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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 | ||
227 | static int set_one_prio(struct task_struct *p, int niceval, int error) | |
228 | { | |
229 | int no_nice; | |
230 | ||
231 | if (p->uid != current->euid && | |
232 | p->euid != current->euid && !capable(CAP_SYS_NICE)) { | |
233 | error = -EPERM; | |
234 | goto out; | |
235 | } | |
e43379f1 | 236 | if (niceval < task_nice(p) && !can_nice(p, niceval)) { |
1da177e4 LT |
237 | error = -EACCES; |
238 | goto out; | |
239 | } | |
240 | no_nice = security_task_setnice(p, niceval); | |
241 | if (no_nice) { | |
242 | error = no_nice; | |
243 | goto out; | |
244 | } | |
245 | if (error == -ESRCH) | |
246 | error = 0; | |
247 | set_user_nice(p, niceval); | |
248 | out: | |
249 | return error; | |
250 | } | |
251 | ||
252 | asmlinkage long sys_setpriority(int which, int who, int niceval) | |
253 | { | |
254 | struct task_struct *g, *p; | |
255 | struct user_struct *user; | |
256 | int error = -EINVAL; | |
257 | ||
258 | if (which > 2 || which < 0) | |
259 | goto out; | |
260 | ||
261 | /* normalize: avoid signed division (rounding problems) */ | |
262 | error = -ESRCH; | |
263 | if (niceval < -20) | |
264 | niceval = -20; | |
265 | if (niceval > 19) | |
266 | niceval = 19; | |
267 | ||
268 | read_lock(&tasklist_lock); | |
269 | switch (which) { | |
270 | case PRIO_PROCESS: | |
271 | if (!who) | |
272 | who = current->pid; | |
273 | p = find_task_by_pid(who); | |
274 | if (p) | |
275 | error = set_one_prio(p, niceval, error); | |
276 | break; | |
277 | case PRIO_PGRP: | |
278 | if (!who) | |
279 | who = process_group(current); | |
280 | do_each_task_pid(who, PIDTYPE_PGID, p) { | |
281 | error = set_one_prio(p, niceval, error); | |
282 | } while_each_task_pid(who, PIDTYPE_PGID, p); | |
283 | break; | |
284 | case PRIO_USER: | |
285 | user = current->user; | |
286 | if (!who) | |
287 | who = current->uid; | |
288 | else | |
289 | if ((who != current->uid) && !(user = find_user(who))) | |
290 | goto out_unlock; /* No processes for this user */ | |
291 | ||
292 | do_each_thread(g, p) | |
293 | if (p->uid == who) | |
294 | error = set_one_prio(p, niceval, error); | |
295 | while_each_thread(g, p); | |
296 | if (who != current->uid) | |
297 | free_uid(user); /* For find_user() */ | |
298 | break; | |
299 | } | |
300 | out_unlock: | |
301 | read_unlock(&tasklist_lock); | |
302 | out: | |
303 | return error; | |
304 | } | |
305 | ||
306 | /* | |
307 | * Ugh. To avoid negative return values, "getpriority()" will | |
308 | * not return the normal nice-value, but a negated value that | |
309 | * has been offset by 20 (ie it returns 40..1 instead of -20..19) | |
310 | * to stay compatible. | |
311 | */ | |
312 | asmlinkage long sys_getpriority(int which, int who) | |
313 | { | |
314 | struct task_struct *g, *p; | |
315 | struct user_struct *user; | |
316 | long niceval, retval = -ESRCH; | |
317 | ||
318 | if (which > 2 || which < 0) | |
319 | return -EINVAL; | |
320 | ||
321 | read_lock(&tasklist_lock); | |
322 | switch (which) { | |
323 | case PRIO_PROCESS: | |
324 | if (!who) | |
325 | who = current->pid; | |
326 | p = find_task_by_pid(who); | |
327 | if (p) { | |
328 | niceval = 20 - task_nice(p); | |
329 | if (niceval > retval) | |
330 | retval = niceval; | |
331 | } | |
332 | break; | |
333 | case PRIO_PGRP: | |
334 | if (!who) | |
335 | who = process_group(current); | |
336 | do_each_task_pid(who, PIDTYPE_PGID, p) { | |
337 | niceval = 20 - task_nice(p); | |
