#include <linux/cred.h>
#include <linux/file.h>
#include <linux/fdtable.h>
+#include <linux/fs_struct.h>
#include <linux/workqueue.h>
#include <linux/security.h>
#include <linux/mount.h>
#include <linux/ptrace.h>
#include <linux/async.h>
#include <linux/uaccess.h>
-#include <linux/shmem_fs.h>
-#include <linux/pipe_fs_i.h>
+#include <linux/initrd.h>
+#include <linux/freezer.h>
#include <trace/events/module.h>
-#define CAP_BSET (void *)1
-#define CAP_PI (void *)2
-
static kernel_cap_t usermodehelper_bset = CAP_FULL_SET;
static kernel_cap_t usermodehelper_inheritable = CAP_FULL_SET;
static DEFINE_SPINLOCK(umh_sysctl_lock);
static DECLARE_RWSEM(umhelper_sem);
-static LIST_HEAD(umh_list);
-static DEFINE_MUTEX(umh_list_lock);
static void call_usermodehelper_freeinfo(struct subprocess_info *info)
{
flush_signal_handlers(current, 1);
spin_unlock_irq(¤t->sighand->siglock);
+ /*
+ * Initial kernel threads share ther FS with init, in order to
+ * get the init root directory. But we've now created a new
+ * thread that is going to execve a user process and has its own
+ * 'struct fs_struct'. Reset umask to the default.
+ */
+ current->fs->umask = 0022;
+
/*
* Our parent (unbound workqueue) runs with elevated scheduling
* priority. Avoid propagating that into the userspace child.
commit_creds(new);
- sub_info->pid = task_pid_nr(current);
- if (sub_info->file) {
- retval = do_execve_file(sub_info->file,
- sub_info->argv, sub_info->envp);
- if (!retval)
- current->flags |= PF_UMH;
- } else
- retval = do_execve(getname_kernel(sub_info->path),
- (const char __user *const __user *)sub_info->argv,
- (const char __user *const __user *)sub_info->envp);
+ wait_for_initramfs();
+ retval = kernel_execve(sub_info->path,
+ (const char *const *)sub_info->argv,
+ (const char *const *)sub_info->envp);
out:
sub_info->retval = retval;
/*
{
pid_t pid;
- /* If SIGCLD is ignored kernel_wait4 won't populate the status. */
+ /* If SIGCLD is ignored do_wait won't populate the status. */
kernel_sigaction(SIGCHLD, SIG_DFL);
- pid = kernel_thread(call_usermodehelper_exec_async, sub_info, SIGCHLD);
- if (pid < 0) {
+ pid = user_mode_thread(call_usermodehelper_exec_async, sub_info, SIGCHLD);
+ if (pid < 0)
sub_info->retval = pid;
- } else {
- 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.
- * But call_usermodehelper_exec_sync() always runs as kernel
- * thread (workqueue) and put_user() to a kernel address works
- * OK for kernel threads, due to their having an mm_segment_t
- * which spans the entire address space.
- *
- * Thus the __user pointer cast is valid here.
- */
- kernel_wait4(pid, (int __user *)&ret, 0, NULL);
-
- /*
- * If ret is 0, either call_usermodehelper_exec_async failed and
- * the real error code is already in sub_info->retval or
- * sub_info->retval is 0 anyway, so don't mess with it then.
- */
- if (ret)
- sub_info->retval = ret;
- }
+ else
+ kernel_wait(pid, &sub_info->retval);
/* Restore default kernel sig handler */
kernel_sigaction(SIGCHLD, SIG_IGN);
-
umh_complete(sub_info);
}
* want to pollute current->children, and we need a parent
* that always ignores SIGCHLD to ensure auto-reaping.
*/
- pid = kernel_thread(call_usermodehelper_exec_async, sub_info,
- CLONE_PARENT | SIGCHLD);
+ pid = user_mode_thread(call_usermodehelper_exec_async, sub_info,
+ CLONE_PARENT | SIGCHLD);
if (pid < 0) {
sub_info->retval = pid;
umh_complete(sub_info);
* @argv: arg vector for process
* @envp: environment for process
* @gfp_mask: gfp mask for memory allocation
- * @cleanup: a cleanup function
* @init: an init function
+ * @cleanup: a cleanup function
* @data: arbitrary context sensitive data
*
* Returns either %NULL on allocation failure, or a subprocess_info
* 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
+ * The cleanup function is just before the 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.
