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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 | 21 | #include <linux/workqueue.h> |
c59ede7b | 22 | #include <linux/capability.h> |
1da177e4 LT |
23 | #include <linux/device.h> |
24 | #include <linux/key.h> | |
25 | #include <linux/times.h> | |
26 | #include <linux/posix-timers.h> | |
27 | #include <linux/security.h> | |
28 | #include <linux/dcookies.h> | |
29 | #include <linux/suspend.h> | |
30 | #include <linux/tty.h> | |
7ed20e1a | 31 | #include <linux/signal.h> |
9f46080c | 32 | #include <linux/cn_proc.h> |
1da177e4 LT |
33 | |
34 | #include <linux/compat.h> | |
35 | #include <linux/syscalls.h> | |
00d7c05a | 36 | #include <linux/kprobes.h> |
1da177e4 LT |
37 | |
38 | #include <asm/uaccess.h> | |
39 | #include <asm/io.h> | |
40 | #include <asm/unistd.h> | |
41 | ||
42 | #ifndef SET_UNALIGN_CTL | |
43 | # define SET_UNALIGN_CTL(a,b) (-EINVAL) | |
44 | #endif | |
45 | #ifndef GET_UNALIGN_CTL | |
46 | # define GET_UNALIGN_CTL(a,b) (-EINVAL) | |
47 | #endif | |
48 | #ifndef SET_FPEMU_CTL | |
49 | # define SET_FPEMU_CTL(a,b) (-EINVAL) | |
50 | #endif | |
51 | #ifndef GET_FPEMU_CTL | |
52 | # define GET_FPEMU_CTL(a,b) (-EINVAL) | |
53 | #endif | |
54 | #ifndef SET_FPEXC_CTL | |
55 | # define SET_FPEXC_CTL(a,b) (-EINVAL) | |
56 | #endif | |
57 | #ifndef GET_FPEXC_CTL | |
58 | # define GET_FPEXC_CTL(a,b) (-EINVAL) | |
59 | #endif | |
60 | ||
61 | /* | |
62 | * this is where the system-wide overflow UID and GID are defined, for | |
63 | * architectures that now have 32-bit UID/GID but didn't in the past | |
64 | */ | |
65 | ||
66 | int overflowuid = DEFAULT_OVERFLOWUID; | |
67 | int overflowgid = DEFAULT_OVERFLOWGID; | |
68 | ||
69 | #ifdef CONFIG_UID16 | |
70 | EXPORT_SYMBOL(overflowuid); | |
71 | EXPORT_SYMBOL(overflowgid); | |
72 | #endif | |
73 | ||
74 | /* | |
75 | * the same as above, but for filesystems which can only store a 16-bit | |
76 | * UID and GID. as such, this is needed on all architectures | |
77 | */ | |
78 | ||
79 | int fs_overflowuid = DEFAULT_FS_OVERFLOWUID; | |
80 | int fs_overflowgid = DEFAULT_FS_OVERFLOWUID; | |
81 | ||
82 | EXPORT_SYMBOL(fs_overflowuid); | |
83 | EXPORT_SYMBOL(fs_overflowgid); | |
84 | ||
85 | /* | |
86 | * this indicates whether you can reboot with ctrl-alt-del: the default is yes | |
87 | */ | |
88 | ||
89 | int C_A_D = 1; | |
90 | int cad_pid = 1; | |
91 | ||
92 | /* | |
93 | * Notifier list for kernel code which wants to be called | |
94 | * at shutdown. This is used to stop any idling DMA operations | |
95 | * and the like. | |
96 | */ | |
97 | ||
98 | static struct notifier_block *reboot_notifier_list; | |
99 | static DEFINE_RWLOCK(notifier_lock); | |
100 | ||
101 | /** | |
102 | * notifier_chain_register - Add notifier to a notifier chain | |
103 | * @list: Pointer to root list pointer | |
104 | * @n: New entry in notifier chain | |
105 | * | |
106 | * Adds a notifier to a notifier chain. | |
107 | * | |
108 | * Currently always returns zero. | |
109 | */ | |
110 | ||
111 | int notifier_chain_register(struct notifier_block **list, struct notifier_block *n) | |
112 | { | |
113 | write_lock(¬ifier_lock); | |
114 | while(*list) | |
115 | { | |
116 | if(n->priority > (*list)->priority) | |
117 | break; | |
118 | list= &((*list)->next); | |
119 | } | |
120 | n->next = *list; | |
121 | *list=n; | |
122 | write_unlock(¬ifier_lock); | |
123 | return 0; | |
124 | } | |
125 | ||
126 | EXPORT_SYMBOL(notifier_chain_register); | |
127 | ||
128 | /** | |
129 | * notifier_chain_unregister - Remove notifier from a notifier chain | |
130 | * @nl: Pointer to root list pointer | |
131 | * @n: New entry in notifier chain | |
132 | * | |
133 | * Removes a notifier from a notifier chain. | |
134 | * | |
135 | * Returns zero on success, or %-ENOENT on failure. | |
136 | */ | |
137 | ||
138 | int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n) | |
139 | { | |
140 | write_lock(¬ifier_lock); | |
