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Greg Kroah-Hartmanb2441312017-11-01 15:07:57 +01001// SPDX-License-Identifier: GPL-2.0
Linus Torvalds1da177e2005-04-16 15:20:36 -07002/*
3 * linux/kernel/capability.c
4 *
5 * Copyright (C) 1997 Andrew Main <zefram@fysh.org>
6 *
Andrew Morgan72c2d582007-10-18 03:05:59 -07007 * Integrated into 2.1.97+, Andrew G. Morgan <morgan@kernel.org>
Linus Torvalds1da177e2005-04-16 15:20:36 -07008 * 30 May 2002: Cleanup, Robert M. Love <rml@tech9.net>
Daniel Walker314f70f2007-10-18 03:06:08 -07009 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070010
Joe Perchesf5645d32014-02-21 14:19:30 -080011#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12
Eric Parise68b75a02008-11-11 21:48:22 +110013#include <linux/audit.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080014#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/mm.h>
Paul Gortmaker9984de12011-05-23 14:51:41 -040016#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/security.h>
18#include <linux/syscalls.h>
Serge E. Hallynb460cbc2007-10-18 23:39:52 -070019#include <linux/pid_namespace.h>
Serge E. Hallyn34867402011-03-23 16:43:17 -070020#include <linux/user_namespace.h>
Linus Torvalds7c0f6ba2016-12-24 11:46:01 -080021#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022
Serge E. Hallyn1f29fae2008-11-05 16:08:52 -060023int file_caps_enabled = 1;
24
25static int __init file_caps_disable(char *str)
26{
27 file_caps_enabled = 0;
28 return 1;
29}
30__setup("no_file_caps", file_caps_disable);
Serge E. Hallyn1f29fae2008-11-05 16:08:52 -060031
Iulia Manda28138932015-04-15 16:16:41 -070032#ifdef CONFIG_MULTIUSER
Andrew Morgane338d262008-02-04 22:29:42 -080033/*
34 * More recent versions of libcap are available from:
35 *
36 * http://www.kernel.org/pub/linux/libs/security/linux-privs/
37 */
38
39static void warn_legacy_capability_use(void)
40{
Joe Perchesf5645d32014-02-21 14:19:30 -080041 char name[sizeof(current->comm)];
Andrew Morgane338d262008-02-04 22:29:42 -080042
Joe Perchesf5645d32014-02-21 14:19:30 -080043 pr_info_once("warning: `%s' uses 32-bit capabilities (legacy support in use)\n",
44 get_task_comm(name, current));
Andrew Morgane338d262008-02-04 22:29:42 -080045}
46
47/*
Andrew G. Morganca05a992008-05-27 22:05:17 -070048 * Version 2 capabilities worked fine, but the linux/capability.h file
49 * that accompanied their introduction encouraged their use without
50 * the necessary user-space source code changes. As such, we have
51 * created a version 3 with equivalent functionality to version 2, but
52 * with a header change to protect legacy source code from using
53 * version 2 when it wanted to use version 1. If your system has code
54 * that trips the following warning, it is using version 2 specific
55 * capabilities and may be doing so insecurely.
56 *
57 * The remedy is to either upgrade your version of libcap (to 2.10+,
58 * if the application is linked against it), or recompile your
59 * application with modern kernel headers and this warning will go
60 * away.
61 */
62
63static void warn_deprecated_v2(void)
64{
Joe Perchesf5645d32014-02-21 14:19:30 -080065 char name[sizeof(current->comm)];
Andrew G. Morganca05a992008-05-27 22:05:17 -070066
Joe Perchesf5645d32014-02-21 14:19:30 -080067 pr_info_once("warning: `%s' uses deprecated v2 capabilities in a way that may be insecure\n",
68 get_task_comm(name, current));
Andrew G. Morganca05a992008-05-27 22:05:17 -070069}
70
71/*
72 * Version check. Return the number of u32s in each capability flag
73 * array, or a negative value on error.
