perf: Validate cpu early in perf_event_alloc()
[linux-2.6.git] / kernel / kmod.c
index 9fcb53a..9cd0591 100644 (file)
@@ -80,16 +80,16 @@ int __request_module(bool wait, const char *fmt, ...)
 #define MAX_KMOD_CONCURRENT 50 /* Completely arbitrary value - KAO */
        static int kmod_loop_msg;
 
-       ret = security_kernel_module_request();
-       if (ret)
-               return ret;
-
        va_start(args, fmt);
        ret = vsnprintf(module_name, MODULE_NAME_LEN, fmt, args);
        va_end(args);
        if (ret >= MODULE_NAME_LEN)
                return -ENAMETOOLONG;
 
+       ret = security_kernel_module_request(module_name);
+       if (ret)
+               return ret;
+
        /* If modprobe needs a service that is in a module, we get a recursive
         * loop.  Limit the number of running kmod threads to max_threads/2 or
         * MAX_KMOD_CONCURRENT, whichever is the smaller.  A cleaner method
@@ -116,27 +116,16 @@ int __request_module(bool wait, const char *fmt, ...)
 
        trace_module_request(module_name, wait, _RET_IP_);
 
-       ret = call_usermodehelper(modprobe_path, argv, envp,
-                       wait ? UMH_WAIT_PROC : UMH_WAIT_EXEC);
+       ret = call_usermodehelper_fns(modprobe_path, argv, envp,
+                       wait ? UMH_WAIT_PROC : UMH_WAIT_EXEC,
+                       NULL, NULL, NULL);
+
        atomic_dec(&kmod_concurrent);
        return ret;
 }
 EXPORT_SYMBOL(__request_module);
 #endif /* CONFIG_MODULES */
 
-struct subprocess_info {
-       struct work_struct work;
-       struct completion *complete;
-       struct cred *cred;
-       char *path;
-       char **argv;
-       char **envp;
-       enum umh_wait wait;
-       int retval;
-       struct file *stdin;
-       void (*cleanup)(char **argv, char **envp);
-};
-
 /*
  * This is the task which runs the usermode application
  */
@@ -145,36 +134,10 @@ static int ____call_usermodehelper(void *data)
        struct subprocess_info *sub_info = data;
        int retval;
 
-       BUG_ON(atomic_read(&sub_info->cred->usage) != 1);
-
-       /* Unblock all signals */
        spin_lock_irq(&current->sighand->siglock);
        flush_signal_handlers(current, 1);
-       sigemptyset(&current->blocked);
-       recalc_sigpending();
        spin_unlock_irq(&current->sighand->siglock);
 
-       /* Install the credentials */
-       commit_creds(sub_info->cred);
-       sub_info->cred = NULL;
-
-       /* Install input pipe when needed */
-       if (sub_info->stdin) {
-               struct files_struct *f = current->files;
-               struct fdtable *fdt;
-               /* no races because files should be private here */
-               sys_close(0);
-               fd_install(0, sub_info->stdin);
-               spin_lock(&f->file_lock);
-               fdt = files_fdtable(f);
-               FD_SET(0, fdt->open_fds);
-               FD_CLR(0, fdt->close_on_exec);
-               spin_unlock(&f->file_lock);
-
-               /* and disallow core files too */
-               current->signal->rlim[RLIMIT_CORE] = (struct rlimit){0, 0};
-       }
-
        /* We can run anywhere, unlike our parent keventd(). */
        set_cpus_allowed_ptr(current, cpu_all_mask);
 
@@ -184,9 +147,18 @@ static int ____call_usermodehelper(void *data)
         */
        set_user_nice(current, 0);
 
-       retval = kernel_execve(sub_info->path, sub_info->argv, sub_info->envp);
+       if (sub_info->init) {
+               retval = sub_info->init(sub_info);
+               if (retval)
+                       goto fail;
+       }
+
+       retval = kernel_execve(sub_info->path,
+                              (const char *const *)sub_info->argv,
+                              (const char *const *)sub_info->envp);
 
