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 | ||
226 | static int set_one_prio(struct task_struct *p, int niceval, int error) | |
227 | { | |
228 | int no_nice; | |
229 | ||
230 | if (p->uid != current->euid && | |
231 | p->euid != current->euid && !capable(CAP_SYS_NICE)) { | |
232 | error = -EPERM; | |
233 | goto out; | |
234 | } | |
e43379f1 | 235 | if (niceval < task_nice(p) && !can_nice(p, niceval)) { |
1da177e4 LT |
236 | error = -EACCES; |
237 | goto out; | |
238 | } | |
239 | no_nice = security_task_setnice(p, niceval); | |
240 | if (no_nice) { | |
241 | error = no_nice; | |
242 | goto out; | |
243 | } | |
244 | if (error == -ESRCH) | |
245 | error = 0; | |
246 | set_user_nice(p, niceval); | |
247 | out: | |
248 | return error; | |
249 | } | |
250 | ||
251 | asmlinkage long sys_setpriority(int which, int who, int niceval) | |
252 | { | |
253 | struct task_struct *g, *p; | |
254 | struct user_struct *user; | |
255 | int error = -EINVAL; | |
256 | ||
257 | if (which > 2 || which < 0) | |
258 | goto out; | |
259 | ||
260 | /* normalize: avoid signed division (rounding problems) */ | |
261 | error = -ESRCH; | |
262 | if (niceval < -20) | |
263 | niceval = -20; | |
264 | if (niceval > 19) | |
265 | niceval = 19; | |
266 | ||
267 | read_lock(&tasklist_lock); | |
268 | switch (which) { | |
269 | case PRIO_PROCESS: | |
270 | if (!who) | |
271 | who = current->pid; | |
272 | p = find_task_by_pid(who); | |
273 | if (p) | |
274 | error = set_one_prio(p, niceval, error); | |
275 | break; | |
276 | case PRIO_PGRP: | |
277 | if (!who) | |
278 | who = process_group(current); | |
279 | do_each_task_pid(who, PIDTYPE_PGID, p) { | |
280 | error = set_one_prio(p, niceval, error); | |
281 | } while_each_task_pid(who, PIDTYPE_PGID, p); | |
282 | break; | |
283 | case PRIO_USER: | |
284 | user = current->user; | |
285 | if (!who) | |
286 | who = current->uid; | |
287 | else | |
288 | if ((who != current->uid) && !(user = find_user(who))) | |
289 | goto out_unlock; /* No processes for this user */ | |
290 | ||
291 | do_each_thread(g, p) | |
292 | if (p->uid == who) | |
293 | error = set_one_prio(p, niceval, error); | |
294 | while_each_thread(g, p); | |
295 | if (who != current->uid) | |
296 | free_uid(user); /* For find_user() */ | |
297 | break; | |
298 | } | |
299 | out_unlock: | |
300 | read_unlock(&tasklist_lock); | |
301 | out: | |
302 | return error; | |
303 | } | |
304 | ||
305 | /* | |
306 | * Ugh. To avoid negative return values, "getpriority()" will | |
307 | * not return the normal nice-value, but a negated value that | |
308 | * has been offset by 20 (ie it returns 40..1 instead of -20..19) | |
309 | * to stay compatible. | |
310 | */ | |
311 | asmlinkage long sys_getpriority(int which, int who) | |
312 | { | |
313 | struct task_struct *g, *p; | |
314 | struct user_struct *user; | |
315 | long niceval, retval = -ESRCH; | |
316 | ||
317 | if (which > 2 || which < 0) | |
318 | return -EINVAL; | |
319 | ||
320 | read_lock(&tasklist_lock); | |
321 | switch (which) { | |
322 | case PRIO_PROCESS: | |
323 | if (!who) | |
324 | who = current->pid; | |
325 | p = find_task_by_pid(who); | |
326 | if (p) { | |
327 | niceval = 20 - task_nice(p); | |
328 | if (niceval > retval) | |
329 | retval = niceval; | |
330 | } | |
331 | break; | |
332 | case PRIO_PGRP: | |
333 | if (!who) | |
334 | who = process_group(current); | |
335 | do_each_task_pid(who, PIDTYPE_PGID, p) { | |
336 | niceval = 20 - task_nice(p); | |
337 | if (niceval > retval) | |
338 | retval = niceval; | |
