mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-24 13:13:57 +08:00
88826276dc
infrastructure work to add and remove marks on vfsmounts. This should get every set up except wiring the functions to the syscalls. Signed-off-by: Eric Paris <eparis@redhat.com>
617 lines
15 KiB
C
617 lines
15 KiB
C
#include <linux/fcntl.h>
|
|
#include <linux/file.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/anon_inodes.h>
|
|
#include <linux/fsnotify_backend.h>
|
|
#include <linux/init.h>
|
|
#include <linux/mount.h>
|
|
#include <linux/namei.h>
|
|
#include <linux/poll.h>
|
|
#include <linux/security.h>
|
|
#include <linux/syscalls.h>
|
|
#include <linux/types.h>
|
|
#include <linux/uaccess.h>
|
|
|
|
#include <asm/ioctls.h>
|
|
|
|
#include "fanotify.h"
|
|
|
|
static struct kmem_cache *fanotify_mark_cache __read_mostly;
|
|
|
|
/*
|
|
* Get an fsnotify notification event if one exists and is small
|
|
* enough to fit in "count". Return an error pointer if the count
|
|
* is not large enough.
|
|
*
|
|
* Called with the group->notification_mutex held.
|
|
*/
|
|
static struct fsnotify_event *get_one_event(struct fsnotify_group *group,
|
|
size_t count)
|
|
{
|
|
BUG_ON(!mutex_is_locked(&group->notification_mutex));
|
|
|
|
pr_debug("%s: group=%p count=%zd\n", __func__, group, count);
|
|
|
|
if (fsnotify_notify_queue_is_empty(group))
|
|
return NULL;
|
|
|
|
if (FAN_EVENT_METADATA_LEN > count)
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
/* held the notification_mutex the whole time, so this is the
|
|
* same event we peeked above */
|
|
return fsnotify_remove_notify_event(group);
|
|
}
|
|
|
|
static int create_fd(struct fsnotify_group *group, struct fsnotify_event *event)
|
|
{
|
|
int client_fd;
|
|
struct dentry *dentry;
|
|
struct vfsmount *mnt;
|
|
struct file *new_file;
|
|
|
|
pr_debug("%s: group=%p event=%p\n", __func__, group, event);
|
|
|
|
client_fd = get_unused_fd();
|
|
if (client_fd < 0)
|
|
return client_fd;
|
|
|
|
if (event->data_type != FSNOTIFY_EVENT_PATH) {
|
|
WARN_ON(1);
|
|
put_unused_fd(client_fd);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/*
|
|
* we need a new file handle for the userspace program so it can read even if it was
|
|
* originally opened O_WRONLY.
|
|
*/
|
|
dentry = dget(event->path.dentry);
|
|
mnt = mntget(event->path.mnt);
|
|
/* it's possible this event was an overflow event. in that case dentry and mnt
|
|
* are NULL; That's fine, just don't call dentry open */
|
|
if (dentry && mnt)
|
|
new_file = dentry_open(dentry, mnt,
|
|
O_RDONLY | O_LARGEFILE | FMODE_NONOTIFY,
|
|
current_cred());
|
|
else
|
|
new_file = ERR_PTR(-EOVERFLOW);
|
|
if (IS_ERR(new_file)) {
|
|
/*
|
|
* we still send an event even if we can't open the file. this
|
|
* can happen when say tasks are gone and we try to open their
|
|
* /proc files or we try to open a WRONLY file like in sysfs
|
|
* we just send the errno to userspace since there isn't much
|
|
* else we can do.