74 */
75static int cap_validate_magic(cap_user_header_t header, unsigned *tocopy)
76{
77 __u32 version;
78
79 if (get_user(version, &header->version))
80 return -EFAULT;
81
82 switch (version) {
83 case _LINUX_CAPABILITY_VERSION_1:
84 warn_legacy_capability_use();
85 *tocopy = _LINUX_CAPABILITY_U32S_1;
86 break;
87 case _LINUX_CAPABILITY_VERSION_2:
88 warn_deprecated_v2();
Gustavo A. R. Silvadf561f662020-08-23 17:36:59 -050089 fallthrough; /* v3 is otherwise equivalent to v2 */
Andrew G. Morganca05a992008-05-27 22:05:17 -070090 case _LINUX_CAPABILITY_VERSION_3:
91 *tocopy = _LINUX_CAPABILITY_U32S_3;
92 break;
93 default:
94 if (put_user((u32)_KERNEL_CAPABILITY_VERSION, &header->version))
95 return -EFAULT;
96 return -EINVAL;
97 }
98
99 return 0;
100}
101
Andrew G. Morganab763c72008-07-23 21:28:25 -0700102/*
David Howellsd84f4f92008-11-14 10:39:23 +1100103 * The only thing that can change the capabilities of the current
104 * process is the current process. As such, we can't be in this code
105 * at the same time as we are in the process of setting capabilities
106 * in this process. The net result is that we can limit our use of
107 * locks to when we are reading the caps of another process.
Andrew G. Morganab763c72008-07-23 21:28:25 -0700108 */
109static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp,
110 kernel_cap_t *pIp, kernel_cap_t *pPp)
111{
112 int ret;
113
114 if (pid && (pid != task_pid_vnr(current))) {
Khadija Kamran6672efb2023-08-07 11:59:29 +0500115 const struct task_struct *target;
Andrew G. Morganab763c72008-07-23 21:28:25 -0700116
Thomas Gleixner86fc80f2009-12-09 17:13:31 +0100117 rcu_read_lock();
Andrew G. Morganab763c72008-07-23 21:28:25 -0700118
119 target = find_task_by_vpid(pid);
120 if (!target)
121 ret = -ESRCH;
122 else
123 ret = security_capget(target, pEp, pIp, pPp);
124
Thomas Gleixner86fc80f2009-12-09 17:13:31 +0100125 rcu_read_unlock();
Andrew G. Morganab763c72008-07-23 21:28:25 -0700126 } else
127 ret = security_capget(current, pEp, pIp, pPp);
128
129 return ret;
130}
131
Randy Dunlap207a7ba2005-07-27 11:45:10 -0700132/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 * sys_capget - get the capabilities of a given process.
Randy Dunlap207a7ba2005-07-27 11:45:10 -0700134 * @header: pointer to struct that contains capability version and
135 * target pid data
136 * @dataptr: pointer to struct that contains the effective, permitted,
137 * and inheritable capabilities that are returned
138 *
139 * Returns 0 on success and < 0 on error.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 */
Heiko Carstensb290ebe2009-01-14 14:14:06 +0100141SYSCALL_DEFINE2(capget, cap_user_header_t, header, cap_user_data_t, dataptr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142{
Daniel Walker314f70f2007-10-18 03:06:08 -0700143 int ret = 0;
144 pid_t pid;
Andrew Morgane338d262008-02-04 22:29:42 -0800145 unsigned tocopy;
146 kernel_cap_t pE, pI, pP;
Linus Torvaldsf122a082023-02-28 11:39:09 -0800147 struct __user_cap_data_struct kdata[2];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148
Andrew G. Morganca05a992008-05-27 22:05:17 -0700149 ret = cap_validate_magic(header, &tocopy);
Andrew G. Morganc4a5af52009-11-23 04:57:52 +0000150 if ((dataptr == NULL) || (ret != 0))
151 return ((dataptr == NULL) && (ret == -EINVAL)) ? 0 : ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152
Daniel Walker314f70f2007-10-18 03:06:08 -0700153 if (get_user(pid, &header->pid))
154 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155
Daniel Walker314f70f2007-10-18 03:06:08 -0700156 if (pid < 0)
157 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158
Andrew G. Morganab763c72008-07-23 21:28:25 -0700159 ret = cap_get_target_pid(pid, &pE, &pI, &pP);
Linus Torvaldsf122a082023-02-28 11:39:09 -0800160 if (ret)
161 return ret;
Andrew Morgane338d262008-02-04 22:29:42 -0800162
Linus Torvaldsf122a082023-02-28 11:39:09 -0800163 /*
164 * Annoying legacy format with 64-bit capabilities exposed
165 * as two sets of 32-bit fields, so we need to split the
166 * capability values up.
