Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | kmod, the new module loader (replaces kerneld) |
| 3 | Kirk Petersen |
| 4 | |
| 5 | Reorganized not to be a daemon by Adam Richter, with guidance |
| 6 | from Greg Zornetzer. |
| 7 | |
| 8 | Modified to avoid chroot and file sharing problems. |
| 9 | Mikael Pettersson |
| 10 | |
| 11 | Limit the concurrent number of kmod modprobes to catch loops from |
| 12 | "modprobe needs a service that is in a module". |
| 13 | Keith Owens <kaos@ocs.com.au> December 1999 |
| 14 | |
| 15 | Unblock all signals when we exec a usermode process. |
| 16 | Shuu Yamaguchi <shuu@wondernetworkresources.com> December 2000 |
| 17 | |
| 18 | call_usermodehelper wait flag, and remove exec_usermodehelper. |
| 19 | Rusty Russell <rusty@rustcorp.com.au> Jan 2003 |
| 20 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 21 | #include <linux/module.h> |
| 22 | #include <linux/sched.h> |
| 23 | #include <linux/syscalls.h> |
| 24 | #include <linux/unistd.h> |
| 25 | #include <linux/kmod.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 26 | #include <linux/slab.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 27 | #include <linux/completion.h> |
Eric Paris | 17f60a7 | 2011-04-01 17:07:50 -0400 | [diff] [blame] | 28 | #include <linux/cred.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | #include <linux/file.h> |
Al Viro | 9f3acc3 | 2008-04-24 07:44:08 -0400 | [diff] [blame] | 30 | #include <linux/fdtable.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 31 | #include <linux/workqueue.h> |
| 32 | #include <linux/security.h> |
| 33 | #include <linux/mount.h> |
| 34 | #include <linux/kernel.h> |
| 35 | #include <linux/init.h> |
Andi Kleen | d025c9d | 2006-09-30 23:29:28 -0700 | [diff] [blame] | 36 | #include <linux/resource.h> |
Rafael J. Wysocki | 8cdd493 | 2007-07-19 01:47:36 -0700 | [diff] [blame] | 37 | #include <linux/notifier.h> |
| 38 | #include <linux/suspend.h> |
Srivatsa S. Bhat | b298d28 | 2011-12-09 23:36:36 +0100 | [diff] [blame] | 39 | #include <linux/rwsem.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 40 | #include <asm/uaccess.h> |
| 41 | |
Li Zefan | 7ead8b8 | 2009-08-17 16:56:28 +0800 | [diff] [blame] | 42 | #include <trace/events/module.h> |
| 43 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 44 | extern int max_threads; |
| 45 | |
| 46 | static struct workqueue_struct *khelper_wq; |
| 47 | |
Eric Paris | 17f60a7 | 2011-04-01 17:07:50 -0400 | [diff] [blame] | 48 | #define CAP_BSET (void *)1 |
| 49 | #define CAP_PI (void *)2 |
| 50 | |
| 51 | static kernel_cap_t usermodehelper_bset = CAP_FULL_SET; |
| 52 | static kernel_cap_t usermodehelper_inheritable = CAP_FULL_SET; |
| 53 | static DEFINE_SPINLOCK(umh_sysctl_lock); |
Srivatsa S. Bhat | b298d28 | 2011-12-09 23:36:36 +0100 | [diff] [blame] | 54 | static DECLARE_RWSEM(umhelper_sem); |
Eric Paris | 17f60a7 | 2011-04-01 17:07:50 -0400 | [diff] [blame] | 55 | |
Johannes Berg | a1ef5ad | 2008-07-08 19:00:17 +0200 | [diff] [blame] | 56 | #ifdef CONFIG_MODULES |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 57 | |
| 58 | /* |
| 59 | modprobe_path is set via /proc/sys. |
| 60 | */ |
| 61 | char modprobe_path[KMOD_PATH_LEN] = "/sbin/modprobe"; |
| 62 | |
| 63 | /** |
Arjan van de Ven | acae051 | 2009-02-08 10:42:01 -0800 | [diff] [blame] | 64 | * __request_module - try to load a kernel module |
| 65 | * @wait: wait (or not) for the operation to complete |
Randy Dunlap | bd4207c | 2009-01-06 14:42:39 -0800 | [diff] [blame] | 66 | * @fmt: printf style format string for the name of the module |
| 67 | * @...: arguments as specified in the format string |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 68 | * |