339 | } while_each_task_pid(who, PIDTYPE_PGID, p); | |
340 | break; | |
341 | case PRIO_USER: | |
342 | user = current->user; | |
343 | if (!who) | |
344 | who = current->uid; | |
345 | else | |
346 | if ((who != current->uid) && !(user = find_user(who))) | |
347 | goto out_unlock; /* No processes for this user */ | |
348 | ||
349 | do_each_thread(g, p) | |
350 | if (p->uid == who) { | |
351 | niceval = 20 - task_nice(p); | |
352 | if (niceval > retval) | |
353 | retval = niceval; | |
354 | } | |
355 | while_each_thread(g, p); | |
356 | if (who != current->uid) | |
357 | free_uid(user); /* for find_user() */ | |
358 | break; | |
359 | } | |
360 | out_unlock: | |
361 | read_unlock(&tasklist_lock); | |
362 | ||
363 | return retval; | |
364 | } | |
365 | ||
e4c94330 EB |
366 | /** |
367 | * emergency_restart - reboot the system | |
368 | * | |
369 | * Without shutting down any hardware or taking any locks | |
370 | * reboot the system. This is called when we know we are in | |
371 | * trouble so this is our best effort to reboot. This is | |
372 | * safe to call in interrupt context. | |
373 | */ | |
7c903473 EB |
374 | void emergency_restart(void) |
375 | { | |
376 | machine_emergency_restart(); | |
377 | } | |
378 | EXPORT_SYMBOL_GPL(emergency_restart); | |
379 | ||
e4c94330 | 380 | void kernel_restart_prepare(char *cmd) |
4a00ea1e EB |
381 | { |
382 | notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd); | |
383 | system_state = SYSTEM_RESTART; | |
4a00ea1e | 384 | device_shutdown(); |
e4c94330 | 385 | } |
1e5d5331 RD |
386 | |
387 | /** | |
388 | * kernel_restart - reboot the system | |
389 | * @cmd: pointer to buffer containing command to execute for restart | |
b8887e6e | 390 | * or %NULL |
1e5d5331 RD |
391 | * |
392 | * Shutdown everything and perform a clean reboot. | |
393 | * This is not safe to call in interrupt context. | |
394 | */ | |
e4c94330 EB |
395 | void kernel_restart(char *cmd) |
396 | { | |
397 | kernel_restart_prepare(cmd); | |
4a00ea1e EB |
398 | if (!cmd) { |
399 | printk(KERN_EMERG "Restarting system.\n"); | |
400 | } else { | |
401 | printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd); | |
402 | } | |
403 | printk(".\n"); | |
404 | machine_restart(cmd); | |
405 | } | |
406 | EXPORT_SYMBOL_GPL(kernel_restart); | |
407 | ||
e4c94330 EB |
408 | /** |
409 | * kernel_kexec - reboot the system | |
410 | * | |
411 | * Move into place and start executing a preloaded standalone | |
412 | * executable. If nothing was preloaded return an error. | |
413 | */ | |
4a00ea1e EB |
414 | void kernel_kexec(void) |
415 | { | |
416 | #ifdef CONFIG_KEXEC | |
417 | struct kimage *image; | |
418 | image = xchg(&kexec_image, 0); | |
419 | if (!image) { | |
420 | return; | |
421 | } | |
e4c94330 | 422 | kernel_restart_prepare(NULL); |
4a00ea1e EB |
423 | printk(KERN_EMERG "Starting new kernel\n"); |
424 | machine_shutdown(); | |
425 | machine_kexec(image); | |
426 | #endif | |
427 | } | |
428 | EXPORT_SYMBOL_GPL(kernel_kexec); | |
429 | ||
e4c94330 EB |
430 | /** |
431 | * kernel_halt - halt the system | |
432 | * | |
433 | * Shutdown everything and perform a clean system halt. | |
434 | */ | |
435 | void kernel_halt_prepare(void) | |
4a00ea1e EB |
436 | { |
437 | notifier_call_chain(&reboot_notifier_list, SYS_HALT, NULL); | |
438 | system_state = SYSTEM_HALT; | |
4a00ea1e | 439 | device_shutdown(); |
e4c94330 EB |
440 | } |
441 | void kernel_halt(void) | |
442 | { | |
443 | kernel_halt_prepare(); | |
4a00ea1e EB |
444 | printk(KERN_EMERG "System halted.\n"); |