|
|
*/
|
|
put_unused_fd(client_fd);
|
|
client_fd = PTR_ERR(new_file);
|
|
} else {
|
|
fd_install(client_fd, new_file);
|
|
}
|
|
|
|
return client_fd;
|
|
}
|
|
|
|
static ssize_t fill_event_metadata(struct fsnotify_group *group,
|
|
struct fanotify_event_metadata *metadata,
|
|
struct fsnotify_event *event)
|
|
{
|
|
pr_debug("%s: group=%p metadata=%p event=%p\n", __func__,
|
|
group, metadata, event);
|
|
|
|
metadata->event_len = FAN_EVENT_METADATA_LEN;
|
|
metadata->vers = FANOTIFY_METADATA_VERSION;
|
|
metadata->mask = fanotify_outgoing_mask(event->mask);
|
|
metadata->pid = pid_vnr(event->tgid);
|
|
metadata->fd = create_fd(group, event);
|
|
|
|
return metadata->fd;
|
|
}
|
|
|
|
static ssize_t copy_event_to_user(struct fsnotify_group *group,
|
|
struct fsnotify_event *event,
|
|
char __user *buf)
|
|
{
|
|
struct fanotify_event_metadata fanotify_event_metadata;
|
|
int ret;
|
|
|
|
pr_debug("%s: group=%p event=%p\n", __func__, group, event);
|
|
|
|
ret = fill_event_metadata(group, &fanotify_event_metadata, event);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
if (copy_to_user(buf, &fanotify_event_metadata, FAN_EVENT_METADATA_LEN))
|
|
return -EFAULT;
|
|
|
|
return FAN_EVENT_METADATA_LEN;
|
|
}
|
|
|
|
/* intofiy userspace file descriptor functions */
|
|
static unsigned int fanotify_poll(struct file *file, poll_table *wait)
|
|
{
|
|
struct fsnotify_group *group = file->private_data;
|
|
int ret = 0;
|
|
|
|
poll_wait(file, &group->notification_waitq, wait);
|
|
mutex_lock(&group->notification_mutex);
|
|
if (!fsnotify_notify_queue_is_empty(group))
|
|
ret = POLLIN | POLLRDNORM;
|
|
mutex_unlock(&group->notification_mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t fanotify_read(struct file *file, char __user *buf,
|
|
size_t count, loff_t *pos)
|
|
{
|
|
struct fsnotify_group *group;
|
|
struct fsnotify_event *kevent;
|
|
char __user *start;
|
|
int ret;
|
|
DEFINE_WAIT(wait);
|
|
|
|
start = buf;
|
|
group = file->private_data;
|
|
|
|
pr_debug("%s: group=%p\n", __func__, group);
|
|
|
|
while (1) {
|
|
prepare_to_wait(&group->notification_waitq, &wait, TASK_INTERRUPTIBLE);
|
|
|
|
mutex_lock(&group->notification_mutex);
|
|
kevent = get_one_event(group, count);
|
|
mutex_unlock(&group->notification_mutex);
|
|
|
|
if (kevent) {
|
|
ret = PTR_ERR(kevent);
|
|
if (IS_ERR(kevent))
|
|
break;
|
|
ret = copy_event_to_user(group, kevent, buf);
|
|
fsnotify_put_event(kevent);
|
|
if (ret < 0)
|
|
break;
|
|
buf += ret;
|
|
count -= ret;
|
|
continue;
|
|
}
|
|
|
|
ret = -EAGAIN;
|
|
if (file->f_flags & O_NONBLOCK)
|
|
break;
|
|
ret = -EINTR;
|
|
if (signal_pending(current))
|
|
break;
|
|
|
|
if (start != buf)
|
|
break;
|
|
|
|
schedule();
|
|
}
|
|
|
|
finish_wait(&group->notification_waitq, &wait);
|
|
if (start != buf && ret != -EFAULT)
|
|
ret = buf - start;
|
|
