Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/kernel/capability.c |
| 3 | * |
| 4 | * Copyright (C) 1997 Andrew Main <zefram@fysh.org> |
| 5 | * |
Andrew Morgan | 72c2d58 | 2007-10-18 03:05:59 -0700 | [diff] [blame] | 6 | * Integrated into 2.1.97+, Andrew G. Morgan <morgan@kernel.org> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 7 | * 30 May 2002: Cleanup, Robert M. Love <rml@tech9.net> |
Daniel Walker | 314f70f | 2007-10-18 03:06:08 -0700 | [diff] [blame] | 8 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 9 | |
Joe Perches | f5645d3 | 2014-02-21 14:19:30 -0800 | [diff] [blame] | 10 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 11 | |
Eric Paris | e68b75a0 | 2008-11-11 21:48:22 +1100 | [diff] [blame] | 12 | #include <linux/audit.h> |
Randy.Dunlap | c59ede7 | 2006-01-11 12:17:46 -0800 | [diff] [blame] | 13 | #include <linux/capability.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 14 | #include <linux/mm.h> |
Paul Gortmaker | 9984de1 | 2011-05-23 14:51:41 -0400 | [diff] [blame] | 15 | #include <linux/export.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 16 | #include <linux/security.h> |
| 17 | #include <linux/syscalls.h> |
Serge E. Hallyn | b460cbc | 2007-10-18 23:39:52 -0700 | [diff] [blame] | 18 | #include <linux/pid_namespace.h> |
Serge E. Hallyn | 3486740 | 2011-03-23 16:43:17 -0700 | [diff] [blame] | 19 | #include <linux/user_namespace.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | #include <asm/uaccess.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 21 | |
| 22 | /* |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 23 | * Leveraged for setting/resetting capabilities |
| 24 | */ |
| 25 | |
| 26 | const kernel_cap_t __cap_empty_set = CAP_EMPTY_SET; |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 27 | EXPORT_SYMBOL(__cap_empty_set); |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 28 | |
Serge E. Hallyn | 1f29fae | 2008-11-05 16:08:52 -0600 | [diff] [blame] | 29 | int file_caps_enabled = 1; |
| 30 | |
| 31 | static int __init file_caps_disable(char *str) |
| 32 | { |
| 33 | file_caps_enabled = 0; |
| 34 | return 1; |
| 35 | } |
| 36 | __setup("no_file_caps", file_caps_disable); |
Serge E. Hallyn | 1f29fae | 2008-11-05 16:08:52 -0600 | [diff] [blame] | 37 | |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 38 | /* |
| 39 | * More recent versions of libcap are available from: |
| 40 | * |
| 41 | * http://www.kernel.org/pub/linux/libs/security/linux-privs/ |
| 42 | */ |
| 43 | |
| 44 | static void warn_legacy_capability_use(void) |
| 45 | { |
Joe Perches | f5645d3 | 2014-02-21 14:19:30 -0800 | [diff] [blame] | 46 | char name[sizeof(current->comm)]; |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 47 | |
Joe Perches | f5645d3 | 2014-02-21 14:19:30 -0800 | [diff] [blame] | 48 | pr_info_once("warning: `%s' uses 32-bit capabilities (legacy support in use)\n", |
| 49 | get_task_comm(name, current)); |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 50 | } |
| 51 | |
| 52 | /* |
Andrew G. Morgan | ca05a99 | 2008-05-27 22:05:17 -0700 | [diff] [blame] | 53 | * Version 2 capabilities worked fine, but the linux/capability.h file |
| 54 | * that accompanied their introduction encouraged their use without |
| 55 | * the necessary user-space source code changes. As such, we have |
| 56 | * created a version 3 with equivalent functionality to version 2, but |
| 57 | * with a header change to protect legacy source code from using |
| 58 | * version 2 when it wanted to use version 1. If your system has code |
| 59 | * that trips the following warning, it is using version 2 specific |
