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Diffstat (limited to 'kernel/usermode_driver.c')
-rw-r--r--kernel/usermode_driver.c126
1 files changed, 97 insertions, 29 deletions
diff --git a/kernel/usermode_driver.c b/kernel/usermode_driver.c
index 46d60d855e93..a86798759f83 100644
--- a/kernel/usermode_driver.c
+++ b/kernel/usermode_driver.c
@@ -4,11 +4,98 @@
*/
#include <linux/shmem_fs.h>
#include <linux/pipe_fs_i.h>
+#include <linux/mount.h>
+#include <linux/fs_struct.h>
+#include <linux/task_work.h>
#include <linux/usermode_driver.h>
static LIST_HEAD(umh_list);
static DEFINE_MUTEX(umh_list_lock);
+static struct vfsmount *blob_to_mnt(const void *data, size_t len, const char *name)
+{
+ struct file_system_type *type;
+ struct vfsmount *mnt;
+ struct file *file;
+ ssize_t written;
+ loff_t pos = 0;
+
+ type = get_fs_type("tmpfs");
+ if (!type)
+ return ERR_PTR(-ENODEV);
+
+ mnt = kern_mount(type);
+ put_filesystem(type);
+ if (IS_ERR(mnt))
+ return mnt;
+
+ file = file_open_root(mnt->mnt_root, mnt, name, O_CREAT | O_WRONLY, 0700);
+ if (IS_ERR(file)) {
+ mntput(mnt);
+ return ERR_CAST(file);
+ }
+
+ written = kernel_write(file, data, len, &pos);
+ if (written != len) {
+ int err = written;
+ if (err >= 0)
+ err = -ENOMEM;
+ filp_close(file, NULL);
+ mntput(mnt);
+ return ERR_PTR(err);
+ }
+
+ fput(file);
+
+ /* Flush delayed fput so exec can open the file read-only */
+ flush_delayed_fput();
+ task_work_run();
+ return mnt;
+}
+
+/**
+ * umd_load_blob - Remember a blob of bytes for fork_usermode_driver
+ * @info: information about usermode driver
+ * @data: a blob of bytes that can be executed as a file
+ * @len: The lentgh of the blob
+ *
+ */
+int umd_load_blob(struct umd_info *info, const void *data, size_t len)
+{
+ struct vfsmount *mnt;
+
+ if (WARN_ON_ONCE(info->wd.dentry || info->wd.mnt))
+ return -EBUSY;
+
+ mnt = blob_to_mnt(data, len, info->driver_name);
+ if (IS_ERR(mnt))
+ return PTR_ERR(mnt);
+
+ info->wd.mnt = mnt;
+ info->wd.dentry = mnt->mnt_root;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(umd_load_blob);
+
+/**
+ * umd_unload_blob - Disassociate @info from a previously loaded blob
+ * @info: information about usermode driver
+ *
+ */
+int umd_unload_blob(struct umd_info *info)
+{
+ if (WARN_ON_ONCE(!info->wd.mnt ||
+ !info->wd.dentry ||
+ info->wd.mnt->mnt_root != info->wd.dentry))
+ return -EINVAL;
+
+ kern_unmount(info->wd.mnt);
+ info->wd.mnt = NULL;
+ info->wd.dentry = NULL;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(umd_unload_blob);
+
static int umd_setup(struct subprocess_info *info, struct cred *new)
{
struct umd_info *umd_info = info->data;
@@ -43,6 +130,7 @@ static int umd_setup(struct subprocess_info *info, struct cred *new)
return err;
}
+ set_fs_pwd(current->fs, &umd_info->wd);
umd_info->pipe_to_umh = to_umh[1];
umd_info->pipe_from_umh = from_umh[0];
umd_info->pid = task_pid_nr(current);
@@ -62,39 +150,21 @@ static void umd_cleanup(struct subprocess_info *info)
}
/**
- * 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)
+ * fork_usermode_driver - fork a usermode driver
+ * @info: information about usermode driver (shouldn't be NULL)
*
- * Returns either negative error or zero which indicates success
- * in executing a blob of bytes as a usermode process. In such
- * case 'struct umd_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.
+ * Returns either negative error or zero which indicates success in
+ * executing a usermode driver. In such case 'struct umd_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 umd_info *info)
+int fork_usermode_driver(struct umd_info *info)
{
struct subprocess_info *sub_info;
char **argv = NULL;
- struct file *file;
- ssize_t written;
- loff_t pos = 0;
int err;
- file = shmem_kernel_file_setup(info->driver_name, 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;
argv = argv_split(GFP_KERNEL, info->driver_name, NULL);
if (!argv)
@@ -106,7 +176,6 @@ int fork_usermode_blob(void *data, size_t len, struct umd_info *info)
if (!sub_info)
goto out;
- sub_info->file = file;
err = call_usermodehelper_exec(sub_info, UMH_WAIT_EXEC);
if (!err) {
mutex_lock(&umh_list_lock);
@@ -116,10 +185,9 @@ int fork_usermode_blob(void *data, size_t len, struct umd_info *info)
out:
if (argv)
argv_free(argv);
- fput(file);
return err;
}
-EXPORT_SYMBOL_GPL(fork_usermode_blob);
+EXPORT_SYMBOL_GPL(fork_usermode_driver);
void __exit_umh(struct task_struct *tsk)
{