From: akpm@linux-foundation.org Subject: [patch 022/120] Forbid user to change file flags on quota files Date: Wed, 14 Nov 2007 16:58:56 -0800 Message-ID: <200711150058.lAF0wv41002605@imap1.linux-foundation.org> Cc: akpm@linux-foundation.org, jack@suse.cz, linux-ext4@vger.kernel.org, lioupayphone@gmail.com, reiserfs-dev@namesys.com, shaggy@austin.ibm.com To: torvalds@linux-foundation.org Return-path: Received: from smtp2.linux-foundation.org ([207.189.120.14]:35390 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751592AbXKOBIX (ORCPT ); Wed, 14 Nov 2007 20:08:23 -0500 Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org From: Jan Kara 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 Cc: LIOU Payphone Cc: Acked-by: Dave Kleikamp Cc: Signed-off-by: Andrew Morton --- fs/ext2/ioctl.c | 5 +++++ fs/ext3/ioctl.c | 5 +++++ fs/ext4/ioctl.c | 5 +++++ fs/jfs/ioctl.c | 3 +++ fs/reiserfs/ioctl.c | 3 +++ 5 files changed, 21 insertions(+) diff -puN fs/ext2/ioctl.c~forbid-user-to-change-file-flags-on-quota-files fs/ext2/ioctl.c --- a/fs/ext2/ioctl.c~forbid-user-to-change-file-flags-on-quota-files +++ a/fs/ext2/ioctl.c @@ -47,6 +47,11 @@ int ext2_ioctl (struct inode * inode, st flags &= ~EXT2_DIRSYNC_FL; mutex_lock(&inode->i_mutex); + /* Is it quota file? Do not allow user to mess with it */ + if (IS_NOQUOTA(inode)) { + mutex_unlock(&inode->i_mutex); + return -EPERM; + } oldflags = ei->i_flags; /* diff -puN fs/ext3/ioctl.c~forbid-user-to-change-file-flags-on-quota-files fs/ext3/ioctl.c --- a/fs/ext3/ioctl.c~forbid-user-to-change-file-flags-on-quota-files +++ a/fs/ext3/ioctl.c @@ -51,6 +51,11 @@ int ext3_ioctl (struct inode * inode, st flags &= ~EXT3_DIRSYNC_FL; mutex_lock(&inode->i_mutex); + /* Is it quota file? Do not allow user to mess with it */ + if (IS_NOQUOTA(inode)) { + mutex_unlock(&inode->i_mutex); + return -EPERM; + } oldflags = ei->i_flags; /* The JOURNAL_DATA flag is modifiable only by root */ diff -puN fs/ext4/ioctl.c~forbid-user-to-change-file-flags-on-quota-files fs/ext4/ioctl.c --- a/fs/ext4/ioctl.c~forbid-user-to-change-file-flags-on-quota-files +++ a/fs/ext4/ioctl.c @@ -51,6 +51,11 @@ int ext4_ioctl (struct inode * inode, st flags &= ~EXT4_DIRSYNC_FL; mutex_lock(&inode->i_mutex); + /* Is it quota file? Do not allow user to mess with it */ + if (IS_NOQUOTA(inode)) { + mutex_unlock(&inode->i_mutex); + return -EPERM; + } oldflags = ei->i_flags; /* The JOURNAL_DATA flag is modifiable only by root */ diff -puN fs/jfs/ioctl.c~forbid-user-to-change-file-flags-on-quota-files fs/jfs/ioctl.c --- a/fs/jfs/ioctl.c~forbid-user-to-change-file-flags-on-quota-files +++ a/fs/jfs/ioctl.c @@ -79,6 +79,9 @@ int jfs_ioctl(struct inode * inode, stru if (!S_ISDIR(inode->i_mode)) flags &= ~JFS_DIRSYNC_FL; + /* Is it quota file? Do not allow user to mess with it */ + if (IS_NOQUOTA(inode)) + return -EPERM; jfs_get_inode_flags(jfs_inode); oldflags = jfs_inode->mode2; diff -puN fs/reiserfs/ioctl.c~forbid-user-to-change-file-flags-on-quota-files fs/reiserfs/ioctl.c --- a/fs/reiserfs/ioctl.c~forbid-user-to-change-file-flags-on-quota-files +++ a/fs/reiserfs/ioctl.c @@ -57,6 +57,9 @@ int reiserfs_ioctl(struct inode *inode, 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)) _