        /* Exec failed? */
+fail:
        sub_info->retval = retval;
        do_exit(0);
 }
@@ -194,9 +166,7 @@ static int ____call_usermodehelper(void *data)
 void call_usermodehelper_freeinfo(struct subprocess_info *info)
 {
        if (info->cleanup)
-               (*info->cleanup)(info->argv, info->envp);
-       if (info->cred)
-               put_cred(info->cred);
+               (*info->cleanup)(info);
        kfree(info);
 }
 EXPORT_SYMBOL(call_usermodehelper_freeinfo);
@@ -207,16 +177,16 @@ static int wait_for_helper(void *data)
        struct subprocess_info *sub_info = data;
        pid_t pid;
 
-       /* Install a handler: if SIGCLD isn't handled sys_wait4 won't
-        * populate the status, but will return -ECHILD. */
-       allow_signal(SIGCHLD);
+       /* If SIGCLD is ignored sys_wait4 won't populate the status. */
+       spin_lock_irq(&current->sighand->siglock);
+       current->sighand->action[SIGCHLD-1].sa.sa_handler = SIG_DFL;
+       spin_unlock_irq(&current->sighand->siglock);
 
        pid = kernel_thread(____call_usermodehelper, sub_info, SIGCHLD);
        if (pid < 0) {
                sub_info->retval = pid;
        } else {
-               int ret;
-
+               int ret = -ECHILD;
                /*
                 * Normally it is bogus to call wait4() from in-kernel because
                 * wait4() wants to write the exit code to a userspace address.
@@ -237,10 +207,7 @@ static int wait_for_helper(void *data)
                        sub_info->retval = ret;
        }
 
-       if (sub_info->wait == UMH_NO_WAIT)
-               call_usermodehelper_freeinfo(sub_info);
-       else
-               complete(sub_info->complete);
+       complete(sub_info->complete);
        return 0;
 }
 
@@ -249,15 +216,13 @@ static void __call_usermodehelper(struct work_struct *work)
 {
        struct subprocess_info *sub_info =
                container_of(work, struct subprocess_info, work);
-       pid_t pid;
        enum umh_wait wait = sub_info->wait;
-
-       BUG_ON(atomic_read(&sub_info->cred->usage) != 1);
+       pid_t pid;
 
        /* CLONE_VFORK: wait until the usermode helper has execve'd
         * successfully We need the data structures to stay around
         * until that is done.  */
-       if (wait == UMH_WAIT_PROC || wait == UMH_NO_WAIT)
+       if (wait == UMH_WAIT_PROC)
                pid = kernel_thread(wait_for_helper, sub_info,
                                    CLONE_FS | CLONE_FILES | SIGCHLD);
        else
@@ -266,15 +231,16 @@ static void __call_usermodehelper(struct work_struct *work)
 
        switch (wait) {
        case UMH_NO_WAIT:
+               call_usermodehelper_freeinfo(sub_info);
                break;
 
        case UMH_WAIT_PROC:
                if (pid > 0)
                        break;
-               sub_info->retval = pid;
                /* FALLTHROUGH */
-
        case UMH_WAIT_EXEC:
+               if (pid < 0)
+                       sub_info->retval = pid;
                complete(sub_info->complete);
        }
 }
@@ -376,80 +342,37 @@ struct subprocess_info *call_usermodehelper_setup(char *path, char **argv,
        sub_info->path = path;
        sub_info->argv = argv;
        sub_info->envp = envp;
-       sub_info->cred = prepare_usermodehelper_creds();
-       if (!sub_info->cred) {
-               kfree(sub_info);
-               return NULL;
-       }
-
   out:
        return sub_info;
 }
 EXPORT_SYMBOL(call_usermodehelper_setup);
 