return ret;
|
|
}
|
|
|
|
static int fanotify_release(struct inode *ignored, struct file *file)
|
|
{
|
|
struct fsnotify_group *group = file->private_data;
|
|
|
|
pr_debug("%s: file=%p group=%p\n", __func__, file, group);
|
|
|
|
/* matches the fanotify_init->fsnotify_alloc_group */
|
|
fsnotify_put_group(group);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static long fanotify_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
|
|
{
|
|
struct fsnotify_group *group;
|
|
struct fsnotify_event_holder *holder;
|
|
void __user *p;
|
|
int ret = -ENOTTY;
|
|
size_t send_len = 0;
|
|
|
|
group = file->private_data;
|
|
|
|
p = (void __user *) arg;
|
|
|
|
switch (cmd) {
|
|
case FIONREAD:
|
|
mutex_lock(&group->notification_mutex);
|
|
list_for_each_entry(holder, &group->notification_list, event_list)
|
|
send_len += FAN_EVENT_METADATA_LEN;
|
|
mutex_unlock(&group->notification_mutex);
|
|
ret = put_user(send_len, (int __user *) p);
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static const struct file_operations fanotify_fops = {
|
|
.poll = fanotify_poll,
|
|
.read = fanotify_read,
|
|
.fasync = NULL,
|
|
.release = fanotify_release,
|
|
.unlocked_ioctl = fanotify_ioctl,
|
|
.compat_ioctl = fanotify_ioctl,
|
|
};
|
|
|
|
static void fanotify_free_mark(struct fsnotify_mark *fsn_mark)
|
|
{
|
|
kmem_cache_free(fanotify_mark_cache, fsn_mark);
|
|
}
|
|
|
|
static int fanotify_find_path(int dfd, const char __user *filename,
|
|
struct path *path, unsigned int flags)
|
|
{
|
|
int ret;
|
|
|
|
pr_debug("%s: dfd=%d filename=%p flags=%x\n", __func__,
|
|
dfd, filename, flags);
|
|
|
|
if (filename == NULL) {
|
|
struct file *file;
|
|
int fput_needed;
|
|
|
|
ret = -EBADF;
|
|
file = fget_light(dfd, &fput_needed);
|
|
if (!file)
|
|
goto out;
|
|
|
|
ret = -ENOTDIR;
|
|
if ((flags & FAN_MARK_ONLYDIR) &&
|
|
!(S_ISDIR(file->f_path.dentry->d_inode->i_mode))) {
|
|
fput_light(file, fput_needed);
|
|
goto out;
|
|
}
|
|
|
|
*path = file->f_path;
|
|
path_get(path);
|
|
fput_light(file, fput_needed);
|
|
} else {
|
|
unsigned int lookup_flags = 0;
|
|
|
|
if (!(flags & FAN_MARK_DONT_FOLLOW))
|
|
lookup_flags |= LOOKUP_FOLLOW;
|
|
if (flags & FAN_MARK_ONLYDIR)
|
|
lookup_flags |= LOOKUP_DIRECTORY;
|
|
|
|
ret = user_path_at(dfd, filename, lookup_flags, path);
|
|
if (ret)
|
|
goto out;
|
|
}
|
|
|
|
/* you can only watch an inode if you have read permissions on it */
|
|
ret = inode_permission(path->dentry->d_inode, MAY_READ);
|
|
if (ret)
|
|
path_put(path);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static void fanotify_update_object_mask(struct fsnotify_group *group,
|
|
struct inode *inode,
|
|
struct vfsmount *mnt,
|
|
struct fsnotify_mark *fsn_mark,
|
|
unsigned int flags,
|
|
__u32 mask)
|
|
{
|
|
__u32 old_mask, new_mask;
|
|
|
|
pr_debug("%s: group=%p inode=%p mnt=%p fsn_mark=%p flags=%x mask=%x\n",
