jffs2: move jffs2_xattr_handlers to .rodata

This makes it harder for accidental or malicious changes to
jffs2_xattr_handlers at runtime.

Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: linux-mtd@lists.infradead.org
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20230930050033.41174-16-wedsonaf@gmail.com
Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

jffs2: reduce stack usage in jffs2_build_xattr_subsystem()

Use kcalloc() for allocation/flush of 128 pointers table to
reduce stack usage.

Function now returns -ENOMEM or 0 on success.

stackusage
Before:
./fs/jffs2/xattr.c:775 jffs2_build_xattr_subsystem 1208
dynamic,bounded

After:
./fs/jffs2/xattr.c:775 jffs2_build_xattr_subsystem 192
dynamic,bounded

Also update definition when CONFIG_JFFS2_FS_XATTR is not enabled

Tested with an MTD mount point and some user set/getfattr.

Many current target on OpenWRT also suffer from a compilation warning
(that become an error with CONFIG_WERROR) with the following output:

fs/jffs2/xattr.c: In function 'jffs2_build_xattr_subsystem':
fs/jffs2/xattr.c:887:1: error: the frame size of 1088 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
887 | }
| ^

Using dynamic allocation fix this compilation warning.

Fixes: c9f700f840bd ("[JFFS2][XATTR] using 'delete marker' for xdatum/xref deletion")
Reported-by: Tim Gardner <tim.gardner@canonical.com>
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Ron Economos <re@w6rz.net>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Cc: stable@vger.kernel.org
Message-Id: <20230506045612.16616-1-ansuelsmth@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

jffs2: Remove jffs2_{get,set,remove}xattr macros

When CONFIG_JFFS2_FS_XATTR is off, jffs2_xattr_handlers is defined as
NULL. With sb->s_xattr == NULL, the generic_{get,set,remove}xattr
functions produce the same result as setting the {get,set,remove}xattr
inode operations to NULL, so there is no need for these macros.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

jffs2: allow to complete xattr integrity check on first GC scan

Unlike file data integrity the xattr data integrity was not checked
before some explicit access to the attribute was made.

This could leave in the system a number of corrupted extended attributes
which will be detected only at access time and possibly at a very late
time compared to the time the corruption actually happened.

This patch adds the ability to check for extended attribute integrity
on first GC scan pass (similar to file data integrity check). This allows
for all present attributes to be completly verified before any use of them.

In order to work correctly this patch also needs the patch allowing
JFFS2 to discriminate between recoverable and non recoverable errors
on extended attributes.

Signed-off-by: Jean-Christophe DUBOIS <jcd@tribudubois.net>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

fs/vfs/security: pass last path component to LSM on inode creation

SELinux would like to implement a new labeling behavior of newly created
inodes. We currently label new inodes based on the parent and the creating
process. This new behavior would also take into account the name of the
new object when deciding the new label. This is not the (supposed) full path,
just the last component of the path.

This is very useful because creating /etc/shadow is different than creating
/etc/passwd but the kernel hooks are unable to differentiate these
operations. We currently require that userspace realize it is doing some
difficult operation like that and than userspace jumps through SELinux hoops
to get things set up correctly. This patch does not implement new
behavior, that is obviously contained in a seperate SELinux patch, but it
does pass the needed name down to the correct LSM hook. If no such name
exists it is fine to pass NULL.

Signed-off-by: Eric Paris <eparis@redhat.com>

jffs2: constify xattr_handler

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

[JFFS2] Whitespace cleanups.

Convert many spaces to tabs; one or two other minor cosmetic fixes.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[JFFS2] Tidy up licensing/copyright boilerplate.

In particular, remove the bit in the LICENCE file about contacting
Red Hat for alternative arrangements. Their errant IS department broke
that arrangement a long time ago -- the policy of collecting copyright
assignments from contributors came to an end when the plug was pulled on
the servers hosting the project, without notice or reason.

We do still dual-license it for use with eCos, with the GPL+exception
licence approved by the FSF as being GPL-compatible. It's just that nobody
has the right to license it differently.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[JFFS2][XATTR] Re-define xd->refcnt as atomic_t

In jffs2_release_xattr_datum(), it refers xd->refcnt to ensure
whether releasing xd is allowed or not.
But we can't hold xattr_sem since this function is called under
spin_lock(&c->erase_completion_lock). Thus we have to refer it
without any locking.

