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 | 7c0f6ba | 2016-12-24 11:46:01 -0800 | [diff] [blame] | 20 | #include <linux/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 | |
Iulia Manda | 2813893 | 2015-04-15 16:16:41 -0700 | [diff] [blame] | 38 | #ifdef CONFIG_MULTIUSER |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 39 | /* |
| 40 | * More recent versions of libcap are available from: |
| 41 | * |
| 42 | * http://www.kernel.org/pub/linux/libs/security/linux-privs/ |
| 43 | */ |
| 44 | |
| 45 | static void warn_legacy_capability_use(void) |
| 46 | { |
Joe Perches | f5645d3 | 2014-02-21 14:19:30 -0800 | [diff] [blame] | 47 | char name[sizeof(current->comm)]; |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 48 | |
Joe Perches | f5645d3 | 2014-02-21 14:19:30 -0800 | [diff] [blame] | 49 | pr_info_once("warning: `%s' uses 32-bit capabilities (legacy support in use)\n", |
| 50 | get_task_comm(name, current)); |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 51 | } |
| 52 | |
| 53 | /* |
Andrew G. Morgan | ca05a99 | 2008-05-27 22:05:17 -0700 | [diff] [blame] | 54 | * Version 2 capabilities worked fine, but the linux/capability.h file |
| 55 | * that accompanied their introduction encouraged their use without |
| 56 | * the necessary user-space source code changes. As such, we have |
| 57 | * created a version 3 with equivalent functionality to version 2, but |
| 58 | * with a header change to protect legacy source code from using |
| 59 | * version 2 when it wanted to use version 1. If your system has code |
| 60 | * that trips the following warning, it is using version 2 specific |
| 61 | * capabilities and may be doing so insecurely. |
| 62 | * |
| 63 | * The remedy is to either upgrade your version of libcap (to 2.10+, |
| 64 | * if the application is linked against it), or recompile your |
| 65 | * application with modern kernel headers and this warning will go |
| 66 | * away. |
| 67 | */ |
| 68 | |
| 69 | static void warn_deprecated_v2(void) |
| 70 | { |
Joe Perches | f5645d3 | 2014-02-21 14:19:30 -0800 | [diff] [blame] | 71 | char name[sizeof(current->comm)]; |
Andrew G. Morgan | ca05a99 | 2008-05-27 22:05:17 -0700 | [diff] [blame] | 72 | |
Joe Perches | f5645d3 | 2014-02-21 14:19:30 -0800 | [diff] [blame] | 73 | pr_info_once("warning: `%s' uses deprecated v2 capabilities in a way that may be insecure\n", |
| 74 | get_task_comm(name, current)); |
Andrew G. Morgan | ca05a99 | 2008-05-27 22:05:17 -0700 | [diff] [blame] | 75 | } |
| 76 | |
| 77 | /* |
| 78 | * Version check. Return the number of u32s in each capability flag |
| 79 | * array, or a negative value on error. |
| 80 | */ |
| 81 | static int cap_validate_magic(cap_user_header_t header, unsigned *tocopy) |
| 82 | { |
| 83 | __u32 version; |
| 84 | |
| 85 | if (get_user(version, &header->version)) |
| 86 | return -EFAULT; |
| 87 | |
| 88 | switch (version) { |
| 89 | case _LINUX_CAPABILITY_VERSION_1: |
| 90 | warn_legacy_capability_use(); |
| 91 | *tocopy = _LINUX_CAPABILITY_U32S_1; |
| 92 | break; |
| 93 | case _LINUX_CAPABILITY_VERSION_2: |
| 94 | warn_deprecated_v2(); |
| 95 | /* |
| 96 | * fall through - v3 is otherwise equivalent to v2. |
| 97 | */ |
| 98 | case _LINUX_CAPABILITY_VERSION_3: |
| 99 | *tocopy = _LINUX_CAPABILITY_U32S_3; |
| 100 | break; |
| 101 | default: |
| 102 | if (put_user((u32)_KERNEL_CAPABILITY_VERSION, &header->version)) |
| 103 | return -EFAULT; |
| 104 | return -EINVAL; |
| 105 | } |
| 106 | |
| 107 | return 0; |
| 108 | } |
| 109 | |
