1 // SPDX-License-Identifier: GPL-2.0 <<
2 /* 1 /*
3 * linux/kernel/capability.c 2 * linux/kernel/capability.c
4 * 3 *
5 * Copyright (C) 1997 Andrew Main <zefram@fys 4 * Copyright (C) 1997 Andrew Main <zefram@fysh.org>
6 * 5 *
7 * Integrated into 2.1.97+, Andrew G. Morgan 6 * Integrated into 2.1.97+, Andrew G. Morgan <morgan@kernel.org>
8 * 30 May 2002: Cleanup, Robert M. Love <rml@t 7 * 30 May 2002: Cleanup, Robert M. Love <rml@tech9.net>
9 */ 8 */
10 9
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt <<
12 <<
13 #include <linux/audit.h> 10 #include <linux/audit.h>
14 #include <linux/capability.h> 11 #include <linux/capability.h>
15 #include <linux/mm.h> 12 #include <linux/mm.h>
16 #include <linux/export.h> 13 #include <linux/export.h>
17 #include <linux/security.h> 14 #include <linux/security.h>
18 #include <linux/syscalls.h> 15 #include <linux/syscalls.h>
19 #include <linux/pid_namespace.h> 16 #include <linux/pid_namespace.h>
20 #include <linux/user_namespace.h> 17 #include <linux/user_namespace.h>
21 #include <linux/uaccess.h> !! 18 #include <asm/uaccess.h>
>> 19
>> 20 /*
>> 21 * Leveraged for setting/resetting capabilities
>> 22 */
>> 23
>> 24 const kernel_cap_t __cap_empty_set = CAP_EMPTY_SET;
>> 25
>> 26 EXPORT_SYMBOL(__cap_empty_set);
22 27
23 int file_caps_enabled = 1; 28 int file_caps_enabled = 1;
24 29
25 static int __init file_caps_disable(char *str) 30 static int __init file_caps_disable(char *str)
26 { 31 {
27 file_caps_enabled = 0; 32 file_caps_enabled = 0;
28 return 1; 33 return 1;
29 } 34 }
30 __setup("no_file_caps", file_caps_disable); 35 __setup("no_file_caps", file_caps_disable);
31 36
32 #ifdef CONFIG_MULTIUSER <<
33 /* 37 /*
34 * More recent versions of libcap are availabl 38 * More recent versions of libcap are available from:
35 * 39 *
36 * http://www.kernel.org/pub/linux/libs/secu 40 * http://www.kernel.org/pub/linux/libs/security/linux-privs/
37 */ 41 */
38 42
39 static void warn_legacy_capability_use(void) 43 static void warn_legacy_capability_use(void)
40 { 44 {
41 char name[sizeof(current->comm)]; !! 45 static int warned;
42 !! 46 if (!warned) {
43 pr_info_once("warning: `%s' uses 32-bi !! 47 char name[sizeof(current->comm)];
44 get_task_comm(name, curre !! 48
>> 49 printk(KERN_INFO "warning: `%s' uses 32-bit capabilities"
>> 50 " (legacy support in use)\n",
>> 51 get_task_comm(name, current));
>> 52 warned = 1;
>> 53 }
45 } 54 }
46 55
47 /* 56 /*
48 * Version 2 capabilities worked fine, but the 57 * Version 2 capabilities worked fine, but the linux/capability.h file
49 * that accompanied their introduction encoura 58 * that accompanied their introduction encouraged their use without
50 * the necessary user-space source code change 59 * the necessary user-space source code changes. As such, we have
51 * created a version 3 with equivalent functio 60 * created a version 3 with equivalent functionality to version 2, but
52 * with a header change to protect legacy sour 61 * with a header change to protect legacy source code from using
53 * version 2 when it wanted to use version 1. 62 * version 2 when it wanted to use version 1. If your system has code
54 * that trips the following warning, it is usi 63 * that trips the following warning, it is using version 2 specific
55 * capabilities and may be doing so insecurely 64 * capabilities and may be doing so insecurely.