338 | if (niceval > retval) | |
339 | retval = niceval; | |
340 | } while_each_task_pid(who, PIDTYPE_PGID, p); | |
341 | break; | |
342 | case PRIO_USER: | |
343 | user = current->user; | |
344 | if (!who) | |
345 | who = current->uid; | |
346 | else | |
347 | if ((who != current->uid) && !(user = find_user(who))) | |
348 | goto out_unlock; /* No processes for this user */ | |
349 | ||
350 | do_each_thread(g, p) | |
351 | if (p->uid == who) { | |
352 | niceval = 20 - task_nice(p); | |
353 | if (niceval > retval) | |
354 | retval = niceval; | |
355 | } | |
356 | while_each_thread(g, p); | |
357 | if (who != current->uid) | |
358 | free_uid(user); /* for find_user() */ | |
359 | break; | |
360 | } | |
361 | out_unlock: | |
362 | read_unlock(&tasklist_lock); | |
363 | ||
364 | return retval; | |
365 | } | |
366 | ||
e4c94330 EB |
367 | /** |
368 | * emergency_restart - reboot the system | |
369 | * | |
370 | * Without shutting down any hardware or taking any locks | |
371 | * reboot the system. This is called when we know we are in | |
372 | * trouble so this is our best effort to reboot. This is | |
373 | * safe to call in interrupt context. | |
374 | */ | |
7c903473 EB |
375 | void emergency_restart(void) |
376 | { | |
377 | machine_emergency_restart(); | |
378 | } | |
379 | EXPORT_SYMBOL_GPL(emergency_restart); | |
380 | ||
e4c94330 | 381 | void kernel_restart_prepare(char *cmd) |
4a00ea1e EB |
382 | { |
383 | notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd); | |
384 | system_state = SYSTEM_RESTART; | |
4a00ea1e | 385 | device_shutdown(); |
e4c94330 | 386 | } |
1e5d5331 RD |
387 | |
388 | /** | |
389 | * kernel_restart - reboot the system | |
390 | * @cmd: pointer to buffer containing command to execute for restart | |
b8887e6e | 391 | * or %NULL |
1e5d5331 RD |
392 | * |
393 | * Shutdown everything and perform a clean reboot. | |
394 | * This is not safe to call in interrupt context. | |
395 | */ | |
e4c94330 EB |
396 | void kernel_restart(char *cmd) |
397 | { | |
398 | kernel_restart_prepare(cmd); | |
4a00ea1e EB |
399 | if (!cmd) { |
400 | printk(KERN_EMERG "Restarting system.\n"); | |
401 | } else { | |
402 | printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd); | |
403 | } | |
404 | printk(".\n"); | |
405 | machine_restart(cmd); | |
406 | } | |
407 | EXPORT_SYMBOL_GPL(kernel_restart); | |
408 | ||
e4c94330 EB |
409 | /** |
410 | * kernel_kexec - reboot the system | |
411 | * | |
412 | * Move into place and start executing a preloaded standalone | |
413 | * executable. If nothing was preloaded return an error. | |
414 | */ | |
4a00ea1e EB |
415 | void kernel_kexec(void) |
416 | { | |
417 | #ifdef CONFIG_KEXEC | |
418 | struct kimage *image; | |
4bb8089c | 419 | image = xchg(&kexec_image, NULL); |
4a00ea1e EB |
420 | if (!image) { |
421 | return; | |
422 | } | |
e4c94330 | 423 | kernel_restart_prepare(NULL); |
4a00ea1e EB |
424 | printk(KERN_EMERG "Starting new kernel\n"); |
425 | machine_shutdown(); | |
426 | machine_kexec(image); | |
427 | #endif | |
428 | } | |
429 | EXPORT_SYMBOL_GPL(kernel_kexec); | |
430 | ||
729b4d4c AS |
431 | void kernel_shutdown_prepare(enum system_states state) |
432 | { | |
433 | notifier_call_chain(&reboot_notifier_list, | |
434 | (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL); | |
435 | system_state = state; | |
436 | device_shutdown(); | |
437 | } | |
e4c94330 EB |
438 | /** |
439 | * kernel_halt - halt the system | |
440 | * | |
441 | * Shutdown everything and perform a clean system halt. | |
442 | */ | |