Andrew G. Morgan | ab763c7 | 2008-07-23 21:28:25 -0700 | [diff] [blame] | 110 | /* |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 111 | * The only thing that can change the capabilities of the current |
| 112 | * process is the current process. As such, we can't be in this code |
| 113 | * at the same time as we are in the process of setting capabilities |
| 114 | * in this process. The net result is that we can limit our use of |
| 115 | * locks to when we are reading the caps of another process. |
Andrew G. Morgan | ab763c7 | 2008-07-23 21:28:25 -0700 | [diff] [blame] | 116 | */ |
| 117 | static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp, |
| 118 | kernel_cap_t *pIp, kernel_cap_t *pPp) |
| 119 | { |
| 120 | int ret; |
| 121 | |
| 122 | if (pid && (pid != task_pid_vnr(current))) { |
| 123 | struct task_struct *target; |
| 124 | |
Thomas Gleixner | 86fc80f | 2009-12-09 17:13:31 +0100 | [diff] [blame] | 125 | rcu_read_lock(); |
Andrew G. Morgan | ab763c7 | 2008-07-23 21:28:25 -0700 | [diff] [blame] | 126 | |
| 127 | target = find_task_by_vpid(pid); |
| 128 | if (!target) |
| 129 | ret = -ESRCH; |
| 130 | else |
| 131 | ret = security_capget(target, pEp, pIp, pPp); |
| 132 | |
Thomas Gleixner | 86fc80f | 2009-12-09 17:13:31 +0100 | [diff] [blame] | 133 | rcu_read_unlock(); |
Andrew G. Morgan | ab763c7 | 2008-07-23 21:28:25 -0700 | [diff] [blame] | 134 | } else |
| 135 | ret = security_capget(current, pEp, pIp, pPp); |
| 136 | |
| 137 | return ret; |
| 138 | } |
| 139 | |
Randy Dunlap | 207a7ba | 2005-07-27 11:45:10 -0700 | [diff] [blame] | 140 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 141 | * sys_capget - get the capabilities of a given process. |
Randy Dunlap | 207a7ba | 2005-07-27 11:45:10 -0700 | [diff] [blame] | 142 | * @header: pointer to struct that contains capability version and |
| 143 | * target pid data |
| 144 | * @dataptr: pointer to struct that contains the effective, permitted, |
| 145 | * and inheritable capabilities that are returned |
| 146 | * |
| 147 | * Returns 0 on success and < 0 on error. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 148 | */ |
Heiko Carstens | b290ebe | 2009-01-14 14:14:06 +0100 | [diff] [blame] | 149 | 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] | 150 | { |
Daniel Walker | 314f70f | 2007-10-18 03:06:08 -0700 | [diff] [blame] | 151 | int ret = 0; |
| 152 | pid_t pid; |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 153 | unsigned tocopy; |
| 154 | kernel_cap_t pE, pI, pP; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 155 | |
Andrew G. Morgan | ca05a99 | 2008-05-27 22:05:17 -0700 | [diff] [blame] | 156 | ret = cap_validate_magic(header, &tocopy); |
Andrew G. Morgan | c4a5af5 | 2009-11-23 04:57:52 +0000 | [diff] [blame] | 157 | if ((dataptr == NULL) || (ret != 0)) |
| 158 | return ((dataptr == NULL) && (ret == -EINVAL)) ? 0 : ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 159 | |
Daniel Walker | 314f70f | 2007-10-18 03:06:08 -0700 | [diff] [blame] | 160 | if (get_user(pid, &header->pid)) |
| 161 | return -EFAULT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 162 | |
Daniel Walker | 314f70f | 2007-10-18 03:06:08 -0700 | [diff] [blame] | 163 | if (pid < 0) |
| 164 | return -EINVAL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 165 | |
Andrew G. Morgan | ab763c7 | 2008-07-23 21:28:25 -0700 | [diff] [blame] | 166 | ret = cap_get_target_pid(pid, &pE, &pI, &pP); |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 167 | if (!ret) { |
