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1da177e4 LT |
1 | /* |
2 | * linux/kernel/sys.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | */ | |
6 | ||
7 | #include <linux/config.h> | |
8 | #include <linux/module.h> | |
9 | #include <linux/mm.h> | |
10 | #include <linux/utsname.h> | |
11 | #include <linux/mman.h> | |
12 | #include <linux/smp_lock.h> | |
13 | #include <linux/notifier.h> | |
14 | #include <linux/reboot.h> | |
15 | #include <linux/prctl.h> | |
16 | #include <linux/init.h> | |
17 | #include <linux/highuid.h> | |
18 | #include <linux/fs.h> | |
dc009d92 EB |
19 | #include <linux/kernel.h> |
20 | #include <linux/kexec.h> | |
1da177e4 LT |
21 | #include <linux/workqueue.h> |
22 | #include <linux/device.h> | |
23 | #include <linux/key.h> | |
24 | #include <linux/times.h> | |
25 | #include <linux/posix-timers.h> | |
26 | #include <linux/security.h> | |
27 | #include <linux/dcookies.h> | |
28 | #include <linux/suspend.h> | |
29 | #include <linux/tty.h> | |
7ed20e1a | 30 | #include <linux/signal.h> |
9f46080c | 31 | #include <linux/cn_proc.h> |
1da177e4 LT |
32 | |
33 | #include <linux/compat.h> | |
34 | #include <linux/syscalls.h> | |
35 | ||
36 | #include <asm/uaccess.h> | |
37 | #include <asm/io.h> | |
38 | #include <asm/unistd.h> | |
39 | ||
40 | #ifndef SET_UNALIGN_CTL | |
41 | # define SET_UNALIGN_CTL(a,b) (-EINVAL) | |
42 | #endif | |
43 | #ifndef GET_UNALIGN_CTL | |
44 | # define GET_UNALIGN_CTL(a,b) (-EINVAL) | |
45 | #endif | |
46 | #ifndef SET_FPEMU_CTL | |
47 | # define SET_FPEMU_CTL(a,b) (-EINVAL) | |
48 | #endif | |
49 | #ifndef GET_FPEMU_CTL | |
50 | # define GET_FPEMU_CTL(a,b) (-EINVAL) | |
51 | #endif | |
52 | #ifndef SET_FPEXC_CTL | |
53 | # define SET_FPEXC_CTL(a,b) (-EINVAL) | |
54 | #endif | |
55 | #ifndef GET_FPEXC_CTL | |
56 | # define GET_FPEXC_CTL(a,b) (-EINVAL) | |
57 | #endif | |
58 | ||
59 | /* | |
60 | * this is where the system-wide overflow UID and GID are defined, for | |
61 | * architectures that now have 32-bit UID/GID but didn't in the past | |
62 | */ | |
63 | ||
64 | int overflowuid = DEFAULT_OVERFLOWUID; | |
65 | int overflowgid = DEFAULT_OVERFLOWGID; | |
66 | ||
67 | #ifdef CONFIG_UID16 | |
68 | EXPORT_SYMBOL(overflowuid); | |
69 | EXPORT_SYMBOL(overflowgid); | |
70 | #endif | |
71 | ||
72 | /* | |
73 | * the same as above, but for filesystems which can only store a 16-bit | |
74 | * UID and GID. as such, this is needed on all architectures | |
75 | */ | |
76 | ||
77 | int fs_overflowuid = DEFAULT_FS_OVERFLOWUID; | |
78 | int fs_overflowgid = DEFAULT_FS_OVERFLOWUID; | |
79 | ||
80 | EXPORT_SYMBOL(fs_overflowuid); | |
81 | EXPORT_SYMBOL(fs_overflowgid); | |
82 | ||
83 | /* | |
84 | * this indicates whether you can reboot with ctrl-alt-del: the default is yes | |
85 | */ | |
86 | ||
87 | int C_A_D = 1; | |
88 | int cad_pid = 1; | |
89 | ||
90 | /* | |
91 | * Notifier list for kernel code which wants to be called | |
92 | * at shutdown. This is used to stop any idling DMA operations | |
93 | * and the like. | |
94 | */ | |
95 | ||
96 | static struct notifier_block *reboot_notifier_list; | |
97 | static DEFINE_RWLOCK(notifier_lock); | |
98 | ||
99 | /** | |
100 | * notifier_chain_register - Add notifier to a notifier chain | |
101 | * @list: Pointer to root list pointer | |
102 | * @n: New entry in notifier chain | |
103 | * | |
104 | * Adds a notifier to a notifier chain. | |
105 | * | |
106 | * Currently always returns zero. | |
107 | */ | |
108 | ||
109 | int notifier_chain_register(struct notifier_block **list, struct notifier_block *n) | |
110 | { | |
111 | write_lock(¬ifier_lock); | |
112 | while(*list) | |
113 | { | |
114 | if(n->priority > (*list)->priority) | |
115 | break; | |
116 | list= &((*list)->next); | |
117 | } | |
118 | n->next = *list; | |
119 | *list=n; | |
120 | write_unlock(¬ifier_lock); | |
121 | return 0; | |
122 | } | |
123 | ||
124 | EXPORT_SYMBOL(notifier_chain_register); | |
125 | ||
