commit 7fcba054373d5dfc43d26e243a5c9b92069972ee upstream
Date: Mon, 28 Jul 2008 15:46:39 -0700
Subject: eCryptfs: use page_alloc not kmalloc to get a page of memory

With SLUB debugging turned on in 2.6.26, I was getting memory corruption
when testing eCryptfs.  The root cause turned out to be that eCryptfs was
doing kmalloc(PAGE_CACHE_SIZE); virt_to_page() and treating that as a nice
page-aligned chunk of memory.  But at least with SLUB debugging on, this
is not always true, and the page we get from virt_to_page does not
necessarily match the PAGE_CACHE_SIZE worth of memory we got from kmalloc.

My simple testcase was 2 loops doing "rm -f fileX; cp /tmp/fileX ." for 2
different multi-megabyte files.  With this change I no longer see the
corruption.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Acked-by: Michael Halcrow <mhalcrow@us.ibm.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

__FUNCTION__ is gcc-specific, use __func__

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Remove the no longer used ecryptfs_header_cache_0.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Jeff Moyer pointed out that a mount; umount loop of ecryptfs, with the same
cipher & other mount options, created a new ecryptfs_key_tfm_cache item
each time, and the cache could grow quite large this way.

Looking at this with mhalcrow, we saw that ecryptfs_parse_options()
unconditionally called ecryptfs_add_new_key_tfm(), which is what was adding
these items.

Refactor ecryptfs_get_tfm_and_mutex_for_cipher_name() to create a new
helper function, ecryptfs_tfm_exists(), which checks for the cipher on the
cached key_tfm_list, and sets a pointer to it if it exists.  This can then
be called from ecryptfs_parse_options(), and new key_tfm's can be added
only when a cached one is not found.

With list locking changes suggested by akpm.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Only the lower byte of cipher_code is ever used, so it makes sense
for its type to be u8.

Signed-off-by: Trevor Highland <trevor.highland@gmail.com>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The printk statements that result when the user does not have the
proper key available could use some refining.

Signed-off-by: Mike Halcrow <mhalcrow@us.ibm.com>
Cc: Mike Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

There is no need to keep re-setting the same key for any given eCryptfs inode.
This patch optimizes the use of the crypto API and helps performance a bit.

Signed-off-by: Trevor Highland <trevor.highland@gmail.com>
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Remove internal references to header extents; just keep track of header bytes
instead.  Headers can easily span multiple pages with the recent persistent
file changes.

Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

- make the following needlessly global code static:
  - crypto.c:ecryptfs_lower_offset_for_extent()
  - crypto.c:key_tfm_list
  - crypto.c:key_tfm_list_mutex
  - inode.c:ecryptfs_getxattr()
  - main.c:ecryptfs_init_persistent_file()

- remove the no longer used mmap.c:ecryptfs_lower_page_cache

- #if 0 the unused read_write.c:ecryptfs_read()

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>