linux/fs/hfsplus
Thomas Hebb db579e76f0 hfsplus: don't store special "osx" xattr prefix on-disk
On Mac OS X, HFS+ extended attributes are not namespaced.  Since we want
to be compatible with OS X filesystems and yet still support the Linux
namespacing system, the hfsplus driver implements a special "osx"
namespace that is reported for any attribute that is not namespaced
on-disk.  However, the current code for getting and setting these
unprefixed attributes is broken.

hfsplus_osx_setattr() and hfsplus_osx_getattr() are passed names that have
already had their "osx." prefixes stripped by the generic functions.  The
functions first, quite correctly, check those names to make sure that they
aren't prefixed with a known namespace, which would allow namespace access
restrictions to be bypassed.  However, the functions then prepend "osx."
to the name they're given before passing it on to hfsplus_getattr() and
hfsplus_setattr().  Not only does this cause the "osx." prefix to be
stored on-disk, defeating its purpose, it also breaks the check for the
special "com.apple.FinderInfo" attribute, which is reported for all files,
and as a consequence makes some userspace applications (e.g.  GNU patch)
fail even when extended attributes are not otherwise in use.

There are five commits which have touched this particular code:

  127e5f5ae5 ("hfsplus: rework functionality of getting, setting and deleting of extended attributes")
  b168fff721 ("hfsplus: use xattr handlers for removexattr")
  bf29e886b2 ("hfsplus: correct usage of HFSPLUS_ATTR_MAX_STRLEN for non-English attributes")
  fcacbd95e121 ("fs/hfsplus: move xattr_name allocation in hfsplus_getxattr()")
  ec1bbd346f18 ("fs/hfsplus: move xattr_name allocation in hfsplus_setxattr()")

The first commit creates the functions to begin with.  The namespace is
prepended by the original code, which I believe was correct at the time,
since hfsplus_?etattr() stripped the prefix if found.  The second commit
removes this behavior from hfsplus_?etattr() and appears to have been
intended to also remove the prefixing from hfsplus_osx_?etattr().
However, what it actually does is remove a necessary strncpy() call
completely, breaking the osx namespace entirely.  The third commit re-adds
the strncpy() call as it was originally, but doesn't mention it in its
commit message.  The final two commits refactor the code and don't affect
its functionality.

This commit does what b168fff attempted to do (prevent the prefix from
being added), but does it properly, instead of passing in an empty buffer
(which is what b168fff actually did).

Fixes: b168fff721 ("hfsplus: use xattr handlers for removexattr")
Signed-off-by: Thomas Hebb <tommyhebb@gmail.com>
Cc: Hin-Tak Leung <htl10@users.sourceforge.net>
Cc: Sergei Antonov <saproj@gmail.com>
Cc: Anton Altaparmakov <anton@tuxera.com>
Cc: Fabian Frederick <fabf@skynet.be>
Cc: Christian Kujau <lists@nerdbynature.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Viacheslav Dubeyko <slava@dubeyko.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-17 09:04:05 -04:00
..
acl.h hfsplus: use generic posix ACL infrastructure 2014-01-25 23:58:20 -05:00
attributes.c hfsplus: remove unused routine hfsplus_attr_build_key_uni 2014-06-06 16:08:09 -07:00
bfind.c fs/hfsplus: replace if/BUG by BUG_ON 2015-04-17 09:04:05 -04:00
bitmap.c hfsplus: remove duplicated message prefix in hfsplus_block_free() 2013-04-30 17:04:05 -07:00
bnode.c hfsplus: fix "unused node is not erased" error 2014-06-06 16:08:10 -07:00
brec.c hfsplus: fix B-tree corruption after insertion at position 0 2015-03-25 16:20:31 -07:00
btree.c hfsplus: fix "unused node is not erased" error 2014-06-06 16:08:10 -07:00
catalog.c hfsplus: add missing curly braces in hfsplus_delete_cat() 2015-04-17 09:04:04 -04:00
dir.c hfsplus: incorrect return value 2015-04-17 09:04:05 -04:00
extents.c fs/hfsplus: fix pr_foo() and hfs_dbg formats 2014-06-06 16:08:10 -07:00
hfsplus_fs.h hfsplus: fix longname handling 2014-12-18 19:08:10 -08:00
hfsplus_raw.h hfsplus: fix "unused node is not erased" error 2014-06-06 16:08:10 -07:00
inode.c hfsplus: fix expand when not enough available space 2015-04-17 09:04:05 -04:00
ioctl.c fs/hfsplus: atomically set inode->i_flags 2015-04-17 09:04:05 -04:00
Kconfig hfsplus: add necessary declarations for POSIX ACLs support 2013-09-11 15:59:00 -07:00
Makefile hfsplus: integrate POSIX ACLs support into driver 2013-09-11 15:59:01 -07:00
options.c fs/hfsplus/options.c: replace seq_printf by seq_puts 2014-06-06 16:08:10 -07:00
part_tbl.c hfsplus: ensure bio requests are not smaller than the hardware sectors 2011-07-22 16:37:44 +02:00
posix_acl.c hfsplus: use generic posix ACL infrastructure 2014-01-25 23:58:20 -05:00
super.c hfsplus: fix longname handling 2014-12-18 19:08:10 -08:00
tables.c
unicode.c Don't pass inode to ->d_hash() and ->d_compare() 2013-06-29 12:57:36 +04:00
wrapper.c fs/hfsplus/wrapper.c: replace shift loop by ilog2 2014-06-06 16:08:10 -07:00
xattr_security.c fs/hfsplus: move xattr_name allocation in hfsplus_setxattr() 2015-04-17 09:04:05 -04:00
xattr_trusted.c fs/hfsplus: move xattr_name allocation in hfsplus_setxattr() 2015-04-17 09:04:05 -04:00
xattr_user.c fs/hfsplus: move xattr_name allocation in hfsplus_setxattr() 2015-04-17 09:04:05 -04:00
xattr.c hfsplus: don't store special "osx" xattr prefix on-disk 2015-04-17 09:04:05 -04:00
xattr.h fs/hfsplus: move xattr_name allocation in hfsplus_setxattr() 2015-04-17 09:04:05 -04:00