syzkaller triggered a NULL pointer dereference in crypto_remove_spawns()
via a program that repeatedly and concurrently requests AEADs
"authenc(cmac(des3_ede-asm),pcbc-aes-aesni)" and hashes "cmac(des3_ede)"
through AF_ALG, where the hashes are requested as "untested"
(CRYPTO_ALG_TESTED is set in ->salg_mask but clear in ->salg_feat; this
causes the template to be instantiated for every request).
Although AF_ALG users really shouldn't be able to request an "untested"
algorithm, the NULL pointer dereference is actually caused by a
longstanding race condition where crypto_remove_spawns() can encounter
an instance which has had spawn(s) "grabbed" but hasn't yet been
registered, resulting in ->cra_users still being NULL.
We probably should properly initialize ->cra_users earlier, but that
would require updating many templates individually. For now just fix
the bug in a simple way that can easily be backported: make
crypto_remove_spawns() treat a NULL ->cra_users list as empty.
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The crypto API was using the -EBUSY return value to indicate
both a hard failure to submit a crypto operation into a
transformation provider when the latter was busy and the backlog
mechanism was not enabled as well as a notification that the
operation was queued into the backlog when the backlog mechanism
was enabled.
Having the same return code indicate two very different conditions
depending on a flag is both error prone and requires extra runtime
check like the following to discern between the cases:
if (err == -EINPROGRESS ||
(err == -EBUSY && (ahash_request_flags(req) &
CRYPTO_TFM_REQ_MAY_BACKLOG)))
This patch changes the return code used to indicate a crypto op
failed due to the transformation provider being transiently busy
to -ENOSPC.
Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
In preparation of introducing crypto_xor_cpy(), which will use separate
operands for input and output, modify the __crypto_xor() implementation,
which it will share with the existing crypto_xor(), which provides the
actual functionality when not using the inline version.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
To prevent unnecessary branching, mark the exit condition of the
primary loop as likely(), given that a carry in a 32-bit counter
occurs very rarely.
On arm64, the resulting code is emitted by GCC as
9a8: cmp w1, #0x3
9ac: add x3, x0, w1, uxtw
9b0: b.ls 9e0 <crypto_inc+0x38>
9b4: ldr w2, [x3,#-4]!
9b8: rev w2, w2
9bc: add w2, w2, #0x1
9c0: rev w4, w2
9c4: str w4, [x3]
9c8: cbz w2, 9d0 <crypto_inc+0x28>
9cc: ret
where the two remaining branch conditions (one for size < 4 and one for
the carry) are statically predicted as non-taken, resulting in optimal
execution in the vast majority of cases.
Also, replace the open coded alignment test with IS_ALIGNED().
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Instead of unconditionally forcing 4 byte alignment for all generic
chaining modes that rely on crypto_xor() or crypto_inc() (which may
result in unnecessary copying of data when the underlying hardware
can perform unaligned accesses efficiently), make those functions
deal with unaligned input explicitly, but only if the Kconfig symbol
HAVE_EFFICIENT_UNALIGNED_ACCESS is set. This will allow us to drop
the alignmasks from the CBC, CMAC, CTR, CTS, PCBC and SEQIV drivers.
For crypto_inc(), this simply involves making the 4-byte stride
conditional on HAVE_EFFICIENT_UNALIGNED_ACCESS being set, given that
it typically operates on 16 byte buffers.
For crypto_xor(), an algorithm is implemented that simply runs through
the input using the largest strides possible if unaligned accesses are
allowed. If they are not, an optimal sequence of memory accesses is
emitted that takes the relative alignment of the input buffers into
account, e.g., if the relative misalignment of dst and src is 4 bytes,
the entire xor operation will be completed using 4 byte loads and stores
(modulo unaligned bits at the start and end). Note that all expressions
involving misalign are simply eliminated by the compiler when
HAVE_EFFICIENT_UNALIGNED_ACCESS is defined.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch adds the helper crypto_inst_setname because the current
helper crypto_alloc_instance2 is no longer useful given that we
now look up the algorithm after we allocate the instance object.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch adds the helper crypto_type_has_alg which is meant
to replace crypto_has_alg for new-style crypto types. Rather
than hard-coding type/mask information they're now retrieved
from the crypto_type object.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Simplify crypto_more_spawns() with list_first_entry_or_null()
and list_next_entry().