445 | machine_halt(); | |
446 | } | |
447 | EXPORT_SYMBOL_GPL(kernel_halt); | |
448 | ||
e4c94330 EB |
449 | /** |
450 | * kernel_power_off - power_off the system | |
451 | * | |
452 | * Shutdown everything and perform a clean system power_off. | |
453 | */ | |
454 | void kernel_power_off_prepare(void) | |
4a00ea1e EB |
455 | { |
456 | notifier_call_chain(&reboot_notifier_list, SYS_POWER_OFF, NULL); | |
457 | system_state = SYSTEM_POWER_OFF; | |
4a00ea1e | 458 | device_shutdown(); |
e4c94330 EB |
459 | } |
460 | void kernel_power_off(void) | |
461 | { | |
462 | kernel_power_off_prepare(); | |
4a00ea1e EB |
463 | printk(KERN_EMERG "Power down.\n"); |
464 | machine_power_off(); | |
465 | } | |
466 | EXPORT_SYMBOL_GPL(kernel_power_off); | |
1da177e4 LT |
467 | |
468 | /* | |
469 | * Reboot system call: for obvious reasons only root may call it, | |
470 | * and even root needs to set up some magic numbers in the registers | |
471 | * so that some mistake won't make this reboot the whole machine. | |
472 | * You can also set the meaning of the ctrl-alt-del-key here. | |
473 | * | |
474 | * reboot doesn't sync: do that yourself before calling this. | |
475 | */ | |
476 | asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg) | |
477 | { | |
478 | char buffer[256]; | |
479 | ||
480 | /* We only trust the superuser with rebooting the system. */ | |
481 | if (!capable(CAP_SYS_BOOT)) | |
482 | return -EPERM; | |
483 | ||
484 | /* For safety, we require "magic" arguments. */ | |
485 | if (magic1 != LINUX_REBOOT_MAGIC1 || | |
486 | (magic2 != LINUX_REBOOT_MAGIC2 && | |
487 | magic2 != LINUX_REBOOT_MAGIC2A && | |
488 | magic2 != LINUX_REBOOT_MAGIC2B && | |
489 | magic2 != LINUX_REBOOT_MAGIC2C)) | |
490 | return -EINVAL; | |
491 | ||
5e38291d EB |
492 | /* Instead of trying to make the power_off code look like |
493 | * halt when pm_power_off is not set do it the easy way. | |
494 | */ | |
495 | if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off) | |
496 | cmd = LINUX_REBOOT_CMD_HALT; | |
497 | ||
1da177e4 LT |
498 | lock_kernel(); |
499 | switch (cmd) { | |
500 | case LINUX_REBOOT_CMD_RESTART: | |
4a00ea1e | 501 | kernel_restart(NULL); |
1da177e4 LT |
502 | break; |
503 | ||
504 | case LINUX_REBOOT_CMD_CAD_ON: | |
505 | C_A_D = 1; | |
506 | break; | |
507 | ||
508 | case LINUX_REBOOT_CMD_CAD_OFF: | |
509 | C_A_D = 0; | |
510 | break; | |
511 | ||
512 | case LINUX_REBOOT_CMD_HALT: | |
4a00ea1e | 513 | kernel_halt(); |
1da177e4 LT |
514 | unlock_kernel(); |
515 | do_exit(0); | |
516 | break; | |
517 | ||
518 | case LINUX_REBOOT_CMD_POWER_OFF: | |
4a00ea1e | 519 | kernel_power_off(); |
1da177e4 LT |
520 | unlock_kernel(); |
521 | do_exit(0); | |
522 | break; | |
523 | ||
524 | case LINUX_REBOOT_CMD_RESTART2: | |
525 | if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) { | |
526 | unlock_kernel(); | |
527 | return -EFAULT; | |
528 | } | |
529 | buffer[sizeof(buffer) - 1] = '\0'; | |
530 | ||
4a00ea1e | 531 | kernel_restart(buffer); |
1da177e4 LT |
532 | break; |
533 | ||
dc009d92 | 534 | case LINUX_REBOOT_CMD_KEXEC: |
4a00ea1e EB |
535 | kernel_kexec(); |
536 | unlock_kernel(); | |
537 | return -EINVAL; | |
538 | ||
1da177e4 LT |
539 | #ifdef CONFIG_SOFTWARE_SUSPEND |
540 | case LINUX_REBOOT_CMD_SW_SUSPEND: | |
541 | { | |
542 | int ret = software_suspend(); | |
543 | unlock_kernel(); | |
544 | return ret; | |
545 | } | |
546 | #endif | |
547 | ||
548 | default: | |
549 | unlock_kernel(); | |
550 | return -EINVAL; | |
551 | } | |
552 | unlock_kernel(); | |
553 | return 0; | |