167 */
168 kdata[0].effective = pE.val; kdata[1].effective = pE.val >> 32;
169 kdata[0].permitted = pP.val; kdata[1].permitted = pP.val >> 32;
170 kdata[0].inheritable = pI.val; kdata[1].inheritable = pI.val >> 32;
Andrew Morgane338d262008-02-04 22:29:42 -0800171
Linus Torvaldsf122a082023-02-28 11:39:09 -0800172 /*
173 * Note, in the case, tocopy < _KERNEL_CAPABILITY_U32S,
174 * we silently drop the upper capabilities here. This
175 * has the effect of making older libcap
176 * implementations implicitly drop upper capability
177 * bits when they perform a: capget/modify/capset
178 * sequence.
179 *
180 * This behavior is considered fail-safe
181 * behavior. Upgrading the application to a newer
182 * version of libcap will enable access to the newer
183 * capabilities.
184 *
185 * An alternative would be to return an error here
186 * (-ERANGE), but that causes legacy applications to
187 * unexpectedly fail; the capget/modify/capset aborts
188 * before modification is attempted and the application
189 * fails.
190 */
191 if (copy_to_user(dataptr, kdata, tocopy * sizeof(kdata[0])))
192 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193
Linus Torvaldsf122a082023-02-28 11:39:09 -0800194 return 0;
195}
196
197static kernel_cap_t mk_kernel_cap(u32 low, u32 high)
198{
199 return (kernel_cap_t) { (low | ((u64)high << 32)) & CAP_VALID_MASK };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200}
201
Randy Dunlap207a7ba2005-07-27 11:45:10 -0700202/**
Andrew G. Morganab763c72008-07-23 21:28:25 -0700203 * sys_capset - set capabilities for a process or (*) a group of processes
Randy Dunlap207a7ba2005-07-27 11:45:10 -0700204 * @header: pointer to struct that contains capability version and
205 * target pid data
206 * @data: pointer to struct that contains the effective, permitted,
207 * and inheritable capabilities
208 *
David Howells1cdcbec2008-11-14 10:39:14 +1100209 * Set capabilities for the current process only. The ability to any other
210 * process(es) has been deprecated and removed.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 *
212 * The restrictions on setting capabilities are specified as:
213 *
David Howells1cdcbec2008-11-14 10:39:14 +1100214 * I: any raised capabilities must be a subset of the old permitted
215 * P: any raised capabilities must be a subset of the old permitted
216 * E: must be set to a subset of new permitted
Randy Dunlap207a7ba2005-07-27 11:45:10 -0700217 *
218 * Returns 0 on success and < 0 on error.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 */
Heiko Carstensb290ebe2009-01-14 14:14:06 +0100220SYSCALL_DEFINE2(capset, cap_user_header_t, header, const cap_user_data_t, data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221{
Linus Torvaldsf122a082023-02-28 11:39:09 -0800222 struct __user_cap_data_struct kdata[2] = { { 0, }, };
223 unsigned tocopy, copybytes;
Daniel Walker314f70f2007-10-18 03:06:08 -0700224 kernel_cap_t inheritable, permitted, effective;
David Howellsd84f4f92008-11-14 10:39:23 +1100225 struct cred *new;
Daniel Walker314f70f2007-10-18 03:06:08 -0700226 int ret;
227 pid_t pid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228
Andrew G. Morganca05a992008-05-27 22:05:17 -0700229 ret = cap_validate_magic(header, &tocopy);