126 | /** | |
127 | * notifier_chain_unregister - Remove notifier from a notifier chain | |
128 | * @nl: Pointer to root list pointer | |
129 | * @n: New entry in notifier chain | |
130 | * | |
131 | * Removes a notifier from a notifier chain. | |
132 | * | |
133 | * Returns zero on success, or %-ENOENT on failure. | |
134 | */ | |
135 | ||
136 | int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n) | |
137 | { | |
138 | write_lock(¬ifier_lock); | |
139 | while((*nl)!=NULL) | |
140 | { | |
141 | if((*nl)==n) | |
142 | { | |
143 | *nl=n->next; | |
144 | write_unlock(¬ifier_lock); | |
145 | return 0; | |
146 | } | |
147 | nl=&((*nl)->next); | |
148 | } | |
149 | write_unlock(¬ifier_lock); | |
150 | return -ENOENT; | |
151 | } | |
152 | ||
153 | EXPORT_SYMBOL(notifier_chain_unregister); | |
154 | ||
155 | /** | |
156 | * notifier_call_chain - Call functions in a notifier chain | |
157 | * @n: Pointer to root pointer of notifier chain | |
158 | * @val: Value passed unmodified to notifier function | |
159 | * @v: Pointer passed unmodified to notifier function | |
160 | * | |
161 | * Calls each function in a notifier chain in turn. | |
162 | * | |
163 | * If the return value of the notifier can be and'd | |
164 | * with %NOTIFY_STOP_MASK, then notifier_call_chain | |
165 | * will return immediately, with the return value of | |
166 | * the notifier function which halted execution. | |
167 | * Otherwise, the return value is the return value | |
168 | * of the last notifier function called. | |
169 | */ | |
170 | ||
171 | int notifier_call_chain(struct notifier_block **n, unsigned long val, void *v) | |
172 | { | |
173 | int ret=NOTIFY_DONE; | |
174 | struct notifier_block *nb = *n; | |
175 | ||
176 | while(nb) | |
177 | { | |
178 | ret=nb->notifier_call(nb,val,v); | |
179 | if(ret&NOTIFY_STOP_MASK) | |
180 | { | |
181 | return ret; | |
182 | } | |
183 | nb=nb->next; | |
184 | } | |
185 | return ret; | |
186 | } | |
187 | ||
188 | EXPORT_SYMBOL(notifier_call_chain); | |
189 | ||
190 | /** | |
191 | * register_reboot_notifier - Register function to be called at reboot time | |
192 | * @nb: Info about notifier function to be called | |
193 | * | |
194 | * Registers a function with the list of functions | |
195 | * to be called at reboot time. | |
196 | * | |
197 | * Currently always returns zero, as notifier_chain_register | |
198 | * always returns zero. | |
199 | */ | |
200 | ||
201 | int register_reboot_notifier(struct notifier_block * nb) | |
202 | { | |
203 | return notifier_chain_register(&reboot_notifier_list, nb); | |
204 | } | |
205 | ||
206 | EXPORT_SYMBOL(register_reboot_notifier); | |
207 | ||
208 | /** | |
209 | * unregister_reboot_notifier - Unregister previously registered reboot notifier | |
210 | * @nb: Hook to be unregistered | |
211 | * | |
212 | * Unregisters a previously registered reboot | |
213 | * notifier function. | |
214 | * | |
215 | * Returns zero on success, or %-ENOENT on failure. | |
216 | */ | |
217 | ||
218 | int unregister_reboot_notifier(struct notifier_block * nb) | |
219 | { | |
220 | return notifier_chain_unregister(&reboot_notifier_list, nb); | |
221 | } | |
222 | ||
223 | EXPORT_SYMBOL(unregister_reboot_notifier); | |
224 | ||
225 | static int set_one_prio(struct task_struct *p, int niceval, int error) | |
226 | { | |
227 | int no_nice; | |
228 | ||
229 | if (p->uid != current->euid && | |
230 | p->euid != current->euid && !capable(CAP_SYS_NICE)) { | |
231 | error = -EPERM; | |
232 | goto out; | |
233 | } | |
e43379f1 | 234 | if (niceval < task_nice(p) && !can_nice(p, niceval)) { |
1da177e4 LT |
235 | error = -EACCES; |
236 | goto out; | |
237 | } | |
238 | no_nice = security_task_setnice(p, niceval); | |
239 | if (no_nice) { | |
240 | error = no_nice; | |
241 | goto out; | |
242 | } | |
243 | if (error == -ESRCH) | |
244 | error = 0; | |
245 | set_user_nice(p, niceval); | |
246 | out: | |
247 | return error; | |
248 | } | |
249 | ||
