Mon Oct 24 23:27:42 1994  Theodore Y. Ts'o  (tytso@rt-11)

	* fcntl.c (sys_fcntl): Liberalize security checks which Alan Cox
		put in.

Thu Oct 20 23:44:22 1994  Theodore Y. Ts'o  (tytso@rt-11)

	* fcntl.c (sys_fcntl): Add more of a security check to the
		F_SETOWN fcntl().

[Tons of changes missed, indeed. This list is worth restarting since
at least some fixes WILL break third-party filesystems. Sorry, but
there was no other way to fix rmdir/rename deadlock, for one.]

Wed Dec  2 (Linus, fill the rest, please)

	* namei.c (do_rmdir) and rmdir method in filesystems:
		Locking of directory we remove was taken to VFS.
		See comments in do_rmdir(). Unfixed filesystems
		will bloody likely deadlock in rmdir().

Thu Dec  3 17:25:31 1998  Al Viro (viro@math.psu.edu)

	* namei.c (do_rmdir):
		Reject non-directories here.
		Two (probably) obsolete checks moved here too: we fail if
		the directory we remove is the same as parent (BUG: we
		serve mountpoints later) or if it lives on a different
		device.
	* sysv/namei.c (sysv_rmdir):	See sysv/CHANGES

Fri Dec  4 00:54:12 1998  AV

	* namei.c (check_sticky): New function check_sticky(dir, inode).
		If dir is sticky check whether we can unlink/rmdir/rename
		the inode. Returns 1 if we can't. If dir isn't sticky -
		return 0 (i.e. no objections). Some filesystems require
		suser() here; some are fine with CAP_FOWNER. The later
		seems more reasonable.
	* namei.c (do_rmdir):
		Moved the check for sticky bit here.
	* affs/{inode,namei}.c:
		All AFFS directories have sticky semantics (i.e. non-owner
		having write permisssions on directory can unlink/rmdir/rename
		only the files he owns), but AFFS didn't set S_ISVTX on them.
		Fixed. NB: maybe this behaviour should be controlled by mount
		option. Obvious values being 'sticky' (current behaviour),
		'nonsticky' (normal behaviour) and maybe some play on 'D'
		permissions bit. FIXME.
	* qnx4/namei.c (qnx4_rmdir):
		Plugged inode leak.
	* ufs/namei.c (ufs_rmdir):
		Changed handling of busy directory to new scheme.

Fri Dec  4 10:30:58 1998  AV

	* namei.c (VFS_rmdir): New function. It gets inode of the parent and
		dentry of the victim, does all checks and applies fs-specific
		rmdir() method. It should be called with semaphores down
		on both the victim and its parent and with bumped d_count on
		victim (see comments in do_rmdir).
	* include/linux/fs.h: Added VFS_rmdir
	* kernel/ksyms.c: Added VFS_rmdir to export list (for NFSD).
	* nfsd/vfs.c: Fixed rmdir handling.

Tue Dec  8 05:55:08 1998  AV
	* vfat/namei.c: Fixed the bug in vfat_rename() introduced in the
		first round of rmdir fixes.

Wed Dec  9 03:06:10 1998  AV
	* namei.c (do_rename): part of fs-independent checks had been moved
		here (sticky bit handling, type mismatches). Cases of
		the source or target being append-only or immutable also went
		here - if we check it for parent we could as well do it for
		children.
	* {affs,ext2,minix,sysv,ufs}/namei.c (do_*_rename):
		Removed tests that went to VFS, it simplified the code big way.
		Fixed a race in check for empty target - we should check for
		extra owners _before_ checking for emptiness, not after it.
	* {ext2,ufs}/namei.c (do_*_rename):
		VERY nasty bug shot: if somebody mkdired /tmp/cca01234, went
		there, rmdired '.', waited till somebody created a file with
		the same name and said mv . /tmp/goodbye_sticky_bit... Well,
		goodbye sticky bit. Down, not across!
	* {minix,sysv}/namei.c (do_*_rename):
		Incorrect check for other owners (i_count instead of d_count).
		Fixed.
	* vfat: Looks like the changes above fixed a bug in VFAT - this beast
		used to allow renaming file over directory and vice versa.