230 if (ret != 0)
231 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232
Daniel Walker314f70f2007-10-18 03:06:08 -0700233 if (get_user(pid, &header->pid))
234 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235
David Howells1cdcbec2008-11-14 10:39:14 +1100236 /* may only affect current now */
237 if (pid != 0 && pid != task_pid_vnr(current))
238 return -EPERM;
239
Arjan van de Ven825332e2009-10-14 08:17:36 +1100240 copybytes = tocopy * sizeof(struct __user_cap_data_struct);
241 if (copybytes > sizeof(kdata))
242 return -EFAULT;
243
244 if (copy_from_user(&kdata, data, copybytes))
Daniel Walker314f70f2007-10-18 03:06:08 -0700245 return -EFAULT;
Andrew Morgane338d262008-02-04 22:29:42 -0800246
Linus Torvaldsf122a082023-02-28 11:39:09 -0800247 effective = mk_kernel_cap(kdata[0].effective, kdata[1].effective);
248 permitted = mk_kernel_cap(kdata[0].permitted, kdata[1].permitted);
249 inheritable = mk_kernel_cap(kdata[0].inheritable, kdata[1].inheritable);
Eric Paris7d8b6c62014-07-23 15:36:26 -0400250
David Howellsd84f4f92008-11-14 10:39:23 +1100251 new = prepare_creds();
252 if (!new)
253 return -ENOMEM;
254
255 ret = security_capset(new, current_cred(),
256 &effective, &inheritable, &permitted);
257 if (ret < 0)
258 goto error;
259
Eric W. Biedermanca24a232013-03-19 00:02:25 -0700260 audit_log_capset(new, current_cred());
Eric Parise68b75a02008-11-11 21:48:22 +1100261
David Howellsd84f4f92008-11-14 10:39:23 +1100262 return commit_creds(new);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263
David Howellsd84f4f92008-11-14 10:39:23 +1100264error:
265 abort_creds(new);
Daniel Walker314f70f2007-10-18 03:06:08 -0700266 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267}
Chris Wright12b59892006-03-25 03:07:41 -0800268
David Howells5cd9c582008-08-14 11:37:28 +0100269/**
Eric Paris25e75702012-01-03 12:25:15 -0500270 * has_ns_capability - Does a task have a capability in a specific user ns
Serge E. Hallyn32632452011-03-23 16:43:21 -0700271 * @t: The task in question
272 * @ns: target user namespace
273 * @cap: The capability to be tested for
274 *
275 * Return true if the specified task has the given superior capability
276 * currently in effect to the specified user namespace, false if not.
277 *
278 * Note that this does not set PF_SUPERPRIV on the task.
279 */
280bool has_ns_capability(struct task_struct *t,
281 struct user_namespace *ns, int cap)
282{
Eric Paris2920a842012-01-03 12:25:15 -0500283 int ret;
284
285 rcu_read_lock();
Micah Mortonc1a85a02019-01-07 16:10:53 -0800286 ret = security_capable(__task_cred(t), ns, cap, CAP_OPT_NONE);
Eric Paris2920a842012-01-03 12:25:15 -0500287 rcu_read_unlock();
Serge E. Hallyn32632452011-03-23 16:43:21 -0700288
289 return (ret == 0);
290}
291
292/**
Eric Paris25e75702012-01-03 12:25:15 -0500293 * has_capability - Does a task have a capability in init_user_ns
294 * @t: The task in question
295 * @cap: The capability to be tested for
296 *
297 * Return true if the specified task has the given superior capability
298 * currently in effect to the initial user namespace, false if not.
299 *
300 * Note that this does not set PF_SUPERPRIV on the task.
