files = get_files_struct(task);
if (files) {
- rcu_read_lock();
+ /*
+ * We are not taking a ref to the file structure, so we must
+ * hold ->file_lock.
+ */
+ spin_lock(&files->file_lock);
file = fcheck_files(files, fd);
if (file) {
*mnt = mntget(file->f_vfsmnt);
*dentry = dget(file->f_dentry);
- rcu_read_unlock();
+ spin_unlock(&files->file_lock);
put_files_struct(files);
return 0;
}
- rcu_read_unlock();
+ spin_unlock(&files->file_lock);
put_files_struct(files);
}
return -ENOENT;
/* If the process being read is separated by chroot from the reading process,
* don't let the reader access the threads.
+ *
+ * note: this does dput(root) and mntput(vfsmnt) on exit.
*/
static int proc_check_chroot(struct dentry *root, struct vfsmount *vfsmnt)
{
struct dentry *de, *base;
struct vfsmount *our_vfsmnt, *mnt;
int res = 0;
+
read_lock(¤t->fs->lock);
our_vfsmnt = mntget(current->fs->rootmnt);
base = dget(current->fs->root);
de = root;
mnt = vfsmnt;
- while (vfsmnt != our_vfsmnt) {
- if (vfsmnt == vfsmnt->mnt_parent)
+ while (mnt != our_vfsmnt) {
+ if (mnt == mnt->mnt_parent)
goto out;
- de = vfsmnt->mnt_mountpoint;
- vfsmnt = vfsmnt->mnt_parent;
+ de = mnt->mnt_mountpoint;
+ mnt = mnt->mnt_parent;
}
if (!is_subdir(de, base))
dput(base);
mntput(our_vfsmnt);
dput(root);
- mntput(mnt);
+ mntput(vfsmnt);
return res;
out:
spin_unlock(&vfsmount_lock);
if (current != task)
return -EPERM;
- if (count > PAGE_SIZE)
- count = PAGE_SIZE;
+ if (count >= PAGE_SIZE)
+ count = PAGE_SIZE - 1;
if (*ppos != 0) {
/* No partial writes. */
if (copy_from_user(page, buf, count))
goto out_free_page;
+ page[count] = '\0';
loginuid = simple_strtoul(page, &tmp, 10);
if (tmp == page) {
length = -EINVAL;
if (!files)
goto out_unlock;
inode->i_mode = S_IFLNK;
- rcu_read_lock();
+
+ /*
+ * We are not taking a ref to the file structure, so we must
+ * hold ->file_lock.
+ */
+ spin_lock(&files->file_lock);
file = fcheck_files(files, fd);
if (!file)
goto out_unlock2;
inode->i_mode |= S_IRUSR | S_IXUSR;
if (file->f_mode & 2)
inode->i_mode |= S_IWUSR | S_IXUSR;
- rcu_read_unlock();
+ spin_unlock(&files->file_lock);
put_files_struct(files);
inode->i_op = &proc_pid_link_inode_operations;
inode->i_size = 64;
return NULL;
out_unlock2:
- rcu_read_unlock();
+ spin_unlock(&files->file_lock);
put_files_struct(files);
out_unlock:
iput(inode);