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