141 | while((*nl)!=NULL) | |
142 | { | |
143 | if((*nl)==n) | |
144 | { | |
145 | *nl=n->next; | |
146 | write_unlock(¬ifier_lock); | |
147 | return 0; | |
148 | } | |
149 | nl=&((*nl)->next); | |
150 | } | |
151 | write_unlock(¬ifier_lock); | |
152 | return -ENOENT; | |
153 | } | |
154 | ||
155 | EXPORT_SYMBOL(notifier_chain_unregister); | |
156 | ||
157 | /** | |
158 | * notifier_call_chain - Call functions in a notifier chain | |
159 | * @n: Pointer to root pointer of notifier chain | |
160 | * @val: Value passed unmodified to notifier function | |
161 | * @v: Pointer passed unmodified to notifier function | |
162 | * | |
163 | * Calls each function in a notifier chain in turn. | |
164 | * | |
165 | * If the return value of the notifier can be and'd | |
166 | * with %NOTIFY_STOP_MASK, then notifier_call_chain | |
167 | * will return immediately, with the return value of | |
168 | * the notifier function which halted execution. | |
169 | * Otherwise, the return value is the return value | |
170 | * of the last notifier function called. | |
171 | */ | |
172 | ||
00d7c05a | 173 | int __kprobes notifier_call_chain(struct notifier_block **n, unsigned long val, void *v) |
1da177e4 LT |
174 | { |
175 | int ret=NOTIFY_DONE; | |
176 | struct notifier_block *nb = *n; | |
177 | ||
178 | while(nb) | |
179 | { | |
180 | ret=nb->notifier_call(nb,val,v); | |
181 | if(ret&NOTIFY_STOP_MASK) | |
182 | { | |
183 | return ret; | |
184 | } | |
185 | nb=nb->next; | |
186 | } | |
187 | return ret; | |
188 | } | |
189 | ||
190 | EXPORT_SYMBOL(notifier_call_chain); | |
191 | ||
192 | /** | |
193 | * register_reboot_notifier - Register function to be called at reboot time | |
194 | * @nb: Info about notifier function to be called | |
195 | * | |
196 | * Registers a function with the list of functions | |
197 | * to be called at reboot time. | |
198 | * | |
199 | * Currently always returns zero, as notifier_chain_register | |
200 | * always returns zero. | |
201 | */ | |
202 | ||
203 | int register_reboot_notifier(struct notifier_block * nb) | |
204 | { | |
205 | return notifier_chain_register(&reboot_notifier_list, nb); | |
206 | } | |
207 | ||
208 | EXPORT_SYMBOL(register_reboot_notifier); | |
209 | ||
210 | /** | |
211 | * unregister_reboot_notifier - Unregister previously registered reboot notifier | |
212 | * @nb: Hook to be unregistered | |
213 | * | |
214 | * Unregisters a previously registered reboot | |
215 | * notifier function. | |
216 | * | |
217 | * Returns zero on success, or %-ENOENT on failure. | |
218 | */ | |
219 | ||
220 | int unregister_reboot_notifier(struct notifier_block * nb) | |
221 | { | |
222 | return notifier_chain_unregister(&reboot_notifier_list, nb); | |
223 | } | |
224 | ||
225 | EXPORT_SYMBOL(unregister_reboot_notifier); | |
226 | ||
e16885c5 IM |
227 | #ifndef CONFIG_SECURITY |
228 | int capable(int cap) | |
229 | { | |
230 | if (cap_raised(current->cap_effective, cap)) { | |
231 | current->flags |= PF_SUPERPRIV; | |
232 | return 1; | |
233 | } | |
234 | return 0; | |
235 | } | |
236 | EXPORT_SYMBOL(capable); | |
237 | #endif | |
238 | ||
1da177e4 LT |
239 | static int set_one_prio(struct task_struct *p, int niceval, int error) |
240 | { | |
241 | int no_nice; | |
242 | ||
243 | if (p->uid != current->euid && | |
244 | p->euid != current->euid && !capable(CAP_SYS_NICE)) { | |
245 | error = -EPERM; | |
246 | goto out; | |
247 | } | |
e43379f1 | 248 | if (niceval < task_nice(p) && !can_nice(p, niceval)) { |
1da177e4 LT |
249 | error = -EACCES; |
250 | goto out; | |
251 | } | |
252 | no_nice = security_task_setnice(p, niceval); | |
253 | if (no_nice) { | |
254 | error = no_nice; | |
255 | goto out; | |
256 | } | |
257 | if (error == -ESRCH) | |
258 | error = 0; | |
259 | set_user_nice(p, niceval); | |
260 | out: | |
261 | return error; | |
262 | } | |
263 | ||
264 | asmlinkage long sys_setpriority(int which, int who, int niceval) | |
265 | { | |
266 | struct task_struct *g, *p; | |