| 60 | * capabilities and may be doing so insecurely. |
| 61 | * |
| 62 | * The remedy is to either upgrade your version of libcap (to 2.10+, |
| 63 | * if the application is linked against it), or recompile your |
| 64 | * application with modern kernel headers and this warning will go |
| 65 | * away. |
| 66 | */ |
| 67 | |
| 68 | static void warn_deprecated_v2(void) |
| 69 | { |
Joe Perches | f5645d3 | 2014-02-21 14:19:30 -0800 | [diff] [blame] | 70 | char name[sizeof(current->comm)]; |
Andrew G. Morgan | ca05a99 | 2008-05-27 22:05:17 -0700 | [diff] [blame] | 71 | |
Joe Perches | f5645d3 | 2014-02-21 14:19:30 -0800 | [diff] [blame] | 72 | pr_info_once("warning: `%s' uses deprecated v2 capabilities in a way that may be insecure\n", |
| 73 | get_task_comm(name, current)); |
Andrew G. Morgan | ca05a99 | 2008-05-27 22:05:17 -0700 | [diff] [blame] | 74 | } |
| 75 | |
| 76 | /* |
| 77 | * Version check. Return the number of u32s in each capability flag |
| 78 | * array, or a negative value on error. |
| 79 | */ |
| 80 | static int cap_validate_magic(cap_user_header_t header, unsigned *tocopy) |
| 81 | { |
| 82 | __u32 version; |
| 83 | |
| 84 | if (get_user(version, &header->version)) |
| 85 | return -EFAULT; |
| 86 | |
| 87 | switch (version) { |
| 88 | case _LINUX_CAPABILITY_VERSION_1: |
| 89 | warn_legacy_capability_use(); |
| 90 | *tocopy = _LINUX_CAPABILITY_U32S_1; |
| 91 | break; |
| 92 | case _LINUX_CAPABILITY_VERSION_2: |
| 93 | warn_deprecated_v2(); |
| 94 | /* |
| 95 | * fall through - v3 is otherwise equivalent to v2. |
| 96 | */ |
| 97 | case _LINUX_CAPABILITY_VERSION_3: |
| 98 | *tocopy = _LINUX_CAPABILITY_U32S_3; |
| 99 | break; |
| 100 | default: |
| 101 | if (put_user((u32)_KERNEL_CAPABILITY_VERSION, &header->version)) |
| 102 | return -EFAULT; |
| 103 | return -EINVAL; |
| 104 | } |
| 105 | |
| 106 | return 0; |
| 107 | } |
| 108 | |
Andrew G. Morgan | ab763c7 | 2008-07-23 21:28:25 -0700 | [diff] [blame] | 109 | /* |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 110 | * The only thing that can change the capabilities of the current |
| 111 | * process is the current process. As such, we can't be in this code |
| 112 | * at the same time as we are in the process of setting capabilities |
| 113 | * in this process. The net result is that we can limit our use of |
| 114 | * locks to when we are reading the caps of another process. |
Andrew G. Morgan | ab763c7 | 2008-07-23 21:28:25 -0700 | [diff] [blame] | 115 | */ |
| 116 | static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp, |
| 117 | kernel_cap_t *pIp, kernel_cap_t *pPp) |
| 118 | { |
| 119 | int ret; |
| 120 | |
| 121 | if (pid && (pid != task_pid_vnr(current))) { |
| 122 | struct task_struct *target; |
| 123 | |
Thomas Gleixner | 86fc80f | 2009-12-09 17:13:31 +0100 | [diff] [blame] | 124 | rcu_read_lock(); |
Andrew G. Morgan | ab763c7 | 2008-07-23 21:28:25 -0700 | [diff] [blame] | 125 | |
| 126 | target = find_task_by_vpid(pid); |
| 127 | if (!target) |
| 128 | ret = -ESRCH; |
| 129 | else |
| 130 | ret = security_capget(target, pEp, pIp, pPp); |
| 131 | |
Thomas Gleixner | 86fc80f | 2009-12-09 17:13:31 +0100 | [diff] [blame] | 132 | rcu_read_unlock(); |
Andrew G. Morgan | ab763c7 | 2008-07-23 21:28:25 -0700 | [diff] [blame] | 133 | } else |
| 134 | ret = security_capget(current, pEp, pIp, pPp); |
| 135 | |
| 136 | return ret; |
| 137 | } |
| 138 | |
Randy Dunlap | 207a7ba | 2005-07-27 11:45:10 -0700 | [diff] [blame] | 139 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 140 | * sys_capget - get the capabilities of a given process. |