56 * 65 *
57 * The remedy is to either upgrade your versio 66 * The remedy is to either upgrade your version of libcap (to 2.10+,
58 * if the application is linked against it), o 67 * if the application is linked against it), or recompile your
59 * application with modern kernel headers and 68 * application with modern kernel headers and this warning will go
60 * away. 69 * away.
61 */ 70 */
62 71
63 static void warn_deprecated_v2(void) 72 static void warn_deprecated_v2(void)
64 { 73 {
65 char name[sizeof(current->comm)]; !! 74 static int warned;
>> 75
>> 76 if (!warned) {
>> 77 char name[sizeof(current->comm)];
66 78
67 pr_info_once("warning: `%s' uses depre !! 79 printk(KERN_INFO "warning: `%s' uses deprecated v2"
68 get_task_comm(name, curre !! 80 " capabilities in a way that may be insecure.\n",
>> 81 get_task_comm(name, current));
>> 82 warned = 1;
>> 83 }
69 } 84 }
70 85
71 /* 86 /*
72 * Version check. Return the number of u32s in 87 * Version check. Return the number of u32s in each capability flag
73 * array, or a negative value on error. 88 * array, or a negative value on error.
74 */ 89 */
75 static int cap_validate_magic(cap_user_header_ 90 static int cap_validate_magic(cap_user_header_t header, unsigned *tocopy)
76 { 91 {
77 __u32 version; 92 __u32 version;
78 93
79 if (get_user(version, &header->version 94 if (get_user(version, &header->version))
80 return -EFAULT; 95 return -EFAULT;
81 96
82 switch (version) { 97 switch (version) {
83 case _LINUX_CAPABILITY_VERSION_1: 98 case _LINUX_CAPABILITY_VERSION_1:
84 warn_legacy_capability_use(); 99 warn_legacy_capability_use();
85 *tocopy = _LINUX_CAPABILITY_U3 100 *tocopy = _LINUX_CAPABILITY_U32S_1;
86 break; 101 break;
87 case _LINUX_CAPABILITY_VERSION_2: 102 case _LINUX_CAPABILITY_VERSION_2:
88 warn_deprecated_v2(); 103 warn_deprecated_v2();
89 fallthrough; /* v3 is other !! 104 /*
>> 105 * fall through - v3 is otherwise equivalent to v2.
>> 106 */
90 case _LINUX_CAPABILITY_VERSION_3: 107 case _LINUX_CAPABILITY_VERSION_3:
91 *tocopy = _LINUX_CAPABILITY_U3 108 *tocopy = _LINUX_CAPABILITY_U32S_3;
92 break; 109 break;
93 default: 110 default:
94 if (put_user((u32)_KERNEL_CAPA 111 if (put_user((u32)_KERNEL_CAPABILITY_VERSION, &header->version))
95 return -EFAULT; 112 return -EFAULT;
96 return -EINVAL; 113 return -EINVAL;
97 } 114 }
98 115
99 return 0; 116 return 0;
100 } 117 }
101 118
102 /* 119 /*
103 * The only thing that can change the capabili 120 * The only thing that can change the capabilities of the current
104 * process is the current process. As such, we 121 * 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 o 122 * at the same time as we are in the process of setting capabilities
106 * in this process. The net result is that we 123 * in this process. The net result is that we can limit our use of
107 * locks to when we are reading the caps of an 124 * locks to when we are reading the caps of another process.
