[PATCH] protect ext2 ioctl modifying append_only immutable etc with i_mutex

Port commit a090d9132c into ext2:

All modifications of ->i_flags in inodes that might be visible to somebody
else must be under ->i_mutex.  That patch fixes ext2 ioctl() setting S_APPEND.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Andrew Morton 2006-12-06 20:37:33 -08:00 committed by Linus Torvalds
parent f5738ceed4
commit 93f210dd9e

View file

@ -44,6 +44,7 @@ int ext2_ioctl (struct inode * inode, struct file * filp, unsigned int cmd,
if (!S_ISDIR(inode->i_mode))
flags &= ~EXT2_DIRSYNC_FL;
mutex_lock(&inode->i_mutex);
oldflags = ei->i_flags;
/*
@ -53,13 +54,16 @@ int ext2_ioctl (struct inode * inode, struct file * filp, unsigned int cmd,
* This test looks nicer. Thanks to Pauline Middelink
*/
if ((flags ^ oldflags) & (EXT2_APPEND_FL | EXT2_IMMUTABLE_FL)) {
if (!capable(CAP_LINUX_IMMUTABLE))
if (!capable(CAP_LINUX_IMMUTABLE)) {
mutex_unlock(&inode->i_mutex);
return -EPERM;
}
}
flags = flags & EXT2_FL_USER_MODIFIABLE;
flags |= oldflags & ~EXT2_FL_USER_MODIFIABLE;
ei->i_flags = flags;
mutex_unlock(&inode->i_mutex);
ext2_set_inode_flags(inode);
inode->i_ctime = CURRENT_TIME_SEC;