Randy Dunlap | 207a7ba | 2005-07-27 11:45:10 -0700 | [diff] [blame] | 141 | * @header: pointer to struct that contains capability version and |
| 142 | * target pid data |
| 143 | * @dataptr: pointer to struct that contains the effective, permitted, |
| 144 | * and inheritable capabilities that are returned |
| 145 | * |
| 146 | * Returns 0 on success and < 0 on error. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 147 | */ |
Heiko Carstens | b290ebe | 2009-01-14 14:14:06 +0100 | [diff] [blame] | 148 | SYSCALL_DEFINE2(capget, cap_user_header_t, header, cap_user_data_t, dataptr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 149 | { |
Daniel Walker | 314f70f | 2007-10-18 03:06:08 -0700 | [diff] [blame] | 150 | int ret = 0; |
| 151 | pid_t pid; |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 152 | unsigned tocopy; |
| 153 | kernel_cap_t pE, pI, pP; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 154 | |
Andrew G. Morgan | ca05a99 | 2008-05-27 22:05:17 -0700 | [diff] [blame] | 155 | ret = cap_validate_magic(header, &tocopy); |
Andrew G. Morgan | c4a5af5 | 2009-11-23 04:57:52 +0000 | [diff] [blame] | 156 | if ((dataptr == NULL) || (ret != 0)) |
| 157 | return ((dataptr == NULL) && (ret == -EINVAL)) ? 0 : ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 158 | |
Daniel Walker | 314f70f | 2007-10-18 03:06:08 -0700 | [diff] [blame] | 159 | if (get_user(pid, &header->pid)) |
| 160 | return -EFAULT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 161 | |
Daniel Walker | 314f70f | 2007-10-18 03:06:08 -0700 | [diff] [blame] | 162 | if (pid < 0) |
| 163 | return -EINVAL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 164 | |
Andrew G. Morgan | ab763c7 | 2008-07-23 21:28:25 -0700 | [diff] [blame] | 165 | ret = cap_get_target_pid(pid, &pE, &pI, &pP); |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 166 | if (!ret) { |
Andrew G. Morgan | ca05a99 | 2008-05-27 22:05:17 -0700 | [diff] [blame] | 167 | struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S]; |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 168 | unsigned i; |
| 169 | |
| 170 | for (i = 0; i < tocopy; i++) { |
| 171 | kdata[i].effective = pE.cap[i]; |
| 172 | kdata[i].permitted = pP.cap[i]; |
| 173 | kdata[i].inheritable = pI.cap[i]; |
| 174 | } |
| 175 | |
| 176 | /* |
Andrew G. Morgan | ca05a99 | 2008-05-27 22:05:17 -0700 | [diff] [blame] | 177 | * Note, in the case, tocopy < _KERNEL_CAPABILITY_U32S, |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 178 | * we silently drop the upper capabilities here. This |
| 179 | * has the effect of making older libcap |
| 180 | * implementations implicitly drop upper capability |
| 181 | * bits when they perform a: capget/modify/capset |
| 182 | * sequence. |
| 183 | * |
| 184 | * This behavior is considered fail-safe |
| 185 | * behavior. Upgrading the application to a newer |
| 186 | * version of libcap will enable access to the newer |
| 187 | * capabilities. |
| 188 | * |
| 189 | * An alternative would be to return an error here |
| 190 | * (-ERANGE), but that causes legacy applications to |
Fabian Frederick | a6c8c69 | 2014-06-04 16:11:19 -0700 | [diff] [blame] | 191 | * unexpectedly fail; the capget/modify/capset aborts |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 192 | * before modification is attempted and the application |
| 193 | * fails. |
| 194 | */ |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 195 | if (copy_to_user(dataptr, kdata, tocopy |
| 196 | * sizeof(struct __user_cap_data_struct))) { |
| 197 | return -EFAULT; |
| 198 | } |
| 199 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 200 | |