This patch redefine xd->refcnt as atomic_t. It enables to refer
xd->refcnt without any locking.

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[JFFS2][XATTR] rid unnecessary writing of delete marker.

In the followinf situation, an explicit delete marker is not
necessary, because we can certainlly detect those obsolete
xattr_datum or xattr_ref on next mounting.

- When to delete xattr_datum node.
- When to delete xattr_ref node on removing inode.
- When to delete xattr_ref node on updating xattr.

This patch rids writing delete marker in those situations.

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[JFFS2][XATTR] using 'delete marker' for xdatum/xref deletion

- When xdatum is removed, a new xdatum with 'delete marker' is
written. (version==0xffffffff means 'delete marker')
- When xref is removed, a new xref with 'delete marker' is written.
(odd-numbered xseqno means 'delete marker')

- delete_xattr_(datum/xref)_delay() are new deletion functions
are added. We can only use them if we can detect the target
obsolete xdatum/xref as a orphan or errir one.
(e.g when inode deletion, or detecting crc error)

[1/3] jffs2-xattr-v6-01-delete_marker.patch

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[JFFS2] Put list of nodes in common part of ic/x_ref/x_datum structure

We'll be using a proper list of nodes in the jffs2_xattr_datum and
jffs2_xattr_ref structures, because the existing code to overwrite
them is just broken. Put it in the common part at the front of the
structure which is shared with the jffs2_inode_cache, so that the
jffs2_link_node_ref() function can do the right thing.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[JFFS2][XATTR] remove senseless comment

remove senseless comment.

[8/10] jffs2-xattr-v5.1-08-remove_senseless_comment.patch

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>

[JFFS2][XATTR] Unify each file header part with any jffs2 file.

Unify each file header part with any jffs2 file.

[7/10] jffs2-xattr-v5.1-07-unify_file_header.patch

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>

[JFFS2][XATTR] '#include <linux/list.h>' was added into xattr.h.

'#include <linux/list.h>' was added into xattr.h.
because 'struct list_head' is used in this header file.

[6/10] jffs2-xattr-v5.1-06-add_list.h.patch

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>

[JFFS2][XATTR] Remove jffs2_garbage_collect_xattr(c, ic)

Remove jffs2_garbage_collect_xattr(c, ic).
jffs2_garbage_collect_xattr_datum/ref() are called from gc.c directly.

In original implementation, jffs2_garbage_collect_xattr(c, ic) returns
with holding a spinlock if 'ic' is inode_cache. But it returns after
releasing a spinlock if 'ic' is xattr_datum/ref.
It looks so confusable behavior. Thus, this patch makes caller manage
locking/unlocking.

[5/10] jffs2-xattr-v5.1-05-update_xattr_gc.patch

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>

[JFFS2][XATTR] Remove 'struct list_head ilist' from jffs2_inode_cache.

This patch can reduce 4-byte of memory usage per inode_cache.

[4/10] jffs2-xattr-v5.1-04-remove_ilist_from_ic.patch

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>

[JFFS2][XATTR] XATTR support on JFFS2 (version. 5)

This attached patches provide xattr support including POSIX-ACL and
SELinux support on JFFS2 (version.5).

There are some significant differences from previous version posted
at last December.
The biggest change is addition of EBS(Erase Block Summary) support.
Currently, both kernel and usermode utility (sumtool) can recognize
xattr nodes which have JFFS2_NODETYPE_XATTR/_XREF nodetype.

In addition, some bugs are fixed.
- A potential race condition was fixed.
- Unexpected fail when updating a xattr by same name/value pair was fixed.
- A bug when removing xattr name/value pair was fixed.

The fundamental structures (such as using two new nodetypes and exclusion
mechanism by rwsem) are unchanged. But most of implementation were reviewed
and updated if necessary.
Espacially, we had to change several internal implementations related to
load_xattr_datum() to avoid a potential race condition.

[1/2] xattr_on_jffs2.kernel.version-5.patch
[2/2] xattr_on_jffs2.utils.version-5.patch

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>