userspace utilities to change the file system's UUID without rewriting
all of the file system metadata.
A number of miscellaneous fixes, the most significant of which are in
the ext4 encryption support. Anyone wishing to use the encryption
feature should backport all of the ext4 crypto patches up to 4.4 to
get fixes to a memory leak and file system corruption bug.
There are also cleanups in ext4's feature test macros and in ext4's
sysfs support code.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o:
"Add support for the CSUM_SEED feature which will allow future
userspace utilities to change the file system's UUID without rewriting
all of the file system metadata.
A number of miscellaneous fixes, the most significant of which are in
the ext4 encryption support. Anyone wishing to use the encryption
feature should backport all of the ext4 crypto patches up to 4.4 to
get fixes to a memory leak and file system corruption bug.
There are also cleanups in ext4's feature test macros and in ext4's
sysfs support code"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (26 commits)
fs/ext4: remove unnecessary new_valid_dev check
ext4: fix abs() usage in ext4_mb_check_group_pa
ext4: do not allow journal_opts for fs w/o journal
ext4: explicit mount options parsing cleanup
ext4, jbd2: ensure entering into panic after recording an error in superblock
[PATCH] fix calculation of meta_bg descriptor backups
ext4: fix potential use after free in __ext4_journal_stop
jbd2: fix checkpoint list cleanup
ext4: fix xfstest generic/269 double revoked buffer bug with bigalloc
ext4: make the bitmap read routines return real error codes
jbd2: clean up feature test macros with predicate functions
ext4: clean up feature test macros with predicate functions
ext4: call out CRC and corruption errors with specific error codes
ext4: store checksum seed in superblock
ext4: reserve code points for the project quota feature
ext4: promote ext4 over ext2 in the default probe order
jbd2: gate checksum calculations on crc driver presence, not sb flags
ext4: use private version of page_zero_new_buffers() for data=journal mode
ext4 crypto: fix bugs in ext4_encrypted_zeroout()
ext4 crypto: replace some BUG_ON()'s with error checks
...
Return value of ext4_derive_key_aes() is stored but not used.
Add test to exit cleanly if ext4_derive_key_aes() fail.
Also fix coverity CID 1309760.
Signed-off-by: Laurent Navet <laurent.navet@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
As suggested by Herbert Xu, we shouldn't allocate a new tfm each time
we read or write a page. Instead we can use a single tfm hanging off
the inode's crypt_info structure for all of our encryption needs for
that inode, since the tfm can be used by multiple crypto requests in
parallel.
Also use cmpxchg() to avoid races that could result in crypt_info
structure getting doubly allocated or doubly freed.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Use slab caches the ext4_crypto_ctx and ext4_crypt_info structures for
slighly better memory efficiency and debuggability.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This is a pretty massive patch which does a number of different things:
1) The per-inode encryption information is now stored in an allocated
data structure, ext4_crypt_info, instead of directly in the node.
This reduces the size usage of an in-memory inode when it is not
using encryption.
2) We drop the ext4_fname_crypto_ctx entirely, and use the per-inode
encryption structure instead. This remove an unnecessary memory
allocation and free for the fname_crypto_ctx as well as allowing us
to reuse the ctfm in a directory for multiple lookups and file
creations.
3) We also cache the inode's policy information in the ext4_crypt_info
structure so we don't have to continually read it out of the
extended attributes.
4) We now keep the keyring key in the inode's encryption structure
instead of releasing it after we are done using it to derive the
per-inode key. This allows us to test to see if the key has been
revoked; if it has, we prevent the use of the derived key and free
it.
5) When an inode is released (or when the derived key is freed), we
will use memset_explicit() to zero out the derived key, so it's not
left hanging around in memory. This implies that when a user logs
out, it is important to first revoke the key, and then unlink it,
and then finally, to use "echo 3 > /proc/sys/vm/drop_caches" to
release any decrypted pages and dcache entries from the system
caches.
6) All this, and we also shrink the number of lines of code by around
100. :-)
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Use struct ext4_encryption_key only for the master key passed via the
kernel keyring.
For internal kernel space users, we now use struct ext4_crypt_info.
This will allow us to put information from the policy structure so we
can cache it and avoid needing to constantly looking up the extended
attribute. We will do this in a spearate patch. This patch is mostly
mechnical to make it easier for patch review.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This obscures the length of the filenames, to decrease the amount of
information leakage. By default, we pad the filenames to the next 4
byte boundaries. This costs nothing, since the directory entries are
aligned to 4 byte boundaries anyway. Filenames can also be padded to
8, 16, or 32 bytes, which will consume more directory space.
Change-Id: Ibb7a0fb76d2c48e2061240a709358ff40b14f322
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Also add the test dummy encryption mode flag so we can more easily
test the encryption patches using xfstests.
Signed-off-by: Michael Halcrow <mhalcrow@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