Wed Dec  9 08:00:27 1998  AV
	* namei.c (VFS_rename): New function. It gets the same arguments as
		->rename() method, does all checks and applies fs-specific
		rmdir() method. It should be called with semaphores down
		on both parents.
	* include/linux/fs.h: Added VFS_rename
	* kernel/ksyms.c: Added VFS_rename to export list (for NFSD).
	* nfsd/vfs.c: Changed rename handling (switched to VFS_rename).

Wed Dec  9 18:16:27 1998  AV
	* namei.c (do_unlink): handling of sticky bit went here.
	* {affs,ext2,minix,qnx4,sysv,ufs}/namei.c (*_unlink):
		removed handling of sticky bit.
	* qnx4/namei.c (qnx4_unlink):
		Yet another inode leak. Fixed.

Thu Dec 10 04:55:26 1998  AV
	* {ext2,minix,sysv,ufs}/namei.c (*_mknod):
		removed meaningless code handling attempts to mknod symlinks
		and directories. VFS protects us from _that_ and if this code
		would ever be called we'ld get a filesystem corruption.

Thu Dec 10 16:58:50 1998  AV
	* namei.c (do_rename): Fixed dentry leak that had been introduced by
		the first round of rmdir fixes.

Fri Dec 11 14:57:17 1998  AV
	* msdos/namei.c (msdos_rmdir): Fixed race in emptiness check.

Sat Dec 12 19:59:57 1998  AV
	* msdos/namei.c (msdos_mkdir): Fixed the evil breakage introduced by
		the changes of rmdir locking scheme. We shouldn't call
		msdos_rmdir from there.

Sun Dec 13 02:05:16 1998  AV
	* namei.c (do_unlink):
		Added new function: vfs_unlink, with the same arguments as
		->unlink() method.
	* kernel/ksyms.c: Made it exported.
	* include/linux/fs.h: Added prototype.
	* nfsd/vfs.c: Changed handling of unlink (switched to vfs_unlink)
	* {ext2,ufs}/namei.c (*_unlink): moved handling of imm./append-only to
		VFS.

Wed Dec 16 06:10:04 1998  AV
	* namei.c (may_create, may_delete): New inline functions.
		They check whether creation/deletion is permitted.
		Checks from other places of namei.c went there.
		Looks like originally I misread permission-related stuff
		both here and in nfsd. In particular, checks for
		immutable are done in permission(). D'oh.
	* unlink on directory should return -EISDIR, not -EPERM as it used to
		do. Fixed.
	* rmdir of immutable/append-only directory shouldn't be allowed. Fixed.

Remains unfixed:
	* UMSDOS_rename is broken. Call it with the dest. existing and being an
		empty directory and you've got EBUSY. At least it doesn't do
		any harm, so that will wait several days till rename cleanup.
		Sigh... It will wait a bit more. Problems with fat-derived
		filesystems are much worse than I thought. Idea of changing
		inode under dentry is broken by design - guess where the
		semaphore sits, for one.
	* umsdos: weird. rename() shouldn't return -EEXIST. BTW, manpage
		for rename(2) is obviously bogus - it mentions EEXIST and
		on the next line (correctly) says that EINVAL should be
		returned. Under the same conditions.
	* rename's handling of races is, erm, not optimal. Looks like I know
		what to do, but this thing needs some more cleanup - we can
		take care of almost all races in VFS and be much more graceful
		wrt locking. Moreover, it would give strong lookup atomicity.
		But it's a lot of changes to lookup and dcache code, so it will
		go after the fs drivers' cleanup.
	* hfs allows mknod. Only for regular files ;-/ IMHO it's bogus.
	* affs allows HARD links to directories. VFS is, to put it politely,
		not too ready to cope with _that_. And I'm not sure it should
		be - looks like they are pretty much similar to symlinks.
	* truncate doesn't give a damn about IO errors and disk overflows (on
		braindead filesystems). I've submitted a patch to Linus, but
		looks like it wasn't applied.
	* msdos: shouldn't we treat SYS as IMMUTABLE? Makes sense, IMHO.
	* minix, qnx and sysv do NOT allow to mkdir sticky directories.
	* {minix,sysv}/namei.c (do_{minix,syv}_{rename,unlink}):
		Stuff related to retries still needs cleanup/fixing.
		Looks like I've found an extremely low-probability race
		there...