250 | asmlinkage long sys_setpriority(int which, int who, int niceval) | |
251 | { | |
252 | struct task_struct *g, *p; | |
253 | struct user_struct *user; | |
254 | int error = -EINVAL; | |
255 | ||
256 | if (which > 2 || which < 0) | |
257 | goto out; | |
258 | ||
259 | /* normalize: avoid signed division (rounding problems) */ | |
260 | error = -ESRCH; | |
261 | if (niceval < -20) | |
262 | niceval = -20; | |
263 | if (niceval > 19) | |
264 | niceval = 19; | |
265 | ||
266 | read_lock(&tasklist_lock); | |
267 | switch (which) { | |
268 | case PRIO_PROCESS: | |
269 | if (!who) | |
270 | who = current->pid; | |
271 | p = find_task_by_pid(who); | |
272 | if (p) | |
273 | error = set_one_prio(p, niceval, error); | |
274 | break; | |
275 | case PRIO_PGRP: | |
276 | if (!who) | |
277 | who = process_group(current); | |
278 | do_each_task_pid(who, PIDTYPE_PGID, p) { | |
279 | error = set_one_prio(p, niceval, error); | |
280 | } while_each_task_pid(who, PIDTYPE_PGID, p); | |
281 | break; | |
282 | case PRIO_USER: | |
283 | user = current->user; | |
284 | if (!who) | |
285 | who = current->uid; | |
286 | else | |
287 | if ((who != current->uid) && !(user = find_user(who))) | |
288 | goto out_unlock; /* No processes for this user */ | |
289 | ||
290 | do_each_thread(g, p) | |
291 | if (p->uid == who) | |
292 | error = set_one_prio(p, niceval, error); | |
293 | while_each_thread(g, p); | |
294 | if (who != current->uid) | |
295 | free_uid(user); /* For find_user() */ | |
296 | break; | |
297 | } | |
298 | out_unlock: | |
299 | read_unlock(&tasklist_lock); | |
300 | out: | |
301 | return error; | |
302 | } | |
303 | ||
304 | /* | |
305 | * Ugh. To avoid negative return values, "getpriority()" will | |
306 | * not return the normal nice-value, but a negated value that | |
307 | * has been offset by 20 (ie it returns 40..1 instead of -20..19) | |
308 | * to stay compatible. | |
309 | */ | |
310 | asmlinkage long sys_getpriority(int which, int who) | |
311 | { | |
312 | struct task_struct *g, *p; | |
313 | struct user_struct *user; | |
314 | long niceval, retval = -ESRCH; | |
315 | ||
316 | if (which > 2 || which < 0) | |
317 | return -EINVAL; | |
318 | ||
319 | read_lock(&tasklist_lock); | |
320 | switch (which) { | |
321 | case PRIO_PROCESS: | |
322 | if (!who) | |
323 | who = current->pid; | |
324 | p = find_task_by_pid(who); | |
325 | if (p) { | |
326 | niceval = 20 - task_nice(p); | |
327 | if (niceval > retval) | |
328 | retval = niceval; | |
329 | } | |
330 | break; | |
331 | case PRIO_PGRP: | |
332 | if (!who) | |
333 | who = process_group(current); | |
334 | do_each_task_pid(who, PIDTYPE_PGID, p) { | |
335 | niceval = 20 - task_nice(p); | |
336 | if (niceval > retval) | |
337 | retval = niceval; | |
338 | } while_each_task_pid(who, PIDTYPE_PGID, p); | |
339 | break; | |
340 | case PRIO_USER: | |
341 | user = current->user; | |
342 | if (!who) | |
343 | who = current->uid; | |
344 | else | |
345 | if ((who != current->uid) && !(user = find_user(who))) | |
346 | goto out_unlock; /* No processes for this user */ | |
347 | ||
348 | do_each_thread(g, p) | |
349 | if (p->uid == who) { | |
350 | niceval = 20 - task_nice(p); | |
351 | if (niceval > retval) | |
352 | retval = niceval; | |
353 | } | |
354 | while_each_thread(g, p); | |
355 | if (who != current->uid) | |
356 | free_uid(user); /* for find_user() */ | |
357 | break; | |
358 | } | |
359 | out_unlock: | |
360 | read_unlock(&tasklist_lock); | |
361 | ||
362 | return retval; | |
363 | } | |
364 | ||
e4c94330 EB |
365 | /** |
366 | * emergency_restart - reboot the system | |
367 | * | |
368 | * Without shutting down any hardware or taking any locks | |
369 | * reboot the system. This is called when we know we are in | |
370 | * trouble so this is our best effort to reboot. This is | |
371 | * safe to call in interrupt context. | |
372 | */ | |
7c903473 EB |
373 | void emergency_restart(void) |
374 | { | |
375 | machine_emergency_restart(); | |