Daniel Walker | 314f70f | 2007-10-18 03:06:08 -0700 | [diff] [blame] | 201 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 202 | } |
| 203 | |
Randy Dunlap | 207a7ba | 2005-07-27 11:45:10 -0700 | [diff] [blame] | 204 | /** |
Andrew G. Morgan | ab763c7 | 2008-07-23 21:28:25 -0700 | [diff] [blame] | 205 | * sys_capset - set capabilities for a process or (*) a group of processes |
Randy Dunlap | 207a7ba | 2005-07-27 11:45:10 -0700 | [diff] [blame] | 206 | * @header: pointer to struct that contains capability version and |
| 207 | * target pid data |
| 208 | * @data: pointer to struct that contains the effective, permitted, |
| 209 | * and inheritable capabilities |
| 210 | * |
David Howells | 1cdcbec | 2008-11-14 10:39:14 +1100 | [diff] [blame] | 211 | * Set capabilities for the current process only. The ability to any other |
| 212 | * process(es) has been deprecated and removed. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 213 | * |
| 214 | * The restrictions on setting capabilities are specified as: |
| 215 | * |
David Howells | 1cdcbec | 2008-11-14 10:39:14 +1100 | [diff] [blame] | 216 | * I: any raised capabilities must be a subset of the old permitted |
| 217 | * P: any raised capabilities must be a subset of the old permitted |
| 218 | * E: must be set to a subset of new permitted |
Randy Dunlap | 207a7ba | 2005-07-27 11:45:10 -0700 | [diff] [blame] | 219 | * |
| 220 | * Returns 0 on success and < 0 on error. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 221 | */ |
Heiko Carstens | b290ebe | 2009-01-14 14:14:06 +0100 | [diff] [blame] | 222 | SYSCALL_DEFINE2(capset, cap_user_header_t, header, const cap_user_data_t, data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 223 | { |
Andrew G. Morgan | ca05a99 | 2008-05-27 22:05:17 -0700 | [diff] [blame] | 224 | struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S]; |
Arjan van de Ven | 825332e | 2009-10-14 08:17:36 +1100 | [diff] [blame] | 225 | unsigned i, tocopy, copybytes; |
Daniel Walker | 314f70f | 2007-10-18 03:06:08 -0700 | [diff] [blame] | 226 | kernel_cap_t inheritable, permitted, effective; |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 227 | struct cred *new; |
Daniel Walker | 314f70f | 2007-10-18 03:06:08 -0700 | [diff] [blame] | 228 | int ret; |
| 229 | pid_t pid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 230 | |
Andrew G. Morgan | ca05a99 | 2008-05-27 22:05:17 -0700 | [diff] [blame] | 231 | ret = cap_validate_magic(header, &tocopy); |
| 232 | if (ret != 0) |
| 233 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 234 | |
Daniel Walker | 314f70f | 2007-10-18 03:06:08 -0700 | [diff] [blame] | 235 | if (get_user(pid, &header->pid)) |
| 236 | return -EFAULT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 237 | |
David Howells | 1cdcbec | 2008-11-14 10:39:14 +1100 | [diff] [blame] | 238 | /* may only affect current now */ |
| 239 | if (pid != 0 && pid != task_pid_vnr(current)) |
| 240 | return -EPERM; |
| 241 | |
Arjan van de Ven | 825332e | 2009-10-14 08:17:36 +1100 | [diff] [blame] | 242 | copybytes = tocopy * sizeof(struct __user_cap_data_struct); |
| 243 | if (copybytes > sizeof(kdata)) |
| 244 | return -EFAULT; |
| 245 | |
| 246 | if (copy_from_user(&kdata, data, copybytes)) |
Daniel Walker | 314f70f | 2007-10-18 03:06:08 -0700 | [diff] [blame] | 247 | return -EFAULT; |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 248 | |
| 249 | for (i = 0; i < tocopy; i++) { |
| 250 | effective.cap[i] = kdata[i].effective; |
| 251 | permitted.cap[i] = kdata[i].permitted; |
| 252 | inheritable.cap[i] = kdata[i].inheritable; |
| 253 | } |