267 | struct user_struct *user; | |
268 | int error = -EINVAL; | |
269 | ||
270 | if (which > 2 || which < 0) | |
271 | goto out; | |
272 | ||
273 | /* normalize: avoid signed division (rounding problems) */ | |
274 | error = -ESRCH; | |
275 | if (niceval < -20) | |
276 | niceval = -20; | |
277 | if (niceval > 19) | |
278 | niceval = 19; | |
279 | ||
280 | read_lock(&tasklist_lock); | |
281 | switch (which) { | |
282 | case PRIO_PROCESS: | |
283 | if (!who) | |
284 | who = current->pid; | |
285 | p = find_task_by_pid(who); | |
286 | if (p) | |
287 | error = set_one_prio(p, niceval, error); | |
288 | break; | |
289 | case PRIO_PGRP: | |
290 | if (!who) | |
291 | who = process_group(current); | |
292 | do_each_task_pid(who, PIDTYPE_PGID, p) { | |
293 | error = set_one_prio(p, niceval, error); | |
294 | } while_each_task_pid(who, PIDTYPE_PGID, p); | |
295 | break; | |
296 | case PRIO_USER: | |
297 | user = current->user; | |
298 | if (!who) | |
299 | who = current->uid; | |
300 | else | |
301 | if ((who != current->uid) && !(user = find_user(who))) | |
302 | goto out_unlock; /* No processes for this user */ | |
303 | ||
304 | do_each_thread(g, p) | |
305 | if (p->uid == who) | |
306 | error = set_one_prio(p, niceval, error); | |
307 | while_each_thread(g, p); | |
308 | if (who != current->uid) | |
309 | free_uid(user); /* For find_user() */ | |
310 | break; | |
311 | } | |
312 | out_unlock: | |
313 | read_unlock(&tasklist_lock); | |
314 | out: | |
315 | return error; | |
316 | } | |
317 | ||
318 | /* | |
319 | * Ugh. To avoid negative return values, "getpriority()" will | |
320 | * not return the normal nice-value, but a negated value that | |
321 | * has been offset by 20 (ie it returns 40..1 instead of -20..19) | |
322 | * to stay compatible. | |
323 | */ | |
324 | asmlinkage long sys_getpriority(int which, int who) | |
325 | { | |
326 | struct task_struct *g, *p; | |
327 | struct user_struct *user; | |
328 | long niceval, retval = -ESRCH; | |
329 | ||
330 | if (which > 2 || which < 0) | |
331 | return -EINVAL; | |
332 | ||
333 | read_lock(&tasklist_lock); | |
334 | switch (which) { | |
335 | case PRIO_PROCESS: | |
336 | if (!who) | |
337 | who = current->pid; | |
338 | p = find_task_by_pid(who); | |
339 | if (p) { | |
340 | niceval = 20 - task_nice(p); | |
341 | if (niceval > retval) | |
342 | retval = niceval; | |
343 | } | |
344 | break; | |
345 | case PRIO_PGRP: | |
346 | if (!who) | |
347 | who = process_group(current); | |
348 | do_each_task_pid(who, PIDTYPE_PGID, p) { | |
349 | niceval = 20 - task_nice(p); | |
350 | if (niceval > retval) | |
351 | retval = niceval; | |
352 | } while_each_task_pid(who, PIDTYPE_PGID, p); | |
353 | break; | |
354 | case PRIO_USER: | |
355 | user = current->user; | |
356 | if (!who) | |
357 | who = current->uid; | |
358 | else | |
359 | if ((who != current->uid) && !(user = find_user(who))) | |
360 | goto out_unlock; /* No processes for this user */ | |
361 | ||
362 | do_each_thread(g, p) | |
363 | if (p->uid == who) { | |
364 | niceval = 20 - task_nice(p); | |
365 | if (niceval > retval) | |
366 | retval = niceval; | |
367 | } | |
368 | while_each_thread(g, p); | |
369 | if (who != current->uid) | |
370 | free_uid(user); /* for find_user() */ | |
371 | break; | |
372 | } | |
373 | out_unlock: | |
374 | read_unlock(&tasklist_lock); | |
375 | ||
376 | return retval; | |
377 | } | |
378 | ||
e4c94330 EB |
379 | /** |
380 | * emergency_restart - reboot the system | |
381 | * | |
382 | * Without shutting down any hardware or taking any locks | |
383 | * reboot the system. This is called when we know we are in | |
384 | * trouble so this is our best effort to reboot. This is | |
385 | * safe to call in interrupt context. | |
386 | */ | |
7c903473 EB |
387 | void emergency_restart(void) |
388 | { | |
389 | machine_emergency_restart(); | |
390 | } | |
391 | EXPORT_SYMBOL_GPL(emergency_restart); | |
392 | ||
e4c94330 | 393 | void kernel_restart_prepare(char *cmd) |