301 */
302bool has_capability(struct task_struct *t, int cap)
303{
304 return has_ns_capability(t, &init_user_ns, cap);
305}
Jike Song19c816e2017-01-12 16:52:02 +0800306EXPORT_SYMBOL(has_capability);
Eric Paris25e75702012-01-03 12:25:15 -0500307
308/**
Eric Paris7b61d642012-01-03 12:25:15 -0500309 * has_ns_capability_noaudit - Does a task have a capability (unaudited)
310 * in a specific user ns.
311 * @t: The task in question
312 * @ns: target user namespace
313 * @cap: The capability to be tested for
314 *
315 * Return true if the specified task has the given superior capability
316 * currently in effect to the specified user namespace, false if not.
317 * Do not write an audit message for the check.
318 *
319 * Note that this does not set PF_SUPERPRIV on the task.
320 */
321bool has_ns_capability_noaudit(struct task_struct *t,
322 struct user_namespace *ns, int cap)
323{
324 int ret;
325
326 rcu_read_lock();
Micah Mortonc1a85a02019-01-07 16:10:53 -0800327 ret = security_capable(__task_cred(t), ns, cap, CAP_OPT_NOAUDIT);
Eric Paris7b61d642012-01-03 12:25:15 -0500328 rcu_read_unlock();
329
330 return (ret == 0);
331}
332
333/**
334 * has_capability_noaudit - Does a task have a capability (unaudited) in the
335 * initial user ns
Serge E. Hallyn32632452011-03-23 16:43:21 -0700336 * @t: The task in question
337 * @cap: The capability to be tested for
338 *
339 * Return true if the specified task has the given superior capability
340 * currently in effect to init_user_ns, false if not. Don't write an
341 * audit message for the check.
342 *
343 * Note that this does not set PF_SUPERPRIV on the task.
344 */
345bool has_capability_noaudit(struct task_struct *t, int cap)
346{
Eric Paris7b61d642012-01-03 12:25:15 -0500347 return has_ns_capability_noaudit(t, &init_user_ns, cap);
Serge E. Hallyn32632452011-03-23 16:43:21 -0700348}
Darrick J. Wongeba05492022-02-25 16:18:30 -0800349EXPORT_SYMBOL(has_capability_noaudit);
Serge E. Hallyn32632452011-03-23 16:43:21 -0700350
Micah Mortonc1a85a02019-01-07 16:10:53 -0800351static bool ns_capable_common(struct user_namespace *ns,
352 int cap,
353 unsigned int opts)
Tyler Hicks98f368e2016-06-02 23:43:21 -0500354{
355 int capable;
356
357 if (unlikely(!cap_valid(cap))) {
358 pr_crit("capable() called with invalid cap=%u\n", cap);
359 BUG();
360 }
361
Micah Mortonc1a85a02019-01-07 16:10:53 -0800362 capable = security_capable(current_cred(), ns, cap, opts);
Tyler Hicks98f368e2016-06-02 23:43:21 -0500363 if (capable == 0) {
364 current->flags |= PF_SUPERPRIV;
365 return true;
366 }
367 return false;
368}
369
Serge E. Hallyn32632452011-03-23 16:43:21 -0700370/**
Serge E. Hallyn34867402011-03-23 16:43:17 -0700371 * ns_capable - Determine if the current task has a superior capability in effect
372 * @ns: The usernamespace we want the capability in
373 * @cap: The capability to be tested for
374 *
375 * Return true if the current task has the given superior capability currently
376 * available for use, false if not.
377 *
378 * This sets PF_SUPERPRIV on the task if the capability is available on the
379 * assumption that it's about to be used.
380 */
381bool ns_capable(struct user_namespace *ns, int cap)
Chris Wright12b59892006-03-25 03:07:41 -0800382{
Micah Mortonc1a85a02019-01-07 16:10:53 -0800383 return ns_capable_common(ns, cap, CAP_OPT_NONE);
Chris Wright12b59892006-03-25 03:07:41 -0800384}
Serge E. Hallyn34867402011-03-23 16:43:17 -0700385EXPORT_SYMBOL(ns_capable);
386
Tyler Hicks98f368e2016-06-02 23:43:21 -0500387/**
388 * ns_capable_noaudit - Determine if the current task has a superior capability
389 * (unaudited) in effect
390 * @ns: The usernamespace we want the capability in
391 * @cap: The capability to be tested for
392 *
393 * Return true if the current task has the given superior capability currently
394 * available for use, false if not.