Andrew G. Morgan | ca05a99 | 2008-05-27 22:05:17 -0700 | [diff] [blame] | 168 | struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S]; |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 169 | unsigned i; |
| 170 | |
| 171 | for (i = 0; i < tocopy; i++) { |
| 172 | kdata[i].effective = pE.cap[i]; |
| 173 | kdata[i].permitted = pP.cap[i]; |
| 174 | kdata[i].inheritable = pI.cap[i]; |
| 175 | } |
| 176 | |
| 177 | /* |
Andrew G. Morgan | ca05a99 | 2008-05-27 22:05:17 -0700 | [diff] [blame] | 178 | * Note, in the case, tocopy < _KERNEL_CAPABILITY_U32S, |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 179 | * we silently drop the upper capabilities here. This |
| 180 | * has the effect of making older libcap |
| 181 | * implementations implicitly drop upper capability |
| 182 | * bits when they perform a: capget/modify/capset |
| 183 | * sequence. |
| 184 | * |
| 185 | * This behavior is considered fail-safe |
| 186 | * behavior. Upgrading the application to a newer |
| 187 | * version of libcap will enable access to the newer |
| 188 | * capabilities. |
| 189 | * |
| 190 | * An alternative would be to return an error here |
| 191 | * (-ERANGE), but that causes legacy applications to |
Fabian Frederick | a6c8c69 | 2014-06-04 16:11:19 -0700 | [diff] [blame] | 192 | * unexpectedly fail; the capget/modify/capset aborts |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 193 | * before modification is attempted and the application |
| 194 | * fails. |
| 195 | */ |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 196 | if (copy_to_user(dataptr, kdata, tocopy |
| 197 | * sizeof(struct __user_cap_data_struct))) { |
| 198 | return -EFAULT; |
| 199 | } |
| 200 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 201 | |
Daniel Walker | 314f70f | 2007-10-18 03:06:08 -0700 | [diff] [blame] | 202 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 203 | } |
| 204 | |
Randy Dunlap | 207a7ba | 2005-07-27 11:45:10 -0700 | [diff] [blame] | 205 | /** |
Andrew G. Morgan | ab763c7 | 2008-07-23 21:28:25 -0700 | [diff] [blame] | 206 | * sys_capset - set capabilities for a process or (*) a group of processes |
Randy Dunlap | 207a7ba | 2005-07-27 11:45:10 -0700 | [diff] [blame] | 207 | * @header: pointer to struct that contains capability version and |
| 208 | * target pid data |
| 209 | * @data: pointer to struct that contains the effective, permitted, |
| 210 | * and inheritable capabilities |
| 211 | * |
David Howells | 1cdcbec | 2008-11-14 10:39:14 +1100 | [diff] [blame] | 212 | * Set capabilities for the current process only. The ability to any other |
| 213 | * process(es) has been deprecated and removed. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 214 | * |
| 215 | * The restrictions on setting capabilities are specified as: |
| 216 | * |
David Howells | 1cdcbec | 2008-11-14 10:39:14 +1100 | [diff] [blame] | 217 | * I: any raised capabilities must be a subset of the old permitted |
| 218 | * P: any raised capabilities must be a subset of the old permitted |
| 219 | * E: must be set to a subset of new permitted |
Randy Dunlap | 207a7ba | 2005-07-27 11:45:10 -0700 | [diff] [blame] | 220 | * |
| 221 | * Returns 0 on success and < 0 on error. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 222 | */ |
Heiko Carstens | b290ebe | 2009-01-14 14:14:06 +0100 | [diff] [blame] | 223 | 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] | 224 | { |
Andrew G. Morgan | ca05a99 | 2008-05-27 22:05:17 -0700 | [diff] [blame] | 225 | struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S]; |