554 | } | |
555 | ||
556 | static void deferred_cad(void *dummy) | |
557 | { | |
abcd9e51 | 558 | kernel_restart(NULL); |
1da177e4 LT |
559 | } |
560 | ||
561 | /* | |
562 | * This function gets called by ctrl-alt-del - ie the keyboard interrupt. | |
563 | * As it's called within an interrupt, it may NOT sync: the only choice | |
564 | * is whether to reboot at once, or just ignore the ctrl-alt-del. | |
565 | */ | |
566 | void ctrl_alt_del(void) | |
567 | { | |
568 | static DECLARE_WORK(cad_work, deferred_cad, NULL); | |
569 | ||
570 | if (C_A_D) | |
571 | schedule_work(&cad_work); | |
572 | else | |
573 | kill_proc(cad_pid, SIGINT, 1); | |
574 | } | |
575 | ||
576 | ||
577 | /* | |
578 | * Unprivileged users may change the real gid to the effective gid | |
579 | * or vice versa. (BSD-style) | |
580 | * | |
581 | * If you set the real gid at all, or set the effective gid to a value not | |
582 | * equal to the real gid, then the saved gid is set to the new effective gid. | |
583 | * | |
584 | * This makes it possible for a setgid program to completely drop its | |
585 | * privileges, which is often a useful assertion to make when you are doing | |
586 | * a security audit over a program. | |
587 | * | |
588 | * The general idea is that a program which uses just setregid() will be | |
589 | * 100% compatible with BSD. A program which uses just setgid() will be | |
590 | * 100% compatible with POSIX with saved IDs. | |
591 | * | |
592 | * SMP: There are not races, the GIDs are checked only by filesystem | |
593 | * operations (as far as semantic preservation is concerned). | |
594 | */ | |
595 | asmlinkage long sys_setregid(gid_t rgid, gid_t egid) | |
596 | { | |
597 | int old_rgid = current->gid; | |
598 | int old_egid = current->egid; | |
599 | int new_rgid = old_rgid; | |
600 | int new_egid = old_egid; | |
601 | int retval; | |
602 | ||
603 | retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE); | |
604 | if (retval) | |
605 | return retval; | |
606 | ||
607 | if (rgid != (gid_t) -1) { | |
608 | if ((old_rgid == rgid) || | |
609 | (current->egid==rgid) || | |
610 | capable(CAP_SETGID)) | |
611 | new_rgid = rgid; | |
612 | else | |
613 | return -EPERM; | |
614 | } | |
615 | if (egid != (gid_t) -1) { | |
616 | if ((old_rgid == egid) || | |
617 | (current->egid == egid) || | |
618 | (current->sgid == egid) || | |
619 | capable(CAP_SETGID)) | |
620 | new_egid = egid; | |
621 | else { | |
622 | return -EPERM; | |
623 | } | |
624 | } | |
625 | if (new_egid != old_egid) | |
626 | { | |
d6e71144 | 627 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 628 | smp_wmb(); |
1da177e4 LT |
629 | } |
630 | if (rgid != (gid_t) -1 || | |
631 | (egid != (gid_t) -1 && egid != old_rgid)) | |
632 | current->sgid = new_egid; | |
633 | current->fsgid = new_egid; | |
634 | current->egid = new_egid; | |
635 | current->gid = new_rgid; | |
636 | key_fsgid_changed(current); | |
9f46080c | 637 | proc_id_connector(current, PROC_EVENT_GID); |
1da177e4 LT |
638 | return 0; |
639 | } | |
640 | ||
641 | /* | |
642 | * setgid() is implemented like SysV w/ SAVED_IDS | |
643 | * | |
644 | * SMP: Same implicit races as above. | |
645 | */ | |
646 | asmlinkage long sys_setgid(gid_t gid) | |
647 | { | |
648 | int old_egid = current->egid; | |
649 | int retval; | |
650 | ||
651 | retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID); | |
652 | if (retval) | |
653 | return retval; | |
654 | ||
655 | if (capable(CAP_SETGID)) | |
656 | { | |
657 | if(old_egid != gid) | |
658 | { | |