395 *
396 * This sets PF_SUPERPRIV on the task if the capability is available on the
397 * assumption that it's about to be used.
398 */
399bool ns_capable_noaudit(struct user_namespace *ns, int cap)
400{
Micah Mortonc1a85a02019-01-07 16:10:53 -0800401 return ns_capable_common(ns, cap, CAP_OPT_NOAUDIT);
Tyler Hicks98f368e2016-06-02 23:43:21 -0500402}
403EXPORT_SYMBOL(ns_capable_noaudit);
Iulia Manda28138932015-04-15 16:16:41 -0700404
405/**
Micah Morton40852272019-01-22 14:42:09 -0800406 * ns_capable_setid - Determine if the current task has a superior capability
407 * in effect, while signalling that this check is being done from within a
Thomas Cedeno111767c2020-07-16 19:13:57 +0000408 * setid or setgroups syscall.
Micah Morton40852272019-01-22 14:42:09 -0800409 * @ns: The usernamespace we want the capability in
410 * @cap: The capability to be tested for
411 *
412 * Return true if the current task has the given superior capability currently
413 * available for use, false if not.
414 *
415 * This sets PF_SUPERPRIV on the task if the capability is available on the
416 * assumption that it's about to be used.
417 */
418bool ns_capable_setid(struct user_namespace *ns, int cap)
419{
420 return ns_capable_common(ns, cap, CAP_OPT_INSETID);
421}
422EXPORT_SYMBOL(ns_capable_setid);
423
424/**
Iulia Manda28138932015-04-15 16:16:41 -0700425 * capable - Determine if the current task has a superior capability in effect
426 * @cap: The capability to be tested for
427 *
428 * Return true if the current task has the given superior capability currently
429 * available for use, false if not.
430 *
431 * This sets PF_SUPERPRIV on the task if the capability is available on the
432 * assumption that it's about to be used.
433 */
434bool capable(int cap)
435{
436 return ns_capable(&init_user_ns, cap);
437}
438EXPORT_SYMBOL(capable);
439#endif /* CONFIG_MULTIUSER */
440
Serge E. Hallyn34867402011-03-23 16:43:17 -0700441/**
Linus Torvalds935d8aa2013-04-14 10:06:31 -0700442 * file_ns_capable - Determine if the file's opener had a capability in effect
443 * @file: The file we want to check
444 * @ns: The usernamespace we want the capability in
445 * @cap: The capability to be tested for
446 *
447 * Return true if task that opened the file had a capability in effect
448 * when the file was opened.
449 *
450 * This does not set PF_SUPERPRIV because the caller may not
451 * actually be privileged.
452 */
Fabian Fredericka6c8c692014-06-04 16:11:19 -0700453bool file_ns_capable(const struct file *file, struct user_namespace *ns,
454 int cap)
Linus Torvalds935d8aa2013-04-14 10:06:31 -0700455{
Micah Mortonc1a85a02019-01-07 16:10:53 -0800456
Linus Torvalds935d8aa2013-04-14 10:06:31 -0700457 if (WARN_ON_ONCE(!cap_valid(cap)))
458 return false;
459
Micah Mortonc1a85a02019-01-07 16:10:53 -0800460 if (security_capable(file->f_cred, ns, cap, CAP_OPT_NONE) == 0)
Linus Torvalds935d8aa2013-04-14 10:06:31 -0700461 return true;
462
463 return false;
464}
465EXPORT_SYMBOL(file_ns_capable);
466
467/**
Eric W. Biedermanf84df2a2016-11-16 22:06:51 -0600468 * privileged_wrt_inode_uidgid - Do capabilities in the namespace work over the inode?