108 */ 125 */
109 static inline int cap_get_target_pid(pid_t pid 126 static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp,
110 kernel_ca 127 kernel_cap_t *pIp, kernel_cap_t *pPp)
111 { 128 {
112 int ret; 129 int ret;
113 130
114 if (pid && (pid != task_pid_vnr(curren 131 if (pid && (pid != task_pid_vnr(current))) {
115 const struct task_struct *targ !! 132 struct task_struct *target;
116 133
117 rcu_read_lock(); 134 rcu_read_lock();
118 135
119 target = find_task_by_vpid(pid 136 target = find_task_by_vpid(pid);
120 if (!target) 137 if (!target)
121 ret = -ESRCH; 138 ret = -ESRCH;
122 else 139 else
123 ret = security_capget( 140 ret = security_capget(target, pEp, pIp, pPp);
124 141
125 rcu_read_unlock(); 142 rcu_read_unlock();
126 } else 143 } else
127 ret = security_capget(current, 144 ret = security_capget(current, pEp, pIp, pPp);
128 145
129 return ret; 146 return ret;
130 } 147 }
131 148
132 /** 149 /**
133 * sys_capget - get the capabilities of a give 150 * sys_capget - get the capabilities of a given process.
134 * @header: pointer to struct that contains ca 151 * @header: pointer to struct that contains capability version and
135 * target pid data 152 * target pid data
136 * @dataptr: pointer to struct that contains t 153 * @dataptr: pointer to struct that contains the effective, permitted,
137 * and inheritable capabilities that are 154 * and inheritable capabilities that are returned
138 * 155 *
139 * Returns 0 on success and < 0 on error. 156 * Returns 0 on success and < 0 on error.
140 */ 157 */
141 SYSCALL_DEFINE2(capget, cap_user_header_t, hea 158 SYSCALL_DEFINE2(capget, cap_user_header_t, header, cap_user_data_t, dataptr)
142 { 159 {
143 int ret = 0; 160 int ret = 0;
144 pid_t pid; 161 pid_t pid;
145 unsigned tocopy; 162 unsigned tocopy;
146 kernel_cap_t pE, pI, pP; 163 kernel_cap_t pE, pI, pP;
147 struct __user_cap_data_struct kdata[2] <<
148 164
149 ret = cap_validate_magic(header, &toco 165 ret = cap_validate_magic(header, &tocopy);
150 if ((dataptr == NULL) || (ret != 0)) 166 if ((dataptr == NULL) || (ret != 0))
151 return ((dataptr == NULL) && ( 167 return ((dataptr == NULL) && (ret == -EINVAL)) ? 0 : ret;
152 168
153 if (get_user(pid, &header->pid)) 169 if (get_user(pid, &header->pid))
154 return -EFAULT; 170 return -EFAULT;
155 171
156 if (pid < 0) 172 if (pid < 0)
157 return -EINVAL; 173 return -EINVAL;
158 174
159 ret = cap_get_target_pid(pid, &pE, &pI 175 ret = cap_get_target_pid(pid, &pE, &pI, &pP);
160 if (ret) !! 176 if (!ret) {
161 return ret; !! 177 struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
162 !! 178 unsigned i;
163 /* !! 179
164 * Annoying legacy format with 64-bit !! 180 for (i = 0; i < tocopy; i++) {
165 * as two sets of 32-bit fields, so we !! 181 kdata[i].effective = pE.cap[i];
166 * capability values up. !! 182 kdata[i].permitted = pP.cap[i];
167 */ !! 183 kdata[i].inheritable = pI.cap[i];
168 kdata[0].effective = pE.val; kdata[1 !! 184 }
169 kdata[0].permitted = pP.val; kdata[1 !! 185
170 kdata[0].inheritable = pI.val; kdata[1 !! 186 /*
171 !! 187 * Note, in the case, tocopy < _KERNEL_CAPABILITY_U32S,
172 /* !! 188 * we silently drop the upper capabilities here. This
173 * Note, in the case, tocopy < _KERNEL !! 189 * has the effect of making older libcap
174 * we silently drop the upper capabili !! 190 * implementations implicitly drop upper capability
175 * has the effect of making older libc !! 191 * bits when they perform a: capget/modify/capset
176 * implementations implicitly drop upp !! 192 * sequence.
