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[PATCH] r/o bind mounts: elevate write count for ioctls()

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Some ioctl()s can cause writes to the filesystem.  Take these, and make them
use mnt_want/drop_write() instead.

[AV: updated]

Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Dave Hansen
2008-02-15 14:37:46 -08:00
committed by Al Viro
parent 20ddee2c75
commit 42a74f206b
9 changed files with 264 additions and 154 deletions
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63
fs/reiserfs/ioctl.c
View File

@@ -4,6 +4,7 @@
#include <linux/capability.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/reiserfs_fs.h>
#include <linux/time.h>
#include <asm/uaccess.h>
@@ -25,6 +26,7 @@ int reiserfs_ioctl(struct inode *inode, struct file *filp, unsigned int cmd,
unsigned long arg)
{
unsigned int flags;
int err = 0;
switch (cmd) {
case REISERFS_IOC_UNPACK:
@@ -48,50 +50,67 @@ int reiserfs_ioctl(struct inode *inode, struct file *filp, unsigned int cmd,
if (!reiserfs_attrs(inode->i_sb))
return -ENOTTY;
if (IS_RDONLY(inode))
return -EROFS;
err = mnt_want_write(filp->f_path.mnt);
if (err)
return err;
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 (!is_owner_or_cap(inode)) {
err = -EPERM;
goto setflags_out;
}
if (get_user(flags, (int __user *)arg)) {
err = -EFAULT;
goto setflags_out;
}
/*
* Is it quota file? Do not allow user to mess with it
*/
if (IS_NOQUOTA(inode)) {
err = -EPERM;
goto setflags_out;
}
if (((flags ^ REISERFS_I(inode)->
i_attrs) & (REISERFS_IMMUTABLE_FL |
REISERFS_APPEND_FL))
&& !capable(CAP_LINUX_IMMUTABLE))
return -EPERM;
&& !capable(CAP_LINUX_IMMUTABLE)) {
err = -EPERM;
goto setflags_out;
}
if ((flags & REISERFS_NOTAIL_FL) &&
S_ISREG(inode->i_mode)) {
int result;
result = reiserfs_unpack(inode, filp);
if (result)
return result;
if (result) {
err = result;
goto setflags_out;
}
}
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;
setflags_out:
mnt_drop_write(filp->f_path.mnt);
return err;
}
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;
err = mnt_want_write(filp->f_path.mnt);
if (err)
return err;
if (get_user(inode->i_generation, (int __user *)arg)) {
err = -EFAULT;
goto setversion_out;
}
inode->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty(inode);
return 0;
setversion_out:
mnt_drop_write(filp->f_path.mnt);
return err;
default:
return -ENOTTY;
}