e4c94330 EB |
443 | void kernel_halt(void) |
444 | { | |
729b4d4c | 445 | kernel_shutdown_prepare(SYSTEM_HALT); |
4a00ea1e EB |
446 | printk(KERN_EMERG "System halted.\n"); |
447 | machine_halt(); | |
448 | } | |
729b4d4c | 449 | |
4a00ea1e EB |
450 | EXPORT_SYMBOL_GPL(kernel_halt); |
451 | ||
e4c94330 EB |
452 | /** |
453 | * kernel_power_off - power_off the system | |
454 | * | |
455 | * Shutdown everything and perform a clean system power_off. | |
456 | */ | |
e4c94330 EB |
457 | void kernel_power_off(void) |
458 | { | |
729b4d4c | 459 | kernel_shutdown_prepare(SYSTEM_POWER_OFF); |
4a00ea1e EB |
460 | printk(KERN_EMERG "Power down.\n"); |
461 | machine_power_off(); | |
462 | } | |
463 | EXPORT_SYMBOL_GPL(kernel_power_off); | |
1da177e4 LT |
464 | /* |
465 | * Reboot system call: for obvious reasons only root may call it, | |
466 | * and even root needs to set up some magic numbers in the registers | |
467 | * so that some mistake won't make this reboot the whole machine. | |
468 | * You can also set the meaning of the ctrl-alt-del-key here. | |
469 | * | |
470 | * reboot doesn't sync: do that yourself before calling this. | |
471 | */ | |
472 | asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg) | |
473 | { | |
474 | char buffer[256]; | |
475 | ||
476 | /* We only trust the superuser with rebooting the system. */ | |
477 | if (!capable(CAP_SYS_BOOT)) | |
478 | return -EPERM; | |
479 | ||
480 | /* For safety, we require "magic" arguments. */ | |
481 | if (magic1 != LINUX_REBOOT_MAGIC1 || | |
482 | (magic2 != LINUX_REBOOT_MAGIC2 && | |
483 | magic2 != LINUX_REBOOT_MAGIC2A && | |
484 | magic2 != LINUX_REBOOT_MAGIC2B && | |
485 | magic2 != LINUX_REBOOT_MAGIC2C)) | |
486 | return -EINVAL; | |
487 | ||
5e38291d EB |
488 | /* Instead of trying to make the power_off code look like |
489 | * halt when pm_power_off is not set do it the easy way. | |
490 | */ | |
491 | if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off) | |
492 | cmd = LINUX_REBOOT_CMD_HALT; | |
493 | ||
1da177e4 LT |
494 | lock_kernel(); |
495 | switch (cmd) { | |
496 | case LINUX_REBOOT_CMD_RESTART: | |
4a00ea1e | 497 | kernel_restart(NULL); |
1da177e4 LT |
498 | break; |
499 | ||
500 | case LINUX_REBOOT_CMD_CAD_ON: | |
501 | C_A_D = 1; | |
502 | break; | |
503 | ||
504 | case LINUX_REBOOT_CMD_CAD_OFF: | |
505 | C_A_D = 0; | |
506 | break; | |
507 | ||
508 | case LINUX_REBOOT_CMD_HALT: | |
4a00ea1e | 509 | kernel_halt(); |
1da177e4 LT |
510 | unlock_kernel(); |
511 | do_exit(0); | |
512 | break; | |
513 | ||
514 | case LINUX_REBOOT_CMD_POWER_OFF: | |
4a00ea1e | 515 | kernel_power_off(); |
1da177e4 LT |
516 | unlock_kernel(); |
517 | do_exit(0); | |
518 | break; | |
519 | ||
520 | case LINUX_REBOOT_CMD_RESTART2: | |
521 | if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) { | |
522 | unlock_kernel(); | |
523 | return -EFAULT; | |
524 | } | |
525 | buffer[sizeof(buffer) - 1] = '\0'; | |
526 | ||
4a00ea1e | 527 | kernel_restart(buffer); |
1da177e4 LT |
528 | break; |
529 | ||
dc009d92 | 530 | case LINUX_REBOOT_CMD_KEXEC: |
4a00ea1e EB |
531 | kernel_kexec(); |
532 | unlock_kernel(); | |
533 | return -EINVAL; | |
534 | ||
1da177e4 LT |
535 | #ifdef CONFIG_SOFTWARE_SUSPEND |
536 | case LINUX_REBOOT_CMD_SW_SUSPEND: | |
537 | { | |
538 | int ret = software_suspend(); | |
539 | unlock_kernel(); | |
540 | return ret; | |
541 | } | |
542 | #endif | |
543 | ||
544 | default: | |
545 | unlock_kernel(); | |
546 | return -EINVAL; | |
547 | } | |
548 | unlock_kernel(); | |
549 | return 0; | |
550 | } | |