4a00ea1e EB |
394 | { |
395 | notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd); | |
396 | system_state = SYSTEM_RESTART; | |
4a00ea1e | 397 | device_shutdown(); |
e4c94330 | 398 | } |
1e5d5331 RD |
399 | |
400 | /** | |
401 | * kernel_restart - reboot the system | |
402 | * @cmd: pointer to buffer containing command to execute for restart | |
b8887e6e | 403 | * or %NULL |
1e5d5331 RD |
404 | * |
405 | * Shutdown everything and perform a clean reboot. | |
406 | * This is not safe to call in interrupt context. | |
407 | */ | |
e4c94330 EB |
408 | void kernel_restart(char *cmd) |
409 | { | |
410 | kernel_restart_prepare(cmd); | |
4a00ea1e EB |
411 | if (!cmd) { |
412 | printk(KERN_EMERG "Restarting system.\n"); | |
413 | } else { | |
414 | printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd); | |
415 | } | |
416 | printk(".\n"); | |
417 | machine_restart(cmd); | |
418 | } | |
419 | EXPORT_SYMBOL_GPL(kernel_restart); | |
420 | ||
e4c94330 EB |
421 | /** |
422 | * kernel_kexec - reboot the system | |
423 | * | |
424 | * Move into place and start executing a preloaded standalone | |
425 | * executable. If nothing was preloaded return an error. | |
426 | */ | |
4a00ea1e EB |
427 | void kernel_kexec(void) |
428 | { | |
429 | #ifdef CONFIG_KEXEC | |
430 | struct kimage *image; | |
4bb8089c | 431 | image = xchg(&kexec_image, NULL); |
4a00ea1e EB |
432 | if (!image) { |
433 | return; | |
434 | } | |
e4c94330 | 435 | kernel_restart_prepare(NULL); |
4a00ea1e EB |
436 | printk(KERN_EMERG "Starting new kernel\n"); |
437 | machine_shutdown(); | |
438 | machine_kexec(image); | |
439 | #endif | |
440 | } | |
441 | EXPORT_SYMBOL_GPL(kernel_kexec); | |
442 | ||
729b4d4c AS |
443 | void kernel_shutdown_prepare(enum system_states state) |
444 | { | |
445 | notifier_call_chain(&reboot_notifier_list, | |
446 | (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL); | |
447 | system_state = state; | |
448 | device_shutdown(); | |
449 | } | |
e4c94330 EB |
450 | /** |
451 | * kernel_halt - halt the system | |
452 | * | |
453 | * Shutdown everything and perform a clean system halt. | |
454 | */ | |
e4c94330 EB |
455 | void kernel_halt(void) |
456 | { | |
729b4d4c | 457 | kernel_shutdown_prepare(SYSTEM_HALT); |
4a00ea1e EB |
458 | printk(KERN_EMERG "System halted.\n"); |
459 | machine_halt(); | |
460 | } | |
729b4d4c | 461 | |
4a00ea1e EB |
462 | EXPORT_SYMBOL_GPL(kernel_halt); |
463 | ||
e4c94330 EB |
464 | /** |
465 | * kernel_power_off - power_off the system | |
466 | * | |
467 | * Shutdown everything and perform a clean system power_off. | |
468 | */ | |
e4c94330 EB |
469 | void kernel_power_off(void) |
470 | { | |
729b4d4c | 471 | kernel_shutdown_prepare(SYSTEM_POWER_OFF); |
4a00ea1e EB |
472 | printk(KERN_EMERG "Power down.\n"); |
473 | machine_power_off(); | |
474 | } | |
475 | EXPORT_SYMBOL_GPL(kernel_power_off); | |
1da177e4 LT |
476 | /* |
477 | * Reboot system call: for obvious reasons only root may call it, | |
478 | * and even root needs to set up some magic numbers in the registers | |
479 | * so that some mistake won't make this reboot the whole machine. | |
480 | * You can also set the meaning of the ctrl-alt-del-key here. | |
481 | * | |
482 | * reboot doesn't sync: do that yourself before calling this. | |
483 | */ | |
484 | asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg) | |
485 | { | |
486 | char buffer[256]; | |
487 | ||
488 | /* We only trust the superuser with rebooting the system. */ | |
489 | if (!capable(CAP_SYS_BOOT)) | |
490 | return -EPERM; | |
491 | ||
492 | /* For safety, we require "magic" arguments. */ | |
493 | if (magic1 != LINUX_REBOOT_MAGIC1 || | |
494 | (magic2 != LINUX_REBOOT_MAGIC2 && | |
495 | magic2 != LINUX_REBOOT_MAGIC2A && | |
496 | magic2 != LINUX_REBOOT_MAGIC2B && | |
497 | magic2 != LINUX_REBOOT_MAGIC2C)) | |
498 | return -EINVAL; | |
499 | ||
5e38291d EB |
500 | /* Instead of trying to make the power_off code look like |