376 | } | |
377 | EXPORT_SYMBOL_GPL(emergency_restart); | |
378 | ||
e4c94330 | 379 | void kernel_restart_prepare(char *cmd) |
4a00ea1e EB |
380 | { |
381 | notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd); | |
382 | system_state = SYSTEM_RESTART; | |
4a00ea1e | 383 | device_shutdown(); |
e4c94330 | 384 | } |
1e5d5331 RD |
385 | |
386 | /** | |
387 | * kernel_restart - reboot the system | |
388 | * @cmd: pointer to buffer containing command to execute for restart | |
389 | * or NULL | |
390 | * | |
391 | * Shutdown everything and perform a clean reboot. | |
392 | * This is not safe to call in interrupt context. | |
393 | */ | |
e4c94330 EB |
394 | void kernel_restart(char *cmd) |
395 | { | |
396 | kernel_restart_prepare(cmd); | |
4a00ea1e EB |
397 | if (!cmd) { |
398 | printk(KERN_EMERG "Restarting system.\n"); | |
399 | } else { | |
400 | printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd); | |
401 | } | |
402 | printk(".\n"); | |
403 | machine_restart(cmd); | |
404 | } | |
405 | EXPORT_SYMBOL_GPL(kernel_restart); | |
406 | ||
e4c94330 EB |
407 | /** |
408 | * kernel_kexec - reboot the system | |
409 | * | |
410 | * Move into place and start executing a preloaded standalone | |
411 | * executable. If nothing was preloaded return an error. | |
412 | */ | |
4a00ea1e EB |
413 | void kernel_kexec(void) |
414 | { | |
415 | #ifdef CONFIG_KEXEC | |
416 | struct kimage *image; | |
417 | image = xchg(&kexec_image, 0); | |
418 | if (!image) { | |
419 | return; | |
420 | } | |
e4c94330 | 421 | kernel_restart_prepare(NULL); |
4a00ea1e EB |
422 | printk(KERN_EMERG "Starting new kernel\n"); |
423 | machine_shutdown(); | |
424 | machine_kexec(image); | |
425 | #endif | |
426 | } | |
427 | EXPORT_SYMBOL_GPL(kernel_kexec); | |
428 | ||
e4c94330 EB |
429 | /** |
430 | * kernel_halt - halt the system | |
431 | * | |
432 | * Shutdown everything and perform a clean system halt. | |
433 | */ | |
434 | void kernel_halt_prepare(void) | |
4a00ea1e EB |
435 | { |
436 | notifier_call_chain(&reboot_notifier_list, SYS_HALT, NULL); | |
437 | system_state = SYSTEM_HALT; | |
4a00ea1e | 438 | device_shutdown(); |
e4c94330 EB |
439 | } |
440 | void kernel_halt(void) | |
441 | { | |
442 | kernel_halt_prepare(); | |
4a00ea1e EB |
443 | printk(KERN_EMERG "System halted.\n"); |
444 | machine_halt(); | |
445 | } | |
446 | EXPORT_SYMBOL_GPL(kernel_halt); | |
447 | ||
e4c94330 EB |
448 | /** |
449 | * kernel_power_off - power_off the system | |
450 | * | |
451 | * Shutdown everything and perform a clean system power_off. | |
452 | */ | |
453 | void kernel_power_off_prepare(void) | |
4a00ea1e EB |
454 | { |
455 | notifier_call_chain(&reboot_notifier_list, SYS_POWER_OFF, NULL); | |
456 | system_state = SYSTEM_POWER_OFF; | |
4a00ea1e | 457 | device_shutdown(); |
e4c94330 EB |
458 | } |
459 | void kernel_power_off(void) | |
460 | { | |
461 | kernel_power_off_prepare(); | |
4a00ea1e EB |
462 | printk(KERN_EMERG "Power down.\n"); |
463 | machine_power_off(); | |
464 | } | |
465 | EXPORT_SYMBOL_GPL(kernel_power_off); | |
1da177e4 LT |
466 | |
467 | /* | |
468 | * Reboot system call: for obvious reasons only root may call it, | |
469 | * and even root needs to set up some magic numbers in the registers | |
470 | * so that some mistake won't make this reboot the whole machine. | |
471 | * You can also set the meaning of the ctrl-alt-del-key here. | |
472 | * | |
473 | * reboot doesn't sync: do that yourself before calling this. | |
474 | */ | |
475 | asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg) | |
476 | { | |
477 | char buffer[256]; | |
478 | ||
479 | /* We only trust the superuser with rebooting the system. */ | |
480 | if (!capable(CAP_SYS_BOOT)) | |
481 | return -EPERM; | |
482 | ||
483 | /* For safety, we require "magic" arguments. */ | |
484 | if (magic1 != LINUX_REBOOT_MAGIC1 || | |
485 | (magic2 != LINUX_REBOOT_MAGIC2 && | |
486 | magic2 != LINUX_REBOOT_MAGIC2A && | |