551 | ||
552 | static void deferred_cad(void *dummy) | |
553 | { | |
abcd9e51 | 554 | kernel_restart(NULL); |
1da177e4 LT |
555 | } |
556 | ||
557 | /* | |
558 | * This function gets called by ctrl-alt-del - ie the keyboard interrupt. | |
559 | * As it's called within an interrupt, it may NOT sync: the only choice | |
560 | * is whether to reboot at once, or just ignore the ctrl-alt-del. | |
561 | */ | |
562 | void ctrl_alt_del(void) | |
563 | { | |
564 | static DECLARE_WORK(cad_work, deferred_cad, NULL); | |
565 | ||
566 | if (C_A_D) | |
567 | schedule_work(&cad_work); | |
568 | else | |
569 | kill_proc(cad_pid, SIGINT, 1); | |
570 | } | |
571 | ||
572 | ||
573 | /* | |
574 | * Unprivileged users may change the real gid to the effective gid | |
575 | * or vice versa. (BSD-style) | |
576 | * | |
577 | * If you set the real gid at all, or set the effective gid to a value not | |
578 | * equal to the real gid, then the saved gid is set to the new effective gid. | |
579 | * | |
580 | * This makes it possible for a setgid program to completely drop its | |
581 | * privileges, which is often a useful assertion to make when you are doing | |
582 | * a security audit over a program. | |
583 | * | |
584 | * The general idea is that a program which uses just setregid() will be | |
585 | * 100% compatible with BSD. A program which uses just setgid() will be | |
586 | * 100% compatible with POSIX with saved IDs. | |
587 | * | |
588 | * SMP: There are not races, the GIDs are checked only by filesystem | |
589 | * operations (as far as semantic preservation is concerned). | |
590 | */ | |
591 | asmlinkage long sys_setregid(gid_t rgid, gid_t egid) | |
592 | { | |
593 | int old_rgid = current->gid; | |
594 | int old_egid = current->egid; | |
595 | int new_rgid = old_rgid; | |
596 | int new_egid = old_egid; | |
597 | int retval; | |
598 | ||
599 | retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE); | |
600 | if (retval) | |
601 | return retval; | |
602 | ||
603 | if (rgid != (gid_t) -1) { | |
604 | if ((old_rgid == rgid) || | |
605 | (current->egid==rgid) || | |
606 | capable(CAP_SETGID)) | |
607 | new_rgid = rgid; | |
608 | else | |
609 | return -EPERM; | |
610 | } | |
611 | if (egid != (gid_t) -1) { | |
612 | if ((old_rgid == egid) || | |
613 | (current->egid == egid) || | |
614 | (current->sgid == egid) || | |
615 | capable(CAP_SETGID)) | |
616 | new_egid = egid; | |
617 | else { | |
618 | return -EPERM; | |
619 | } | |
620 | } | |
621 | if (new_egid != old_egid) | |
622 | { | |
d6e71144 | 623 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 624 | smp_wmb(); |
1da177e4 LT |
625 | } |
626 | if (rgid != (gid_t) -1 || | |
627 | (egid != (gid_t) -1 && egid != old_rgid)) | |
628 | current->sgid = new_egid; | |
629 | current->fsgid = new_egid; | |
630 | current->egid = new_egid; | |
631 | current->gid = new_rgid; | |
632 | key_fsgid_changed(current); | |
9f46080c | 633 | proc_id_connector(current, PROC_EVENT_GID); |
1da177e4 LT |
634 | return 0; |
635 | } | |
636 | ||
637 | /* | |
638 | * setgid() is implemented like SysV w/ SAVED_IDS | |
639 | * | |
640 | * SMP: Same implicit races as above. | |
641 | */ | |
642 | asmlinkage long sys_setgid(gid_t gid) | |
643 | { | |
644 | int old_egid = current->egid; | |
645 | int retval; | |
646 | ||
647 | retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID); | |
648 | if (retval) | |
649 | return retval; | |
650 | ||
651 | if (capable(CAP_SETGID)) | |
652 | { | |
653 | if(old_egid != gid) | |
654 | { | |