501 | * halt when pm_power_off is not set do it the easy way. | |
502 | */ | |
503 | if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off) | |
504 | cmd = LINUX_REBOOT_CMD_HALT; | |
505 | ||
1da177e4 LT |
506 | lock_kernel(); |
507 | switch (cmd) { | |
508 | case LINUX_REBOOT_CMD_RESTART: | |
4a00ea1e | 509 | kernel_restart(NULL); |
1da177e4 LT |
510 | break; |
511 | ||
512 | case LINUX_REBOOT_CMD_CAD_ON: | |
513 | C_A_D = 1; | |
514 | break; | |
515 | ||
516 | case LINUX_REBOOT_CMD_CAD_OFF: | |
517 | C_A_D = 0; | |
518 | break; | |
519 | ||
520 | case LINUX_REBOOT_CMD_HALT: | |
4a00ea1e | 521 | kernel_halt(); |
1da177e4 LT |
522 | unlock_kernel(); |
523 | do_exit(0); | |
524 | break; | |
525 | ||
526 | case LINUX_REBOOT_CMD_POWER_OFF: | |
4a00ea1e | 527 | kernel_power_off(); |
1da177e4 LT |
528 | unlock_kernel(); |
529 | do_exit(0); | |
530 | break; | |
531 | ||
532 | case LINUX_REBOOT_CMD_RESTART2: | |
533 | if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) { | |
534 | unlock_kernel(); | |
535 | return -EFAULT; | |
536 | } | |
537 | buffer[sizeof(buffer) - 1] = '\0'; | |
538 | ||
4a00ea1e | 539 | kernel_restart(buffer); |
1da177e4 LT |
540 | break; |
541 | ||
dc009d92 | 542 | case LINUX_REBOOT_CMD_KEXEC: |
4a00ea1e EB |
543 | kernel_kexec(); |
544 | unlock_kernel(); | |
545 | return -EINVAL; | |
546 | ||
1da177e4 LT |
547 | #ifdef CONFIG_SOFTWARE_SUSPEND |
548 | case LINUX_REBOOT_CMD_SW_SUSPEND: | |
549 | { | |
550 | int ret = software_suspend(); | |
551 | unlock_kernel(); | |
552 | return ret; | |
553 | } | |
554 | #endif | |
555 | ||
556 | default: | |
557 | unlock_kernel(); | |
558 | return -EINVAL; | |
559 | } | |
560 | unlock_kernel(); | |
561 | return 0; | |
562 | } | |
563 | ||
564 | static void deferred_cad(void *dummy) | |
565 | { | |
abcd9e51 | 566 | kernel_restart(NULL); |
1da177e4 LT |
567 | } |
568 | ||
569 | /* | |
570 | * This function gets called by ctrl-alt-del - ie the keyboard interrupt. | |
571 | * As it's called within an interrupt, it may NOT sync: the only choice | |
572 | * is whether to reboot at once, or just ignore the ctrl-alt-del. | |
573 | */ | |
574 | void ctrl_alt_del(void) | |
575 | { | |
576 | static DECLARE_WORK(cad_work, deferred_cad, NULL); | |
577 | ||
578 | if (C_A_D) | |
579 | schedule_work(&cad_work); | |
580 | else | |
581 | kill_proc(cad_pid, SIGINT, 1); | |
582 | } | |
583 | ||
584 | ||
585 | /* | |
586 | * Unprivileged users may change the real gid to the effective gid | |
587 | * or vice versa. (BSD-style) | |
588 | * | |
589 | * If you set the real gid at all, or set the effective gid to a value not | |
590 | * equal to the real gid, then the saved gid is set to the new effective gid. | |
591 | * | |
592 | * This makes it possible for a setgid program to completely drop its | |
593 | * privileges, which is often a useful assertion to make when you are doing | |
594 | * a security audit over a program. | |
595 | * | |
596 | * The general idea is that a program which uses just setregid() will be | |
597 | * 100% compatible with BSD. A program which uses just setgid() will be | |
598 | * 100% compatible with POSIX with saved IDs. | |
599 | * | |
600 | * SMP: There are not races, the GIDs are checked only by filesystem | |
601 | * operations (as far as semantic preservation is concerned). | |
602 | */ | |
603 | asmlinkage long sys_setregid(gid_t rgid, gid_t egid) | |
604 | { | |
605 | int old_rgid = current->gid; | |
606 | int old_egid = current->egid; | |
607 | int new_rgid = old_rgid; | |
608 | int new_egid = old_egid; | |
609 | int retval; | |
610 | ||
611 | retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE); | |
612 | if (retval) | |
613 | return retval; | |
614 | ||
615 | if (rgid != (gid_t) -1) { | |
616 | if ((old_rgid == rgid) || | |
617 | (current->egid==rgid) || | |
618 | capable(CAP_SETGID)) | |
619 | new_rgid = rgid; | |
620 | else | |
621 | return -EPERM; | |
622 | } | |
623 | if (egid != (gid_t) -1) { | |