Arjan van de Ven | 825332e | 2009-10-14 08:17:36 +1100 | [diff] [blame] | 226 | unsigned i, tocopy, copybytes; |
Daniel Walker | 314f70f | 2007-10-18 03:06:08 -0700 | [diff] [blame] | 227 | kernel_cap_t inheritable, permitted, effective; |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 228 | struct cred *new; |
Daniel Walker | 314f70f | 2007-10-18 03:06:08 -0700 | [diff] [blame] | 229 | int ret; |
| 230 | pid_t pid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 231 | |
Andrew G. Morgan | ca05a99 | 2008-05-27 22:05:17 -0700 | [diff] [blame] | 232 | ret = cap_validate_magic(header, &tocopy); |
| 233 | if (ret != 0) |
| 234 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 235 | |
Daniel Walker | 314f70f | 2007-10-18 03:06:08 -0700 | [diff] [blame] | 236 | if (get_user(pid, &header->pid)) |
| 237 | return -EFAULT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 238 | |
David Howells | 1cdcbec | 2008-11-14 10:39:14 +1100 | [diff] [blame] | 239 | /* may only affect current now */ |
| 240 | if (pid != 0 && pid != task_pid_vnr(current)) |
| 241 | return -EPERM; |
| 242 | |
Arjan van de Ven | 825332e | 2009-10-14 08:17:36 +1100 | [diff] [blame] | 243 | copybytes = tocopy * sizeof(struct __user_cap_data_struct); |
| 244 | if (copybytes > sizeof(kdata)) |
| 245 | return -EFAULT; |
| 246 | |
| 247 | if (copy_from_user(&kdata, data, copybytes)) |
Daniel Walker | 314f70f | 2007-10-18 03:06:08 -0700 | [diff] [blame] | 248 | return -EFAULT; |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 249 | |
| 250 | for (i = 0; i < tocopy; i++) { |
| 251 | effective.cap[i] = kdata[i].effective; |
| 252 | permitted.cap[i] = kdata[i].permitted; |
| 253 | inheritable.cap[i] = kdata[i].inheritable; |
| 254 | } |
Andrew G. Morgan | ca05a99 | 2008-05-27 22:05:17 -0700 | [diff] [blame] | 255 | while (i < _KERNEL_CAPABILITY_U32S) { |
Andrew Morgan | e338d26 | 2008-02-04 22:29:42 -0800 | [diff] [blame] | 256 | effective.cap[i] = 0; |
| 257 | permitted.cap[i] = 0; |
| 258 | inheritable.cap[i] = 0; |
| 259 | i++; |
| 260 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 261 | |
Eric Paris | 7d8b6c6 | 2014-07-23 15:36:26 -0400 | [diff] [blame] | 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; |
| 265 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 266 | new = prepare_creds(); |
| 267 | if (!new) |
| 268 | return -ENOMEM; |
| 269 | |
| 270 | ret = security_capset(new, current_cred(), |
| 271 | &effective, &inheritable, &permitted); |
| 272 | if (ret < 0) |
| 273 | goto error; |
| 274 | |
Eric W. Biederman | ca24a23 | 2013-03-19 00:02:25 -0700 | [diff] [blame] | 275 | audit_log_capset(new, current_cred()); |
Eric Paris | e68b75a0 | 2008-11-11 21:48:22 +1100 | [diff] [blame] | 276 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 277 | return commit_creds(new); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 278 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 279 | error: |
| 280 | abort_creds(new); |
Daniel Walker | 314f70f | 2007-10-18 03:06:08 -0700 | [diff] [blame] | 281 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 282 | } |
Chris Wright | 12b5989 | 2006-03-25 03:07:41 -0800 | [diff] [blame] | 283 | |
David Howells | 5cd9c58 | 2008-08-14 11:37:28 +0100 | [diff] [blame] | 284 | /** |
Eric Paris | 25e7570 | 2012-01-03 12:25:15 -0500 | [diff] [blame] | 285 | * 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] | 286 | * @t: The task in question |
| 287 | * @ns: target user namespace |
| 288 | * @cap: The capability to be tested for |
| 289 | * |
