We need to consistently enforce that keyed hashes cannot be used without
setting the key. To do this we need a reliable way to determine whether
a given hash algorithm is keyed or not. AF_ALG currently does this by
checking for the presence of a ->setkey() method. However, this is
actually slightly broken because the CRC-32 algorithms implement
->setkey() but can also be used without a key. (The CRC-32 "key" is not
actually a cryptographic key but rather represents the initial state.
If not overridden, then a default initial state is used.)
Prepare to fix this by introducing a flag CRYPTO_ALG_OPTIONAL_KEY which
indicates that the algorithm has a ->setkey() method, but it is not
required to be called. Then set it on all the CRC-32 algorithms.
The same also applies to the Adler-32 implementation in Lustre.
Also, the cryptd and mcryptd templates have to pass through the flag
from their underlying algorithm.
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
In crc32c_vpmsum() we call enable_kernel_altivec() without first
disabling preemption, which is not allowed:
WARNING: CPU: 9 PID: 2949 at ../arch/powerpc/kernel/process.c:277 enable_kernel_altivec+0x100/0x120
Modules linked in: dm_thin_pool dm_persistent_data dm_bio_prison dm_bufio libcrc32c vmx_crypto ...
CPU: 9 PID: 2949 Comm: docker Not tainted 4.11.0-rc5-compiler_gcc-6.3.1-00033-g308ac7563944 #381
...
NIP [c00000000001e320] enable_kernel_altivec+0x100/0x120
LR [d000000003df0910] crc32c_vpmsum+0x108/0x150 [crc32c_vpmsum]
Call Trace:
0xc138fd09 (unreliable)
crc32c_vpmsum+0x108/0x150 [crc32c_vpmsum]
crc32c_vpmsum_update+0x3c/0x60 [crc32c_vpmsum]
crypto_shash_update+0x88/0x1c0
crc32c+0x64/0x90 [libcrc32c]
dm_bm_checksum+0x48/0x80 [dm_persistent_data]
sb_check+0x84/0x120 [dm_thin_pool]
dm_bm_validate_buffer.isra.0+0xc0/0x1b0 [dm_persistent_data]
dm_bm_read_lock+0x80/0xf0 [dm_persistent_data]
__create_persistent_data_objects+0x16c/0x810 [dm_thin_pool]
dm_pool_metadata_open+0xb0/0x1a0 [dm_thin_pool]
pool_ctr+0x4cc/0xb60 [dm_thin_pool]
dm_table_add_target+0x16c/0x3c0
table_load+0x184/0x400
ctl_ioctl+0x2f0/0x560
dm_ctl_ioctl+0x38/0x50
do_vfs_ioctl+0xd8/0x920
SyS_ioctl+0x68/0xc0
system_call+0x38/0xfc
It used to be sufficient just to call pagefault_disable(), because that
also disabled preemption. But the two were decoupled in commit 8222dbe21e
("sched/preempt, mm/fault: Decouple preemption from the page fault
logic") in mid 2015.
So add the missing preempt_disable/enable(). We should also call
disable_kernel_fp(), although it does nothing by default, there is a
debug switch to make it active and all enables should be paired with
disables.
Fixes: 6dd7a82cc5 ("crypto: powerpc - Add POWER8 optimised crc32c")
Cc: stable@vger.kernel.org # v4.8+
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Turning on crypto self-tests on a POWER8 shows:
alg: hash: Test 1 failed for crc32c-vpmsum
00000000: ff ff ff ff
Comparing the code with the Intel CRC32c implementation on which
ours is based shows that we are doing an init with 0, not ~0
as CRC32c requires.
This probably wasn't caught because btrfs does its own weird
open-coded initialisation.
Initialise our internal context to ~0 on init.
This makes the self-tests pass, and btrfs continues to work.
Fixes: 6dd7a82cc5 ("crypto: powerpc - Add POWER8 optimised crc32c")
Cc: Anton Blanchard <anton@samba.org>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Axtens <dja@axtens.net>
Acked-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch utilises the GENERIC_CPU_AUTOPROBE infrastructure
to automatically load the crc32c-vpmsum module if the CPU supports
it.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Use the vector polynomial multiply-sum instructions in POWER8 to
speed up crc32c.
This is just over 41x faster than the slice-by-8 method that it
replaces. Measurements on a 4.1 GHz POWER8 show it sustaining
52 GiB/sec.
A simple btrfs write performance test:
dd if=/dev/zero of=/mnt/tmpfile bs=1M count=4096
sync
is over 3.7x faster.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Eric Biggers