d6e71144 | 659 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 660 | smp_wmb(); |
1da177e4 LT |
661 | } |
662 | current->gid = current->egid = current->sgid = current->fsgid = gid; | |
663 | } | |
664 | else if ((gid == current->gid) || (gid == current->sgid)) | |
665 | { | |
666 | if(old_egid != gid) | |
667 | { | |
d6e71144 | 668 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 669 | smp_wmb(); |
1da177e4 LT |
670 | } |
671 | current->egid = current->fsgid = gid; | |
672 | } | |
673 | else | |
674 | return -EPERM; | |
675 | ||
676 | key_fsgid_changed(current); | |
9f46080c | 677 | proc_id_connector(current, PROC_EVENT_GID); |
1da177e4 LT |
678 | return 0; |
679 | } | |
680 | ||
681 | static int set_user(uid_t new_ruid, int dumpclear) | |
682 | { | |
683 | struct user_struct *new_user; | |
684 | ||
685 | new_user = alloc_uid(new_ruid); | |
686 | if (!new_user) | |
687 | return -EAGAIN; | |
688 | ||
689 | if (atomic_read(&new_user->processes) >= | |
690 | current->signal->rlim[RLIMIT_NPROC].rlim_cur && | |
691 | new_user != &root_user) { | |
692 | free_uid(new_user); | |
693 | return -EAGAIN; | |
694 | } | |
695 | ||
696 | switch_uid(new_user); | |
697 | ||
698 | if(dumpclear) | |
699 | { | |
d6e71144 | 700 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 701 | smp_wmb(); |
1da177e4 LT |
702 | } |
703 | current->uid = new_ruid; | |
704 | return 0; | |
705 | } | |
706 | ||
707 | /* | |
708 | * Unprivileged users may change the real uid to the effective uid | |
709 | * or vice versa. (BSD-style) | |
710 | * | |
711 | * If you set the real uid at all, or set the effective uid to a value not | |
712 | * equal to the real uid, then the saved uid is set to the new effective uid. | |
713 | * | |
714 | * This makes it possible for a setuid program to completely drop its | |
715 | * privileges, which is often a useful assertion to make when you are doing | |
716 | * a security audit over a program. | |
717 | * | |
718 | * The general idea is that a program which uses just setreuid() will be | |
719 | * 100% compatible with BSD. A program which uses just setuid() will be | |
720 | * 100% compatible with POSIX with saved IDs. | |
721 | */ | |
722 | asmlinkage long sys_setreuid(uid_t ruid, uid_t euid) | |
723 | { | |
724 | int old_ruid, old_euid, old_suid, new_ruid, new_euid; | |
725 | int retval; | |
726 | ||
727 | retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE); | |
728 | if (retval) | |
729 | return retval; | |
730 | ||
731 | new_ruid = old_ruid = current->uid; | |
732 | new_euid = old_euid = current->euid; | |
733 | old_suid = current->suid; | |
734 | ||
735 | if (ruid != (uid_t) -1) { | |
736 | new_ruid = ruid; | |
737 | if ((old_ruid != ruid) && | |
738 | (current->euid != ruid) && | |
739 | !capable(CAP_SETUID)) | |
740 | return -EPERM; | |
741 | } | |
742 | ||
743 | if (euid != (uid_t) -1) { | |
744 | new_euid = euid; | |
745 | if ((old_ruid != euid) && | |
746 | (current->euid != euid) && | |
747 | (current->suid != euid) && | |
748 | !capable(CAP_SETUID)) | |
749 | return -EPERM; | |
750 | } | |
751 | ||
752 | if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0) | |
753 | return -EAGAIN; | |
754 | ||
755 | if (new_euid != old_euid) | |
756 | { | |
d6e71144 | 757 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 758 | smp_wmb(); |
1da177e4 LT |
759 | } |
760 | current->fsuid = current->euid = new_euid; | |
761 | if (ruid != (uid_t) -1 || | |
762 | (euid != (uid_t) -1 && euid != old_ruid)) | |
763 | current->suid = current->euid; | |