624 | if ((old_rgid == egid) || | |
625 | (current->egid == egid) || | |
626 | (current->sgid == egid) || | |
627 | capable(CAP_SETGID)) | |
628 | new_egid = egid; | |
629 | else { | |
630 | return -EPERM; | |
631 | } | |
632 | } | |
633 | if (new_egid != old_egid) | |
634 | { | |
d6e71144 | 635 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 636 | smp_wmb(); |
1da177e4 LT |
637 | } |
638 | if (rgid != (gid_t) -1 || | |
639 | (egid != (gid_t) -1 && egid != old_rgid)) | |
640 | current->sgid = new_egid; | |
641 | current->fsgid = new_egid; | |
642 | current->egid = new_egid; | |
643 | current->gid = new_rgid; | |
644 | key_fsgid_changed(current); | |
9f46080c | 645 | proc_id_connector(current, PROC_EVENT_GID); |
1da177e4 LT |
646 | return 0; |
647 | } | |
648 | ||
649 | /* | |
650 | * setgid() is implemented like SysV w/ SAVED_IDS | |
651 | * | |
652 | * SMP: Same implicit races as above. | |
653 | */ | |
654 | asmlinkage long sys_setgid(gid_t gid) | |
655 | { | |
656 | int old_egid = current->egid; | |
657 | int retval; | |
658 | ||
659 | retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID); | |
660 | if (retval) | |
661 | return retval; | |
662 | ||
663 | if (capable(CAP_SETGID)) | |
664 | { | |
665 | if(old_egid != gid) | |
666 | { | |
d6e71144 | 667 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 668 | smp_wmb(); |
1da177e4 LT |
669 | } |
670 | current->gid = current->egid = current->sgid = current->fsgid = gid; | |
671 | } | |
672 | else if ((gid == current->gid) || (gid == current->sgid)) | |
673 | { | |
674 | if(old_egid != gid) | |
675 | { | |
d6e71144 | 676 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 677 | smp_wmb(); |
1da177e4 LT |
678 | } |
679 | current->egid = current->fsgid = gid; | |
680 | } | |
681 | else | |
682 | return -EPERM; | |
683 | ||
684 | key_fsgid_changed(current); | |
9f46080c | 685 | proc_id_connector(current, PROC_EVENT_GID); |
1da177e4 LT |
686 | return 0; |
687 | } | |
688 | ||
689 | static int set_user(uid_t new_ruid, int dumpclear) | |
690 | { | |
691 | struct user_struct *new_user; | |
692 | ||
693 | new_user = alloc_uid(new_ruid); | |
694 | if (!new_user) | |
695 | return -EAGAIN; | |
696 | ||
697 | if (atomic_read(&new_user->processes) >= | |
698 | current->signal->rlim[RLIMIT_NPROC].rlim_cur && | |
699 | new_user != &root_user) { | |
700 | free_uid(new_user); | |
701 | return -EAGAIN; | |
702 | } | |
703 | ||
704 | switch_uid(new_user); | |
705 | ||
706 | if(dumpclear) | |
707 | { | |
d6e71144 | 708 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 709 | smp_wmb(); |
1da177e4 LT |
710 | } |
711 | current->uid = new_ruid; | |
712 | return 0; | |
713 | } | |
714 | ||
715 | /* | |
716 | * Unprivileged users may change the real uid to the effective uid | |
717 | * or vice versa. (BSD-style) | |
718 | * | |
719 | * If you set the real uid at all, or set the effective uid to a value not | |
720 | * equal to the real uid, then the saved uid is set to the new effective uid. | |
721 | * | |
722 | * This makes it possible for a setuid program to completely drop its | |
723 | * privileges, which is often a useful assertion to make when you are doing | |
724 | * a security audit over a program. | |
725 | * | |
726 | * The general idea is that a program which uses just setreuid() will be | |
727 | * 100% compatible with BSD. A program which uses just setuid() will be | |
728 | * 100% compatible with POSIX with saved IDs. | |
729 | */ | |
730 | asmlinkage long sys_setreuid(uid_t ruid, uid_t euid) | |
731 | { | |
732 | int old_ruid, old_euid, old_suid, new_ruid, new_euid; | |
733 | int retval; | |
734 | ||
735 | retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE); | |
736 | if (retval) | |
737 | return retval; | |
738 | ||
739 | new_ruid = old_ruid = current->uid; | |
740 | new_euid = old_euid = current->euid; | |
741 | old_suid = current->suid; | |
742 | ||
743 | if (ruid != (uid_t) -1) { | |
744 | new_ruid = ruid; | |
