1 files changed, 38 insertions, 155 deletions

diff --git a/kernel/kmod.c b/kernel/kmod.c
index bf0e231d9702..6e9b19667a8d 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -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 +147,16 @@ static int ____call_usermodehelper(void *data)
          */
         set_user_nice(current, 0);
 
+        if (sub_info->init) {
+                retval = sub_info->init(sub_info);
+                if (retval)
+                        goto fail;
+        }
+
         retval = kernel_execve(sub_info->path, sub_info->argv, sub_info->envp);
 
         /* Exec failed? */
+fail:
         sub_info->retval = retval;
         do_exit(0);
 }
@@ -194,9 +164,7 @@ 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 +175,16 @@ 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 +205,7 @@ 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 +214,13 @@ 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 +229,16 @@ 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 +340,37 @@ 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 +390,6 @@ 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;
@@ -498,41 +416,6 @@ 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) {
-                call_usermodehelper_freeinfo(sub_info);
-                return ret;
-        }
-
-        ret = call_usermodehelper_exec(sub_info, UMH_WAIT_EXEC);
-        if (ret < 0)    /* Failed to execute helper, close pipe */
-                filp_close(*filp, NULL);
-
-        return ret;
-}
-EXPORT_SYMBOL(call_usermodehelper_pipe);
-
 void __init usermodehelper_init(void)
 {
         khelper_wq = create_singlethread_workqueue("khelper");