d6e71144 | 655 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 656 | smp_wmb(); |
1da177e4 LT |
657 | } |
658 | current->gid = current->egid = current->sgid = current->fsgid = gid; | |
659 | } | |
660 | else if ((gid == current->gid) || (gid == current->sgid)) | |
661 | { | |
662 | if(old_egid != gid) | |
663 | { | |
d6e71144 | 664 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 665 | smp_wmb(); |
1da177e4 LT |
666 | } |
667 | current->egid = current->fsgid = gid; | |
668 | } | |
669 | else | |
670 | return -EPERM; | |
671 | ||
672 | key_fsgid_changed(current); | |
9f46080c | 673 | proc_id_connector(current, PROC_EVENT_GID); |
1da177e4 LT |
674 | return 0; |
675 | } | |
676 | ||
677 | static int set_user(uid_t new_ruid, int dumpclear) | |
678 | { | |
679 | struct user_struct *new_user; | |
680 | ||
681 | new_user = alloc_uid(new_ruid); | |
682 | if (!new_user) | |
683 | return -EAGAIN; | |
684 | ||
685 | if (atomic_read(&new_user->processes) >= | |
686 | current->signal->rlim[RLIMIT_NPROC].rlim_cur && | |
687 | new_user != &root_user) { | |
688 | free_uid(new_user); | |
689 | return -EAGAIN; | |
690 | } | |
691 | ||
692 | switch_uid(new_user); | |
693 | ||
694 | if(dumpclear) | |
695 | { | |
d6e71144 | 696 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 697 | smp_wmb(); |
1da177e4 LT |
698 | } |
699 | current->uid = new_ruid; | |
700 | return 0; | |
701 | } | |
702 | ||
703 | /* | |
704 | * Unprivileged users may change the real uid to the effective uid | |
705 | * or vice versa. (BSD-style) | |
706 | * | |
707 | * If you set the real uid at all, or set the effective uid to a value not | |
708 | * equal to the real uid, then the saved uid is set to the new effective uid. | |
709 | * | |
710 | * This makes it possible for a setuid program to completely drop its | |
711 | * privileges, which is often a useful assertion to make when you are doing | |
712 | * a security audit over a program. | |
713 | * | |
714 | * The general idea is that a program which uses just setreuid() will be | |
715 | * 100% compatible with BSD. A program which uses just setuid() will be | |
716 | * 100% compatible with POSIX with saved IDs. | |
717 | */ | |
718 | asmlinkage long sys_setreuid(uid_t ruid, uid_t euid) | |
719 | { | |
720 | int old_ruid, old_euid, old_suid, new_ruid, new_euid; | |
721 | int retval; | |
722 | ||
723 | retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE); | |
724 | if (retval) | |
725 | return retval; | |
726 | ||
727 | new_ruid = old_ruid = current->uid; | |
728 | new_euid = old_euid = current->euid; | |
729 | old_suid = current->suid; | |
730 | ||
731 | if (ruid != (uid_t) -1) { | |
732 | new_ruid = ruid; | |
733 | if ((old_ruid != ruid) && | |
734 | (current->euid != ruid) && | |
735 | !capable(CAP_SETUID)) | |
736 | return -EPERM; | |
737 | } | |
738 | ||
739 | if (euid != (uid_t) -1) { | |
740 | new_euid = euid; | |
741 | if ((old_ruid != euid) && | |
742 | (current->euid != euid) && | |
743 | (current->suid != euid) && | |
744 | !capable(CAP_SETUID)) | |
745 | return -EPERM; | |
746 | } | |
747 | ||
748 | if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0) | |
749 | return -EAGAIN; | |
750 | ||
751 | if (new_euid != old_euid) | |
752 | { | |
d6e71144 | 753 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 754 | smp_wmb(); |
1da177e4 LT |
755 | } |
756 | current->fsuid = current->euid = new_euid; | |
757 | if (ruid != (uid_t) -1 || | |
758 | (euid != (uid_t) -1 && euid != old_ruid)) | |
759 | current->suid = current->euid; | |
