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Commit 93f210dd authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds
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[PATCH] protect ext2 ioctl modifying append_only immutable etc with i_mutex 



Port commit a090d913 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: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent f5738cee

fs/ext2/ioctl.c

+5 −1
Original line number Diff line number Diff line
@@ -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;