|
|
__func__, group, inode, mnt, fsn_mark, flags, mask);
|
|
|
|
spin_lock(&fsn_mark->lock);
|
|
old_mask = fsn_mark->mask;
|
|
if (flags & FAN_MARK_ADD)
|
|
fsn_mark->mask |= mask;
|
|
else if (flags & FAN_MARK_REMOVE)
|
|
fsn_mark->mask &= ~mask;
|
|
else
|
|
BUG();
|
|
new_mask = fsn_mark->mask;
|
|
spin_unlock(&fsn_mark->lock);
|
|
|
|
if (!new_mask)
|
|
fsnotify_destroy_mark(fsn_mark);
|
|
|
|
/* we made changes to a mask, update the group mask and the object mask
|
|
* so things happen quickly. */
|
|
if (old_mask != new_mask) {
|
|
__u32 dropped, do_object, do_group;
|
|
|
|
/* more bits in old than in new? */
|
|
dropped = (old_mask & ~new_mask);
|
|
/* more bits in this fsn_mark than the group? */
|
|
do_group = (new_mask & ~group->mask);
|
|
|
|
if (inode) {
|
|
/* more bits in this fsn_mark than the object's mask? */
|
|
do_object = (new_mask & ~inode->i_fsnotify_mask);
|
|
/* update the object with this new fsn_mark */
|
|
if (dropped || do_object)
|
|
fsnotify_recalc_inode_mask(inode);
|
|
} else if (mnt) {
|
|
/* more bits in this fsn_mark than the object's mask? */
|
|
do_object = (new_mask & ~mnt->mnt_fsnotify_mask);
|
|
/* update the object with this new fsn_mark */
|
|
if (dropped || do_object)
|
|
fsnotify_recalc_vfsmount_mask(mnt);
|
|
} else {
|
|
BUG();
|
|
}
|
|
|
|
/* update the group mask with the new mask */
|
|
if (dropped || do_group)
|
|
fsnotify_recalc_group_mask(group);
|
|
}
|
|
}
|
|
|
|
static int fanotify_remove_mark(struct fsnotify_group *group, struct inode *inode,
|
|
struct vfsmount *mnt, unsigned int flags, __u32 mask)
|
|
{
|
|
struct fsnotify_mark *fsn_mark = NULL;
|
|
|
|
BUG_ON(inode && mnt);
|
|
BUG_ON(!inode && !mnt);
|
|
|
|
if (inode)
|
|
fsn_mark = fsnotify_find_inode_mark(group, inode);
|
|
else if (mnt)
|
|
fsn_mark = fsnotify_find_vfsmount_mark(group, mnt);
|
|
else
|
|
BUG();
|
|
|
|
if (!fsn_mark)
|
|
return -ENOENT;
|
|
|
|
fanotify_update_object_mask(group, inode, mnt, fsn_mark, flags, mask);
|
|
|
|
/* matches the fsnotify_find_inode_mark() */
|
|
fsnotify_put_mark(fsn_mark);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct fsnotify_mark *fanotify_add_vfsmount_mark(struct fsnotify_group *group,
|
|
struct vfsmount *mnt)
|
|
{
|
|
struct fsnotify_mark *fsn_mark;
|
|
|
|
fsn_mark = fsnotify_find_vfsmount_mark(group, mnt);
|
|
if (!fsn_mark) {
|
|
struct fsnotify_mark *new_fsn_mark;
|
|
int ret;
|
|
|
|
fsn_mark = ERR_PTR(-ENOMEM);
|
|
new_fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL);
|
|
if (!new_fsn_mark)
|
|
goto out;
|
|
|
|
fsnotify_init_mark(new_fsn_mark, fanotify_free_mark);
|
|
ret = fsnotify_add_mark(new_fsn_mark, group, NULL, mnt, 0);
|
|
if (ret) {
|
|
fsn_mark = ERR_PTR(ret);
|
|
fanotify_free_mark(new_fsn_mark);
|
|
goto out;
|
|
}
|
|
|
|
fsn_mark = new_fsn_mark;
|
|
}
|
|