745 | if ((old_ruid != ruid) && | |
746 | (current->euid != ruid) && | |
747 | !capable(CAP_SETUID)) | |
748 | return -EPERM; | |
749 | } | |
750 | ||
751 | if (euid != (uid_t) -1) { | |
752 | new_euid = euid; | |
753 | if ((old_ruid != euid) && | |
754 | (current->euid != euid) && | |
755 | (current->suid != euid) && | |
756 | !capable(CAP_SETUID)) | |
757 | return -EPERM; | |
758 | } | |
759 | ||
760 | if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0) | |
761 | return -EAGAIN; | |
762 | ||
763 | if (new_euid != old_euid) | |
764 | { | |
d6e71144 | 765 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 766 | smp_wmb(); |
1da177e4 LT |
767 | } |
768 | current->fsuid = current->euid = new_euid; | |
769 | if (ruid != (uid_t) -1 || | |
770 | (euid != (uid_t) -1 && euid != old_ruid)) | |
771 | current->suid = current->euid; | |
772 | current->fsuid = current->euid; | |
773 | ||
774 | key_fsuid_changed(current); | |
9f46080c | 775 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
776 | |
777 | return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE); | |
778 | } | |
779 | ||
780 | ||
781 | ||
782 | /* | |
783 | * setuid() is implemented like SysV with SAVED_IDS | |
784 | * | |
785 | * Note that SAVED_ID's is deficient in that a setuid root program | |
786 | * like sendmail, for example, cannot set its uid to be a normal | |
787 | * user and then switch back, because if you're root, setuid() sets | |
788 | * the saved uid too. If you don't like this, blame the bright people | |
789 | * in the POSIX committee and/or USG. Note that the BSD-style setreuid() | |
790 | * will allow a root program to temporarily drop privileges and be able to | |
791 | * regain them by swapping the real and effective uid. | |
792 | */ | |
793 | asmlinkage long sys_setuid(uid_t uid) | |
794 | { | |
795 | int old_euid = current->euid; | |
796 | int old_ruid, old_suid, new_ruid, new_suid; | |
797 | int retval; | |
798 | ||
799 | retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID); | |
800 | if (retval) | |
801 | return retval; | |
802 | ||
803 | old_ruid = new_ruid = current->uid; | |
804 | old_suid = current->suid; | |
805 | new_suid = old_suid; | |
806 | ||
807 | if (capable(CAP_SETUID)) { | |
808 | if (uid != old_ruid && set_user(uid, old_euid != uid) < 0) | |
809 | return -EAGAIN; | |
810 | new_suid = uid; | |
811 | } else if ((uid != current->uid) && (uid != new_suid)) | |
812 | return -EPERM; | |
813 | ||
814 | if (old_euid != uid) | |
815 | { | |
d6e71144 | 816 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 817 | smp_wmb(); |
1da177e4 LT |
818 | } |
819 | current->fsuid = current->euid = uid; | |
820 | current->suid = new_suid; | |
821 | ||
822 | key_fsuid_changed(current); | |
9f46080c | 823 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
824 | |
825 | return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID); | |
826 | } | |
827 | ||
828 | ||
829 | /* | |
830 | * This function implements a generic ability to update ruid, euid, | |
831 | * and suid. This allows you to implement the 4.4 compatible seteuid(). | |
832 | */ | |
833 | asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid) | |
834 | { | |
835 | int old_ruid = current->uid; | |
836 | int old_euid = current->euid; | |
837 | int old_suid = current->suid; | |
838 | int retval; | |
839 | ||
840 | retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES); | |
841 | if (retval) | |
842 | return retval; | |
843 | ||
844 | if (!capable(CAP_SETUID)) { | |
845 | if ((ruid != (uid_t) -1) && (ruid != current->uid) && | |
846 | (ruid != current->euid) && (ruid != current->suid)) | |
847 | return -EPERM; | |
848 | if ((euid != (uid_t) -1) && (euid != current->uid) && | |
849 | (euid != current->euid) && (euid != current->suid)) | |
850 | return -EPERM; | |
851 | if ((suid != (uid_t) -1) && (suid != current->uid) && | |
852 | (suid != current->euid) && (suid != current->suid)) | |
853 | return -EPERM; | |
854 | } | |