 /**
- * call_usermodehelper_setkeys - set the session keys for usermode helper
- * @info: a subprocess_info returned by call_usermodehelper_setup
- * @session_keyring: the session keyring for the process
- */
-void call_usermodehelper_setkeys(struct subprocess_info *info,
-                                struct key *session_keyring)
-{
-#ifdef CONFIG_KEYS
-       struct thread_group_cred *tgcred = info->cred->tgcred;
-       key_put(tgcred->session_keyring);
-       tgcred->session_keyring = key_get(session_keyring);
-#else
-       BUG();
-#endif
-}
-EXPORT_SYMBOL(call_usermodehelper_setkeys);
-
-/**
- * call_usermodehelper_setcleanup - set a cleanup function
+ * call_usermodehelper_setfns - set a cleanup/init function
  * @info: a subprocess_info returned by call_usermodehelper_setup
  * @cleanup: a cleanup function
+ * @init: an init function
+ * @data: arbitrary context sensitive data
  *
- * The cleanup function is just befor ethe subprocess_info is about to
+ * The init function is used to customize the helper process prior to
+ * exec.  A non-zero return code causes the process to error out, exit,
+ * and return the failure to the calling process
+ *
+ * The cleanup function is just before ethe subprocess_info is about to
  * be freed.  This can be used for freeing the argv and envp.  The
  * Function must be runnable in either a process context or the
  * context in which call_usermodehelper_exec is called.
  */
-void call_usermodehelper_setcleanup(struct subprocess_info *info,
-                                   void (*cleanup)(char **argv, char **envp))
+void call_usermodehelper_setfns(struct subprocess_info *info,
+                   int (*init)(struct subprocess_info *info),
+                   void (*cleanup)(struct subprocess_info *info),
+                   void *data)
 {
        info->cleanup = cleanup;
+       info->init = init;
+       info->data = data;
 }
-EXPORT_SYMBOL(call_usermodehelper_setcleanup);
-
-/**
- * call_usermodehelper_stdinpipe - set up a pipe to be used for stdin
- * @sub_info: a subprocess_info returned by call_usermodehelper_setup
- * @filp: set to the write-end of a pipe
- *
- * This constructs a pipe, and sets the read end to be the stdin of the
- * subprocess, and returns the write-end in *@filp.
- */
-int call_usermodehelper_stdinpipe(struct subprocess_info *sub_info,
-                                 struct file **filp)
-{
-       struct file *f;
-
-       f = create_write_pipe(0);
-       if (IS_ERR(f))
-               return PTR_ERR(f);
-       *filp = f;
-
-       f = create_read_pipe(f, 0);
-       if (IS_ERR(f)) {
-               free_write_pipe(*filp);
-               return PTR_ERR(f);
-       }
-       sub_info->stdin = f;
-
-       return 0;
-}
-EXPORT_SYMBOL(call_usermodehelper_stdinpipe);
+EXPORT_SYMBOL(call_usermodehelper_setfns);
 
 /**
  * call_usermodehelper_exec - start a usermode application
@@ -469,9 +392,6 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info,
        DECLARE_COMPLETION_ONSTACK(done);
        int retval = 0;
 
-       BUG_ON(atomic_read(&sub_info->cred->usage) != 1);
-       validate_creds(sub_info->cred);
-
        helper_lock();
        if (sub_info->path[0] == '\0')
                goto out;
@@ -498,39 +418,6 @@ unlock:
 }
 EXPORT_SYMBOL(call_usermodehelper_exec);
 
-/**
- * call_usermodehelper_pipe - call a usermode helper process with a pipe stdin
- * @path: path to usermode executable
- * @argv: arg vector for process
- * @envp: environment for process
- * @filp: set to the write-end of a pipe
- *
- * This is a simple wrapper which executes a usermode-helper function
- * with a pipe as stdin.  It is implemented entirely in terms of
- * lower-level call_usermodehelper_* functions.
- */
-int call_usermodehelper_pipe(char *path, char **argv, char **envp,
-                            struct file **filp)
-{
-       struct subprocess_info *sub_info;
-       int ret;
-
-       sub_info = call_usermodehelper_setup(path, argv, envp, GFP_KERNEL);
-       if (sub_info == NULL)
-               return -ENOMEM;
-
-       ret = call_usermodehelper_stdinpipe(sub_info, filp);
-       if (ret < 0)
-               goto out;
-
-       return call_usermodehelper_exec(sub_info, UMH_WAIT_EXEC);
-
-  out:
-       call_usermodehelper_freeinfo(sub_info);
-       return ret;
-}
-EXPORT_SYMBOL(call_usermodehelper_pipe);
-
 void __init usermodehelper_init(void)
 {
        khelper_wq = create_singlethread_workqueue("khelper");