out:
|
|
return fsn_mark;
|
|
}
|
|
|
|
static struct fsnotify_mark *fanotify_add_inode_mark(struct fsnotify_group *group,
|
|
struct inode *inode)
|
|
{
|
|
struct fsnotify_mark *fsn_mark;
|
|
|
|
pr_debug("%s: group=%p inode=%p\n", __func__, group, inode);
|
|
|
|
fsn_mark = fsnotify_find_inode_mark(group, inode);
|
|
if (!fsn_mark) {
|
|
struct fsnotify_mark *new_fsn_mark;
|
|
int ret;
|
|
|
|
fsn_mark = ERR_PTR(-ENOMEM);
|
|
new_fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL);
|
|
if (!new_fsn_mark)
|
|
goto out;
|
|
|
|
fsnotify_init_mark(new_fsn_mark, fanotify_free_mark);
|
|
ret = fsnotify_add_mark(new_fsn_mark, group, inode, NULL, 0);
|
|
if (ret) {
|
|
fsn_mark = ERR_PTR(ret);
|
|
fanotify_free_mark(new_fsn_mark);
|
|
goto out;
|
|
}
|
|
|
|
fsn_mark = new_fsn_mark;
|
|
}
|
|
out:
|
|
return fsn_mark;
|
|
}
|
|
|
|
static int fanotify_add_mark(struct fsnotify_group *group, struct inode *inode,
|
|
struct vfsmount *mnt, unsigned int flags, __u32 mask)
|
|
{
|
|
struct fsnotify_mark *fsn_mark;
|
|
|
|
pr_debug("%s: group=%p inode=%p mnt=%p flags=%x mask=%x\n",
|
|
__func__, group, inode, mnt, flags, mask);
|
|
|
|
BUG_ON(inode && mnt);
|
|
BUG_ON(!inode && !mnt);
|
|
|
|
if (inode)
|
|
fsn_mark = fanotify_add_inode_mark(group, inode);
|
|
else if (mnt)
|
|
fsn_mark = fanotify_add_vfsmount_mark(group, mnt);
|
|
else
|
|
BUG();
|
|
|
|
if (IS_ERR(fsn_mark))
|
|
goto out;
|
|
|
|
fanotify_update_object_mask(group, inode, mnt, fsn_mark, flags, mask);
|
|
|
|
/* match the init or the find.... */
|
|
fsnotify_put_mark(fsn_mark);
|
|
out:
|
|
return PTR_ERR(fsn_mark);
|
|
}
|
|
|
|
static int fanotify_update_mark(struct fsnotify_group *group,
|
|
struct inode *inode, struct vfsmount *mnt,
|
|
int flags, __u32 mask)
|
|
{
|
|
pr_debug("%s: group=%p inode=%p mnt=%p flags=%x mask=%x\n",
|
|
__func__, group, inode, mnt, flags, mask);
|
|
|
|
BUG_ON(inode && mnt);
|
|
BUG_ON(!inode && !mnt);
|
|
|
|
if (flags & FAN_MARK_ADD)
|
|
fanotify_add_mark(group, inode, mnt, flags, mask);
|
|
else if (flags & FAN_MARK_REMOVE)
|
|
fanotify_remove_mark(group, inode, mnt, flags, mask);
|
|
else
|
|
BUG();
|
|
|
|
return 0;
|
|
}
|
|
|
|
static bool fanotify_mark_validate_input(int flags,
|
|
__u32 mask)
|
|
{
|
|
pr_debug("%s: flags=%x mask=%x\n", __func__, flags, mask);
|
|
|
|
/* are flags valid of this operation? */
|
|
if (!fanotify_mark_flags_valid(flags))
|
|
return false;
|
|
/* is the mask valid? */
|
|
if (!fanotify_mask_valid(mask))
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
/* fanotify syscalls */
|
|
SYSCALL_DEFINE3(fanotify_init, unsigned int, flags, unsigned int, event_f_flags,
|
|
unsigned int, priority)
|
|
{
|
|
struct fsnotify_group *group;
|
|
int f_flags, fd;
|
|
|
|
pr_debug("%s: flags=%d event_f_flags=%d priority=%d\n",
|
|
__func__, flags, event_f_flags, priority);
|