Andrew G. Morgan | ca05a99 | 2008-05-27 22:05:17 -0700 | [diff] [blame] | 254 | while (i < _KERNEL_CAPABILITY_U32S) { |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 255 | effective.cap[i] = 0; |
| 256 | permitted.cap[i] = 0; |
| 257 | inheritable.cap[i] = 0; |
| 258 | i++; |
| 259 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 260 | |
Eric Paris | 7d8b6c6 | 2014-07-23 15:36:26 -0400 | [diff] [blame] | 261 | effective.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK; |
| 262 | permitted.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK; |
| 263 | inheritable.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK; |
| 264 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 265 | new = prepare_creds(); |
| 266 | if (!new) |
| 267 | return -ENOMEM; |
| 268 | |
| 269 | ret = security_capset(new, current_cred(), |
| 270 | &effective, &inheritable, &permitted); |
| 271 | if (ret < 0) |
| 272 | goto error; |
| 273 | |
Eric W. Biederman | ca24a23 | 2013-03-19 00:02:25 -0700 | [diff] [blame] | 274 | audit_log_capset(new, current_cred()); |
Eric Paris | e68b75a0 | 2008-11-11 21:48:22 +1100 | [diff] [blame] | 275 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 276 | return commit_creds(new); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 277 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 278 | error: |
| 279 | abort_creds(new); |
Daniel Walker | 314f70f | 2007-10-18 03:06:08 -0700 | [diff] [blame] | 280 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 281 | } |
Chris Wright | 12b5989 | 2006-03-25 03:07:41 -0800 | [diff] [blame] | 282 | |
David Howells | 5cd9c58 | 2008-08-14 11:37:28 +0100 | [diff] [blame] | 283 | /** |
Eric Paris | 25e7570 | 2012-01-03 12:25:15 -0500 | [diff] [blame] | 284 | * has_ns_capability - Does a task have a capability in a specific user ns |
Serge E. Hallyn | 3263245 | 2011-03-23 16:43:21 -0700 | [diff] [blame] | 285 | * @t: The task in question |
| 286 | * @ns: target user namespace |
| 287 | * @cap: The capability to be tested for |
| 288 | * |
| 289 | * Return true if the specified task has the given superior capability |
| 290 | * currently in effect to the specified user namespace, false if not. |
| 291 | * |
| 292 | * Note that this does not set PF_SUPERPRIV on the task. |
| 293 | */ |
| 294 | bool has_ns_capability(struct task_struct *t, |
| 295 | struct user_namespace *ns, int cap) |
| 296 | { |
Eric Paris | 2920a84 | 2012-01-03 12:25:15 -0500 | [diff] [blame] | 297 | int ret; |
| 298 | |
| 299 | rcu_read_lock(); |
| 300 | ret = security_capable(__task_cred(t), ns, cap); |
| 301 | rcu_read_unlock(); |
Serge E. Hallyn | 3263245 | 2011-03-23 16:43:21 -0700 | [diff] [blame] | 302 | |
| 303 | return (ret == 0); |
| 304 | } |
| 305 | |
| 306 | /** |
Eric Paris | 25e7570 | 2012-01-03 12:25:15 -0500 | [diff] [blame] | 307 | * has_capability - Does a task have a capability in init_user_ns |
| 308 | * @t: The task in question |
| 309 | * @cap: The capability to be tested for |
| 310 | * |
| 311 | * Return true if the specified task has the given superior capability |
| 312 | * currently in effect to the initial user namespace, false if not. |
| 313 | * |
| 314 | * Note that this does not set PF_SUPERPRIV on the task. |
| 315 | */ |
| 316 | bool has_capability(struct task_struct *t, int cap) |
| 317 | { |
| 318 | return has_ns_capability(t, &init_user_ns, cap); |
| 319 | } |
| 320 | |
| 321 | /** |
Eric Paris | 7b61d64 | 2012-01-03 12:25:15 -0500 | [diff] [blame] | 322 | * has_ns_capability_noaudit - Does a task have a capability (unaudited) |
| 323 | * in a specific user ns. |
| 324 | * @t: The task in question |