760 | current->fsuid = current->euid; | |
761 | ||
762 | key_fsuid_changed(current); | |
9f46080c | 763 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
764 | |
765 | return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE); | |
766 | } | |
767 | ||
768 | ||
769 | ||
770 | /* | |
771 | * setuid() is implemented like SysV with SAVED_IDS | |
772 | * | |
773 | * Note that SAVED_ID's is deficient in that a setuid root program | |
774 | * like sendmail, for example, cannot set its uid to be a normal | |
775 | * user and then switch back, because if you're root, setuid() sets | |
776 | * the saved uid too. If you don't like this, blame the bright people | |
777 | * in the POSIX committee and/or USG. Note that the BSD-style setreuid() | |
778 | * will allow a root program to temporarily drop privileges and be able to | |
779 | * regain them by swapping the real and effective uid. | |
780 | */ | |
781 | asmlinkage long sys_setuid(uid_t uid) | |
782 | { | |
783 | int old_euid = current->euid; | |
784 | int old_ruid, old_suid, new_ruid, new_suid; | |
785 | int retval; | |
786 | ||
787 | retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID); | |
788 | if (retval) | |
789 | return retval; | |
790 | ||
791 | old_ruid = new_ruid = current->uid; | |
792 | old_suid = current->suid; | |
793 | new_suid = old_suid; | |
794 | ||
795 | if (capable(CAP_SETUID)) { | |
796 | if (uid != old_ruid && set_user(uid, old_euid != uid) < 0) | |
797 | return -EAGAIN; | |
798 | new_suid = uid; | |
799 | } else if ((uid != current->uid) && (uid != new_suid)) | |
800 | return -EPERM; | |
801 | ||
802 | if (old_euid != uid) | |
803 | { | |
d6e71144 | 804 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 805 | smp_wmb(); |
1da177e4 LT |
806 | } |
807 | current->fsuid = current->euid = uid; | |
808 | current->suid = new_suid; | |
809 | ||
810 | key_fsuid_changed(current); | |
9f46080c | 811 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
812 | |
813 | return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID); | |
814 | } | |
815 | ||
816 | ||
817 | /* | |
818 | * This function implements a generic ability to update ruid, euid, | |
819 | * and suid. This allows you to implement the 4.4 compatible seteuid(). | |
820 | */ | |
821 | asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid) | |
822 | { | |
823 | int old_ruid = current->uid; | |
824 | int old_euid = current->euid; | |
825 | int old_suid = current->suid; | |
826 | int retval; | |
827 | ||
828 | retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES); | |
829 | if (retval) | |
830 | return retval; | |
831 | ||
832 | if (!capable(CAP_SETUID)) { | |
833 | if ((ruid != (uid_t) -1) && (ruid != current->uid) && | |
834 | (ruid != current->euid) && (ruid != current->suid)) | |
835 | return -EPERM; | |
836 | if ((euid != (uid_t) -1) && (euid != current->uid) && | |
837 | (euid != current->euid) && (euid != current->suid)) | |
838 | return -EPERM; | |
839 | if ((suid != (uid_t) -1) && (suid != current->uid) && | |
840 | (suid != current->euid) && (suid != current->suid)) | |
841 | return -EPERM; | |
842 | } | |
843 | if (ruid != (uid_t) -1) { | |
844 | if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0) | |
845 | return -EAGAIN; | |
846 | } | |
847 | if (euid != (uid_t) -1) { | |
848 | if (euid != current->euid) | |
849 | { | |
d6e71144 | 850 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 851 | smp_wmb(); |
1da177e4 LT |
852 | } |
853 | current->euid = euid; | |
854 | } | |
855 | current->fsuid = current->euid; | |