| 290 | * Return true if the specified task has the given superior capability |
| 291 | * currently in effect to the specified user namespace, false if not. |
| 292 | * |
| 293 | * Note that this does not set PF_SUPERPRIV on the task. |
| 294 | */ |
| 295 | bool has_ns_capability(struct task_struct *t, |
| 296 | struct user_namespace *ns, int cap) |
| 297 | { |
Eric Paris | 2920a84 | 2012-01-03 12:25:15 -0500 | [diff] [blame] | 298 | int ret; |
| 299 | |
| 300 | rcu_read_lock(); |
| 301 | ret = security_capable(__task_cred(t), ns, cap); |
| 302 | rcu_read_unlock(); |
Serge E. Hallyn | 3263245 | 2011-03-23 16:43:21 -0700 | [diff] [blame] | 303 | |
| 304 | return (ret == 0); |
| 305 | } |
| 306 | |
| 307 | /** |
Eric Paris | 25e7570 | 2012-01-03 12:25:15 -0500 | [diff] [blame] | 308 | * has_capability - Does a task have a capability in init_user_ns |
| 309 | * @t: The task in question |
| 310 | * @cap: The capability to be tested for |
| 311 | * |
| 312 | * Return true if the specified task has the given superior capability |
| 313 | * currently in effect to the initial user namespace, false if not. |
| 314 | * |
| 315 | * Note that this does not set PF_SUPERPRIV on the task. |
| 316 | */ |
| 317 | bool has_capability(struct task_struct *t, int cap) |
| 318 | { |
| 319 | return has_ns_capability(t, &init_user_ns, cap); |
| 320 | } |
Jike Song | 19c816e | 2017-01-12 16:52:02 +0800 | [diff] [blame] | 321 | EXPORT_SYMBOL(has_capability); |
Eric Paris | 25e7570 | 2012-01-03 12:25:15 -0500 | [diff] [blame] | 322 | |
| 323 | /** |
Eric Paris | 7b61d64 | 2012-01-03 12:25:15 -0500 | [diff] [blame] | 324 | * has_ns_capability_noaudit - Does a task have a capability (unaudited) |
| 325 | * in a specific user ns. |
| 326 | * @t: The task in question |
| 327 | * @ns: target user namespace |
| 328 | * @cap: The capability to be tested for |
| 329 | * |
| 330 | * Return true if the specified task has the given superior capability |
| 331 | * currently in effect to the specified user namespace, false if not. |
| 332 | * Do not write an audit message for the check. |
| 333 | * |
| 334 | * Note that this does not set PF_SUPERPRIV on the task. |
| 335 | */ |
| 336 | bool has_ns_capability_noaudit(struct task_struct *t, |
| 337 | struct user_namespace *ns, int cap) |
| 338 | { |
| 339 | int ret; |
| 340 | |
| 341 | rcu_read_lock(); |
| 342 | ret = security_capable_noaudit(__task_cred(t), ns, cap); |
| 343 | rcu_read_unlock(); |
| 344 | |
| 345 | return (ret == 0); |
| 346 | } |
| 347 | |
| 348 | /** |
| 349 | * has_capability_noaudit - Does a task have a capability (unaudited) in the |
| 350 | * initial user ns |
Serge E. Hallyn | 3263245 | 2011-03-23 16:43:21 -0700 | [diff] [blame] | 351 | * @t: The task in question |
| 352 | * @cap: The capability to be tested for |
| 353 | * |
| 354 | * Return true if the specified task has the given superior capability |
| 355 | * currently in effect to init_user_ns, false if not. Don't write an |
| 356 | * audit message for the check. |
| 357 | * |
| 358 | * Note that this does not set PF_SUPERPRIV on the task. |
| 359 | */ |
| 360 | bool has_capability_noaudit(struct task_struct *t, int cap) |
| 361 | { |
Eric Paris | 7b61d64 | 2012-01-03 12:25:15 -0500 | [diff] [blame] | 362 | return has_ns_capability_noaudit(t, &init_user_ns, cap); |
Serge E. Hallyn | 3263245 | 2011-03-23 16:43:21 -0700 | [diff] [blame] | 363 | } |
| 364 | |
Tyler Hicks | 98f368e | 2016-06-02 23:43:21 -0500 | [diff] [blame] | 365 | static bool ns_capable_common(struct user_namespace *ns, int cap, bool audit) |