764 | current->fsuid = current->euid; | |
765 | ||
766 | key_fsuid_changed(current); | |
9f46080c | 767 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
768 | |
769 | return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE); | |
770 | } | |
771 | ||
772 | ||
773 | ||
774 | /* | |
775 | * setuid() is implemented like SysV with SAVED_IDS | |
776 | * | |
777 | * Note that SAVED_ID's is deficient in that a setuid root program | |
778 | * like sendmail, for example, cannot set its uid to be a normal | |
779 | * user and then switch back, because if you're root, setuid() sets | |
780 | * the saved uid too. If you don't like this, blame the bright people | |
781 | * in the POSIX committee and/or USG. Note that the BSD-style setreuid() | |
782 | * will allow a root program to temporarily drop privileges and be able to | |
783 | * regain them by swapping the real and effective uid. | |
784 | */ | |
785 | asmlinkage long sys_setuid(uid_t uid) | |
786 | { | |
787 | int old_euid = current->euid; | |
788 | int old_ruid, old_suid, new_ruid, new_suid; | |
789 | int retval; | |
790 | ||
791 | retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID); | |
792 | if (retval) | |
793 | return retval; | |
794 | ||
795 | old_ruid = new_ruid = current->uid; | |
796 | old_suid = current->suid; | |
797 | new_suid = old_suid; | |
798 | ||
799 | if (capable(CAP_SETUID)) { | |
800 | if (uid != old_ruid && set_user(uid, old_euid != uid) < 0) | |
801 | return -EAGAIN; | |
802 | new_suid = uid; | |
803 | } else if ((uid != current->uid) && (uid != new_suid)) | |
804 | return -EPERM; | |
805 | ||
806 | if (old_euid != uid) | |
807 | { | |
d6e71144 | 808 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 809 | smp_wmb(); |
1da177e4 LT |
810 | } |
811 | current->fsuid = current->euid = uid; | |
812 | current->suid = new_suid; | |
813 | ||
814 | key_fsuid_changed(current); | |
9f46080c | 815 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
816 | |
817 | return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID); | |
818 | } | |
819 | ||
820 | ||
821 | /* | |
822 | * This function implements a generic ability to update ruid, euid, | |
823 | * and suid. This allows you to implement the 4.4 compatible seteuid(). | |
824 | */ | |
825 | asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid) | |
826 | { | |
827 | int old_ruid = current->uid; | |
828 | int old_euid = current->euid; | |
829 | int old_suid = current->suid; | |
830 | int retval; | |
831 | ||
832 | retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES); | |
833 | if (retval) | |
834 | return retval; | |
835 | ||
836 | if (!capable(CAP_SETUID)) { | |
837 | if ((ruid != (uid_t) -1) && (ruid != current->uid) && | |
838 | (ruid != current->euid) && (ruid != current->suid)) | |
839 | return -EPERM; | |
840 | if ((euid != (uid_t) -1) && (euid != current->uid) && | |
841 | (euid != current->euid) && (euid != current->suid)) | |
842 | return -EPERM; | |
843 | if ((suid != (uid_t) -1) && (suid != current->uid) && | |
844 | (suid != current->euid) && (suid != current->suid)) | |
845 | return -EPERM; | |
846 | } | |
847 | if (ruid != (uid_t) -1) { | |
848 | if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0) | |
849 | return -EAGAIN; | |
850 | } | |
851 | if (euid != (uid_t) -1) { | |
852 | if (euid != current->euid) | |
853 | { | |
d6e71144 | 854 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 855 | smp_wmb(); |
1da177e4 LT |
856 | } |
857 | current->euid = euid; | |
858 | } | |
859 | current->fsuid = current->euid; | |