| 69 | * Load a module using the user mode module loader. The function returns |
| 70 | * zero on success or a negative errno code on failure. Note that a |
| 71 | * successful module load does not mean the module did not then unload |
| 72 | * and exit on an error of its own. Callers must check that the service |
| 73 | * they requested is now available not blindly invoke it. |
| 74 | * |
| 75 | * If module auto-loading support is disabled then this function |
| 76 | * becomes a no-operation. |
| 77 | */ |
Arjan van de Ven | acae051 | 2009-02-08 10:42:01 -0800 | [diff] [blame] | 78 | int __request_module(bool wait, const char *fmt, ...) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 79 | { |
| 80 | va_list args; |
| 81 | char module_name[MODULE_NAME_LEN]; |
| 82 | unsigned int max_modprobes; |
| 83 | int ret; |
| 84 | char *argv[] = { modprobe_path, "-q", "--", module_name, NULL }; |
| 85 | static char *envp[] = { "HOME=/", |
| 86 | "TERM=linux", |
| 87 | "PATH=/sbin:/usr/sbin:/bin:/usr/bin", |
| 88 | NULL }; |
| 89 | static atomic_t kmod_concurrent = ATOMIC_INIT(0); |
| 90 | #define MAX_KMOD_CONCURRENT 50 /* Completely arbitrary value - KAO */ |
| 91 | static int kmod_loop_msg; |
| 92 | |
| 93 | va_start(args, fmt); |
| 94 | ret = vsnprintf(module_name, MODULE_NAME_LEN, fmt, args); |
| 95 | va_end(args); |
| 96 | if (ret >= MODULE_NAME_LEN) |
| 97 | return -ENAMETOOLONG; |
| 98 | |
Eric Paris | dd8dbf2 | 2009-11-03 16:35:32 +1100 | [diff] [blame] | 99 | ret = security_kernel_module_request(module_name); |
| 100 | if (ret) |
| 101 | return ret; |
| 102 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 103 | /* If modprobe needs a service that is in a module, we get a recursive |
| 104 | * loop. Limit the number of running kmod threads to max_threads/2 or |
| 105 | * MAX_KMOD_CONCURRENT, whichever is the smaller. A cleaner method |
| 106 | * would be to run the parents of this process, counting how many times |
| 107 | * kmod was invoked. That would mean accessing the internals of the |
| 108 | * process tables to get the command line, proc_pid_cmdline is static |
| 109 | * and it is not worth changing the proc code just to handle this case. |
| 110 | * KAO. |
| 111 | * |
| 112 | * "trace the ppid" is simple, but will fail if someone's |
| 113 | * parent exits. I think this is as good as it gets. --RR |
| 114 | */ |
| 115 | max_modprobes = min(max_threads/2, MAX_KMOD_CONCURRENT); |
| 116 | atomic_inc(&kmod_concurrent); |
| 117 | if (atomic_read(&kmod_concurrent) > max_modprobes) { |
| 118 | /* We may be blaming an innocent here, but unlikely */ |
Jiri Kosina | 37252db | 2011-10-26 13:10:39 +1030 | [diff] [blame] | 119 | if (kmod_loop_msg < 5) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 120 | printk(KERN_ERR |
| 121 | "request_module: runaway loop modprobe %s\n", |
| 122 | module_name); |
Jiri Kosina | 37252db | 2011-10-26 13:10:39 +1030 | [diff] [blame] | 123 | kmod_loop_msg++; |
| 124 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 125 | atomic_dec(&kmod_concurrent); |
| 126 | return -ENOMEM; |
| 127 | } |
| 128 | |
Li Zefan | 7ead8b8 | 2009-08-17 16:56:28 +0800 | [diff] [blame] | 129 | trace_module_request(module_name, wait, _RET_IP_); |
| 130 | |
Neil Horman | a06a4dc | 2010-05-26 14:42:58 -0700 | [diff] [blame] | 131 | ret = call_usermodehelper_fns(modprobe_path, argv, envp, |
| 132 | wait ? UMH_WAIT_PROC : UMH_WAIT_EXEC, |
| 133 | NULL, NULL, NULL); |
| 134 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 135 | atomic_dec(&kmod_concurrent); |
| 136 | return ret; |
| 137 | } |
Arjan van de Ven | acae051 | 2009-02-08 10:42:01 -0800 | [diff] [blame] | 138 | EXPORT_SYMBOL(__request_module); |