177 * bits when they perform a: capget/mo !! 193 *
178 * sequence. !! 194 * This behavior is considered fail-safe
179 * !! 195 * behavior. Upgrading the application to a newer
180 * This behavior is considered fail-sa !! 196 * version of libcap will enable access to the newer
181 * behavior. Upgrading the application !! 197 * capabilities.
182 * version of libcap will enable acces !! 198 *
183 * capabilities. !! 199 * An alternative would be to return an error here
184 * !! 200 * (-ERANGE), but that causes legacy applications to
185 * An alternative would be to return a !! 201 * unexpectidly fail; the capget/modify/capset aborts
186 * (-ERANGE), but that causes legacy a !! 202 * before modification is attempted and the application
187 * unexpectedly fail; the capget/modif !! 203 * fails.
188 * before modification is attempted an !! 204 */
189 * fails. !! 205 if (copy_to_user(dataptr, kdata, tocopy
190 */ !! 206 * sizeof(struct __user_cap_data_struct))) {
191 if (copy_to_user(dataptr, kdata, tocop !! 207 return -EFAULT;
192 return -EFAULT; !! 208 }
193 !! 209 }
194 return 0; <<
195 } <<
196 210
197 static kernel_cap_t mk_kernel_cap(u32 low, u32 !! 211 return ret;
198 { <<
199 return (kernel_cap_t) { (low | ((u64)h <<
200 } 212 }
201 213
202 /** 214 /**
203 * sys_capset - set capabilities for a process 215 * sys_capset - set capabilities for a process or (*) a group of processes
204 * @header: pointer to struct that contains ca 216 * @header: pointer to struct that contains capability version and
205 * target pid data 217 * target pid data
206 * @data: pointer to struct that contains the 218 * @data: pointer to struct that contains the effective, permitted,
207 * and inheritable capabilities 219 * and inheritable capabilities
208 * 220 *
209 * Set capabilities for the current process on 221 * Set capabilities for the current process only. The ability to any other
210 * process(es) has been deprecated and removed 222 * process(es) has been deprecated and removed.
211 * 223 *
212 * The restrictions on setting capabilities ar 224 * The restrictions on setting capabilities are specified as:
213 * 225 *
214 * I: any raised capabilities must be a subset 226 * I: any raised capabilities must be a subset of the old permitted
215 * P: any raised capabilities must be a subset 227 * P: any raised capabilities must be a subset of the old permitted
216 * E: must be set to a subset of new permitted 228 * E: must be set to a subset of new permitted
217 * 229 *
218 * Returns 0 on success and < 0 on error. 230 * Returns 0 on success and < 0 on error.
219 */ 231 */
220 SYSCALL_DEFINE2(capset, cap_user_header_t, hea 232 SYSCALL_DEFINE2(capset, cap_user_header_t, header, const cap_user_data_t, data)
221 { 233 {
222 struct __user_cap_data_struct kdata[2] !! 234 struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
223 unsigned tocopy, copybytes; !! 235 unsigned i, tocopy, copybytes;
224 kernel_cap_t inheritable, permitted, e 236 kernel_cap_t inheritable, permitted, effective;
225 struct cred *new; 237 struct cred *new;
226 int ret; 238 int ret;
227 pid_t pid; 239 pid_t pid;
228 240
229 ret = cap_validate_magic(header, &toco 241 ret = cap_validate_magic(header, &tocopy);
230 if (ret != 0) 242 if (ret != 0)
231 return ret; 243 return ret;
232 244
233 if (get_user(pid, &header->pid)) 245 if (get_user(pid, &header->pid))
234 return -EFAULT; 246 return -EFAULT;
235 247
236 /* may only affect current now */ 248 /* may only affect current now */
237 if (pid != 0 && pid != task_pid_vnr(cu 249 if (pid != 0 && pid != task_pid_vnr(current))
238 return -EPERM; 250 return -EPERM;