| 366 | { |
| 367 | int capable; |
| 368 | |
| 369 | if (unlikely(!cap_valid(cap))) { |
| 370 | pr_crit("capable() called with invalid cap=%u\n", cap); |
| 371 | BUG(); |
| 372 | } |
| 373 | |
| 374 | capable = audit ? security_capable(current_cred(), ns, cap) : |
| 375 | security_capable_noaudit(current_cred(), ns, cap); |
| 376 | if (capable == 0) { |
| 377 | current->flags |= PF_SUPERPRIV; |
| 378 | return true; |
| 379 | } |
| 380 | return false; |
| 381 | } |
| 382 | |
Serge E. Hallyn | 3263245 | 2011-03-23 16:43:21 -0700 | [diff] [blame] | 383 | /** |
Serge E. Hallyn | 3486740 | 2011-03-23 16:43:17 -0700 | [diff] [blame] | 384 | * ns_capable - Determine if the current task has a superior capability in effect |
| 385 | * @ns: The usernamespace we want the capability in |
| 386 | * @cap: The capability to be tested for |
| 387 | * |
| 388 | * Return true if the current task has the given superior capability currently |
| 389 | * available for use, false if not. |
| 390 | * |
| 391 | * This sets PF_SUPERPRIV on the task if the capability is available on the |
| 392 | * assumption that it's about to be used. |
| 393 | */ |
| 394 | bool ns_capable(struct user_namespace *ns, int cap) |
Chris Wright | 12b5989 | 2006-03-25 03:07:41 -0800 | [diff] [blame] | 395 | { |
Tyler Hicks | 98f368e | 2016-06-02 23:43:21 -0500 | [diff] [blame] | 396 | return ns_capable_common(ns, cap, true); |
Chris Wright | 12b5989 | 2006-03-25 03:07:41 -0800 | [diff] [blame] | 397 | } |
Serge E. Hallyn | 3486740 | 2011-03-23 16:43:17 -0700 | [diff] [blame] | 398 | EXPORT_SYMBOL(ns_capable); |
| 399 | |
Tyler Hicks | 98f368e | 2016-06-02 23:43:21 -0500 | [diff] [blame] | 400 | /** |
| 401 | * ns_capable_noaudit - Determine if the current task has a superior capability |
| 402 | * (unaudited) in effect |
| 403 | * @ns: The usernamespace we want the capability in |
| 404 | * @cap: The capability to be tested for |
| 405 | * |
| 406 | * Return true if the current task has the given superior capability currently |
| 407 | * available for use, false if not. |
| 408 | * |
| 409 | * This sets PF_SUPERPRIV on the task if the capability is available on the |
| 410 | * assumption that it's about to be used. |
| 411 | */ |
| 412 | bool ns_capable_noaudit(struct user_namespace *ns, int cap) |
| 413 | { |
| 414 | return ns_capable_common(ns, cap, false); |
| 415 | } |
| 416 | EXPORT_SYMBOL(ns_capable_noaudit); |
Iulia Manda | 2813893 | 2015-04-15 16:16:41 -0700 | [diff] [blame] | 417 | |
| 418 | /** |
| 419 | * capable - Determine if the current task has a superior capability in effect |
| 420 | * @cap: The capability to be tested for |
| 421 | * |
| 422 | * Return true if the current task has the given superior capability currently |
| 423 | * available for use, false if not. |
| 424 | * |
| 425 | * This sets PF_SUPERPRIV on the task if the capability is available on the |
| 426 | * assumption that it's about to be used. |
| 427 | */ |
| 428 | bool capable(int cap) |
| 429 | { |
| 430 | return ns_capable(&init_user_ns, cap); |
| 431 | } |
| 432 | EXPORT_SYMBOL(capable); |
| 433 | #endif /* CONFIG_MULTIUSER */ |
| 434 | |
Serge E. Hallyn | 3486740 | 2011-03-23 16:43:17 -0700 | [diff] [blame] | 435 | /** |
Linus Torvalds | 935d8aa | 2013-04-14 10:06:31 -0700 | [diff] [blame] | 436 | * file_ns_capable - Determine if the file's opener had a capability in effect |
| 437 | * @file: The file we want to check |
| 438 | * @ns: The usernamespace we want the capability in |
| 439 | * @cap: The capability to be tested for |