Rusty Russell | 118a906 | 2008-10-17 02:38:36 -0500 | [diff] [blame] | 139 | #endif /* CONFIG_MODULES */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 140 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 141 | /* |
| 142 | * This is the task which runs the usermode application |
| 143 | */ |
| 144 | static int ____call_usermodehelper(void *data) |
| 145 | { |
| 146 | struct subprocess_info *sub_info = data; |
Eric Paris | 17f60a7 | 2011-04-01 17:07:50 -0400 | [diff] [blame] | 147 | struct cred *new; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 148 | int retval; |
| 149 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 150 | spin_lock_irq(¤t->sighand->siglock); |
| 151 | flush_signal_handlers(current, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 152 | spin_unlock_irq(¤t->sighand->siglock); |
| 153 | |
| 154 | /* We can run anywhere, unlike our parent keventd(). */ |
Rusty Russell | 1a2142a | 2009-03-30 22:05:10 -0600 | [diff] [blame] | 155 | set_cpus_allowed_ptr(current, cpu_all_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 156 | |
Jan Engelhardt | b73a7e7 | 2007-05-08 00:28:24 -0700 | [diff] [blame] | 157 | /* |
| 158 | * Our parent is keventd, which runs with elevated scheduling priority. |
| 159 | * Avoid propagating that into the userspace child. |
| 160 | */ |
| 161 | set_user_nice(current, 0); |
| 162 | |
Eric Paris | 17f60a7 | 2011-04-01 17:07:50 -0400 | [diff] [blame] | 163 | retval = -ENOMEM; |
| 164 | new = prepare_kernel_cred(current); |
| 165 | if (!new) |
| 166 | goto fail; |
| 167 | |
| 168 | spin_lock(&umh_sysctl_lock); |
| 169 | new->cap_bset = cap_intersect(usermodehelper_bset, new->cap_bset); |
| 170 | new->cap_inheritable = cap_intersect(usermodehelper_inheritable, |
| 171 | new->cap_inheritable); |
| 172 | spin_unlock(&umh_sysctl_lock); |
| 173 | |
David Howells | 8796699 | 2011-06-17 11:25:59 +0100 | [diff] [blame] | 174 | if (sub_info->init) { |
| 175 | retval = sub_info->init(sub_info, new); |
| 176 | if (retval) { |
| 177 | abort_creds(new); |
| 178 | goto fail; |
| 179 | } |
| 180 | } |
| 181 | |
Eric Paris | 17f60a7 | 2011-04-01 17:07:50 -0400 | [diff] [blame] | 182 | commit_creds(new); |
| 183 | |
David Howells | d762746 | 2010-08-17 23:52:56 +0100 | [diff] [blame] | 184 | retval = kernel_execve(sub_info->path, |
| 185 | (const char *const *)sub_info->argv, |
| 186 | (const char *const *)sub_info->envp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 187 | |
| 188 | /* Exec failed? */ |
Neil Horman | a06a4dc | 2010-05-26 14:42:58 -0700 | [diff] [blame] | 189 | fail: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 190 | sub_info->retval = retval; |
| 191 | do_exit(0); |
| 192 | } |
| 193 | |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 194 | void call_usermodehelper_freeinfo(struct subprocess_info *info) |
| 195 | { |
| 196 | if (info->cleanup) |
Neil Horman | a06a4dc | 2010-05-26 14:42:58 -0700 | [diff] [blame] | 197 | (*info->cleanup)(info); |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 198 | kfree(info); |
| 199 | } |
| 200 | EXPORT_SYMBOL(call_usermodehelper_freeinfo); |
| 201 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 202 | /* Keventd can't block, but this (a child) can. */ |
| 203 | static int wait_for_helper(void *data) |
| 204 | { |
| 205 | struct subprocess_info *sub_info = data; |
| 206 | pid_t pid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 207 | |
Oleg Nesterov | 7d64224 | 2010-05-26 14:43:03 -0700 | [diff] [blame] | 208 | /* If SIGCLD is ignored sys_wait4 won't populate the status. */ |
| 209 | spin_lock_irq(¤t->sighand->siglock); |
| 210 | current->sighand->action[SIGCHLD-1].sa.sa_handler = SIG_DFL; |
| 211 | spin_unlock_irq(¤t->sighand->siglock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 212 | |