487 | magic2 != LINUX_REBOOT_MAGIC2B && | |
488 | magic2 != LINUX_REBOOT_MAGIC2C)) | |
489 | return -EINVAL; | |
490 | ||
491 | lock_kernel(); | |
492 | switch (cmd) { | |
493 | case LINUX_REBOOT_CMD_RESTART: | |
4a00ea1e | 494 | kernel_restart(NULL); |
1da177e4 LT |
495 | break; |
496 | ||
497 | case LINUX_REBOOT_CMD_CAD_ON: | |
498 | C_A_D = 1; | |
499 | break; | |
500 | ||
501 | case LINUX_REBOOT_CMD_CAD_OFF: | |
502 | C_A_D = 0; | |
503 | break; | |
504 | ||
505 | case LINUX_REBOOT_CMD_HALT: | |
4a00ea1e | 506 | kernel_halt(); |
1da177e4 LT |
507 | unlock_kernel(); |
508 | do_exit(0); | |
509 | break; | |
510 | ||
511 | case LINUX_REBOOT_CMD_POWER_OFF: | |
4a00ea1e | 512 | kernel_power_off(); |
1da177e4 LT |
513 | unlock_kernel(); |
514 | do_exit(0); | |
515 | break; | |
516 | ||
517 | case LINUX_REBOOT_CMD_RESTART2: | |
518 | if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) { | |
519 | unlock_kernel(); | |
520 | return -EFAULT; | |
521 | } | |
522 | buffer[sizeof(buffer) - 1] = '\0'; | |
523 | ||
4a00ea1e | 524 | kernel_restart(buffer); |
1da177e4 LT |
525 | break; |
526 | ||
dc009d92 | 527 | case LINUX_REBOOT_CMD_KEXEC: |
4a00ea1e EB |
528 | kernel_kexec(); |
529 | unlock_kernel(); | |
530 | return -EINVAL; | |
531 | ||
1da177e4 LT |
532 | #ifdef CONFIG_SOFTWARE_SUSPEND |
533 | case LINUX_REBOOT_CMD_SW_SUSPEND: | |
534 | { | |
535 | int ret = software_suspend(); | |
536 | unlock_kernel(); | |
537 | return ret; | |
538 | } | |
539 | #endif | |
540 | ||
541 | default: | |
542 | unlock_kernel(); | |
543 | return -EINVAL; | |
544 | } | |
545 | unlock_kernel(); | |
546 | return 0; | |
547 | } | |
548 | ||
549 | static void deferred_cad(void *dummy) | |
550 | { | |
abcd9e51 | 551 | kernel_restart(NULL); |
1da177e4 LT |
552 | } |
553 | ||
554 | /* | |
555 | * This function gets called by ctrl-alt-del - ie the keyboard interrupt. | |
556 | * As it's called within an interrupt, it may NOT sync: the only choice | |
557 | * is whether to reboot at once, or just ignore the ctrl-alt-del. | |
558 | */ | |
559 | void ctrl_alt_del(void) | |
560 | { | |
561 | static DECLARE_WORK(cad_work, deferred_cad, NULL); | |
562 | ||
563 | if (C_A_D) | |
564 | schedule_work(&cad_work); | |
565 | else | |
566 | kill_proc(cad_pid, SIGINT, 1); | |
567 | } | |
568 | ||
569 | ||
570 | /* | |
571 | * Unprivileged users may change the real gid to the effective gid | |
572 | * or vice versa. (BSD-style) | |
573 | * | |
574 | * If you set the real gid at all, or set the effective gid to a value not | |
575 | * equal to the real gid, then the saved gid is set to the new effective gid. | |
576 | * | |
577 | * This makes it possible for a setgid program to completely drop its | |
578 | * privileges, which is often a useful assertion to make when you are doing | |
579 | * a security audit over a program. | |
580 | * | |
581 | * The general idea is that a program which uses just setregid() will be | |
582 | * 100% compatible with BSD. A program which uses just setgid() will be | |
583 | * 100% compatible with POSIX with saved IDs. | |
584 | * | |
585 | * SMP: There are not races, the GIDs are checked only by filesystem | |
586 | * operations (as far as semantic preservation is concerned). | |
587 | */ | |
588 | asmlinkage long sys_setregid(gid_t rgid, gid_t egid) | |
589 | { | |
590 | int old_rgid = current->gid; | |
591 | int old_egid = current->egid; | |
592 | int new_rgid = old_rgid; | |
593 | int new_egid = old_egid; | |
594 | int retval; | |
595 | ||
596 | retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE); | |
597 | if (retval) | |
598 | return retval; | |
599 | ||
600 | if (rgid != (gid_t) -1) { | |
601 | if ((old_rgid == rgid) || | |
602 | (current->egid==rgid) || | |
603 | capable(CAP_SETGID)) | |
604 | new_rgid = rgid; | |
605 | else | |
606 | return -EPERM; | |
607 | } | |
608 | if (egid != (gid_t) -1) { | |
609 | if ((old_rgid == egid) || | |
610 | (current->egid == egid) || | |
