kernel-ark/fs/reiserfs/ioctl.c
Jan Kara e47776a0a4 Forbid user to change file flags on quota files
Forbid user from changing file flags on quota files.  User has no bussiness
in playing with these flags when quota is on.  Furthermore there is a
remote possibility of deadlock due to a lock inversion between quota file's
i_mutex and transaction's start (i_mutex for quota file is locked only when
trasaction is started in quota operations) in ext3 and ext4.

Signed-off-by: Jan Kara <jack@suse.cz>
Cc: LIOU Payphone <lioupayphone@gmail.com>
Cc: <linux-ext4@vger.kernel.org>
Acked-by: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: <reiserfs-dev@namesys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-11-14 18:45:38 -08:00

203 lines
5.1 KiB
C

/*
* Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
*/
#include <linux/capability.h>
#include <linux/fs.h>
#include <linux/reiserfs_fs.h>
#include <linux/time.h>
#include <asm/uaccess.h>
#include <linux/pagemap.h>
#include <linux/smp_lock.h>
#include <linux/compat.h>
static int reiserfs_unpack(struct inode *inode, struct file *filp);
/*
** reiserfs_ioctl - handler for ioctl for inode
** supported commands:
** 1) REISERFS_IOC_UNPACK - try to unpack tail from direct item into indirect
** and prevent packing file (argument arg has to be non-zero)
** 2) REISERFS_IOC_[GS]ETFLAGS, REISERFS_IOC_[GS]ETVERSION
** 3) That's all for a while ...
*/
int reiserfs_ioctl(struct inode *inode, struct file *filp, unsigned int cmd,
unsigned long arg)
{
unsigned int flags;
switch (cmd) {
case REISERFS_IOC_UNPACK:
if (S_ISREG(inode->i_mode)) {
if (arg)
return reiserfs_unpack(inode, filp);
else
return 0;
} else
return -ENOTTY;
/* following two cases are taken from fs/ext2/ioctl.c by Remy
Card (card@masi.ibp.fr) */
case REISERFS_IOC_GETFLAGS:
if (!reiserfs_attrs(inode->i_sb))
return -ENOTTY;
flags = REISERFS_I(inode)->i_attrs;
i_attrs_to_sd_attrs(inode, (__u16 *) & flags);
return put_user(flags, (int __user *)arg);
case REISERFS_IOC_SETFLAGS:{
if (!reiserfs_attrs(inode->i_sb))
return -ENOTTY;
if (IS_RDONLY(inode))
return -EROFS;
if (!is_owner_or_cap(inode))
return -EPERM;
if (get_user(flags, (int __user *)arg))
return -EFAULT;
/* Is it quota file? Do not allow user to mess with it. */
if (IS_NOQUOTA(inode))
return -EPERM;
if (((flags ^ REISERFS_I(inode)->
i_attrs) & (REISERFS_IMMUTABLE_FL |
REISERFS_APPEND_FL))
&& !capable(CAP_LINUX_IMMUTABLE))
return -EPERM;
if ((flags & REISERFS_NOTAIL_FL) &&
S_ISREG(inode->i_mode)) {
int result;
result = reiserfs_unpack(inode, filp);
if (result)
return result;
}
sd_attrs_to_i_attrs(flags, inode);
REISERFS_I(inode)->i_attrs = flags;
inode->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty(inode);
return 0;
}
case REISERFS_IOC_GETVERSION:
return put_user(inode->i_generation, (int __user *)arg);
case REISERFS_IOC_SETVERSION:
if (!is_owner_or_cap(inode))
return -EPERM;
if (IS_RDONLY(inode))
return -EROFS;
if (get_user(inode->i_generation, (int __user *)arg))
return -EFAULT;
inode->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty(inode);
return 0;
default:
return -ENOTTY;
}
}
#ifdef CONFIG_COMPAT
long reiserfs_compat_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
struct inode *inode = file->f_path.dentry->d_inode;
int ret;
/* These are just misnamed, they actually get/put from/to user an int */
switch (cmd) {
case REISERFS_IOC32_UNPACK:
cmd = REISERFS_IOC_UNPACK;
break;
case REISERFS_IOC32_GETFLAGS:
cmd = REISERFS_IOC_GETFLAGS;
break;
case REISERFS_IOC32_SETFLAGS:
cmd = REISERFS_IOC_SETFLAGS;
break;
case REISERFS_IOC32_GETVERSION:
cmd = REISERFS_IOC_GETVERSION;
break;
case REISERFS_IOC32_SETVERSION:
cmd = REISERFS_IOC_SETVERSION;
break;
default:
return -ENOIOCTLCMD;
}
lock_kernel();
ret = reiserfs_ioctl(inode, file, cmd, (unsigned long) compat_ptr(arg));
unlock_kernel();
return ret;
}
#endif
int reiserfs_commit_write(struct file *f, struct page *page,
unsigned from, unsigned to);
int reiserfs_prepare_write(struct file *f, struct page *page,
unsigned from, unsigned to);
/*
** reiserfs_unpack
** Function try to convert tail from direct item into indirect.
** It set up nopack attribute in the REISERFS_I(inode)->nopack
*/
static int reiserfs_unpack(struct inode *inode, struct file *filp)
{
int retval = 0;
int index;
struct page *page;
struct address_space *mapping;
unsigned long write_from;
unsigned long blocksize = inode->i_sb->s_blocksize;
if (inode->i_size == 0) {
REISERFS_I(inode)->i_flags |= i_nopack_mask;
return 0;
}
/* ioctl already done */
if (REISERFS_I(inode)->i_flags & i_nopack_mask) {
return 0;
}
/* we need to make sure nobody is changing the file size beneath
** us
*/
mutex_lock(&inode->i_mutex);
reiserfs_write_lock(inode->i_sb);
write_from = inode->i_size & (blocksize - 1);
/* if we are on a block boundary, we are already unpacked. */
if (write_from == 0) {
REISERFS_I(inode)->i_flags |= i_nopack_mask;
goto out;
}
/* we unpack by finding the page with the tail, and calling
** reiserfs_prepare_write on that page. This will force a
** reiserfs_get_block to unpack the tail for us.
*/
index = inode->i_size >> PAGE_CACHE_SHIFT;
mapping = inode->i_mapping;
page = grab_cache_page(mapping, index);
retval = -ENOMEM;
if (!page) {
goto out;
}
retval = reiserfs_prepare_write(NULL, page, write_from, write_from);
if (retval)
goto out_unlock;
/* conversion can change page contents, must flush */
flush_dcache_page(page);
retval = reiserfs_commit_write(NULL, page, write_from, write_from);
REISERFS_I(inode)->i_flags |= i_nopack_mask;
out_unlock:
unlock_page(page);
page_cache_release(page);
out:
mutex_unlock(&inode->i_mutex);
reiserfs_write_unlock(inode->i_sb);
return retval;
}