| 213 | pid = kernel_thread(____call_usermodehelper, sub_info, SIGCHLD); |
| 214 | if (pid < 0) { |
| 215 | sub_info->retval = pid; |
| 216 | } else { |
Oleg Nesterov | 7d64224 | 2010-05-26 14:43:03 -0700 | [diff] [blame] | 217 | int ret = -ECHILD; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 218 | /* |
| 219 | * Normally it is bogus to call wait4() from in-kernel because |
| 220 | * wait4() wants to write the exit code to a userspace address. |
| 221 | * But wait_for_helper() always runs as keventd, and put_user() |
| 222 | * to a kernel address works OK for kernel threads, due to their |
| 223 | * having an mm_segment_t which spans the entire address space. |
| 224 | * |
| 225 | * Thus the __user pointer cast is valid here. |
| 226 | */ |
Björn Steinbrink | 111dbe0 | 2006-09-29 02:00:46 -0700 | [diff] [blame] | 227 | sys_wait4(pid, (int __user *)&ret, 0, NULL); |
| 228 | |
| 229 | /* |
| 230 | * If ret is 0, either ____call_usermodehelper failed and the |
| 231 | * real error code is already in sub_info->retval or |
| 232 | * sub_info->retval is 0 anyway, so don't mess with it then. |
| 233 | */ |
| 234 | if (ret) |
| 235 | sub_info->retval = ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 236 | } |
| 237 | |
Oleg Nesterov | d47419c | 2010-05-26 14:43:04 -0700 | [diff] [blame] | 238 | complete(sub_info->complete); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 239 | return 0; |
| 240 | } |
| 241 | |
| 242 | /* This is run by khelper thread */ |
David Howells | 65f27f3 | 2006-11-22 14:55:48 +0000 | [diff] [blame] | 243 | static void __call_usermodehelper(struct work_struct *work) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 244 | { |
David Howells | 65f27f3 | 2006-11-22 14:55:48 +0000 | [diff] [blame] | 245 | struct subprocess_info *sub_info = |
| 246 | container_of(work, struct subprocess_info, work); |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 247 | enum umh_wait wait = sub_info->wait; |
Oleg Nesterov | d47419c | 2010-05-26 14:43:04 -0700 | [diff] [blame] | 248 | pid_t pid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 249 | |
| 250 | /* CLONE_VFORK: wait until the usermode helper has execve'd |
| 251 | * successfully We need the data structures to stay around |
| 252 | * until that is done. */ |
Oleg Nesterov | d47419c | 2010-05-26 14:43:04 -0700 | [diff] [blame] | 253 | if (wait == UMH_WAIT_PROC) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 254 | pid = kernel_thread(wait_for_helper, sub_info, |
| 255 | CLONE_FS | CLONE_FILES | SIGCHLD); |
| 256 | else |
| 257 | pid = kernel_thread(____call_usermodehelper, sub_info, |
| 258 | CLONE_VFORK | SIGCHLD); |
| 259 | |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 260 | switch (wait) { |
| 261 | case UMH_NO_WAIT: |
Oleg Nesterov | d47419c | 2010-05-26 14:43:04 -0700 | [diff] [blame] | 262 | call_usermodehelper_freeinfo(sub_info); |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 263 | break; |
Andi Kleen | a98f0dd | 2007-02-13 13:26:23 +0100 | [diff] [blame] | 264 | |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 265 | case UMH_WAIT_PROC: |
| 266 | if (pid > 0) |
| 267 | break; |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 268 | /* FALLTHROUGH */ |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 269 | case UMH_WAIT_EXEC: |
Oleg Nesterov | 04b1c38 | 2010-05-26 14:43:05 -0700 | [diff] [blame] | 270 | if (pid < 0) |
| 271 | sub_info->retval = pid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 272 | complete(sub_info->complete); |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 273 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 274 | } |
| 275 | |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 276 | /* |