860 | if (suid != (uid_t) -1) | |
861 | current->suid = suid; | |
862 | ||
863 | key_fsuid_changed(current); | |
9f46080c | 864 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
865 | |
866 | return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES); | |
867 | } | |
868 | ||
869 | asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid) | |
870 | { | |
871 | int retval; | |
872 | ||
873 | if (!(retval = put_user(current->uid, ruid)) && | |
874 | !(retval = put_user(current->euid, euid))) | |
875 | retval = put_user(current->suid, suid); | |
876 | ||
877 | return retval; | |
878 | } | |
879 | ||
880 | /* | |
881 | * Same as above, but for rgid, egid, sgid. | |
882 | */ | |
883 | asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid) | |
884 | { | |
885 | int retval; | |
886 | ||
887 | retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES); | |
888 | if (retval) | |
889 | return retval; | |
890 | ||
891 | if (!capable(CAP_SETGID)) { | |
892 | if ((rgid != (gid_t) -1) && (rgid != current->gid) && | |
893 | (rgid != current->egid) && (rgid != current->sgid)) | |
894 | return -EPERM; | |
895 | if ((egid != (gid_t) -1) && (egid != current->gid) && | |
896 | (egid != current->egid) && (egid != current->sgid)) | |
897 | return -EPERM; | |
898 | if ((sgid != (gid_t) -1) && (sgid != current->gid) && | |
899 | (sgid != current->egid) && (sgid != current->sgid)) | |
900 | return -EPERM; | |
901 | } | |
902 | if (egid != (gid_t) -1) { | |
903 | if (egid != current->egid) | |
904 | { | |
d6e71144 | 905 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 906 | smp_wmb(); |
1da177e4 LT |
907 | } |
908 | current->egid = egid; | |
909 | } | |
910 | current->fsgid = current->egid; | |
911 | if (rgid != (gid_t) -1) | |
912 | current->gid = rgid; | |
913 | if (sgid != (gid_t) -1) | |
914 | current->sgid = sgid; | |
915 | ||
916 | key_fsgid_changed(current); | |
9f46080c | 917 | proc_id_connector(current, PROC_EVENT_GID); |
1da177e4 LT |
918 | return 0; |
919 | } | |
920 | ||
921 | asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid) | |
922 | { | |
923 | int retval; | |
924 | ||
925 | if (!(retval = put_user(current->gid, rgid)) && | |
926 | !(retval = put_user(current->egid, egid))) | |
927 | retval = put_user(current->sgid, sgid); | |
928 | ||
929 | return retval; | |
930 | } | |
931 | ||
932 | ||
933 | /* | |
934 | * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This | |
935 | * is used for "access()" and for the NFS daemon (letting nfsd stay at | |
936 | * whatever uid it wants to). It normally shadows "euid", except when | |
937 | * explicitly set by setfsuid() or for access.. | |
938 | */ | |
939 | asmlinkage long sys_setfsuid(uid_t uid) | |
940 | { | |
941 | int old_fsuid; | |
942 | ||
943 | old_fsuid = current->fsuid; | |
944 | if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS)) | |
945 | return old_fsuid; | |
946 | ||
947 | if (uid == current->uid || uid == current->euid || | |
948 | uid == current->suid || uid == current->fsuid || | |
949 | capable(CAP_SETUID)) | |
950 | { | |
951 | if (uid != old_fsuid) | |
952 | { | |
d6e71144 | 953 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 954 | smp_wmb(); |
1da177e4 LT |
955 | } |
956 | current->fsuid = uid; | |
957 | } | |
958 | ||
959 | key_fsuid_changed(current); | |
9f46080c | 960 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
961 | |
962 | security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS); | |
963 | ||
964 | return old_fsuid; | |
965 | } | |
966 | ||
967 | /* | |
968 |