239 251
240 copybytes = tocopy * sizeof(struct __u 252 copybytes = tocopy * sizeof(struct __user_cap_data_struct);
241 if (copybytes > sizeof(kdata)) 253 if (copybytes > sizeof(kdata))
242 return -EFAULT; 254 return -EFAULT;
243 255
244 if (copy_from_user(&kdata, data, copyb 256 if (copy_from_user(&kdata, data, copybytes))
245 return -EFAULT; 257 return -EFAULT;
246 258
247 effective = mk_kernel_cap(kdata[0].e !! 259 for (i = 0; i < tocopy; i++) {
248 permitted = mk_kernel_cap(kdata[0].p !! 260 effective.cap[i] = kdata[i].effective;
249 inheritable = mk_kernel_cap(kdata[0].i !! 261 permitted.cap[i] = kdata[i].permitted;
>> 262 inheritable.cap[i] = kdata[i].inheritable;
>> 263 }
>> 264 while (i < _KERNEL_CAPABILITY_U32S) {
>> 265 effective.cap[i] = 0;
>> 266 permitted.cap[i] = 0;
>> 267 inheritable.cap[i] = 0;
>> 268 i++;
>> 269 }
>> 270
>> 271 effective.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK;
>> 272 permitted.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK;
>> 273 inheritable.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK;
250 274
251 new = prepare_creds(); 275 new = prepare_creds();
252 if (!new) 276 if (!new)
253 return -ENOMEM; 277 return -ENOMEM;
254 278
255 ret = security_capset(new, current_cre 279 ret = security_capset(new, current_cred(),
256 &effective, &inh 280 &effective, &inheritable, &permitted);
257 if (ret < 0) 281 if (ret < 0)
258 goto error; 282 goto error;
259 283
260 audit_log_capset(new, current_cred()); !! 284 audit_log_capset(pid, new, current_cred());
261 285
262 return commit_creds(new); 286 return commit_creds(new);
263 287
264 error: 288 error:
265 abort_creds(new); 289 abort_creds(new);
266 return ret; 290 return ret;
267 } 291 }
268 292
269 /** 293 /**
270 * has_ns_capability - Does a task have a capa 294 * has_ns_capability - Does a task have a capability in a specific user ns
271 * @t: The task in question 295 * @t: The task in question
272 * @ns: target user namespace 296 * @ns: target user namespace
273 * @cap: The capability to be tested for 297 * @cap: The capability to be tested for
274 * 298 *
275 * Return true if the specified task has the g 299 * Return true if the specified task has the given superior capability
276 * currently in effect to the specified user n 300 * currently in effect to the specified user namespace, false if not.
277 * 301 *
278 * Note that this does not set PF_SUPERPRIV on 302 * Note that this does not set PF_SUPERPRIV on the task.
279 */ 303 */
280 bool has_ns_capability(struct task_struct *t, 304 bool has_ns_capability(struct task_struct *t,
281 struct user_namespace * 305 struct user_namespace *ns, int cap)
282 { 306 {
283 int ret; 307 int ret;
284 308
285 rcu_read_lock(); 309 rcu_read_lock();
286 ret = security_capable(__task_cred(t), !! 310 ret = security_capable(__task_cred(t), ns, cap);
287 rcu_read_unlock(); 311 rcu_read_unlock();
288 312
289 return (ret == 0); 313 return (ret == 0);
290 } 314 }
291 315
292 /** 316 /**
293 * has_capability - Does a task have a capabil 317 * has_capability - Does a task have a capability in init_user_ns
294 * @t: The task in question 318 * @t: The task in question
295 * @cap: The capability to be tested for 319 * @cap: The capability to be tested for
296 * 320 *
297 * Return true if the specified task has the g 321 * Return true if the specified task has the given superior capability
298 * currently in effect to the initial user nam 322 * currently in effect to the initial user namespace, false if not.
299 * 323 *
300 * Note that this does not set PF_SUPERPRIV on 324 * Note that this does not set PF_SUPERPRIV on the task.