| 277 | * If set, call_usermodehelper_exec() will exit immediately returning -EBUSY |
| 278 | * (used for preventing user land processes from being created after the user |
| 279 | * land has been frozen during a system-wide hibernation or suspend operation). |
Srivatsa S. Bhat | b298d28 | 2011-12-09 23:36:36 +0100 | [diff] [blame] | 280 | * Should always be manipulated under umhelper_sem acquired for write. |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 281 | */ |
Linus Torvalds | 288d5ab | 2011-08-03 22:03:29 -1000 | [diff] [blame] | 282 | static int usermodehelper_disabled = 1; |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 283 | |
| 284 | /* Number of helpers running */ |
| 285 | static atomic_t running_helpers = ATOMIC_INIT(0); |
| 286 | |
| 287 | /* |
Srivatsa S. Bhat | 5307427 | 2011-11-15 21:59:21 +0100 | [diff] [blame] | 288 | * Wait queue head used by usermodehelper_disable() to wait for all running |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 289 | * helpers to finish. |
| 290 | */ |
| 291 | static DECLARE_WAIT_QUEUE_HEAD(running_helpers_waitq); |
| 292 | |
| 293 | /* |
| 294 | * Time to wait for running_helpers to become zero before the setting of |
Srivatsa S. Bhat | 5307427 | 2011-11-15 21:59:21 +0100 | [diff] [blame] | 295 | * usermodehelper_disabled in usermodehelper_disable() fails |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 296 | */ |
| 297 | #define RUNNING_HELPERS_TIMEOUT (5 * HZ) |
| 298 | |
Srivatsa S. Bhat | b298d28 | 2011-12-09 23:36:36 +0100 | [diff] [blame] | 299 | void read_lock_usermodehelper(void) |
| 300 | { |
| 301 | down_read(&umhelper_sem); |
| 302 | } |
| 303 | EXPORT_SYMBOL_GPL(read_lock_usermodehelper); |
| 304 | |
| 305 | void read_unlock_usermodehelper(void) |
| 306 | { |
| 307 | up_read(&umhelper_sem); |
| 308 | } |
| 309 | EXPORT_SYMBOL_GPL(read_unlock_usermodehelper); |
| 310 | |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 311 | /** |
| 312 | * usermodehelper_disable - prevent new helpers from being started |
| 313 | */ |
| 314 | int usermodehelper_disable(void) |
Rafael J. Wysocki | 8cdd493 | 2007-07-19 01:47:36 -0700 | [diff] [blame] | 315 | { |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 316 | long retval; |
| 317 | |
Srivatsa S. Bhat | b298d28 | 2011-12-09 23:36:36 +0100 | [diff] [blame] | 318 | down_write(&umhelper_sem); |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 319 | usermodehelper_disabled = 1; |
Srivatsa S. Bhat | b298d28 | 2011-12-09 23:36:36 +0100 | [diff] [blame] | 320 | up_write(&umhelper_sem); |
| 321 | |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 322 | /* |
| 323 | * From now on call_usermodehelper_exec() won't start any new |
| 324 | * helpers, so it is sufficient if running_helpers turns out to |
| 325 | * be zero at one point (it may be increased later, but that |
| 326 | * doesn't matter). |
| 327 | */ |
| 328 | retval = wait_event_timeout(running_helpers_waitq, |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 329 | atomic_read(&running_helpers) == 0, |
| 330 | RUNNING_HELPERS_TIMEOUT); |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 331 | if (retval) |
| 332 | return 0; |
Rafael J. Wysocki | 8cdd493 | 2007-07-19 01:47:36 -0700 | [diff] [blame] | 333 | |
Srivatsa S. Bhat | b298d28 | 2011-12-09 23:36:36 +0100 | [diff] [blame] | 334 | down_write(&umhelper_sem); |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 335 | usermodehelper_disabled = 0; |
Srivatsa S. Bhat | b298d28 | 2011-12-09 23:36:36 +0100 | [diff] [blame] | 336 | up_write(&umhelper_sem); |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 337 | return -EAGAIN; |
| 338 | } |
| 339 | |
| 340 | /** |
| 341 | * usermodehelper_enable - allow new helpers to be started again |
| 342 | */ |