856 | if (suid != (uid_t) -1) | |
857 | current->suid = suid; | |
858 | ||
859 | key_fsuid_changed(current); | |
9f46080c | 860 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
861 | |
862 | return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES); | |
863 | } | |
864 | ||
865 | asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid) | |
866 | { | |
867 | int retval; | |
868 | ||
869 | if (!(retval = put_user(current->uid, ruid)) && | |
870 | !(retval = put_user(current->euid, euid))) | |
871 | retval = put_user(current->suid, suid); | |
872 | ||
873 | return retval; | |
874 | } | |
875 | ||
876 | /* | |
877 | * Same as above, but for rgid, egid, sgid. | |
878 | */ | |
879 | asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid) | |
880 | { | |
881 | int retval; | |
882 | ||
883 | retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES); | |
884 | if (retval) | |
885 | return retval; | |
886 | ||
887 | if (!capable(CAP_SETGID)) { | |
888 | if ((rgid != (gid_t) -1) && (rgid != current->gid) && | |
889 | (rgid != current->egid) && (rgid != current->sgid)) | |
890 | return -EPERM; | |
891 | if ((egid != (gid_t) -1) && (egid != current->gid) && | |
892 | (egid != current->egid) && (egid != current->sgid)) | |
893 | return -EPERM; | |
894 | if ((sgid != (gid_t) -1) && (sgid != current->gid) && | |
895 | (sgid != current->egid) && (sgid != current->sgid)) | |
896 | return -EPERM; | |
897 | } | |
898 | if (egid != (gid_t) -1) { | |
899 | if (egid != current->egid) | |
900 | { | |
d6e71144 | 901 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 902 | smp_wmb(); |
1da177e4 LT |
903 | } |
904 | current->egid = egid; | |
905 | } | |
906 | current->fsgid = current->egid; | |
907 | if (rgid != (gid_t) -1) | |
908 | current->gid = rgid; | |
909 | if (sgid != (gid_t) -1) | |
910 | current->sgid = sgid; | |
911 | ||
912 | key_fsgid_changed(current); | |
9f46080c | 913 | proc_id_connector(current, PROC_EVENT_GID); |
1da177e4 LT |
914 | return 0; |
915 | } | |
916 | ||
917 | asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid) | |
918 | { | |
919 | int retval; | |
920 | ||
921 | if (!(retval = put_user(current->gid, rgid)) && | |
922 | !(retval = put_user(current->egid, egid))) | |
923 | retval = put_user(current->sgid, sgid); | |
924 | ||
925 | return retval; | |
926 | } | |
927 | ||
928 | ||
929 | /* | |
930 | * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This | |
931 | * is used for "access()" and for the NFS daemon (letting nfsd stay at | |
932 | * whatever uid it wants to). It normally shadows "euid", except when | |
933 | * explicitly set by setfsuid() or for access.. | |
934 | */ | |
935 | asmlinkage long sys_setfsuid(uid_t uid) | |
936 | { | |
937 | int old_fsuid; | |
938 | ||
939 | old_fsuid = current->fsuid; | |
940 | if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS)) | |
941 | return old_fsuid; | |
942 | ||
943 | if (uid == current->uid || uid == current->euid || | |
944 | uid == current->suid || uid == current->fsuid || | |
945 | capable(CAP_SETUID)) | |
946 | { | |
947 | if (uid != old_fsuid) | |
948 | { | |
d6e71144 | 949 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 950 | smp_wmb(); |
1da177e4 LT |
951 | } |
952 | current->fsuid = uid; | |
953 | } | |
954 | ||
955 | key_fsuid_changed(current); | |
9f46080c | 956 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
957 | |
958 | security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS); | |
959 | ||
960 | return old_fsuid; | |
961 | } | |
962 | ||
963 | /* | |
964 |