}
EXPORT_SYMBOL(call_usermodehelper_setup);
-struct subprocess_info *call_usermodehelper_setup_file(struct file *file,
- int (*init)(struct subprocess_info *info, struct cred *new),
- void (*cleanup)(struct subprocess_info *info), void *data)
-{
- struct subprocess_info *sub_info;
- struct umh_info *info = data;
- const char *cmdline = (info->cmdline) ? info->cmdline : "usermodehelper";
-
- sub_info = kzalloc(sizeof(struct subprocess_info), GFP_KERNEL);
- if (!sub_info)
- return NULL;
-
- sub_info->argv = argv_split(GFP_KERNEL, cmdline, NULL);
- if (!sub_info->argv) {
- kfree(sub_info);
- return NULL;
- }
-
- INIT_WORK(&sub_info->work, call_usermodehelper_exec_work);
- sub_info->path = "none";
- sub_info->file = file;
- sub_info->init = init;
- sub_info->cleanup = cleanup;
- sub_info->data = data;
- return sub_info;
-}
-
-static int umh_pipe_setup(struct subprocess_info *info, struct cred *new)
-{
- struct umh_info *umh_info = info->data;
- struct file *from_umh[2];
- struct file *to_umh[2];
- int err;
-
- /* create pipe to send data to umh */
- err = create_pipe_files(to_umh, 0);
- if (err)
- return err;
- err = replace_fd(0, to_umh[0], 0);
- fput(to_umh[0]);
- if (err < 0) {
- fput(to_umh[1]);
- return err;
- }
-
- /* create pipe to receive data from umh */
- err = create_pipe_files(from_umh, 0);
- if (err) {
- fput(to_umh[1]);
- replace_fd(0, NULL, 0);
- return err;
- }
- err = replace_fd(1, from_umh[1], 0);
- fput(from_umh[1]);
- if (err < 0) {
- fput(to_umh[1]);
- replace_fd(0, NULL, 0);
- fput(from_umh[0]);
- return err;
- }
-
- umh_info->pipe_to_umh = to_umh[1];
- umh_info->pipe_from_umh = from_umh[0];
- return 0;
-}
-
-static void umh_clean_and_save_pid(struct subprocess_info *info)
-{
- struct umh_info *umh_info = info->data;
-
- argv_free(info->argv);
- umh_info->pid = info->pid;
-}
-
-/**
- * fork_usermode_blob - fork a blob of bytes as a usermode process
- * @data: a blob of bytes that can be do_execv-ed as a file
- * @len: length of the blob
- * @info: information about usermode process (shouldn't be NULL)
- *
- * If info->cmdline is set it will be used as command line for the
- * user process, else "usermodehelper" is used.
- *
- * Returns either negative error or zero which indicates success
- * in executing a blob of bytes as a usermode process. In such
- * case 'struct umh_info *info' is populated with two pipes
- * and a pid of the process. The caller is responsible for health
- * check of the user process, killing it via pid, and closing the
- * pipes when user process is no longer needed.
- */
-int fork_usermode_blob(void *data, size_t len, struct umh_info *info)
-{
- struct subprocess_info *sub_info;
- struct file *file;
- ssize_t written;
- loff_t pos = 0;
- int err;
-
- file = shmem_kernel_file_setup("", len, 0);
- if (IS_ERR(file))
- return PTR_ERR(file);
-
- written = kernel_write(file, data, len, &pos);
- if (written != len) {
- err = written;
- if (err >= 0)
- err = -ENOMEM;
- goto out;
- }
-
- err = -ENOMEM;
- sub_info = call_usermodehelper_setup_file(file, umh_pipe_setup,
- umh_clean_and_save_pid, info);
- if (!sub_info)
- goto out;
-
- err = call_usermodehelper_exec(sub_info, UMH_WAIT_EXEC);
- if (!err) {
- mutex_lock(&umh_list_lock);
- list_add(&info->list, &umh_list);
- mutex_unlock(&umh_list_lock);
- }
-out:
- fput(file);
- return err;
-}
-EXPORT_SYMBOL_GPL(fork_usermode_blob);
-
/**
* call_usermodehelper_exec - start a usermode application
- * @sub_info: information about the subprocessa
+ * @sub_info: information about the subprocess
* @wait: wait for the application to finish and return status.
* when UMH_NO_WAIT don't wait at all, but you get no useful error back
* when the program couldn't be exec'ed. This makes it safe to call
* Runs a user-space application. The application is started
* asynchronously if wait is not set, and runs as a child of system workqueues.
* (ie. it runs with full root capabilities and optimized affinity).
+ *
+ * Note: successful return value does not guarantee the helper was called at
+ * all. You can't rely on sub_info->{init,cleanup} being called even for
+ * UMH_WAIT_* wait modes as STATIC_USERMODEHELPER_PATH="" turns all helpers
+ * into a successful no-op.