611 | (current->sgid == egid) || | |
612 | capable(CAP_SETGID)) | |
613 | new_egid = egid; | |
614 | else { | |
615 | return -EPERM; | |
616 | } | |
617 | } | |
618 | if (new_egid != old_egid) | |
619 | { | |
d6e71144 | 620 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 621 | smp_wmb(); |
1da177e4 LT |
622 | } |
623 | if (rgid != (gid_t) -1 || | |
624 | (egid != (gid_t) -1 && egid != old_rgid)) | |
625 | current->sgid = new_egid; | |
626 | current->fsgid = new_egid; | |
627 | current->egid = new_egid; | |
628 | current->gid = new_rgid; | |
629 | key_fsgid_changed(current); | |
9f46080c | 630 | proc_id_connector(current, PROC_EVENT_GID); |
1da177e4 LT |
631 | return 0; |
632 | } | |
633 | ||
634 | /* | |
635 | * setgid() is implemented like SysV w/ SAVED_IDS | |
636 | * | |
637 | * SMP: Same implicit races as above. | |
638 | */ | |
639 | asmlinkage long sys_setgid(gid_t gid) | |
640 | { | |
641 | int old_egid = current->egid; | |
642 | int retval; | |
643 | ||
644 | retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID); | |
645 | if (retval) | |
646 | return retval; | |
647 | ||
648 | if (capable(CAP_SETGID)) | |
649 | { | |
650 | if(old_egid != gid) | |
651 | { | |
d6e71144 | 652 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 653 | smp_wmb(); |
1da177e4 LT |
654 | } |
655 | current->gid = current->egid = current->sgid = current->fsgid = gid; | |
656 | } | |
657 | else if ((gid == current->gid) || (gid == current->sgid)) | |
658 | { | |
659 | if(old_egid != gid) | |
660 | { | |
d6e71144 | 661 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 662 | smp_wmb(); |
1da177e4 LT |
663 | } |
664 | current->egid = current->fsgid = gid; | |
665 | } | |
666 | else | |
667 | return -EPERM; | |
668 | ||
669 | key_fsgid_changed(current); | |
9f46080c | 670 | proc_id_connector(current, PROC_EVENT_GID); |
1da177e4 LT |
671 | return 0; |
672 | } | |
673 | ||
674 | static int set_user(uid_t new_ruid, int dumpclear) | |
675 | { | |
676 | struct user_struct *new_user; | |
677 | ||
678 | new_user = alloc_uid(new_ruid); | |
679 | if (!new_user) | |
680 | return -EAGAIN; | |
681 | ||
682 | if (atomic_read(&new_user->processes) >= | |
683 | current->signal->rlim[RLIMIT_NPROC].rlim_cur && | |
684 | new_user != &root_user) { | |
685 | free_uid(new_user); | |
686 | return -EAGAIN; | |
687 | } | |
688 | ||
689 | switch_uid(new_user); | |
690 | ||
691 | if(dumpclear) | |
692 | { | |
d6e71144 | 693 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 694 | smp_wmb(); |
1da177e4 LT |
695 | } |
696 | current->uid = new_ruid; | |
697 | return 0; | |
698 | } | |
699 | ||
700 | /* | |
701 | * Unprivileged users may change the real uid to the effective uid | |
702 | * or vice versa. (BSD-style) | |
703 | * | |
704 | * If you set the real uid at all, or set the effective uid to a value not | |
705 | * equal to the real uid, then the saved uid is set to the new effective uid. | |
706 | * | |
707 | * This makes it possible for a setuid program to completely drop its | |
708 | * privileges, which is often a useful assertion to make when you are doing | |
709 | * a security audit over a program. | |
710 | * | |
711 | * The general idea is that a program which uses just setreuid() will be | |
712 | * 100% compatible with BSD. A program which uses just setuid() will be | |
713 | * 100% compatible with POSIX with saved IDs. | |
714 | */ | |
715 | asmlinkage long sys_setreuid(uid_t ruid, uid_t euid) | |
716 | { | |
717 | int old_ruid, old_euid, old_suid, new_ruid, new_euid; | |
718 | int retval; | |
719 | ||
720 | retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE); | |
721 | if (retval) | |
722 | return retval; | |
723 | ||
724 | new_ruid = old_ruid = current->uid; | |
725 | new_euid = old_euid = current->euid; | |
726 | old_suid = current->suid; | |
727 | ||
728 | if (ruid != (uid_t) -1) { | |
729 | new_ruid = ruid; | |
730 | if ((old_ruid != ruid) && | |