301 */ 325 */
302 bool has_capability(struct task_struct *t, int 326 bool has_capability(struct task_struct *t, int cap)
303 { 327 {
304 return has_ns_capability(t, &init_user 328 return has_ns_capability(t, &init_user_ns, cap);
305 } 329 }
306 EXPORT_SYMBOL(has_capability); <<
307 330
308 /** 331 /**
309 * has_ns_capability_noaudit - Does a task hav 332 * has_ns_capability_noaudit - Does a task have a capability (unaudited)
310 * in a specific user ns. 333 * in a specific user ns.
311 * @t: The task in question 334 * @t: The task in question
312 * @ns: target user namespace 335 * @ns: target user namespace
313 * @cap: The capability to be tested for 336 * @cap: The capability to be tested for
314 * 337 *
315 * Return true if the specified task has the g 338 * Return true if the specified task has the given superior capability
316 * currently in effect to the specified user n 339 * currently in effect to the specified user namespace, false if not.
317 * Do not write an audit message for the check 340 * Do not write an audit message for the check.
318 * 341 *
319 * Note that this does not set PF_SUPERPRIV on 342 * Note that this does not set PF_SUPERPRIV on the task.
320 */ 343 */
321 bool has_ns_capability_noaudit(struct task_str 344 bool has_ns_capability_noaudit(struct task_struct *t,
322 struct user_nam 345 struct user_namespace *ns, int cap)
323 { 346 {
324 int ret; 347 int ret;
325 348
326 rcu_read_lock(); 349 rcu_read_lock();
327 ret = security_capable(__task_cred(t), !! 350 ret = security_capable_noaudit(__task_cred(t), ns, cap);
328 rcu_read_unlock(); 351 rcu_read_unlock();
329 352
330 return (ret == 0); 353 return (ret == 0);
331 } 354 }
332 355
333 /** 356 /**
334 * has_capability_noaudit - Does a task have a 357 * has_capability_noaudit - Does a task have a capability (unaudited) in the
335 * initial user ns 358 * initial user ns
336 * @t: The task in question 359 * @t: The task in question
337 * @cap: The capability to be tested for 360 * @cap: The capability to be tested for
338 * 361 *
339 * Return true if the specified task has the g 362 * Return true if the specified task has the given superior capability
340 * currently in effect to init_user_ns, false 363 * currently in effect to init_user_ns, false if not. Don't write an
341 * audit message for the check. 364 * audit message for the check.
342 * 365 *
343 * Note that this does not set PF_SUPERPRIV on 366 * Note that this does not set PF_SUPERPRIV on the task.
344 */ 367 */
345 bool has_capability_noaudit(struct task_struct 368 bool has_capability_noaudit(struct task_struct *t, int cap)
346 { 369 {
347 return has_ns_capability_noaudit(t, &i 370 return has_ns_capability_noaudit(t, &init_user_ns, cap);
348 } 371 }
349 EXPORT_SYMBOL(has_capability_noaudit); <<
350 <<
351 static bool ns_capable_common(struct user_name <<
352 int cap, <<
353 unsigned int opt <<
354 { <<
355 int capable; <<
356 <<
357 if (unlikely(!cap_valid(cap))) { <<
358 pr_crit("capable() called with <<
359 BUG(); <<
360 } <<
361 <<
362 capable = security_capable(current_cre <<
363 if (capable == 0) { <<
364 current->flags |= PF_SUPERPRIV <<
365 return true; <<
366 } <<
367 return false; <<
368 } <<
369 372
370 /** 373 /**
371 * ns_capable - Determine if the current task 374 * ns_capable - Determine if the current task has a superior capability in effect
372 * @ns: The usernamespace we want the capabil 375 * @ns: The usernamespace we want the capability in
373 * @cap: The capability to be tested for 376 * @cap: The capability to be tested for
374 * 377 *
375 * Return true if the current task has the giv 378 * Return true if the current task has the given superior capability currently
376 * available for use, false if not. 379 * available for use, false if not.