469 * @ns: The user namespace in question
Gaosheng Cuia4951082023-05-11 09:27:15 +0800470 * @idmap: idmap of the mount @inode was found from
Eric W. Biedermanf84df2a2016-11-16 22:06:51 -0600471 * @inode: The inode in question
472 *
473 * Return true if the inode uid and gid are within the namespace.
474 */
Christian Brauner0558c1b2021-01-21 14:19:23 +0100475bool privileged_wrt_inode_uidgid(struct user_namespace *ns,
Christian Brauner9452e932023-01-13 12:49:27 +0100476 struct mnt_idmap *idmap,
Christian Brauner0558c1b2021-01-21 14:19:23 +0100477 const struct inode *inode)
Eric W. Biedermanf84df2a2016-11-16 22:06:51 -0600478{
Christian Braunere67fe632023-01-13 12:49:30 +0100479 return vfsuid_has_mapping(ns, i_uid_into_vfsuid(idmap, inode)) &&
480 vfsgid_has_mapping(ns, i_gid_into_vfsgid(idmap, inode));
Eric W. Biedermanf84df2a2016-11-16 22:06:51 -0600481}
482
483/**
Andy Lutomirski23adbe12014-06-10 12:45:42 -0700484 * capable_wrt_inode_uidgid - Check nsown_capable and uid and gid mapped
Gaosheng Cuia4951082023-05-11 09:27:15 +0800485 * @idmap: idmap of the mount @inode was found from
Eric W. Biederman1a48e2a2011-11-14 16:24:06 -0800486 * @inode: The inode in question
487 * @cap: The capability in question
488 *
Andy Lutomirski23adbe12014-06-10 12:45:42 -0700489 * Return true if the current task has the given capability targeted at
490 * its own user namespace and that the given inode's uid and gid are
491 * mapped into the current user namespace.
Eric W. Biederman1a48e2a2011-11-14 16:24:06 -0800492 */
Christian Brauner9452e932023-01-13 12:49:27 +0100493bool capable_wrt_inode_uidgid(struct mnt_idmap *idmap,
Christian Brauner0558c1b2021-01-21 14:19:23 +0100494 const struct inode *inode, int cap)
Eric W. Biederman1a48e2a2011-11-14 16:24:06 -0800495{
496 struct user_namespace *ns = current_user_ns();
497
Christian Brauner0558c1b2021-01-21 14:19:23 +0100498 return ns_capable(ns, cap) &&
Christian Brauner9452e932023-01-13 12:49:27 +0100499 privileged_wrt_inode_uidgid(ns, idmap, inode);
Eric W. Biederman1a48e2a2011-11-14 16:24:06 -0800500}
Andy Lutomirski23adbe12014-06-10 12:45:42 -0700501EXPORT_SYMBOL(capable_wrt_inode_uidgid);
Eric W. Biederman64b875f2016-11-14 18:48:07 -0600502
503/**
504 * ptracer_capable - Determine if the ptracer holds CAP_SYS_PTRACE in the namespace
505 * @tsk: The task that may be ptraced
506 * @ns: The user namespace to search for CAP_SYS_PTRACE in
507 *
508 * Return true if the task that is ptracing the current task had CAP_SYS_PTRACE
509 * in the specified user namespace.
510 */
511bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns)
512{
513 int ret = 0; /* An absent tracer adds no restrictions */
514 const struct cred *cred;
Micah Mortonc1a85a02019-01-07 16:10:53 -0800515
Eric W. Biederman64b875f2016-11-14 18:48:07 -0600516 rcu_read_lock();
517 cred = rcu_dereference(tsk->ptracer_cred);
518 if (cred)
Micah Mortonc1a85a02019-01-07 16:10:53 -0800519 ret = security_capable(cred, ns, CAP_SYS_PTRACE,
520 CAP_OPT_NOAUDIT);
Eric W. Biederman64b875f2016-11-14 18:48:07 -0600521 rcu_read_unlock();
522 return (ret == 0);
523}