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