377 * 380 *
378 * This sets PF_SUPERPRIV on the task if the c 381 * This sets PF_SUPERPRIV on the task if the capability is available on the
379 * assumption that it's about to be used. 382 * assumption that it's about to be used.
380 */ 383 */
381 bool ns_capable(struct user_namespace *ns, int 384 bool ns_capable(struct user_namespace *ns, int cap)
382 { 385 {
383 return ns_capable_common(ns, cap, CAP_ !! 386 if (unlikely(!cap_valid(cap))) {
>> 387 printk(KERN_CRIT "capable() called with invalid cap=%u\n", cap);
>> 388 BUG();
>> 389 }
>> 390
>> 391 if (security_capable(current_cred(), ns, cap) == 0) {
>> 392 current->flags |= PF_SUPERPRIV;
>> 393 return true;
>> 394 }
>> 395 return false;
384 } 396 }
385 EXPORT_SYMBOL(ns_capable); 397 EXPORT_SYMBOL(ns_capable);
386 398
387 /** 399 /**
388 * ns_capable_noaudit - Determine if the curre !! 400 * file_ns_capable - Determine if the file's opener had a capability in effect
389 * (unaudited) in effect !! 401 * @file: The file we want to check
390 * @ns: The usernamespace we want the capabil 402 * @ns: The usernamespace we want the capability in
391 * @cap: The capability to be tested for 403 * @cap: The capability to be tested for
392 * 404 *
393 * Return true if the current task has the giv !! 405 * Return true if task that opened the file had a capability in effect
394 * available for use, false if not. !! 406 * when the file was opened.
395 * 407 *
396 * This sets PF_SUPERPRIV on the task if the c !! 408 * This does not set PF_SUPERPRIV because the caller may not
397 * assumption that it's about to be used. !! 409 * actually be privileged.
398 */ 410 */
399 bool ns_capable_noaudit(struct user_namespace !! 411 bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap)
400 { 412 {
401 return ns_capable_common(ns, cap, CAP_ !! 413 if (WARN_ON_ONCE(!cap_valid(cap)))
402 } !! 414 return false;
403 EXPORT_SYMBOL(ns_capable_noaudit); <<
404 415
405 /** !! 416 if (security_capable(file->f_cred, ns, cap) == 0)
406 * ns_capable_setid - Determine if the current !! 417 return true;
407 * in effect, while signalling that this check !! 418
408 * setid or setgroups syscall. !! 419 return false;
409 * @ns: The usernamespace we want the capabil <<
410 * @cap: The capability to be tested for <<
411 * <<
412 * Return true if the current task has the giv <<
413 * available for use, false if not. <<
414 * <<
415 * This sets PF_SUPERPRIV on the task if the c <<
416 * assumption that it's about to be used. <<
417 */ <<
418 bool ns_capable_setid(struct user_namespace *n <<
419 { <<
420 return ns_capable_common(ns, cap, CAP_ <<
421 } 420 }
422 EXPORT_SYMBOL(ns_capable_setid); !! 421 EXPORT_SYMBOL(file_ns_capable);
423 422
424 /** 423 /**
425 * capable - Determine if the current task has 424 * capable - Determine if the current task has a superior capability in effect
426 * @cap: The capability to be tested for 425 * @cap: The capability to be tested for
427 * 426 *
428 * Return true if the current task has the giv 427 * Return true if the current task has the given superior capability currently
429 * available for use, false if not. 428 * available for use, false if not.
430 * 429 *
431 * This sets PF_SUPERPRIV on the task if the c 430 * This sets PF_SUPERPRIV on the task if the capability is available on the
432 * assumption that it's about to be used. 431 * assumption that it's about to be used.