| 325 | * @ns: target user namespace |
| 326 | * @cap: The capability to be tested for |
| 327 | * |
| 328 | * Return true if the specified task has the given superior capability |
| 329 | * currently in effect to the specified user namespace, false if not. |
| 330 | * Do not write an audit message for the check. |
| 331 | * |
| 332 | * Note that this does not set PF_SUPERPRIV on the task. |
| 333 | */ |
| 334 | bool has_ns_capability_noaudit(struct task_struct *t, |
| 335 | struct user_namespace *ns, int cap) |
| 336 | { |
| 337 | int ret; |
| 338 | |
| 339 | rcu_read_lock(); |
| 340 | ret = security_capable_noaudit(__task_cred(t), ns, cap); |
| 341 | rcu_read_unlock(); |
| 342 | |
| 343 | return (ret == 0); |
| 344 | } |
| 345 | |
| 346 | /** |
| 347 | * has_capability_noaudit - Does a task have a capability (unaudited) in the |
| 348 | * initial user ns |
Serge E. Hallyn | 3263245 | 2011-03-23 16:43:21 -0700 | [diff] [blame] | 349 | * @t: The task in question |
| 350 | * @cap: The capability to be tested for |
| 351 | * |
| 352 | * Return true if the specified task has the given superior capability |
| 353 | * currently in effect to init_user_ns, false if not. Don't write an |
| 354 | * audit message for the check. |
| 355 | * |
| 356 | * Note that this does not set PF_SUPERPRIV on the task. |
| 357 | */ |
| 358 | bool has_capability_noaudit(struct task_struct *t, int cap) |
| 359 | { |
Eric Paris | 7b61d64 | 2012-01-03 12:25:15 -0500 | [diff] [blame] | 360 | return has_ns_capability_noaudit(t, &init_user_ns, cap); |
Serge E. Hallyn | 3263245 | 2011-03-23 16:43:21 -0700 | [diff] [blame] | 361 | } |
| 362 | |
| 363 | /** |
Serge E. Hallyn | 3486740 | 2011-03-23 16:43:17 -0700 | [diff] [blame] | 364 | * ns_capable - Determine if the current task has a superior capability in effect |
| 365 | * @ns: The usernamespace we want the capability in |
| 366 | * @cap: The capability to be tested for |
| 367 | * |
| 368 | * Return true if the current task has the given superior capability currently |
| 369 | * available for use, false if not. |
| 370 | * |
| 371 | * This sets PF_SUPERPRIV on the task if the capability is available on the |
| 372 | * assumption that it's about to be used. |
| 373 | */ |
| 374 | bool ns_capable(struct user_namespace *ns, int cap) |
Chris Wright | 12b5989 | 2006-03-25 03:07:41 -0800 | [diff] [blame] | 375 | { |
Eric Paris | 637d32d | 2008-10-29 15:42:12 +1100 | [diff] [blame] | 376 | if (unlikely(!cap_valid(cap))) { |
Joe Perches | f5645d3 | 2014-02-21 14:19:30 -0800 | [diff] [blame] | 377 | pr_crit("capable() called with invalid cap=%u\n", cap); |
Eric Paris | 637d32d | 2008-10-29 15:42:12 +1100 | [diff] [blame] | 378 | BUG(); |
| 379 | } |
| 380 | |
Linus Torvalds | 951880e | 2012-01-17 10:19:41 -0800 | [diff] [blame] | 381 | if (security_capable(current_cred(), ns, cap) == 0) { |
David Howells | 5cd9c58 | 2008-08-14 11:37:28 +0100 | [diff] [blame] | 382 | current->flags |= PF_SUPERPRIV; |
Serge E. Hallyn | 3486740 | 2011-03-23 16:43:17 -0700 | [diff] [blame] | 383 | return true; |
Chris Wright | 12b5989 | 2006-03-25 03:07:41 -0800 | [diff] [blame] | 384 | } |
Serge E. Hallyn | 3486740 | 2011-03-23 16:43:17 -0700 | [diff] [blame] | 385 | return false; |
Chris Wright | 12b5989 | 2006-03-25 03:07:41 -0800 | [diff] [blame] | 386 | } |
Serge E. Hallyn | 3486740 | 2011-03-23 16:43:17 -0700 | [diff] [blame] | 387 | EXPORT_SYMBOL(ns_capable); |
| 388 | |
| 389 | /** |
Linus Torvalds | 935d8aa | 2013-04-14 10:06:31 -0700 | [diff] [blame] | 390 | * file_ns_capable - Determine if the file's opener had a capability in effect |