| 343 | void usermodehelper_enable(void) |
| 344 | { |
Srivatsa S. Bhat | b298d28 | 2011-12-09 23:36:36 +0100 | [diff] [blame] | 345 | down_write(&umhelper_sem); |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 346 | usermodehelper_disabled = 0; |
Srivatsa S. Bhat | b298d28 | 2011-12-09 23:36:36 +0100 | [diff] [blame] | 347 | up_write(&umhelper_sem); |
Rafael J. Wysocki | 8cdd493 | 2007-07-19 01:47:36 -0700 | [diff] [blame] | 348 | } |
| 349 | |
Rafael J. Wysocki | a144c6a | 2011-05-06 20:09:42 +0200 | [diff] [blame] | 350 | /** |
| 351 | * usermodehelper_is_disabled - check if new helpers are allowed to be started |
| 352 | */ |
| 353 | bool usermodehelper_is_disabled(void) |
| 354 | { |
| 355 | return usermodehelper_disabled; |
| 356 | } |
| 357 | EXPORT_SYMBOL_GPL(usermodehelper_is_disabled); |
| 358 | |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 359 | static void helper_lock(void) |
| 360 | { |
| 361 | atomic_inc(&running_helpers); |
| 362 | smp_mb__after_atomic_inc(); |
| 363 | } |
| 364 | |
| 365 | static void helper_unlock(void) |
| 366 | { |
| 367 | if (atomic_dec_and_test(&running_helpers)) |
| 368 | wake_up(&running_helpers_waitq); |
| 369 | } |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 370 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 371 | /** |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 372 | * call_usermodehelper_setup - prepare to call a usermode helper |
Randy Dunlap | 61df47c | 2007-07-26 10:40:56 -0700 | [diff] [blame] | 373 | * @path: path to usermode executable |
| 374 | * @argv: arg vector for process |
| 375 | * @envp: environment for process |
KOSAKI Motohiro | ac331d1 | 2008-07-25 01:45:38 -0700 | [diff] [blame] | 376 | * @gfp_mask: gfp mask for memory allocation |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 377 | * |
Randy Dunlap | 61df47c | 2007-07-26 10:40:56 -0700 | [diff] [blame] | 378 | * Returns either %NULL on allocation failure, or a subprocess_info |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 379 | * structure. This should be passed to call_usermodehelper_exec to |
| 380 | * exec the process and free the structure. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 381 | */ |
KOSAKI Motohiro | ac331d1 | 2008-07-25 01:45:38 -0700 | [diff] [blame] | 382 | struct subprocess_info *call_usermodehelper_setup(char *path, char **argv, |
| 383 | char **envp, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 384 | { |
Andi Kleen | a98f0dd | 2007-02-13 13:26:23 +0100 | [diff] [blame] | 385 | struct subprocess_info *sub_info; |
KOSAKI Motohiro | ac331d1 | 2008-07-25 01:45:38 -0700 | [diff] [blame] | 386 | sub_info = kzalloc(sizeof(struct subprocess_info), gfp_mask); |
Andi Kleen | a98f0dd | 2007-02-13 13:26:23 +0100 | [diff] [blame] | 387 | if (!sub_info) |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 388 | goto out; |
Andi Kleen | a98f0dd | 2007-02-13 13:26:23 +0100 | [diff] [blame] | 389 | |
| 390 | INIT_WORK(&sub_info->work, __call_usermodehelper); |
Andi Kleen | a98f0dd | 2007-02-13 13:26:23 +0100 | [diff] [blame] | 391 | sub_info->path = path; |
| 392 | sub_info->argv = argv; |
| 393 | sub_info->envp = envp; |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 394 | out: |
| 395 | return sub_info; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 396 | } |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 397 | EXPORT_SYMBOL(call_usermodehelper_setup); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 398 | |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 399 | /** |
Neil Horman | a06a4dc | 2010-05-26 14:42:58 -0700 | [diff] [blame] | 400 | * call_usermodehelper_setfns - set a cleanup/init function |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 401 | * @info: a subprocess_info returned by call_usermodehelper_setup |