855 | if (ruid != (uid_t) -1) { | |
856 | if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0) | |
857 | return -EAGAIN; | |
858 | } | |
859 | if (euid != (uid_t) -1) { | |
860 | if (euid != current->euid) | |
861 | { | |
d6e71144 | 862 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 863 | smp_wmb(); |
1da177e4 LT |
864 | } |
865 | current->euid = euid; | |
866 | } | |
867 | current->fsuid = current->euid; | |
868 | if (suid != (uid_t) -1) | |
869 | current->suid = suid; | |
870 | ||
871 | key_fsuid_changed(current); | |
9f46080c | 872 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
873 | |
874 | return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES); | |
875 | } | |
876 | ||
877 | asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid) | |
878 | { | |
879 | int retval; | |
880 | ||
881 | if (!(retval = put_user(current->uid, ruid)) && | |
882 | !(retval = put_user(current->euid, euid))) | |
883 | retval = put_user(current->suid, suid); | |
884 | ||
885 | return retval; | |
886 | } | |
887 | ||
888 | /* | |
889 | * Same as above, but for rgid, egid, sgid. | |
890 | */ | |
891 | asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid) | |
892 | { | |
893 | int retval; | |
894 | ||
895 | retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES); | |
896 | if (retval) | |
897 | return retval; | |
898 | ||
899 | if (!capable(CAP_SETGID)) { | |
900 | if ((rgid != (gid_t) -1) && (rgid != current->gid) && | |
901 | (rgid != current->egid) && (rgid != current->sgid)) | |
902 | return -EPERM; | |
903 | if ((egid != (gid_t) -1) && (egid != current->gid) && | |
904 | (egid != current->egid) && (egid != current->sgid)) | |
905 | return -EPERM; | |
906 | if ((sgid != (gid_t) -1) && (sgid != current->gid) && | |
907 | (sgid != current->egid) && (sgid != current->sgid)) | |
908 | return -EPERM; | |
909 | } | |
910 | if (egid != (gid_t) -1) { | |
911 | if (egid != current->egid) | |
912 | { | |
d6e71144 | 913 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 914 | smp_wmb(); |
1da177e4 LT |
915 | } |
916 | current->egid = egid; | |
917 | } | |
918 | current->fsgid = current->egid; | |
919 | if (rgid != (gid_t) -1) | |
920 | current->gid = rgid; | |
921 | if (sgid != (gid_t) -1) | |
922 | current->sgid = sgid; | |
923 | ||
924 | key_fsgid_changed(current); | |
9f46080c | 925 | proc_id_connector(current, PROC_EVENT_GID); |
1da177e4 LT |
926 | return 0; |
927 | } | |
928 | ||
929 | asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid) | |
930 | { | |
931 | int retval; | |
932 | ||
933 | if (!(retval = put_user(current->gid, rgid)) && | |
934 | !(retval = put_user(current->egid, egid))) | |
935 | retval = put_user(current->sgid, sgid); | |
936 | ||
937 | return retval; | |
938 | } | |
939 | ||
940 | ||
941 | /* | |
942 | * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This | |
943 | * is used for "access()" and for the NFS daemon (letting nfsd stay at | |
944 | * whatever uid it wants to). It normally shadows "euid", except when | |
945 | * explicitly set by setfsuid() or for access.. | |
946 | */ | |
947 | asmlinkage long sys_setfsuid(uid_t uid) | |
948 | { | |
949 | int old_fsuid; | |
950 | ||
951 | old_fsuid = current->fsuid; | |
952 | if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS)) | |
953 | return old_fsuid; | |
954 | ||
955 | if (uid == current->uid || uid == current->euid || | |
956 | uid == current->suid || uid == current->fsuid || | |
957 | capable(CAP_SETUID)) | |
958 | { | |
959 | if (uid != old_fsuid) | |
960 | { | |
d6e71144 | 961 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 962 | smp_wmb(); |
1da177e4 LT |
963 | } |
964 | current->fsuid = uid; | |
965 | } | |
966 | ||
967 | key_fsuid_changed(current); | |
9f46080c | 968 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
969 | |
970 | security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS); | |
971 | ||
972 | return old_fsuid; | |
973 | } | |
974 | ||
975 | /* | |
976 |