Signed-off-by: Geliang Tang <geliangtang@163.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Currently a number of Crypto API operations may fail when a signal
occurs. This causes nasty problems as the caller of those operations
are often not in a good position to restart the operation.
In fact there is currently no need for those operations to be
interrupted by user signals at all. All we need is for them to
be killable.
This patch replaces the relevant calls of signal_pending with
fatal_signal_pending, and wait_for_completion_interruptible with
wait_for_completion_killable, respectively.
Cc: stable@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Currently the task of freeing an instance is given to the crypto
template. However, it has no type information on the instance so
we have to resort to checking type information at runtime.
This patch introduces a free function to crypto_type that will be
used to free an instance. This can then be used to free an instance
in a type-safe manner.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch ensures that the tfm context always has enough extra
memory to ensure that it is aligned according to cra_alignment.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch adds a new primitive crypto_grab_spawn which is meant
to replace crypto_init_spawn and crypto_init_spawn2. Under the
new scheme the user no longer has to worry about reference counting
the alg object before it is subsumed by the spawn.
It is pretty much an exact copy of crypto_grab_aead.
Prior to calling this function spawn->frontend and spawn->inst
must have been set.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The commit 59afdc7b32 ("crypto:
api - Move module sig ifdef into accessor function") broke the
build when modules are completely disabled because we directly
dereference module->name.
This patch fixes this by using the accessor function module_name.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
All users of fips_enabled should include linux/fips.h directly
instead of getting it through internal.h.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Currently we're hiding mod->sig_ok under an ifdef in open code.
This patch adds a module_sig_ok accessor function and removes that
ifdef.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
This patch adds a crypto_alg_extsize helper that can be used
by algorithm types such as pcompress and shash.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Commit 9c521a200b ("crypto: api - remove instance when test failed")
tried to grab a module reference count before the module was even set.
Worse, it then goes on to free the module reference count after it is
set so you quickly end up with a negative module reference count which
prevents people from using any instances belonging to that module.
This patch moves the module initialisation before the reference
count.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A cipher instance is added to the list of instances unconditionally
regardless of whether the associated test failed. However, a failed
test implies that during another lookup, the cipher instance will
be added to the list again as it will not be found by the lookup
code.
That means that the list can be filled up with instances whose tests
failed.
Note: tests only fail in reality in FIPS mode when a cipher is not
marked as fips_allowed=1. This can be seen with cmac(des3_ede) that does
not have a fips_allowed=1. When allocating the cipher, the allocation
fails with -ENOENT due to the missing fips_allowed=1 flag (which
causes the testmgr to return EINVAL). Yet, the instance of
cmac(des3_ede) is shown in /proc/crypto. Allocating the cipher again
fails again, but a 2nd instance is listed in /proc/crypto.
The patch simply de-registers the instance when the testing failed.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
We currently initialise the crypto_alg ref count in the function
__crypto_register_alg. As one of the callers of that function
crypto_register_instance needs to obtain a ref count before it
calls __crypto_register_alg, we need to move the initialisation
out of there.
Since both callers of __crypto_register_alg call crypto_check_alg,
this is the logical place to perform the initialisation.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Stephan Mueller <smueller@chronox.de>
This patch makes crypto_unregister_instance take a crypto_instance
instead of a crypto_alg. This allows us to remove a duplicate
CRYPTO_ALG_INSTANCE check in crypto_unregister_instance.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
There are multiple problems in crypto_unregister_instance:
1) The cra_refcnt BUG_ON check is racy and can cause crashes.
2) The cra_refcnt check shouldn't exist at all.
3) There is no reference on tmpl to protect the tmpl->free call.
This patch rewrites the function using crypto_remove_spawn which
now morphs into crypto_remove_instance.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Fixed style error identified by checkpatch.
WARNING: Missing a blank line after declarations
+ int err = crypto_remove_alg(&inst->alg, &users);
+ BUG_ON(err);
Signed-off-by: Joshua I. James <joshua@cybercrimetech.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
