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[PATCH] protect ext3 ioctl modifying append_only, immutable, etc. with i_mutex

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All modifications of ->i_flags in inodes that might be visible to
somebody else must be under ->i_mutex.  That patch fixes ext3 ioctl()
setting S_APPEND and friends.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Al Viro 2006-04-26 07:32:40 +01:00 committed by Linus Torvalds
parent 6ad0013b31
commit a090d9132c
1 changed files with 14 additions and 4 deletions
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18
fs/ext3/ioctl.c
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@ -48,6 +48,7 @@ int ext3_ioctl (struct inode * inode, struct file * filp, unsigned int cmd,
if (!S_ISDIR(inode->i_mode))
flags &= ~EXT3_DIRSYNC_FL;
mutex_lock(&inode->i_mutex);
oldflags = ei->i_flags;
/* The JOURNAL_DATA flag is modifiable only by root */
@ -60,8 +61,10 @@ int ext3_ioctl (struct inode * inode, struct file * filp, unsigned int cmd,
* This test looks nicer. Thanks to Pauline Middelink
*/
if ((flags ^ oldflags) & (EXT3_APPEND_FL | EXT3_IMMUTABLE_FL)) {
if (!capable(CAP_LINUX_IMMUTABLE))
if (!capable(CAP_LINUX_IMMUTABLE)) {
mutex_unlock(&inode->i_mutex);
return -EPERM;
}
}
/*
@ -69,14 +72,18 @@ int ext3_ioctl (struct inode * inode, struct file * filp, unsigned int cmd,
* the relevant capability.
*/
if ((jflag ^ oldflags) & (EXT3_JOURNAL_DATA_FL)) {
if (!capable(CAP_SYS_RESOURCE))
if (!capable(CAP_SYS_RESOURCE)) {
mutex_unlock(&inode->i_mutex);
return -EPERM;
}
}
handle = ext3_journal_start(inode, 1);
if (IS_ERR(handle))
if (IS_ERR(handle)) {
mutex_unlock(&inode->i_mutex);
return PTR_ERR(handle);
}
if (IS_SYNC(inode))
handle->h_sync = 1;
err = ext3_reserve_inode_write(handle, inode, &iloc);
@ -93,11 +100,14 @@ int ext3_ioctl (struct inode * inode, struct file * filp, unsigned int cmd,
err = ext3_mark_iloc_dirty(handle, inode, &iloc);
flags_err:
ext3_journal_stop(handle);
if (err)
if (err) {
mutex_unlock(&inode->i_mutex);
return err;
}
if ((jflag ^ oldflags) & (EXT3_JOURNAL_DATA_FL))
err = ext3_change_inode_journal_flag(inode, jflag);
mutex_unlock(&inode->i_mutex);
return err;
}
case EXT3_IOC_GETVERSION: