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> |
Al Viro | a74fb73 | 2012-10-10 21:28:25 -0400 | [diff] [blame] | 40 | #include <linux/ptrace.h> |
Tejun Heo | 0fdff3e | 2013-01-22 16:48:03 -0800 | [diff] [blame] | 41 | #include <linux/async.h> |
Linus Torvalds | 7c0f6ba | 2016-12-24 11:46:01 -0800 | [diff] [blame] | 42 | #include <linux/uaccess.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | |
Li Zefan | 7ead8b8 | 2009-08-17 16:56:28 +0800 | [diff] [blame] | 44 | #include <trace/events/module.h> |
| 45 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 46 | extern int max_threads; |
| 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 | |
Oleg Nesterov | 1cc684a | 2012-03-23 15:02:50 -0700 | [diff] [blame] | 63 | static void free_modprobe_argv(struct subprocess_info *info) |
| 64 | { |
| 65 | kfree(info->argv[3]); /* check call_modprobe() */ |
| 66 | kfree(info->argv); |
| 67 | } |
| 68 | |
Oleg Nesterov | 3e63a93 | 2012-03-23 15:02:49 -0700 | [diff] [blame] | 69 | static int call_modprobe(char *module_name, int wait) |
| 70 | { |
Lucas De Marchi | f634460 | 2013-04-30 15:28:03 -0700 | [diff] [blame] | 71 | struct subprocess_info *info; |
Oleg Nesterov | 3e63a93 | 2012-03-23 15:02:49 -0700 | [diff] [blame] | 72 | static char *envp[] = { |
| 73 | "HOME=/", |
| 74 | "TERM=linux", |
| 75 | "PATH=/sbin:/usr/sbin:/bin:/usr/bin", |
| 76 | NULL |
| 77 | }; |
| 78 | |
Oleg Nesterov | 1cc684a | 2012-03-23 15:02:50 -0700 | [diff] [blame] | 79 | char **argv = kmalloc(sizeof(char *[5]), GFP_KERNEL); |
| 80 | if (!argv) |
| 81 | goto out; |
| 82 | |
| 83 | module_name = kstrdup(module_name, GFP_KERNEL); |
| 84 | if (!module_name) |
| 85 | goto free_argv; |
| 86 | |
| 87 | argv[0] = modprobe_path; |
| 88 | argv[1] = "-q"; |
| 89 | argv[2] = "--"; |
| 90 | argv[3] = module_name; /* check free_modprobe_argv() */ |
| 91 | argv[4] = NULL; |
Oleg Nesterov | 3e63a93 | 2012-03-23 15:02:49 -0700 | [diff] [blame] | 92 | |
Lucas De Marchi | f634460 | 2013-04-30 15:28:03 -0700 | [diff] [blame] | 93 | info = call_usermodehelper_setup(modprobe_path, argv, envp, GFP_KERNEL, |
| 94 | NULL, free_modprobe_argv, NULL); |
| 95 | if (!info) |
| 96 | goto free_module_name; |
| 97 | |
| 98 | return call_usermodehelper_exec(info, wait | UMH_KILLABLE); |
| 99 | |
| 100 | free_module_name: |
| 101 | kfree(module_name); |
Oleg Nesterov | 1cc684a | 2012-03-23 15:02:50 -0700 | [diff] [blame] | 102 | free_argv: |
| 103 | kfree(argv); |
| 104 | out: |
| 105 | return -ENOMEM; |
Oleg Nesterov | 3e63a93 | 2012-03-23 15:02:49 -0700 | [diff] [blame] | 106 | } |
| 107 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 108 | /** |
Arjan van de Ven | acae051 | 2009-02-08 10:42:01 -0800 | [diff] [blame] | 109 | * __request_module - try to load a kernel module |
| 110 | * @wait: wait (or not) for the operation to complete |
Randy Dunlap | bd4207c | 2009-01-06 14:42:39 -0800 | [diff] [blame] | 111 | * @fmt: printf style format string for the name of the module |
| 112 | * @...: arguments as specified in the format string |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 113 | * |
| 114 | * Load a module using the user mode module loader. The function returns |
NeilBrown | 60b61a6 | 2015-09-09 15:38:10 -0700 | [diff] [blame] | 115 | * zero on success or a negative errno code or positive exit code from |
| 116 | * "modprobe" on failure. Note that a successful module load does not mean |
| 117 | * the module did not then unload and exit on an error of its own. Callers |
| 118 | * must check that the service they requested is now available not blindly |
| 119 | * invoke it. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 120 | * |
| 121 | * If module auto-loading support is disabled then this function |
| 122 | * becomes a no-operation. |
| 123 | */ |
Arjan van de Ven | acae051 | 2009-02-08 10:42:01 -0800 | [diff] [blame] | 124 | int __request_module(bool wait, const char *fmt, ...) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 125 | { |
| 126 | va_list args; |
| 127 | char module_name[MODULE_NAME_LEN]; |
| 128 | unsigned int max_modprobes; |
| 129 | int ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 130 | static atomic_t kmod_concurrent = ATOMIC_INIT(0); |
| 131 | #define MAX_KMOD_CONCURRENT 50 /* Completely arbitrary value - KAO */ |
| 132 | static int kmod_loop_msg; |
| 133 | |
Tejun Heo | 0fdff3e | 2013-01-22 16:48:03 -0800 | [diff] [blame] | 134 | /* |
| 135 | * We don't allow synchronous module loading from async. Module |
| 136 | * init may invoke async_synchronize_full() which will end up |
| 137 | * waiting for this task which already is waiting for the module |
| 138 | * loading to complete, leading to a deadlock. |
| 139 | */ |
| 140 | WARN_ON_ONCE(wait && current_is_async()); |
| 141 | |
Oleg Nesterov | 7f57cfa | 2013-07-03 15:08:15 -0700 | [diff] [blame] | 142 | if (!modprobe_path[0]) |
| 143 | return 0; |
| 144 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 145 | va_start(args, fmt); |
| 146 | ret = vsnprintf(module_name, MODULE_NAME_LEN, fmt, args); |
| 147 | va_end(args); |
| 148 | if (ret >= MODULE_NAME_LEN) |
| 149 | return -ENAMETOOLONG; |
| 150 | |
Eric Paris | dd8dbf2 | 2009-11-03 16:35:32 +1100 | [diff] [blame] | 151 | ret = security_kernel_module_request(module_name); |
| 152 | if (ret) |
| 153 | return ret; |
| 154 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 155 | /* If modprobe needs a service that is in a module, we get a recursive |
| 156 | * loop. Limit the number of running kmod threads to max_threads/2 or |
| 157 | * MAX_KMOD_CONCURRENT, whichever is the smaller. A cleaner method |
| 158 | * would be to run the parents of this process, counting how many times |
| 159 | * kmod was invoked. That would mean accessing the internals of the |
| 160 | * process tables to get the command line, proc_pid_cmdline is static |
| 161 | * and it is not worth changing the proc code just to handle this case. |
| 162 | * KAO. |
| 163 | * |
| 164 | * "trace the ppid" is simple, but will fail if someone's |
| 165 | * parent exits. I think this is as good as it gets. --RR |
| 166 | */ |
| 167 | max_modprobes = min(max_threads/2, MAX_KMOD_CONCURRENT); |
| 168 | atomic_inc(&kmod_concurrent); |
| 169 | if (atomic_read(&kmod_concurrent) > max_modprobes) { |
| 170 | /* We may be blaming an innocent here, but unlikely */ |
Jiri Kosina | 37252db | 2011-10-26 13:10:39 +1030 | [diff] [blame] | 171 | if (kmod_loop_msg < 5) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 172 | printk(KERN_ERR |
| 173 | "request_module: runaway loop modprobe %s\n", |
| 174 | module_name); |
Jiri Kosina | 37252db | 2011-10-26 13:10:39 +1030 | [diff] [blame] | 175 | kmod_loop_msg++; |
| 176 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 177 | atomic_dec(&kmod_concurrent); |
| 178 | return -ENOMEM; |
| 179 | } |
| 180 | |
Li Zefan | 7ead8b8 | 2009-08-17 16:56:28 +0800 | [diff] [blame] | 181 | trace_module_request(module_name, wait, _RET_IP_); |
| 182 | |
Oleg Nesterov | 3e63a93 | 2012-03-23 15:02:49 -0700 | [diff] [blame] | 183 | ret = call_modprobe(module_name, wait ? UMH_WAIT_PROC : UMH_WAIT_EXEC); |
Neil Horman | a06a4dc | 2010-05-26 14:42:58 -0700 | [diff] [blame] | 184 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 185 | atomic_dec(&kmod_concurrent); |
| 186 | return ret; |
| 187 | } |
Arjan van de Ven | acae051 | 2009-02-08 10:42:01 -0800 | [diff] [blame] | 188 | EXPORT_SYMBOL(__request_module); |
Rusty Russell | 118a906 | 2008-10-17 02:38:36 -0500 | [diff] [blame] | 189 | #endif /* CONFIG_MODULES */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 190 | |
Martin Schwidefsky | 0baf2a4 | 2014-10-29 14:50:35 -0700 | [diff] [blame] | 191 | static void call_usermodehelper_freeinfo(struct subprocess_info *info) |
| 192 | { |
| 193 | if (info->cleanup) |
| 194 | (*info->cleanup)(info); |
| 195 | kfree(info); |
| 196 | } |
| 197 | |
| 198 | static void umh_complete(struct subprocess_info *sub_info) |
| 199 | { |
| 200 | struct completion *comp = xchg(&sub_info->complete, NULL); |
| 201 | /* |
| 202 | * See call_usermodehelper_exec(). If xchg() returns NULL |
| 203 | * we own sub_info, the UMH_KILLABLE caller has gone away |
| 204 | * or the caller used UMH_NO_WAIT. |
| 205 | */ |
| 206 | if (comp) |
| 207 | complete(comp); |
| 208 | else |
| 209 | call_usermodehelper_freeinfo(sub_info); |
| 210 | } |
| 211 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 212 | /* |
| 213 | * This is the task which runs the usermode application |
| 214 | */ |
Frederic Weisbecker | b6b50a8 | 2015-09-09 15:38:13 -0700 | [diff] [blame] | 215 | static int call_usermodehelper_exec_async(void *data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 216 | { |
| 217 | struct subprocess_info *sub_info = data; |
Eric Paris | 17f60a7 | 2011-04-01 17:07:50 -0400 | [diff] [blame] | 218 | struct cred *new; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 219 | int retval; |
| 220 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 221 | spin_lock_irq(¤t->sighand->siglock); |
| 222 | flush_signal_handlers(current, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 223 | spin_unlock_irq(¤t->sighand->siglock); |
| 224 | |
Jan Engelhardt | b73a7e7 | 2007-05-08 00:28:24 -0700 | [diff] [blame] | 225 | /* |
Frederic Weisbecker | 90f0230 | 2015-09-09 15:38:22 -0700 | [diff] [blame] | 226 | * Our parent (unbound workqueue) runs with elevated scheduling |
Frederic Weisbecker | b639e86 | 2015-09-09 15:38:19 -0700 | [diff] [blame] | 227 | * priority. Avoid propagating that into the userspace child. |
Jan Engelhardt | b73a7e7 | 2007-05-08 00:28:24 -0700 | [diff] [blame] | 228 | */ |
| 229 | set_user_nice(current, 0); |
| 230 | |
Eric Paris | 17f60a7 | 2011-04-01 17:07:50 -0400 | [diff] [blame] | 231 | retval = -ENOMEM; |
| 232 | new = prepare_kernel_cred(current); |
| 233 | if (!new) |
Martin Schwidefsky | 0baf2a4 | 2014-10-29 14:50:35 -0700 | [diff] [blame] | 234 | goto out; |
Eric Paris | 17f60a7 | 2011-04-01 17:07:50 -0400 | [diff] [blame] | 235 | |
| 236 | spin_lock(&umh_sysctl_lock); |
| 237 | new->cap_bset = cap_intersect(usermodehelper_bset, new->cap_bset); |
| 238 | new->cap_inheritable = cap_intersect(usermodehelper_inheritable, |
| 239 | new->cap_inheritable); |
| 240 | spin_unlock(&umh_sysctl_lock); |
| 241 | |
David Howells | 8796699 | 2011-06-17 11:25:59 +0100 | [diff] [blame] | 242 | if (sub_info->init) { |
| 243 | retval = sub_info->init(sub_info, new); |
| 244 | if (retval) { |
| 245 | abort_creds(new); |
Martin Schwidefsky | 0baf2a4 | 2014-10-29 14:50:35 -0700 | [diff] [blame] | 246 | goto out; |
David Howells | 8796699 | 2011-06-17 11:25:59 +0100 | [diff] [blame] | 247 | } |
| 248 | } |
| 249 | |
Eric Paris | 17f60a7 | 2011-04-01 17:07:50 -0400 | [diff] [blame] | 250 | commit_creds(new); |
| 251 | |
Linus Torvalds | c4ad8f9 | 2014-02-05 12:54:53 -0800 | [diff] [blame] | 252 | retval = do_execve(getname_kernel(sub_info->path), |
Al Viro | ae903ca | 2012-12-14 12:44:11 -0500 | [diff] [blame] | 253 | (const char __user *const __user *)sub_info->argv, |
| 254 | (const char __user *const __user *)sub_info->envp); |
Martin Schwidefsky | 0baf2a4 | 2014-10-29 14:50:35 -0700 | [diff] [blame] | 255 | out: |
| 256 | sub_info->retval = retval; |
Frederic Weisbecker | b6b50a8 | 2015-09-09 15:38:13 -0700 | [diff] [blame] | 257 | /* |
| 258 | * call_usermodehelper_exec_sync() will call umh_complete |
| 259 | * if UHM_WAIT_PROC. |
| 260 | */ |
Oleg Nesterov | 7117bc8 | 2014-12-10 15:54:39 -0800 | [diff] [blame] | 261 | if (!(sub_info->wait & UMH_WAIT_PROC)) |
Martin Schwidefsky | 0baf2a4 | 2014-10-29 14:50:35 -0700 | [diff] [blame] | 262 | umh_complete(sub_info); |
Al Viro | a74fb73 | 2012-10-10 21:28:25 -0400 | [diff] [blame] | 263 | if (!retval) |
| 264 | return 0; |
Al Viro | fb45550 | 2012-10-10 20:09:44 -0400 | [diff] [blame] | 265 | do_exit(0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 266 | } |
| 267 | |
Frederic Weisbecker | bb304a5 | 2015-09-09 15:38:25 -0700 | [diff] [blame] | 268 | /* Handles UMH_WAIT_PROC. */ |
| 269 | static void call_usermodehelper_exec_sync(struct subprocess_info *sub_info) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 270 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 271 | pid_t pid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 272 | |
Oleg Nesterov | 7d64224 | 2010-05-26 14:43:03 -0700 | [diff] [blame] | 273 | /* If SIGCLD is ignored sys_wait4 won't populate the status. */ |
Oleg Nesterov | 76e0a6f | 2014-06-06 14:37:02 -0700 | [diff] [blame] | 274 | kernel_sigaction(SIGCHLD, SIG_DFL); |
Frederic Weisbecker | b6b50a8 | 2015-09-09 15:38:13 -0700 | [diff] [blame] | 275 | pid = kernel_thread(call_usermodehelper_exec_async, sub_info, SIGCHLD); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 276 | if (pid < 0) { |
| 277 | sub_info->retval = pid; |
| 278 | } else { |
Oleg Nesterov | 7d64224 | 2010-05-26 14:43:03 -0700 | [diff] [blame] | 279 | int ret = -ECHILD; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 280 | /* |
| 281 | * Normally it is bogus to call wait4() from in-kernel because |
| 282 | * wait4() wants to write the exit code to a userspace address. |
Frederic Weisbecker | b639e86 | 2015-09-09 15:38:19 -0700 | [diff] [blame] | 283 | * But call_usermodehelper_exec_sync() always runs as kernel |
Frederic Weisbecker | bb304a5 | 2015-09-09 15:38:25 -0700 | [diff] [blame] | 284 | * thread (workqueue) and put_user() to a kernel address works |
| 285 | * OK for kernel threads, due to their having an mm_segment_t |
| 286 | * which spans the entire address space. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 287 | * |
| 288 | * Thus the __user pointer cast is valid here. |
| 289 | */ |
Björn Steinbrink | 111dbe0 | 2006-09-29 02:00:46 -0700 | [diff] [blame] | 290 | sys_wait4(pid, (int __user *)&ret, 0, NULL); |
| 291 | |
| 292 | /* |
Frederic Weisbecker | b6b50a8 | 2015-09-09 15:38:13 -0700 | [diff] [blame] | 293 | * If ret is 0, either call_usermodehelper_exec_async failed and |
| 294 | * the real error code is already in sub_info->retval or |
Björn Steinbrink | 111dbe0 | 2006-09-29 02:00:46 -0700 | [diff] [blame] | 295 | * sub_info->retval is 0 anyway, so don't mess with it then. |
| 296 | */ |
| 297 | if (ret) |
| 298 | sub_info->retval = ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 299 | } |
| 300 | |
Frederic Weisbecker | bb304a5 | 2015-09-09 15:38:25 -0700 | [diff] [blame] | 301 | /* Restore default kernel sig handler */ |
| 302 | kernel_sigaction(SIGCHLD, SIG_IGN); |
| 303 | |
Oleg Nesterov | b344992 | 2012-03-23 15:02:47 -0700 | [diff] [blame] | 304 | umh_complete(sub_info); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 305 | } |
| 306 | |
Frederic Weisbecker | b639e86 | 2015-09-09 15:38:19 -0700 | [diff] [blame] | 307 | /* |
Frederic Weisbecker | bb304a5 | 2015-09-09 15:38:25 -0700 | [diff] [blame] | 308 | * We need to create the usermodehelper kernel thread from a task that is affine |
Frederic Weisbecker | 90f0230 | 2015-09-09 15:38:22 -0700 | [diff] [blame] | 309 | * to an optimized set of CPUs (or nohz housekeeping ones) such that they |
| 310 | * inherit a widest affinity irrespective of call_usermodehelper() callers with |
| 311 | * possibly reduced affinity (eg: per-cpu workqueues). We don't want |
| 312 | * usermodehelper targets to contend a busy CPU. |
Frederic Weisbecker | b639e86 | 2015-09-09 15:38:19 -0700 | [diff] [blame] | 313 | * |
Frederic Weisbecker | bb304a5 | 2015-09-09 15:38:25 -0700 | [diff] [blame] | 314 | * Unbound workqueues provide such wide affinity and allow to block on |
| 315 | * UMH_WAIT_PROC requests without blocking pending request (up to some limit). |
Frederic Weisbecker | 90f0230 | 2015-09-09 15:38:22 -0700 | [diff] [blame] | 316 | * |
| 317 | * Besides, workqueues provide the privilege level that caller might not have |
| 318 | * to perform the usermodehelper request. |
Frederic Weisbecker | b639e86 | 2015-09-09 15:38:19 -0700 | [diff] [blame] | 319 | * |
| 320 | */ |
Frederic Weisbecker | b6b50a8 | 2015-09-09 15:38:13 -0700 | [diff] [blame] | 321 | static void call_usermodehelper_exec_work(struct work_struct *work) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 322 | { |
David Howells | 65f27f3 | 2006-11-22 14:55:48 +0000 | [diff] [blame] | 323 | struct subprocess_info *sub_info = |
| 324 | container_of(work, struct subprocess_info, work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 325 | |
Frederic Weisbecker | bb304a5 | 2015-09-09 15:38:25 -0700 | [diff] [blame] | 326 | if (sub_info->wait & UMH_WAIT_PROC) { |
| 327 | call_usermodehelper_exec_sync(sub_info); |
| 328 | } else { |
| 329 | pid_t pid; |
Oleg Nesterov | 5211613 | 2015-10-22 13:32:08 -0700 | [diff] [blame] | 330 | /* |
| 331 | * Use CLONE_PARENT to reparent it to kthreadd; we do not |
| 332 | * want to pollute current->children, and we need a parent |
| 333 | * that always ignores SIGCHLD to ensure auto-reaping. |
| 334 | */ |
Frederic Weisbecker | b6b50a8 | 2015-09-09 15:38:13 -0700 | [diff] [blame] | 335 | pid = kernel_thread(call_usermodehelper_exec_async, sub_info, |
Oleg Nesterov | 5211613 | 2015-10-22 13:32:08 -0700 | [diff] [blame] | 336 | CLONE_PARENT | SIGCHLD); |
Frederic Weisbecker | bb304a5 | 2015-09-09 15:38:25 -0700 | [diff] [blame] | 337 | if (pid < 0) { |
| 338 | sub_info->retval = pid; |
| 339 | umh_complete(sub_info); |
| 340 | } |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 341 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 342 | } |
| 343 | |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 344 | /* |
| 345 | * If set, call_usermodehelper_exec() will exit immediately returning -EBUSY |
| 346 | * (used for preventing user land processes from being created after the user |
| 347 | * 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] | 348 | * Should always be manipulated under umhelper_sem acquired for write. |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 349 | */ |
Rafael J. Wysocki | 247bc03 | 2012-03-28 23:30:28 +0200 | [diff] [blame] | 350 | static enum umh_disable_depth usermodehelper_disabled = UMH_DISABLED; |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 351 | |
| 352 | /* Number of helpers running */ |
| 353 | static atomic_t running_helpers = ATOMIC_INIT(0); |
| 354 | |
| 355 | /* |
Srivatsa S. Bhat | 5307427 | 2011-11-15 21:59:21 +0100 | [diff] [blame] | 356 | * 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] | 357 | * helpers to finish. |
| 358 | */ |
| 359 | static DECLARE_WAIT_QUEUE_HEAD(running_helpers_waitq); |
| 360 | |
| 361 | /* |
Rafael J. Wysocki | 9b78c1d | 2012-03-28 23:30:02 +0200 | [diff] [blame] | 362 | * Used by usermodehelper_read_lock_wait() to wait for usermodehelper_disabled |
| 363 | * to become 'false'. |
| 364 | */ |
| 365 | static DECLARE_WAIT_QUEUE_HEAD(usermodehelper_disabled_waitq); |
| 366 | |
| 367 | /* |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 368 | * 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] | 369 | * usermodehelper_disabled in usermodehelper_disable() fails |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 370 | */ |
| 371 | #define RUNNING_HELPERS_TIMEOUT (5 * HZ) |
| 372 | |
Rafael J. Wysocki | fe2e39d8 | 2012-03-28 23:29:45 +0200 | [diff] [blame] | 373 | int usermodehelper_read_trylock(void) |
Srivatsa S. Bhat | b298d28 | 2011-12-09 23:36:36 +0100 | [diff] [blame] | 374 | { |
Rafael J. Wysocki | 247bc03 | 2012-03-28 23:30:28 +0200 | [diff] [blame] | 375 | DEFINE_WAIT(wait); |
Rafael J. Wysocki | fe2e39d8 | 2012-03-28 23:29:45 +0200 | [diff] [blame] | 376 | int ret = 0; |
Srivatsa S. Bhat | b298d28 | 2011-12-09 23:36:36 +0100 | [diff] [blame] | 377 | |
Rafael J. Wysocki | fe2e39d8 | 2012-03-28 23:29:45 +0200 | [diff] [blame] | 378 | down_read(&umhelper_sem); |
Rafael J. Wysocki | 247bc03 | 2012-03-28 23:30:28 +0200 | [diff] [blame] | 379 | for (;;) { |
| 380 | prepare_to_wait(&usermodehelper_disabled_waitq, &wait, |
| 381 | TASK_INTERRUPTIBLE); |
| 382 | if (!usermodehelper_disabled) |
| 383 | break; |
| 384 | |
| 385 | if (usermodehelper_disabled == UMH_DISABLED) |
| 386 | ret = -EAGAIN; |
| 387 | |
Rafael J. Wysocki | fe2e39d8 | 2012-03-28 23:29:45 +0200 | [diff] [blame] | 388 | up_read(&umhelper_sem); |
Rafael J. Wysocki | 247bc03 | 2012-03-28 23:30:28 +0200 | [diff] [blame] | 389 | |
| 390 | if (ret) |
| 391 | break; |
| 392 | |
| 393 | schedule(); |
| 394 | try_to_freeze(); |
| 395 | |
| 396 | down_read(&umhelper_sem); |
Rafael J. Wysocki | fe2e39d8 | 2012-03-28 23:29:45 +0200 | [diff] [blame] | 397 | } |
Rafael J. Wysocki | 247bc03 | 2012-03-28 23:30:28 +0200 | [diff] [blame] | 398 | finish_wait(&usermodehelper_disabled_waitq, &wait); |
Rafael J. Wysocki | fe2e39d8 | 2012-03-28 23:29:45 +0200 | [diff] [blame] | 399 | return ret; |
| 400 | } |
| 401 | EXPORT_SYMBOL_GPL(usermodehelper_read_trylock); |
| 402 | |
Rafael J. Wysocki | 9b78c1d | 2012-03-28 23:30:02 +0200 | [diff] [blame] | 403 | long usermodehelper_read_lock_wait(long timeout) |
| 404 | { |
| 405 | DEFINE_WAIT(wait); |
| 406 | |
| 407 | if (timeout < 0) |
| 408 | return -EINVAL; |
| 409 | |
| 410 | down_read(&umhelper_sem); |
| 411 | for (;;) { |
| 412 | prepare_to_wait(&usermodehelper_disabled_waitq, &wait, |
| 413 | TASK_UNINTERRUPTIBLE); |
| 414 | if (!usermodehelper_disabled) |
| 415 | break; |
| 416 | |
| 417 | up_read(&umhelper_sem); |
| 418 | |
| 419 | timeout = schedule_timeout(timeout); |
| 420 | if (!timeout) |
| 421 | break; |
| 422 | |
| 423 | down_read(&umhelper_sem); |
| 424 | } |
| 425 | finish_wait(&usermodehelper_disabled_waitq, &wait); |
| 426 | return timeout; |
| 427 | } |
| 428 | EXPORT_SYMBOL_GPL(usermodehelper_read_lock_wait); |
| 429 | |
Rafael J. Wysocki | fe2e39d8 | 2012-03-28 23:29:45 +0200 | [diff] [blame] | 430 | void usermodehelper_read_unlock(void) |
Srivatsa S. Bhat | b298d28 | 2011-12-09 23:36:36 +0100 | [diff] [blame] | 431 | { |
| 432 | up_read(&umhelper_sem); |
| 433 | } |
Rafael J. Wysocki | fe2e39d8 | 2012-03-28 23:29:45 +0200 | [diff] [blame] | 434 | EXPORT_SYMBOL_GPL(usermodehelper_read_unlock); |
Srivatsa S. Bhat | b298d28 | 2011-12-09 23:36:36 +0100 | [diff] [blame] | 435 | |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 436 | /** |
Rafael J. Wysocki | 247bc03 | 2012-03-28 23:30:28 +0200 | [diff] [blame] | 437 | * __usermodehelper_set_disable_depth - Modify usermodehelper_disabled. |
Randy Dunlap | 9b3c98c | 2012-05-31 16:26:15 -0700 | [diff] [blame] | 438 | * @depth: New value to assign to usermodehelper_disabled. |
Rafael J. Wysocki | 247bc03 | 2012-03-28 23:30:28 +0200 | [diff] [blame] | 439 | * |
| 440 | * Change the value of usermodehelper_disabled (under umhelper_sem locked for |
| 441 | * writing) and wakeup tasks waiting for it to change. |
Rafael J. Wysocki | 9b78c1d | 2012-03-28 23:30:02 +0200 | [diff] [blame] | 442 | */ |
Rafael J. Wysocki | 247bc03 | 2012-03-28 23:30:28 +0200 | [diff] [blame] | 443 | void __usermodehelper_set_disable_depth(enum umh_disable_depth depth) |
Rafael J. Wysocki | 9b78c1d | 2012-03-28 23:30:02 +0200 | [diff] [blame] | 444 | { |
| 445 | down_write(&umhelper_sem); |
Rafael J. Wysocki | 247bc03 | 2012-03-28 23:30:28 +0200 | [diff] [blame] | 446 | usermodehelper_disabled = depth; |
Rafael J. Wysocki | 9b78c1d | 2012-03-28 23:30:02 +0200 | [diff] [blame] | 447 | wake_up(&usermodehelper_disabled_waitq); |
| 448 | up_write(&umhelper_sem); |
| 449 | } |
| 450 | |
| 451 | /** |
Rafael J. Wysocki | 247bc03 | 2012-03-28 23:30:28 +0200 | [diff] [blame] | 452 | * __usermodehelper_disable - Prevent new helpers from being started. |
| 453 | * @depth: New value to assign to usermodehelper_disabled. |
| 454 | * |
| 455 | * Set usermodehelper_disabled to @depth and wait for running helpers to exit. |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 456 | */ |
Rafael J. Wysocki | 247bc03 | 2012-03-28 23:30:28 +0200 | [diff] [blame] | 457 | int __usermodehelper_disable(enum umh_disable_depth depth) |
Rafael J. Wysocki | 8cdd493 | 2007-07-19 01:47:36 -0700 | [diff] [blame] | 458 | { |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 459 | long retval; |
| 460 | |
Rafael J. Wysocki | 247bc03 | 2012-03-28 23:30:28 +0200 | [diff] [blame] | 461 | if (!depth) |
| 462 | return -EINVAL; |
| 463 | |
Srivatsa S. Bhat | b298d28 | 2011-12-09 23:36:36 +0100 | [diff] [blame] | 464 | down_write(&umhelper_sem); |
Rafael J. Wysocki | 247bc03 | 2012-03-28 23:30:28 +0200 | [diff] [blame] | 465 | usermodehelper_disabled = depth; |
Srivatsa S. Bhat | b298d28 | 2011-12-09 23:36:36 +0100 | [diff] [blame] | 466 | up_write(&umhelper_sem); |
| 467 | |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 468 | /* |
| 469 | * From now on call_usermodehelper_exec() won't start any new |
| 470 | * helpers, so it is sufficient if running_helpers turns out to |
| 471 | * be zero at one point (it may be increased later, but that |
| 472 | * doesn't matter). |
| 473 | */ |
| 474 | retval = wait_event_timeout(running_helpers_waitq, |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 475 | atomic_read(&running_helpers) == 0, |
| 476 | RUNNING_HELPERS_TIMEOUT); |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 477 | if (retval) |
| 478 | return 0; |
Rafael J. Wysocki | 8cdd493 | 2007-07-19 01:47:36 -0700 | [diff] [blame] | 479 | |
Rafael J. Wysocki | 247bc03 | 2012-03-28 23:30:28 +0200 | [diff] [blame] | 480 | __usermodehelper_set_disable_depth(UMH_ENABLED); |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 481 | return -EAGAIN; |
| 482 | } |
| 483 | |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 484 | static void helper_lock(void) |
| 485 | { |
| 486 | atomic_inc(&running_helpers); |
Peter Zijlstra | 4e857c5 | 2014-03-17 18:06:10 +0100 | [diff] [blame] | 487 | smp_mb__after_atomic(); |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 488 | } |
| 489 | |
| 490 | static void helper_unlock(void) |
| 491 | { |
| 492 | if (atomic_dec_and_test(&running_helpers)) |
| 493 | wake_up(&running_helpers_waitq); |
| 494 | } |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 495 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 496 | /** |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 497 | * call_usermodehelper_setup - prepare to call a usermode helper |
Randy Dunlap | 61df47c | 2007-07-26 10:40:56 -0700 | [diff] [blame] | 498 | * @path: path to usermode executable |
| 499 | * @argv: arg vector for process |
| 500 | * @envp: environment for process |
KOSAKI Motohiro | ac331d1 | 2008-07-25 01:45:38 -0700 | [diff] [blame] | 501 | * @gfp_mask: gfp mask for memory allocation |
Lucas De Marchi | 938e4b2 | 2013-04-30 15:28:02 -0700 | [diff] [blame] | 502 | * @cleanup: a cleanup function |
| 503 | * @init: an init function |
| 504 | * @data: arbitrary context sensitive data |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 505 | * |
Randy Dunlap | 61df47c | 2007-07-26 10:40:56 -0700 | [diff] [blame] | 506 | * Returns either %NULL on allocation failure, or a subprocess_info |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 507 | * structure. This should be passed to call_usermodehelper_exec to |
| 508 | * exec the process and free the structure. |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 509 | * |
Neil Horman | a06a4dc | 2010-05-26 14:42:58 -0700 | [diff] [blame] | 510 | * The init function is used to customize the helper process prior to |
| 511 | * exec. A non-zero return code causes the process to error out, exit, |
| 512 | * and return the failure to the calling process |
| 513 | * |
| 514 | * The cleanup function is just before ethe subprocess_info is about to |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 515 | * be freed. This can be used for freeing the argv and envp. The |
| 516 | * Function must be runnable in either a process context or the |
| 517 | * context in which call_usermodehelper_exec is called. |
| 518 | */ |
Lucas De Marchi | 938e4b2 | 2013-04-30 15:28:02 -0700 | [diff] [blame] | 519 | struct subprocess_info *call_usermodehelper_setup(char *path, char **argv, |
| 520 | char **envp, gfp_t gfp_mask, |
| 521 | int (*init)(struct subprocess_info *info, struct cred *new), |
| 522 | void (*cleanup)(struct subprocess_info *info), |
| 523 | void *data) |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 524 | { |
Lucas De Marchi | 938e4b2 | 2013-04-30 15:28:02 -0700 | [diff] [blame] | 525 | struct subprocess_info *sub_info; |
| 526 | sub_info = kzalloc(sizeof(struct subprocess_info), gfp_mask); |
| 527 | if (!sub_info) |
| 528 | goto out; |
| 529 | |
Frederic Weisbecker | b6b50a8 | 2015-09-09 15:38:13 -0700 | [diff] [blame] | 530 | INIT_WORK(&sub_info->work, call_usermodehelper_exec_work); |
Lucas De Marchi | 938e4b2 | 2013-04-30 15:28:02 -0700 | [diff] [blame] | 531 | sub_info->path = path; |
| 532 | sub_info->argv = argv; |
| 533 | sub_info->envp = envp; |
| 534 | |
| 535 | sub_info->cleanup = cleanup; |
| 536 | sub_info->init = init; |
| 537 | sub_info->data = data; |
| 538 | out: |
| 539 | return sub_info; |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 540 | } |
Lucas De Marchi | 938e4b2 | 2013-04-30 15:28:02 -0700 | [diff] [blame] | 541 | EXPORT_SYMBOL(call_usermodehelper_setup); |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 542 | |
| 543 | /** |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 544 | * call_usermodehelper_exec - start a usermode application |
| 545 | * @sub_info: information about the subprocessa |
| 546 | * @wait: wait for the application to finish and return status. |
Lucas De Marchi | 66e5b7e | 2013-04-30 15:28:09 -0700 | [diff] [blame] | 547 | * when UMH_NO_WAIT don't wait at all, but you get no useful error back |
| 548 | * when the program couldn't be exec'ed. This makes it safe to call |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 549 | * from interrupt context. |
| 550 | * |
| 551 | * Runs a user-space application. The application is started |
Frederic Weisbecker | 90f0230 | 2015-09-09 15:38:22 -0700 | [diff] [blame] | 552 | * asynchronously if wait is not set, and runs as a child of system workqueues. |
| 553 | * (ie. it runs with full root capabilities and optimized affinity). |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 554 | */ |
Oleg Nesterov | 9d944ef | 2012-03-23 15:02:48 -0700 | [diff] [blame] | 555 | int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait) |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 556 | { |
| 557 | DECLARE_COMPLETION_ONSTACK(done); |
Nigel Cunningham | 7846803 | 2008-01-17 15:21:21 -0800 | [diff] [blame] | 558 | int retval = 0; |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 559 | |
Tetsuo Handa | 4c1c7be | 2013-09-30 13:45:08 -0700 | [diff] [blame] | 560 | if (!sub_info->path) { |
| 561 | call_usermodehelper_freeinfo(sub_info); |
| 562 | return -EINVAL; |
| 563 | } |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 564 | helper_lock(); |
Frederic Weisbecker | 90f0230 | 2015-09-09 15:38:22 -0700 | [diff] [blame] | 565 | if (usermodehelper_disabled) { |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 566 | retval = -EBUSY; |
| 567 | goto out; |
| 568 | } |
Tetsuo Handa | 0f20784 | 2012-07-30 14:42:20 -0700 | [diff] [blame] | 569 | /* |
Martin Schwidefsky | 0baf2a4 | 2014-10-29 14:50:35 -0700 | [diff] [blame] | 570 | * Set the completion pointer only if there is a waiter. |
| 571 | * This makes it possible to use umh_complete to free |
| 572 | * the data structure in case of UMH_NO_WAIT. |
| 573 | */ |
| 574 | sub_info->complete = (wait == UMH_NO_WAIT) ? NULL : &done; |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 575 | sub_info->wait = wait; |
| 576 | |
Frederic Weisbecker | 90f0230 | 2015-09-09 15:38:22 -0700 | [diff] [blame] | 577 | queue_work(system_unbound_wq, &sub_info->work); |
Nigel Cunningham | 7846803 | 2008-01-17 15:21:21 -0800 | [diff] [blame] | 578 | if (wait == UMH_NO_WAIT) /* task has freed sub_info */ |
| 579 | goto unlock; |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 580 | |
Oleg Nesterov | d0bd587 | 2012-03-23 15:02:47 -0700 | [diff] [blame] | 581 | if (wait & UMH_KILLABLE) { |
| 582 | retval = wait_for_completion_killable(&done); |
| 583 | if (!retval) |
| 584 | goto wait_done; |
| 585 | |
| 586 | /* umh_complete() will see NULL and free sub_info */ |
| 587 | if (xchg(&sub_info->complete, NULL)) |
| 588 | goto unlock; |
| 589 | /* fallthrough, umh_complete() was already called */ |
| 590 | } |
| 591 | |
| 592 | wait_for_completion(&done); |
| 593 | wait_done: |
| 594 | retval = sub_info->retval; |
Nigel Cunningham | 7846803 | 2008-01-17 15:21:21 -0800 | [diff] [blame] | 595 | out: |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 596 | call_usermodehelper_freeinfo(sub_info); |
Nigel Cunningham | 7846803 | 2008-01-17 15:21:21 -0800 | [diff] [blame] | 597 | unlock: |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 598 | helper_unlock(); |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 599 | return retval; |