731 | (current->euid != ruid) && | |
732 | !capable(CAP_SETUID)) | |
733 | return -EPERM; | |
734 | } | |
735 | ||
736 | if (euid != (uid_t) -1) { | |
737 | new_euid = euid; | |
738 | if ((old_ruid != euid) && | |
739 | (current->euid != euid) && | |
740 | (current->suid != euid) && | |
741 | !capable(CAP_SETUID)) | |
742 | return -EPERM; | |
743 | } | |
744 | ||
745 | if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0) | |
746 | return -EAGAIN; | |
747 | ||
748 | if (new_euid != old_euid) | |
749 | { | |
d6e71144 | 750 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 751 | smp_wmb(); |
1da177e4 LT |
752 | } |
753 | current->fsuid = current->euid = new_euid; | |
754 | if (ruid != (uid_t) -1 || | |
755 | (euid != (uid_t) -1 && euid != old_ruid)) | |
756 | current->suid = current->euid; | |
757 | current->fsuid = current->euid; | |
758 | ||
759 | key_fsuid_changed(current); | |
9f46080c | 760 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
761 | |
762 | return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE); | |
763 | } | |
764 | ||
765 | ||
766 | ||
767 | /* | |
768 | * setuid() is implemented like SysV with SAVED_IDS | |
769 | * | |
770 | * Note that SAVED_ID's is deficient in that a setuid root program | |
771 | * like sendmail, for example, cannot set its uid to be a normal | |
772 | * user and then switch back, because if you're root, setuid() sets | |
773 | * the saved uid too. If you don't like this, blame the bright people | |
774 | * in the POSIX committee and/or USG. Note that the BSD-style setreuid() | |
775 | * will allow a root program to temporarily drop privileges and be able to | |
776 | * regain them by swapping the real and effective uid. | |
777 | */ | |
778 | asmlinkage long sys_setuid(uid_t uid) | |
779 | { | |
780 | int old_euid = current->euid; | |
781 | int old_ruid, old_suid, new_ruid, new_suid; | |
782 | int retval; | |
783 | ||
784 | retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID); | |
785 | if (retval) | |
786 | return retval; | |
787 | ||
788 | old_ruid = new_ruid = current->uid; | |
789 | old_suid = current->suid; | |
790 | new_suid = old_suid; | |
791 | ||
792 | if (capable(CAP_SETUID)) { | |
793 | if (uid != old_ruid && set_user(uid, old_euid != uid) < 0) | |
794 | return -EAGAIN; | |
795 | new_suid = uid; | |
796 | } else if ((uid != current->uid) && (uid != new_suid)) | |
797 | return -EPERM; | |
798 | ||
799 | if (old_euid != uid) | |
800 | { | |
d6e71144 | 801 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 802 | smp_wmb(); |
1da177e4 LT |
803 | } |
804 | current->fsuid = current->euid = uid; | |
805 | current->suid = new_suid; | |
806 | ||
807 | key_fsuid_changed(current); | |
9f46080c | 808 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
809 | |
810 | return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID); | |
811 | } | |
812 | ||
813 | ||
814 | /* | |
815 | * This function implements a generic ability to update ruid, euid, | |
816 | * and suid. This allows you to implement the 4.4 compatible seteuid(). | |
817 | */ | |
818 | asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid) | |
819 | { | |
820 | int old_ruid = current->uid; | |
821 | int old_euid = current->euid; | |
822 | int old_suid = current->suid; | |
823 | int retval; | |
824 | ||
825 | retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES); | |
826 | if (retval) | |
827 | return retval; | |
828 | ||
829 | if (!capable(CAP_SETUID)) { | |
830 | if ((ruid != (uid_t) -1) && (ruid != current->uid) && | |
831 | (ruid != current->euid) && (ruid != current->suid)) | |
832 | return -EPERM; | |
833 | if ((euid != (uid_t) -1) && (euid != current->uid) && | |
834 | (euid != current->euid) && (euid != current->suid)) | |
835 | return -EPERM; | |
836 | if ((suid != (uid_t) -1) && (suid != current->uid) && | |
837 | (suid != current->euid) && (suid != current->suid)) | |
838 | return -EPERM; | |
839 | } | |
840 | if (ruid != (uid_t) -1) { | |