|
|
|
if (event_f_flags)
|
|
return -EINVAL;
|
|
if (priority)
|
|
return -EINVAL;
|
|
|
|
if (!capable(CAP_SYS_ADMIN))
|
|
return -EACCES;
|
|
|
|
if (flags & ~FAN_ALL_INIT_FLAGS)
|
|
return -EINVAL;
|
|
|
|
f_flags = (O_RDONLY | FMODE_NONOTIFY);
|
|
if (flags & FAN_CLOEXEC)
|
|
f_flags |= O_CLOEXEC;
|
|
if (flags & FAN_NONBLOCK)
|
|
f_flags |= O_NONBLOCK;
|
|
|
|
/* fsnotify_alloc_group takes a ref. Dropped in fanotify_release */
|
|
group = fsnotify_alloc_group(&fanotify_fsnotify_ops);
|
|
if (IS_ERR(group))
|
|
return PTR_ERR(group);
|
|
|
|
fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags);
|
|
if (fd < 0)
|
|
goto out_put_group;
|
|
|
|
return fd;
|
|
|
|
out_put_group:
|
|
fsnotify_put_group(group);
|
|
return fd;
|
|
}
|
|
|
|
SYSCALL_DEFINE(fanotify_mark)(int fanotify_fd, unsigned int flags,
|
|
__u64 mask, int dfd,
|
|
const char __user * pathname)
|
|
{
|
|
struct inode *inode;
|
|
struct fsnotify_group *group;
|
|
struct file *filp;
|
|
struct path path;
|
|
int ret, fput_needed;
|
|
|
|
pr_debug("%s: fanotify_fd=%d flags=%x dfd=%d pathname=%p mask=%llx\n",
|
|
__func__, fanotify_fd, flags, dfd, pathname, mask);
|
|
|
|
/* we only use the lower 32 bits as of right now. */
|
|
if (mask & ((__u64)0xffffffff << 32))
|
|
return -EINVAL;
|
|
|
|
if (!fanotify_mark_validate_input(flags, mask))
|
|
return -EINVAL;
|
|
|
|
filp = fget_light(fanotify_fd, &fput_needed);
|
|
if (unlikely(!filp))
|
|
return -EBADF;
|
|
|
|
/* verify that this is indeed an fanotify instance */
|
|
ret = -EINVAL;
|
|
if (unlikely(filp->f_op != &fanotify_fops))
|
|
goto fput_and_out;
|
|
|
|
ret = fanotify_find_path(dfd, pathname, &path, flags);
|
|
if (ret)
|
|
goto fput_and_out;
|
|
|
|
/* inode held in place by reference to path; group by fget on fd */
|
|
inode = path.dentry->d_inode;
|
|
group = filp->private_data;
|
|
|
|
/* create/update an inode mark */
|
|
ret = fanotify_update_mark(group, inode, NULL, flags, mask);
|
|
|
|
path_put(&path);
|
|
fput_and_out:
|
|
fput_light(filp, fput_needed);
|
|
return ret;
|
|
}
|
|
|
|
#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
|
|
asmlinkage long SyS_fanotify_mark(long fanotify_fd, long flags, __u64 mask,
|
|
long dfd, long pathname)
|
|
{
|
|
return SYSC_fanotify_mark((int) fanotify_fd, (unsigned int) flags,
|
|
mask, (int) dfd,
|
|
(const char __user *) pathname);
|
|
}
|
|
SYSCALL_ALIAS(sys_fanotify_mark, SyS_fanotify_mark);
|
|
#endif
|
|
|
|
/*
|
|
* fanotify_user_setup - Our initialization function. Note that we cannnot return
|
|
* error because we have compiled-in VFS hooks. So an (unlikely) failure here
|
|
* must result in panic().
|
|
*/
|
|
static int __init fanotify_user_setup(void)
|
|
{
|
|
fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, SLAB_PANIC);
|
|
|
|
return 0;
|
|
}
|
|
device_initcall(fanotify_user_setup);
|