| 402 | * @cleanup: a cleanup function |
Neil Horman | a06a4dc | 2010-05-26 14:42:58 -0700 | [diff] [blame] | 403 | * @init: an init function |
| 404 | * @data: arbitrary context sensitive data |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 405 | * |
Neil Horman | a06a4dc | 2010-05-26 14:42:58 -0700 | [diff] [blame] | 406 | * The init function is used to customize the helper process prior to |
| 407 | * exec. A non-zero return code causes the process to error out, exit, |
| 408 | * and return the failure to the calling process |
| 409 | * |
| 410 | * The cleanup function is just before ethe subprocess_info is about to |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 411 | * be freed. This can be used for freeing the argv and envp. The |
| 412 | * Function must be runnable in either a process context or the |
| 413 | * context in which call_usermodehelper_exec is called. |
| 414 | */ |
Neil Horman | a06a4dc | 2010-05-26 14:42:58 -0700 | [diff] [blame] | 415 | void call_usermodehelper_setfns(struct subprocess_info *info, |
David Howells | 8796699 | 2011-06-17 11:25:59 +0100 | [diff] [blame] | 416 | int (*init)(struct subprocess_info *info, struct cred *new), |
Neil Horman | a06a4dc | 2010-05-26 14:42:58 -0700 | [diff] [blame] | 417 | void (*cleanup)(struct subprocess_info *info), |
| 418 | void *data) |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 419 | { |
| 420 | info->cleanup = cleanup; |
Neil Horman | a06a4dc | 2010-05-26 14:42:58 -0700 | [diff] [blame] | 421 | info->init = init; |
| 422 | info->data = data; |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 423 | } |
Neil Horman | a06a4dc | 2010-05-26 14:42:58 -0700 | [diff] [blame] | 424 | EXPORT_SYMBOL(call_usermodehelper_setfns); |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 425 | |
| 426 | /** |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 427 | * call_usermodehelper_exec - start a usermode application |
| 428 | * @sub_info: information about the subprocessa |
| 429 | * @wait: wait for the application to finish and return status. |
| 430 | * when -1 don't wait at all, but you get no useful error back when |
| 431 | * the program couldn't be exec'ed. This makes it safe to call |
| 432 | * from interrupt context. |
| 433 | * |
| 434 | * Runs a user-space application. The application is started |
| 435 | * asynchronously if wait is not set, and runs as a child of keventd. |
| 436 | * (ie. it runs with full root capabilities). |
| 437 | */ |
| 438 | int call_usermodehelper_exec(struct subprocess_info *sub_info, |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 439 | enum umh_wait wait) |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 440 | { |
| 441 | DECLARE_COMPLETION_ONSTACK(done); |
Nigel Cunningham | 7846803 | 2008-01-17 15:21:21 -0800 | [diff] [blame] | 442 | int retval = 0; |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 443 | |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 444 | helper_lock(); |
Nigel Cunningham | 7846803 | 2008-01-17 15:21:21 -0800 | [diff] [blame] | 445 | if (sub_info->path[0] == '\0') |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 446 | goto out; |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 447 | |
Rafael J. Wysocki | 8cdd493 | 2007-07-19 01:47:36 -0700 | [diff] [blame] | 448 | if (!khelper_wq || usermodehelper_disabled) { |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 449 | retval = -EBUSY; |
| 450 | goto out; |
| 451 | } |
| 452 | |
| 453 | sub_info->complete = &done; |
| 454 | sub_info->wait = wait; |
| 455 | |
| 456 | queue_work(khelper_wq, &sub_info->work); |