841 | if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0) | |
842 | return -EAGAIN; | |
843 | } | |
844 | if (euid != (uid_t) -1) { | |
845 | if (euid != current->euid) | |
846 | { | |
d6e71144 | 847 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 848 | smp_wmb(); |
1da177e4 LT |
849 | } |
850 | current->euid = euid; | |
851 | } | |
852 | current->fsuid = current->euid; | |
853 | if (suid != (uid_t) -1) | |
854 | current->suid = suid; | |
855 | ||
856 | key_fsuid_changed(current); | |
9f46080c | 857 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
858 | |
859 | return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES); | |
860 | } | |
861 | ||
862 | asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid) | |
863 | { | |
864 | int retval; | |
865 | ||
866 | if (!(retval = put_user(current->uid, ruid)) && | |
867 | !(retval = put_user(current->euid, euid))) | |
868 | retval = put_user(current->suid, suid); | |
869 | ||
870 | return retval; | |
871 | } | |
872 | ||
873 | /* | |
874 | * Same as above, but for rgid, egid, sgid. | |
875 | */ | |
876 | asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid) | |
877 | { | |
878 | int retval; | |
879 | ||
880 | retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES); | |
881 | if (retval) | |
882 | return retval; | |
883 | ||
884 | if (!capable(CAP_SETGID)) { | |
885 | if ((rgid != (gid_t) -1) && (rgid != current->gid) && | |
886 | (rgid != current->egid) && (rgid != current->sgid)) | |
887 | return -EPERM; | |
888 | if ((egid != (gid_t) -1) && (egid != current->gid) && | |
889 | (egid != current->egid) && (egid != current->sgid)) | |
890 | return -EPERM; | |
891 | if ((sgid != (gid_t) -1) && (sgid != current->gid) && | |
892 | (sgid != current->egid) && (sgid != current->sgid)) | |
893 | return -EPERM; | |
894 | } | |
895 | if (egid != (gid_t) -1) { | |
896 | if (egid != current->egid) | |
897 | { | |
d6e71144 | 898 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 899 | smp_wmb(); |
1da177e4 LT |
900 | } |
901 | current->egid = egid; | |
902 | } | |
903 | current->fsgid = current->egid; | |
904 | if (rgid != (gid_t) -1) | |
905 | current->gid = rgid; | |
906 | if (sgid != (gid_t) -1) | |
907 | current->sgid = sgid; | |
908 | ||
909 | key_fsgid_changed(current); | |
9f46080c | 910 | proc_id_connector(current, PROC_EVENT_GID); |
1da177e4 LT |
911 | return 0; |
912 | } | |
913 | ||
914 | asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid) | |
915 | { | |
916 | int retval; | |
917 | ||
918 | if (!(retval = put_user(current->gid, rgid)) && | |
919 | !(retval = put_user(current->egid, egid))) | |
920 | retval = put_user(current->sgid, sgid); | |
921 | ||
922 | return retval; | |
923 | } | |
924 | ||
925 | ||
926 | /* | |
927 | * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This | |
928 | * is used for "access()" and for the NFS daemon (letting nfsd stay at | |
929 | * whatever uid it wants to). It normally shadows "euid", except when | |
930 | * explicitly set by setfsuid() or for access.. | |
931 | */ | |
932 | asmlinkage long sys_setfsuid(uid_t uid) | |
933 | { | |
934 | int old_fsuid; | |
935 | ||
936 | old_fsuid = current->fsuid; | |
937 | if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS)) | |
938 | return old_fsuid; | |
939 | ||
940 | if (uid == current->uid || uid == current->euid || | |
941 | uid == current->suid || uid == current->fsuid || | |
942 | capable(CAP_SETUID)) | |
943 | { | |
944 | if (uid != old_fsuid) | |
945 | { | |
d6e71144 | 946 | current->mm->dumpable = suid_dumpable; |
d59dd462 | 947 | smp_wmb(); |
1da177e4 LT |
948 | } |
949 | current->fsuid = uid; | |
950 | } | |
951 | ||
952 | key_fsuid_changed(current); | |
9f46080c | 953 | proc_id_connector(current, PROC_EVENT_UID); |
1da177e4 LT |
954 | |
955 | security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS); | |
956 | ||
957 | return old_fsuid; | |
958 | } | |
959 | ||
960 | /* | |
961 |