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

Browse source 
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 <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Dave Hansen <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Al Viro <[email protected]>
This commit is contained in:
Dave Hansen 2008-02-15 14:37:46 -08:00 • committed by Al Viro
commit 42a74f206b
9 changed files with 265 additions and 155 deletions
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103
fs/ext3/ioctl.c
View file

@ -12,6 +12,7 @@
#include <linux/capability.h>
#include <linux/ext3_fs.h>
#include <linux/ext3_jbd.h>
#include <linux/mount.h>
#include <linux/time.h>
#include <linux/compat.h>
#include <linux/smp_lock.h>
@ -38,14 +39,19 @@ int ext3_ioctl (struct inode * inode, struct file * filp, unsigned int cmd,
unsigned int oldflags;
unsigned int jflag;
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 -EACCES;
if (!is_owner_or_cap(inode)) {
err = -EACCES;
goto flags_out;
}
if (get_user(flags, (int __user *) arg))
return -EFAULT;
if (get_user(flags, (int __user *) arg)) {
err = -EFAULT;
goto flags_out;
}
if (!S_ISDIR(inode->i_mode))
flags &= ~EXT3_DIRSYNC_FL;
@ -54,7 +60,8 @@ int ext3_ioctl (struct inode * inode, struct file * filp, unsigned int cmd,
/* Is it quota file? Do not allow user to mess with it */
if (IS_NOQUOTA(inode)) {
mutex_unlock(&inode->i_mutex);
return -EPERM;
err = -EPERM;
goto flags_out;
}
oldflags = ei->i_flags;
@ -70,7 +77,8 @@ int ext3_ioctl (struct inode * inode, struct file * filp, unsigned int cmd,
if ((flags ^ oldflags) & (EXT3_APPEND_FL | EXT3_IMMUTABLE_FL)) {
if (!capable(CAP_LINUX_IMMUTABLE)) {
mutex_unlock(&inode->i_mutex);
return -EPERM;
err = -EPERM;
goto flags_out;
}
}
@ -81,7 +89,8 @@ int ext3_ioctl (struct inode * inode, struct file * filp, unsigned int cmd,
if ((jflag ^ oldflags) & (EXT3_JOURNAL_DATA_FL)) {
if (!capable(CAP_SYS_RESOURCE)) {
mutex_unlock(&inode->i_mutex);
return -EPERM;
err = -EPERM;
goto flags_out;
}
}
@ -89,7 +98,8 @@ int ext3_ioctl (struct inode * inode, struct file * filp, unsigned int cmd,
handle = ext3_journal_start(inode, 1);
if (IS_ERR(handle)) {
mutex_unlock(&inode->i_mutex);
return PTR_ERR(handle);
err = PTR_ERR(handle);
goto flags_out;
}
if (IS_SYNC(inode))
handle->h_sync = 1;
@ -115,6 +125,8 @@ flags_err:
if ((jflag ^ oldflags) & (EXT3_JOURNAL_DATA_FL))
err = ext3_change_inode_journal_flag(inode, jflag);
mutex_unlock(&inode->i_mutex);
flags_out:
mnt_drop_write(filp->f_path.mnt);
return err;
}
case EXT3_IOC_GETVERSION:
@ -129,14 +141,18 @@ flags_err:
if (!is_owner_or_cap(inode))
return -EPERM;
if (IS_RDONLY(inode))
return -EROFS;
if (get_user(generation, (int __user *) arg))
return -EFAULT;
err = mnt_want_write(filp->f_path.mnt);
if (err)
return err;
if (get_user(generation, (int __user *) arg)) {
err = -EFAULT;
goto setversion_out;
}
handle = ext3_journal_start(inode, 1);
if (IS_ERR(handle))
return PTR_ERR(handle);
if (IS_ERR(handle)) {
err = PTR_ERR(handle);
goto setversion_out;
}
err = ext3_reserve_inode_write(handle, inode, &iloc);
if (err == 0) {
inode->i_ctime = CURRENT_TIME_SEC;
@ -144,6 +160,8 @@ flags_err:
err = ext3_mark_iloc_dirty(handle, inode, &iloc);
}
ext3_journal_stop(handle);
setversion_out:
mnt_drop_write(filp->f_path.mnt);
return err;
}
#ifdef CONFIG_JBD_DEBUG
@ -179,18 +197,24 @@ flags_err:
}
return -ENOTTY;
case EXT3_IOC_SETRSVSZ: {
int err;
if (!test_opt(inode->i_sb, RESERVATION) ||!S_ISREG(inode->i_mode))
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 -EACCES;
if (!is_owner_or_cap(inode)) {
err = -EACCES;
goto setrsvsz_out;
}
if (get_user(rsv_window_size, (int __user *)arg))
return -EFAULT;
if (get_user(rsv_window_size, (int __user *)arg)) {
err = -EFAULT;
goto setrsvsz_out;
}
if (rsv_window_size > EXT3_MAX_RESERVE_BLOCKS)
rsv_window_size = EXT3_MAX_RESERVE_BLOCKS;
@ -208,7 +232,9 @@ flags_err:
rsv->rsv_goal_size = rsv_window_size;
}
mutex_unlock(&ei->truncate_mutex);
return 0;
setrsvsz_out:
mnt_drop_write(filp->f_path.mnt);
return err;
}
case EXT3_IOC_GROUP_EXTEND: {
ext3_fsblk_t n_blocks_count;
@ -218,17 +244,20 @@ flags_err:
if (!capable(CAP_SYS_RESOURCE))
return -EPERM;
if (IS_RDONLY(inode))
return -EROFS;
if (get_user(n_blocks_count, (__u32 __user *)arg))
return -EFAULT;
err = mnt_want_write(filp->f_path.mnt);
if (err)
return err;
if (get_user(n_blocks_count, (__u32 __user *)arg)) {
err = -EFAULT;
goto group_extend_out;
}
err = ext3_group_extend(sb, EXT3_SB(sb)->s_es, n_blocks_count);
journal_lock_updates(EXT3_SB(sb)->s_journal);
journal_flush(EXT3_SB(sb)->s_journal);
journal_unlock_updates(EXT3_SB(sb)->s_journal);
group_extend_out:
mnt_drop_write(filp->f_path.mnt);
return err;
}
case EXT3_IOC_GROUP_ADD: {
@ -239,18 +268,22 @@ flags_err:
if (!capable(CAP_SYS_RESOURCE))
return -EPERM;
if (IS_RDONLY(inode))
return -EROFS;
err = mnt_want_write(filp->f_path.mnt);
if (err)
return err;
if (copy_from_user(&input, (struct ext3_new_group_input __user *)arg,
sizeof(input)))
return -EFAULT;
sizeof(input))) {
err = -EFAULT;
goto group_add_out;
}
err = ext3_group_add(sb, &input);
journal_lock_updates(EXT3_SB(sb)->s_journal);
journal_flush(EXT3_SB(sb)->s_journal);
journal_unlock_updates(EXT3_SB(sb)->s_journal);
group_add_out:
mnt_drop_write(filp->f_path.mnt);
return err;
}