*/
int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait)
{
+ unsigned int state = TASK_UNINTERRUPTIBLE;
DECLARE_COMPLETION_ONSTACK(done);
int retval = 0;
if (wait == UMH_NO_WAIT) /* task has freed sub_info */
goto unlock;
+ if (wait & UMH_FREEZABLE)
+ state |= TASK_FREEZABLE;
+
if (wait & UMH_KILLABLE) {
- retval = wait_for_completion_killable(&done);
+ retval = wait_for_completion_state(&done, state | TASK_KILLABLE);
if (!retval)
goto wait_done;
/* umh_complete() will see NULL and free sub_info */
if (xchg(&sub_info->complete, NULL))
goto unlock;
- /* fallthrough, umh_complete() was already called */
+
+ /*
+ * fallthrough; in case of -ERESTARTSYS now do uninterruptible
+ * wait_for_completion_state(). Since umh_complete() shall call
+ * complete() in a moment if xchg() above returned NULL, this
+ * uninterruptible wait_for_completion_state() will not block
+ * SIGKILL'ed processes for long.
+ */
}
+ wait_for_completion_state(&done, state);
- wait_for_completion(&done);
wait_done:
retval = sub_info->retval;
out:
}
EXPORT_SYMBOL(call_usermodehelper);
+#if defined(CONFIG_SYSCTL)
static int proc_cap_handler(struct ctl_table *table, int write,
- void __user *buffer, size_t *lenp, loff_t *ppos)
+ void *buffer, size_t *lenp, loff_t *ppos)
{
struct ctl_table t;
- unsigned long cap_array[_KERNEL_CAPABILITY_U32S];
- kernel_cap_t new_cap;
- int err, i;
+ unsigned long cap_array[2];
+ kernel_cap_t new_cap, *cap;
+ int err;
if (write && (!capable(CAP_SETPCAP) ||
!capable(CAP_SYS_MODULE)))
/*
* convert from the global kernel_cap_t to the ulong array to print to
* userspace if this is a read.
+ *
+ * Legacy format: capabilities are exposed as two 32-bit values
*/
+ cap = table->data;
spin_lock(&umh_sysctl_lock);
- for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++) {
- if (table->data == CAP_BSET)
- cap_array[i] = usermodehelper_bset.cap[i];
- else if (table->data == CAP_PI)
- cap_array[i] = usermodehelper_inheritable.cap[i];
- else
- BUG();
- }
+ cap_array[0] = (u32) cap->val;
+ cap_array[1] = cap->val >> 32;
spin_unlock(&umh_sysctl_lock);
t = *table;
if (err < 0)
return err;
- /*
- * convert from the sysctl array of ulongs to the kernel_cap_t
- * internal representation
- */
- for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++)
- new_cap.cap[i] = cap_array[i];
+ new_cap.val = (u32)cap_array[0];
+ new_cap.val += (u64)cap_array[1] << 32;
/*
* Drop everything not in the new_cap (but don't add things)
*/
if (write) {
spin_lock(&umh_sysctl_lock);
- if (table->data == CAP_BSET)
- usermodehelper_bset = cap_intersect(usermodehelper_bset, new_cap);
- if (table->data == CAP_PI)
- usermodehelper_inheritable = cap_intersect(usermodehelper_inheritable, new_cap);
+ *cap = cap_intersect(*cap, new_cap);
spin_unlock(&umh_sysctl_lock);
}
return 0;
}
-void __exit_umh(struct task_struct *tsk)
-{
- struct umh_info *info;
- pid_t pid = tsk->pid;
-
- mutex_lock(&umh_list_lock);
- list_for_each_entry(info, &umh_list, list) {
- if (info->pid == pid) {
- list_del(&info->list);
- mutex_unlock(&umh_list_lock);
- goto out;
- }
- }
- mutex_unlock(&umh_list_lock);
- return;
-out:
- if (info->cleanup)
- info->cleanup(info);
-}
-
-struct ctl_table usermodehelper_table[] = {
+static struct ctl_table usermodehelper_table[] = {
{
.procname = "bset",
- .data = CAP_BSET,
- .maxlen = _KERNEL_CAPABILITY_U32S * sizeof(unsigned long),
+ .data = &usermodehelper_bset,
+ .maxlen = 2 * sizeof(unsigned long),
.mode = 0600,
.proc_handler = proc_cap_handler,
},
{
.procname = "inheritable",
- .data = CAP_PI,
- .maxlen = _KERNEL_CAPABILITY_U32S * sizeof(unsigned long),
+ .data = &usermodehelper_inheritable,
+ .maxlen = 2 * sizeof(unsigned long),
.mode = 0600,
.proc_handler = proc_cap_handler,
},
{ }
};
+
+static int __init init_umh_sysctls(void)
+{
+ register_sysctl_init("kernel/usermodehelper", usermodehelper_table);
+ return 0;
+}
+early_initcall(init_umh_sysctls);
+#endif /* CONFIG_SYSCTL */
git.samba.org / sfrench / cifs-2.6.git / blobdiff