| 440 | * |
| 441 | * Return true if task that opened the file had a capability in effect |
| 442 | * when the file was opened. |
| 443 | * |
| 444 | * This does not set PF_SUPERPRIV because the caller may not |
| 445 | * actually be privileged. |
| 446 | */ |
Fabian Frederick | a6c8c69 | 2014-06-04 16:11:19 -0700 | [diff] [blame] | 447 | bool file_ns_capable(const struct file *file, struct user_namespace *ns, |
| 448 | int cap) |
Linus Torvalds | 935d8aa | 2013-04-14 10:06:31 -0700 | [diff] [blame] | 449 | { |
| 450 | if (WARN_ON_ONCE(!cap_valid(cap))) |
| 451 | return false; |
| 452 | |
| 453 | if (security_capable(file->f_cred, ns, cap) == 0) |
| 454 | return true; |
| 455 | |
| 456 | return false; |
| 457 | } |
| 458 | EXPORT_SYMBOL(file_ns_capable); |
| 459 | |
| 460 | /** |
Eric W. Biederman | f84df2a | 2016-11-16 22:06:51 -0600 | [diff] [blame] | 461 | * privileged_wrt_inode_uidgid - Do capabilities in the namespace work over the inode? |
| 462 | * @ns: The user namespace in question |
| 463 | * @inode: The inode in question |
| 464 | * |
| 465 | * Return true if the inode uid and gid are within the namespace. |
| 466 | */ |
| 467 | bool privileged_wrt_inode_uidgid(struct user_namespace *ns, const struct inode *inode) |
| 468 | { |
| 469 | return kuid_has_mapping(ns, inode->i_uid) && |
| 470 | kgid_has_mapping(ns, inode->i_gid); |
| 471 | } |
| 472 | |
| 473 | /** |
Andy Lutomirski | 23adbe1 | 2014-06-10 12:45:42 -0700 | [diff] [blame] | 474 | * 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] | 475 | * @inode: The inode in question |
| 476 | * @cap: The capability in question |
| 477 | * |
Andy Lutomirski | 23adbe1 | 2014-06-10 12:45:42 -0700 | [diff] [blame] | 478 | * Return true if the current task has the given capability targeted at |
| 479 | * its own user namespace and that the given inode's uid and gid are |
| 480 | * mapped into the current user namespace. |
Eric W. Biederman | 1a48e2a | 2011-11-14 16:24:06 -0800 | [diff] [blame] | 481 | */ |
Andy Lutomirski | 23adbe1 | 2014-06-10 12:45:42 -0700 | [diff] [blame] | 482 | bool capable_wrt_inode_uidgid(const struct inode *inode, int cap) |
Eric W. Biederman | 1a48e2a | 2011-11-14 16:24:06 -0800 | [diff] [blame] | 483 | { |
| 484 | struct user_namespace *ns = current_user_ns(); |
| 485 | |
Eric W. Biederman | f84df2a | 2016-11-16 22:06:51 -0600 | [diff] [blame] | 486 | return ns_capable(ns, cap) && privileged_wrt_inode_uidgid(ns, inode); |
Eric W. Biederman | 1a48e2a | 2011-11-14 16:24:06 -0800 | [diff] [blame] | 487 | } |
Andy Lutomirski | 23adbe1 | 2014-06-10 12:45:42 -0700 | [diff] [blame] | 488 | EXPORT_SYMBOL(capable_wrt_inode_uidgid); |
Eric W. Biederman | 64b875f | 2016-11-14 18:48:07 -0600 | [diff] [blame] | 489 | |
| 490 | /** |
| 491 | * ptracer_capable - Determine if the ptracer holds CAP_SYS_PTRACE in the namespace |
| 492 | * @tsk: The task that may be ptraced |
| 493 | * @ns: The user namespace to search for CAP_SYS_PTRACE in |
| 494 | * |
| 495 | * Return true if the task that is ptracing the current task had CAP_SYS_PTRACE |
| 496 | * in the specified user namespace. |
| 497 | */ |
| 498 | bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns) |
| 499 | { |
| 500 | int ret = 0; /* An absent tracer adds no restrictions */ |
| 501 | const struct cred *cred; |
| 502 | rcu_read_lock(); |
| 503 | cred = rcu_dereference(tsk->ptracer_cred); |
| 504 | if (cred) |
| 505 | ret = security_capable_noaudit(cred, ns, CAP_SYS_PTRACE); |
| 506 | rcu_read_unlock(); |
| 507 | return (ret == 0); |
| 508 | } |