![Jan Kara](/assets/img/avatar_default.png)
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>
170 lines
4.1 KiB
C
170 lines
4.1 KiB
C
/*
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* linux/fs/ext2/ioctl.c
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*
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* Copyright (C) 1993, 1994, 1995
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* Remy Card (card@masi.ibp.fr)
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* Laboratoire MASI - Institut Blaise Pascal
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* Universite Pierre et Marie Curie (Paris VI)
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*/
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#include "ext2.h"
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#include <linux/capability.h>
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#include <linux/time.h>
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#include <linux/sched.h>
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#include <linux/compat.h>
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#include <linux/smp_lock.h>
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#include <asm/current.h>
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#include <asm/uaccess.h>
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int ext2_ioctl (struct inode * inode, struct file * filp, unsigned int cmd,
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unsigned long arg)
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{
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struct ext2_inode_info *ei = EXT2_I(inode);
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unsigned int flags;
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unsigned short rsv_window_size;
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ext2_debug ("cmd = %u, arg = %lu\n", cmd, arg);
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switch (cmd) {
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case EXT2_IOC_GETFLAGS:
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ext2_get_inode_flags(ei);
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flags = ei->i_flags & EXT2_FL_USER_VISIBLE;
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return put_user(flags, (int __user *) arg);
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case EXT2_IOC_SETFLAGS: {
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unsigned int oldflags;
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if (IS_RDONLY(inode))
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return -EROFS;
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if (!is_owner_or_cap(inode))
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return -EACCES;
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if (get_user(flags, (int __user *) arg))
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return -EFAULT;
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if (!S_ISDIR(inode->i_mode))
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flags &= ~EXT2_DIRSYNC_FL;
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mutex_lock(&inode->i_mutex);
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/* Is it quota file? Do not allow user to mess with it */
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if (IS_NOQUOTA(inode)) {
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mutex_unlock(&inode->i_mutex);
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return -EPERM;
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}
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oldflags = ei->i_flags;
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/*
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* The IMMUTABLE and APPEND_ONLY flags can only be changed by
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* the relevant capability.
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*
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* This test looks nicer. Thanks to Pauline Middelink
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*/
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if ((flags ^ oldflags) & (EXT2_APPEND_FL | EXT2_IMMUTABLE_FL)) {
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if (!capable(CAP_LINUX_IMMUTABLE)) {
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mutex_unlock(&inode->i_mutex);
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return -EPERM;
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}
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}
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flags = flags & EXT2_FL_USER_MODIFIABLE;
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flags |= oldflags & ~EXT2_FL_USER_MODIFIABLE;
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ei->i_flags = flags;
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mutex_unlock(&inode->i_mutex);
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ext2_set_inode_flags(inode);
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inode->i_ctime = CURRENT_TIME_SEC;
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mark_inode_dirty(inode);
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return 0;
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}
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case EXT2_IOC_GETVERSION:
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return put_user(inode->i_generation, (int __user *) arg);
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case EXT2_IOC_SETVERSION:
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if (!is_owner_or_cap(inode))
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return -EPERM;
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if (IS_RDONLY(inode))
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return -EROFS;
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if (get_user(inode->i_generation, (int __user *) arg))
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return -EFAULT;
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inode->i_ctime = CURRENT_TIME_SEC;
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mark_inode_dirty(inode);
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return 0;
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case EXT2_IOC_GETRSVSZ:
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if (test_opt(inode->i_sb, RESERVATION)
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&& S_ISREG(inode->i_mode)
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&& ei->i_block_alloc_info) {
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rsv_window_size = ei->i_block_alloc_info->rsv_window_node.rsv_goal_size;
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return put_user(rsv_window_size, (int __user *)arg);
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}
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return -ENOTTY;
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case EXT2_IOC_SETRSVSZ: {
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if (!test_opt(inode->i_sb, RESERVATION) ||!S_ISREG(inode->i_mode))
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return -ENOTTY;
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if (IS_RDONLY(inode))
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return -EROFS;
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if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
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return -EACCES;
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if (get_user(rsv_window_size, (int __user *)arg))
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return -EFAULT;
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if (rsv_window_size > EXT2_MAX_RESERVE_BLOCKS)
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rsv_window_size = EXT2_MAX_RESERVE_BLOCKS;
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/*
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* need to allocate reservation structure for this inode
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* before set the window size
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*/
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/*
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* XXX What lock should protect the rsv_goal_size?
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* Accessed in ext2_get_block only. ext3 uses i_truncate.
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*/
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mutex_lock(&ei->truncate_mutex);
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if (!ei->i_block_alloc_info)
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ext2_init_block_alloc_info(inode);
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if (ei->i_block_alloc_info){
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struct ext2_reserve_window_node *rsv = &ei->i_block_alloc_info->rsv_window_node;
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rsv->rsv_goal_size = rsv_window_size;
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}
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mutex_unlock(&ei->truncate_mutex);
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return 0;
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}
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default:
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return -ENOTTY;
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}
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}
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#ifdef CONFIG_COMPAT
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long ext2_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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{
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struct inode *inode = file->f_path.dentry->d_inode;
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int ret;
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/* These are just misnamed, they actually get/put from/to user an int */
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switch (cmd) {
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case EXT2_IOC32_GETFLAGS:
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cmd = EXT2_IOC_GETFLAGS;
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break;
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case EXT2_IOC32_SETFLAGS:
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cmd = EXT2_IOC_SETFLAGS;
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break;
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case EXT2_IOC32_GETVERSION:
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cmd = EXT2_IOC_GETVERSION;
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break;
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case EXT2_IOC32_SETVERSION:
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cmd = EXT2_IOC_SETVERSION;
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break;
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default:
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return -ENOIOCTLCMD;
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}
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lock_kernel();
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ret = ext2_ioctl(inode, file, cmd, (unsigned long) compat_ptr(arg));
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unlock_kernel();
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return ret;
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}
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#endif
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