Nigel Cunningham | 7846803 | 2008-01-17 15:21:21 -0800 | [diff] [blame] | 457 | if (wait == UMH_NO_WAIT) /* task has freed sub_info */ |
| 458 | goto unlock; |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 459 | wait_for_completion(&done); |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 460 | retval = sub_info->retval; |
| 461 | |
Nigel Cunningham | 7846803 | 2008-01-17 15:21:21 -0800 | [diff] [blame] | 462 | out: |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 463 | call_usermodehelper_freeinfo(sub_info); |
Nigel Cunningham | 7846803 | 2008-01-17 15:21:21 -0800 | [diff] [blame] | 464 | unlock: |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 465 | helper_unlock(); |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 466 | return retval; |
| 467 | } |
| 468 | EXPORT_SYMBOL(call_usermodehelper_exec); |
| 469 | |
Eric Paris | 17f60a7 | 2011-04-01 17:07:50 -0400 | [diff] [blame] | 470 | static int proc_cap_handler(struct ctl_table *table, int write, |
| 471 | void __user *buffer, size_t *lenp, loff_t *ppos) |
| 472 | { |
| 473 | struct ctl_table t; |
| 474 | unsigned long cap_array[_KERNEL_CAPABILITY_U32S]; |
| 475 | kernel_cap_t new_cap; |
| 476 | int err, i; |
| 477 | |
| 478 | if (write && (!capable(CAP_SETPCAP) || |
| 479 | !capable(CAP_SYS_MODULE))) |
| 480 | return -EPERM; |
| 481 | |
| 482 | /* |
| 483 | * convert from the global kernel_cap_t to the ulong array to print to |
| 484 | * userspace if this is a read. |
| 485 | */ |
| 486 | spin_lock(&umh_sysctl_lock); |
| 487 | for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++) { |
| 488 | if (table->data == CAP_BSET) |
| 489 | cap_array[i] = usermodehelper_bset.cap[i]; |
| 490 | else if (table->data == CAP_PI) |
| 491 | cap_array[i] = usermodehelper_inheritable.cap[i]; |
| 492 | else |
| 493 | BUG(); |
| 494 | } |
| 495 | spin_unlock(&umh_sysctl_lock); |
| 496 | |
| 497 | t = *table; |
| 498 | t.data = &cap_array; |
| 499 | |
| 500 | /* |
| 501 | * actually read or write and array of ulongs from userspace. Remember |
| 502 | * these are least significant 32 bits first |
| 503 | */ |
| 504 | err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos); |
| 505 | if (err < 0) |
| 506 | return err; |
| 507 | |
| 508 | /* |
| 509 | * convert from the sysctl array of ulongs to the kernel_cap_t |
| 510 | * internal representation |
| 511 | */ |
| 512 | for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++) |
| 513 | new_cap.cap[i] = cap_array[i]; |
| 514 | |
| 515 | /* |
| 516 | * Drop everything not in the new_cap (but don't add things) |
| 517 | */ |
| 518 | spin_lock(&umh_sysctl_lock); |
| 519 | if (write) { |
| 520 | if (table->data == CAP_BSET) |
| 521 | usermodehelper_bset = cap_intersect(usermodehelper_bset, new_cap); |
| 522 | if (table->data == CAP_PI) |
| 523 | usermodehelper_inheritable = cap_intersect(usermodehelper_inheritable, new_cap); |
| 524 | } |
| 525 | spin_unlock(&umh_sysctl_lock); |
| 526 | |
| 527 | return 0; |
| 528 | } |
| 529 | |
| 530 | struct ctl_table usermodehelper_table[] = { |
| 531 | { |
| 532 | .procname = "bset", |
| 533 | .data = CAP_BSET, |
| 534 | .maxlen = _KERNEL_CAPABILITY_U32S * sizeof(unsigned long), |
| 535 | .mode = 0600, |
| 536 | .proc_handler = proc_cap_handler, |
| 537 | }, |
| 538 | { |
| 539 | .procname = "inheritable", |
| 540 | .data = CAP_PI, |
| 541 | .maxlen = _KERNEL_CAPABILITY_U32S * sizeof(unsigned long), |
| 542 | .mode = 0600, |
| 543 | .proc_handler = proc_cap_handler, |
| 544 | }, |
| 545 | { } |
| 546 | }; |
| 547 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 548 | void __init usermodehelper_init(void) |
| 549 | { |
| 550 | khelper_wq = create_singlethread_workqueue("khelper"); |
| 551 | BUG_ON(!khelper_wq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 552 | } |