forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
191 lines
4.3 KiB
191 lines
4.3 KiB
// SPDX-License-Identifier: GPL-2.0-only |
|
/* |
|
* umd - User mode driver support |
|
*/ |
|
#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 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, 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; |
|
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; |
|
} |
|
|
|
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->tgid = get_pid(task_tgid(current)); |
|
return 0; |
|
} |
|
|
|
static void umd_cleanup(struct subprocess_info *info) |
|
{ |
|
struct umd_info *umd_info = info->data; |
|
|
|
/* cleanup if umh_setup() was successful but exec failed */ |
|
if (info->retval) |
|
umd_cleanup_helper(umd_info); |
|
} |
|
|
|
/** |
|
* umd_cleanup_helper - release the resources which were allocated in umd_setup |
|
* @info: information about usermode driver |
|
*/ |
|
void umd_cleanup_helper(struct umd_info *info) |
|
{ |
|
fput(info->pipe_to_umh); |
|
fput(info->pipe_from_umh); |
|
put_pid(info->tgid); |
|
info->tgid = NULL; |
|
} |
|
EXPORT_SYMBOL_GPL(umd_cleanup_helper); |
|
|
|
/** |
|
* 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 usermode driver. In such case 'struct umd_info *info' |
|
* is populated with two pipes and a tgid of the process. The caller is |
|
* responsible for health check of the user process, killing it via |
|
* tgid, and closing the pipes when user process is no longer needed. |
|
*/ |
|
int fork_usermode_driver(struct umd_info *info) |
|
{ |
|
struct subprocess_info *sub_info; |
|
const char *argv[] = { info->driver_name, NULL }; |
|
int err; |
|
|
|
if (WARN_ON_ONCE(info->tgid)) |
|
return -EBUSY; |
|
|
|
err = -ENOMEM; |
|
sub_info = call_usermodehelper_setup(info->driver_name, |
|
(char **)argv, NULL, GFP_KERNEL, |
|
umd_setup, umd_cleanup, info); |
|
if (!sub_info) |
|
goto out; |
|
|
|
err = call_usermodehelper_exec(sub_info, UMH_WAIT_EXEC); |
|
out: |
|
return err; |
|
} |
|
EXPORT_SYMBOL_GPL(fork_usermode_driver); |
|
|
|
|
|
|