| 391 | * @file: The file we want to check |
| 392 | * @ns: The usernamespace we want the capability in |
| 393 | * @cap: The capability to be tested for |
| 394 | * |
| 395 | * Return true if task that opened the file had a capability in effect |
| 396 | * when the file was opened. |
| 397 | * |
| 398 | * This does not set PF_SUPERPRIV because the caller may not |
| 399 | * actually be privileged. |
| 400 | */ |
Fabian Frederick | a6c8c69 | 2014-06-04 16:11:19 -0700 | [diff] [blame] | 401 | bool file_ns_capable(const struct file *file, struct user_namespace *ns, |
| 402 | int cap) |
Linus Torvalds | 935d8aa | 2013-04-14 10:06:31 -0700 | [diff] [blame] | 403 | { |
| 404 | if (WARN_ON_ONCE(!cap_valid(cap))) |
| 405 | return false; |
| 406 | |
| 407 | if (security_capable(file->f_cred, ns, cap) == 0) |
| 408 | return true; |
| 409 | |
| 410 | return false; |
| 411 | } |
| 412 | EXPORT_SYMBOL(file_ns_capable); |
| 413 | |
| 414 | /** |
Eric Paris | 105ddf4 | 2012-01-03 12:25:15 -0500 | [diff] [blame] | 415 | * capable - Determine if the current task has a superior capability in effect |
| 416 | * @cap: The capability to be tested for |
Serge E. Hallyn | 3486740 | 2011-03-23 16:43:17 -0700 | [diff] [blame] | 417 | * |
Eric Paris | 105ddf4 | 2012-01-03 12:25:15 -0500 | [diff] [blame] | 418 | * Return true if the current task has the given superior capability currently |
| 419 | * available for use, false if not. |
| 420 | * |
| 421 | * This sets PF_SUPERPRIV on the task if the capability is available on the |
| 422 | * assumption that it's about to be used. |
Serge E. Hallyn | 3486740 | 2011-03-23 16:43:17 -0700 | [diff] [blame] | 423 | */ |
Eric Paris | 105ddf4 | 2012-01-03 12:25:15 -0500 | [diff] [blame] | 424 | bool capable(int cap) |
Serge E. Hallyn | 3486740 | 2011-03-23 16:43:17 -0700 | [diff] [blame] | 425 | { |
Eric Paris | 105ddf4 | 2012-01-03 12:25:15 -0500 | [diff] [blame] | 426 | return ns_capable(&init_user_ns, cap); |
Serge E. Hallyn | 3486740 | 2011-03-23 16:43:17 -0700 | [diff] [blame] | 427 | } |
Eric Paris | 105ddf4 | 2012-01-03 12:25:15 -0500 | [diff] [blame] | 428 | EXPORT_SYMBOL(capable); |
Serge E. Hallyn | 47a150e | 2011-05-13 04:27:54 +0100 | [diff] [blame] | 429 | |
| 430 | /** |
Andy Lutomirski | 23adbe1 | 2014-06-10 12:45:42 -0700 | [diff] [blame] | 431 | * capable_wrt_inode_uidgid - Check nsown_capable and uid and gid mapped |
Eric W. Biederman | 1a48e2a | 2011-11-14 16:24:06 -0800 | [diff] [blame] | 432 | * @inode: The inode in question |
| 433 | * @cap: The capability in question |
| 434 | * |
Andy Lutomirski | 23adbe1 | 2014-06-10 12:45:42 -0700 | [diff] [blame] | 435 | * Return true if the current task has the given capability targeted at |
| 436 | * its own user namespace and that the given inode's uid and gid are |
| 437 | * mapped into the current user namespace. |
Eric W. Biederman | 1a48e2a | 2011-11-14 16:24:06 -0800 | [diff] [blame] | 438 | */ |
Andy Lutomirski | 23adbe1 | 2014-06-10 12:45:42 -0700 | [diff] [blame] | 439 | bool capable_wrt_inode_uidgid(const struct inode *inode, int cap) |
Eric W. Biederman | 1a48e2a | 2011-11-14 16:24:06 -0800 | [diff] [blame] | 440 | { |
| 441 | struct user_namespace *ns = current_user_ns(); |
| 442 | |
Andy Lutomirski | 23adbe1 | 2014-06-10 12:45:42 -0700 | [diff] [blame] | 443 | return ns_capable(ns, cap) && kuid_has_mapping(ns, inode->i_uid) && |
| 444 | kgid_has_mapping(ns, inode->i_gid); |
Eric W. Biederman | 1a48e2a | 2011-11-14 16:24:06 -0800 | [diff] [blame] | 445 | } |
Andy Lutomirski | 23adbe1 | 2014-06-10 12:45:42 -0700 | [diff] [blame] | 446 | EXPORT_SYMBOL(capable_wrt_inode_uidgid); |