433 */ 432 */
434 bool capable(int cap) 433 bool capable(int cap)
435 { 434 {
436 return ns_capable(&init_user_ns, cap); 435 return ns_capable(&init_user_ns, cap);
437 } 436 }
438 EXPORT_SYMBOL(capable); 437 EXPORT_SYMBOL(capable);
439 #endif /* CONFIG_MULTIUSER */ <<
440 438
441 /** 439 /**
442 * file_ns_capable - Determine if the file's o !! 440 * nsown_capable - Check superior capability to one's own user_ns
443 * @file: The file we want to check !! 441 * @cap: The capability in question
444 * @ns: The usernamespace we want the capabil <<
445 * @cap: The capability to be tested for <<
446 * <<
447 * Return true if task that opened the file ha <<
448 * when the file was opened. <<
449 * <<
450 * This does not set PF_SUPERPRIV because the <<
451 * actually be privileged. <<
452 */ <<
453 bool file_ns_capable(const struct file *file, <<
454 int cap) <<
455 { <<
456 <<
457 if (WARN_ON_ONCE(!cap_valid(cap))) <<
458 return false; <<
459 <<
460 if (security_capable(file->f_cred, ns, <<
461 return true; <<
462 <<
463 return false; <<
464 } <<
465 EXPORT_SYMBOL(file_ns_capable); <<
466 <<
467 /** <<
468 * privileged_wrt_inode_uidgid - Do capabiliti <<
469 * @ns: The user namespace in question <<
470 * @idmap: idmap of the mount @inode was found <<
471 * @inode: The inode in question <<
472 * 442 *
473 * Return true if the inode uid and gid are wi !! 443 * Return true if the current task has the given superior capability
>> 444 * targeted at its own user namespace.
474 */ 445 */
475 bool privileged_wrt_inode_uidgid(struct user_n !! 446 bool nsown_capable(int cap)
476 struct mnt_id <<
477 const struct <<
478 { 447 {
479 return vfsuid_has_mapping(ns, i_uid_in !! 448 return ns_capable(current_user_ns(), cap);
480 vfsgid_has_mapping(ns, i_gid_in <<
481 } 449 }
482 450
483 /** 451 /**
484 * capable_wrt_inode_uidgid - Check nsown_capa 452 * capable_wrt_inode_uidgid - Check nsown_capable and uid and gid mapped
485 * @idmap: idmap of the mount @inode was found <<
486 * @inode: The inode in question 453 * @inode: The inode in question
487 * @cap: The capability in question 454 * @cap: The capability in question
488 * 455 *
489 * Return true if the current task has the giv 456 * Return true if the current task has the given capability targeted at
490 * its own user namespace and that the given i 457 * its own user namespace and that the given inode's uid and gid are
491 * mapped into the current user namespace. 458 * mapped into the current user namespace.
492 */ 459 */
493 bool capable_wrt_inode_uidgid(struct mnt_idmap !! 460 bool capable_wrt_inode_uidgid(const struct inode *inode, int cap)
494 const struct ino <<
495 { 461 {
496 struct user_namespace *ns = current_us 462 struct user_namespace *ns = current_user_ns();
497 463
498 return ns_capable(ns, cap) && !! 464 return ns_capable(ns, cap) && kuid_has_mapping(ns, inode->i_uid) &&
499 privileged_wrt_inode_uidgid(ns, !! 465 kgid_has_mapping(ns, inode->i_gid);
500 } <<
501 EXPORT_SYMBOL(capable_wrt_inode_uidgid); <<
502 <<
503 /** <<
504 * ptracer_capable - Determine if the ptracer <<
505 * @tsk: The task that may be ptraced <<
506 * @ns: The user namespace to search for CAP_S <<
507 * <<
508 * Return true if the task that is ptracing th <<
509 * in the specified user namespace. <<
510 */ <<
511 bool ptracer_capable(struct task_struct *tsk, <<
512 { <<
513 int ret = 0; /* An absent tracer adds <<
514 const struct cred *cred; <<
515 <<
516 rcu_read_lock(); <<
517 cred = rcu_dereference(tsk->ptracer_cr <<
518 if (cred) <<
519 ret = security_capable(cred, n <<
520 CAP_OPT <<
521 rcu_read_unlock(); <<
522 return (ret == 0); <<
523 } 466 }
524 467
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