | |
958 | ||
959 | if (uid == current->uid || uid == current->euid || | |
960 | uid == current->suid || uid == current->fsuid || | |
961 | capable(CAP_SETUID)) | |
962 | { | |
963 | if (uid != old_fsuid) | |
964 | { | |
d6e71144 | 965 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 966 | smp_wmb(); |
1da177e4 LT |
967 | } |
968 | current->fsuid = uid; | |
969 | } | |
970 | ||
971 | key_fsuid_changed(current); | |
9f46080c | 972 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
973 | |
974 | security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS); | |
975 | ||
976 | return old_fsuid; | |
977 | } | |
978 | ||
979 | /* | |
980 |