1 files changed, 38 insertions, 155 deletions

diff --git a/kernel/kmod.c b/kernel/kmod.c
index bf0e231..6e9b196 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");