| 600 | } |
Lucas De Marchi | 938e4b2 | 2013-04-30 15:28:02 -0700 | [diff] [blame] | 601 | EXPORT_SYMBOL(call_usermodehelper_exec); |
Boaz Harrosh | 785042f | 2012-05-31 16:26:15 -0700 | [diff] [blame] | 602 | |
Lucas De Marchi | 66e5b7e | 2013-04-30 15:28:09 -0700 | [diff] [blame] | 603 | /** |
| 604 | * call_usermodehelper() - prepare and start a usermode application |
| 605 | * @path: path to usermode executable |
| 606 | * @argv: arg vector for process |
| 607 | * @envp: environment for process |
| 608 | * @wait: wait for the application to finish and return status. |
| 609 | * when UMH_NO_WAIT don't wait at all, but you get no useful error back |
| 610 | * when the program couldn't be exec'ed. This makes it safe to call |
| 611 | * from interrupt context. |
| 612 | * |
| 613 | * This function is the equivalent to use call_usermodehelper_setup() and |
| 614 | * call_usermodehelper_exec(). |
Andrew Morton | 79c743d | 2012-07-30 14:42:17 -0700 | [diff] [blame] | 615 | */ |
Lucas De Marchi | 66e5b7e | 2013-04-30 15:28:09 -0700 | [diff] [blame] | 616 | int call_usermodehelper(char *path, char **argv, char **envp, int wait) |
Boaz Harrosh | 785042f | 2012-05-31 16:26:15 -0700 | [diff] [blame] | 617 | { |
| 618 | struct subprocess_info *info; |
| 619 | gfp_t gfp_mask = (wait == UMH_NO_WAIT) ? GFP_ATOMIC : GFP_KERNEL; |
| 620 | |
Lucas De Marchi | 938e4b2 | 2013-04-30 15:28:02 -0700 | [diff] [blame] | 621 | info = call_usermodehelper_setup(path, argv, envp, gfp_mask, |
Lucas De Marchi | 66e5b7e | 2013-04-30 15:28:09 -0700 | [diff] [blame] | 622 | NULL, NULL, NULL); |
Boaz Harrosh | 785042f | 2012-05-31 16:26:15 -0700 | [diff] [blame] | 623 | if (info == NULL) |
| 624 | return -ENOMEM; |
| 625 | |
Boaz Harrosh | 785042f | 2012-05-31 16:26:15 -0700 | [diff] [blame] | 626 | return call_usermodehelper_exec(info, wait); |
| 627 | } |
Lucas De Marchi | 66e5b7e | 2013-04-30 15:28:09 -0700 | [diff] [blame] | 628 | EXPORT_SYMBOL(call_usermodehelper); |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 629 | |
Eric Paris | 17f60a7 | 2011-04-01 17:07:50 -0400 | [diff] [blame] | 630 | static int proc_cap_handler(struct ctl_table *table, int write, |
| 631 | void __user *buffer, size_t *lenp, loff_t *ppos) |
| 632 | { |
| 633 | struct ctl_table t; |
| 634 | unsigned long cap_array[_KERNEL_CAPABILITY_U32S]; |
| 635 | kernel_cap_t new_cap; |
| 636 | int err, i; |
| 637 | |
| 638 | if (write && (!capable(CAP_SETPCAP) || |
| 639 | !capable(CAP_SYS_MODULE))) |
| 640 | return -EPERM; |
| 641 | |
| 642 | /* |
| 643 | * convert from the global kernel_cap_t to the ulong array to print to |
| 644 | * userspace if this is a read. |
| 645 | */ |
| 646 | spin_lock(&umh_sysctl_lock); |
| 647 | for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++) { |
| 648 | if (table->data == CAP_BSET) |
| 649 | cap_array[i] = usermodehelper_bset.cap[i]; |
| 650 | else if (table->data == CAP_PI) |
| 651 | cap_array[i] = usermodehelper_inheritable.cap[i]; |
| 652 | else |
| 653 | BUG(); |
| 654 | } |
| 655 | spin_unlock(&umh_sysctl_lock); |
| 656 | |
| 657 | t = *table; |
| 658 | t.data = &cap_array; |
| 659 | |
| 660 | /* |
| 661 | * actually read or write and array of ulongs from userspace. Remember |
| 662 | * these are least significant 32 bits first |
| 663 | */ |
| 664 | err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos); |
| 665 | if (err < 0) |
| 666 | return err; |
| 667 | |
| 668 | /* |
| 669 | * convert from the sysctl array of ulongs to the kernel_cap_t |
| 670 | * internal representation |
| 671 | */ |
| 672 | for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++) |
| 673 | new_cap.cap[i] = cap_array[i]; |
| 674 | |
| 675 | /* |
| 676 | * Drop everything not in the new_cap (but don't add things) |
| 677 | */ |
| 678 | spin_lock(&umh_sysctl_lock); |
| 679 | if (write) { |
| 680 | if (table->data == CAP_BSET) |
| 681 | usermodehelper_bset = cap_intersect(usermodehelper_bset, new_cap); |
| 682 | if (table->data == CAP_PI) |
| 683 | usermodehelper_inheritable = cap_intersect(usermodehelper_inheritable, new_cap); |
| 684 | } |
| 685 | spin_unlock(&umh_sysctl_lock); |
| 686 | |
| 687 | return 0; |
| 688 | } |
| 689 | |
| 690 | struct ctl_table usermodehelper_table[] = { |
| 691 | { |
| 692 | .procname = "bset", |
| 693 | .data = CAP_BSET, |
| 694 | .maxlen = _KERNEL_CAPABILITY_U32S * sizeof(unsigned long), |
| 695 | .mode = 0600, |
| 696 | .proc_handler = proc_cap_handler, |
| 697 | }, |
| 698 | { |
| 699 | .procname = "inheritable", |
| 700 | .data = CAP_PI, |
| 701 | .maxlen = _KERNEL_CAPABILITY_U32S * sizeof(unsigned long), |
| 702 | .mode = 0600, |
| 703 | .proc_handler = proc_cap_handler, |
| 704 | }, |
| 705 | { } |
| 706 | }; |