Currently, almost none of the keyed hash algorithms check whether a key
has been set before proceeding. Some algorithms are okay with this and
will effectively just use a key of all 0's or some other bogus default.
However, others will severely break, as demonstrated using
"hmac(sha3-512-generic)", the unkeyed use of which causes a kernel crash
via a (potentially exploitable) stack buffer overflow.
A while ago, this problem was solved for AF_ALG by pairing each hash
transform with a 'has_key' bool. However, there are still other places
in the kernel where userspace can specify an arbitrary hash algorithm by
name, and the kernel uses it as unkeyed hash without checking whether it
is really unkeyed. Examples of this include:
- KEYCTL_DH_COMPUTE, via the KDF extension
- dm-verity
- dm-crypt, via the ESSIV support
- dm-integrity, via the "internal hash" mode with no key given
- drbd (Distributed Replicated Block Device)
This bug is especially bad for KEYCTL_DH_COMPUTE as that requires no
privileges to call.
Fix the bug for all users by adding a flag CRYPTO_TFM_NEED_KEY to the
->crt_flags of each hash transform that indicates whether the transform
still needs to be keyed or not. Then, make the hash init, import, and
digest functions return -ENOKEY if the key is still needed.
The new flag also replaces the 'has_key' bool which algif_hash was
previously using, thereby simplifying the algif_hash implementation.
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>
Templates that use an shash spawn can use crypto_shash_alg_has_setkey()
to determine whether the underlying algorithm requires a key or not.
But there was no corresponding function for ahash spawns. Add it.
Note that the new function actually has to support both shash and ahash
algorithms, since the ahash API can be used with either.
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Now that -EBUSY return code only indicates backlog queueing
we can safely remove the now redundant check for the
CRYPTO_TFM_REQ_MAY_BACKLOG flag when -EBUSY is returned.
Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
There are already helpers to (un)register multiple normal
and AEAD algos. Add one for ahashes too.
Signed-off-by: Lars Persson <larper@axis.com>
Signed-off-by: Rabin Vincent <rabinv@axis.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The ahash API modifies the request's callback function in order
to clean up after itself in some corner cases (unaligned final
and missing finup).
When the request is complete ahash will restore the original
callback and everything is fine. However, when the request gets
an EBUSY on a full queue, an EINPROGRESS callback is made while
the request is still ongoing.
In this case the ahash API will incorrectly call its own callback.
This patch fixes the problem by creating a temporary request
object on the stack which is used to relay EINPROGRESS back to
the original completion function.
This patch also adds code to preserve the original flags value.
Fixes: ab6bf4e5e5 ("crypto: hash - Fix the pointer voodoo in...")
Cc: <stable@vger.kernel.org>
Reported-by: Sabrina Dubroca <sd@queasysnail.net>
Tested-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Continuing from this commit: 52f5684c8e
("kernel: use macros from compiler.h instead of __attribute__((...))")
I submitted 4 total patches. They are part of task I've taken up to
increase compiler portability in the kernel. I've cleaned up the
subsystems under /kernel /mm /block and /security, this patch targets
/crypto.
There is <linux/compiler.h> which provides macros for various gcc specific
constructs. Eg: __weak for __attribute__((weak)). I've cleaned all
instances of gcc specific attributes with the right macros for the crypto
subsystem.
I had to make one additional change into compiler-gcc.h for the case when
one wants to use this: __attribute__((aligned) and not specify an alignment
factor. From the gcc docs, this will result in the largest alignment for
that data type on the target machine so I've named the macro
__aligned_largest. Please advise if another name is more appropriate.
Signed-off-by: Gideon Israel Dsouza <gidisrael@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The function crypto_ahash_extsize did not include padding when
computing the tfm context size. This patch fixes this by using
the generic crypto_alg_extsize helper.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The crypto hash walk code is broken when supplied with an offset
greater than or equal to PAGE_SIZE. This patch fixes it by adjusting
walk->pg and walk->offset when this happens.
Cc: <stable@vger.kernel.org>
Reported-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch removes all traces of the crypto_hash interface, now
that everyone has switched over to shash or ahash.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch adds a way for ahash users to determine whether a key
is required by a crypto_ahash transform.
Cc: stable@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Unlike shash algorithms, ahash drivers must implement export
and import as their descriptors may contain hardware state and
cannot be exported as is. Unfortunately some ahash drivers did
not provide them and end up causing crashes with algif_hash.
This patch adds a check to prevent these drivers from registering
ahash algorithms until they are fixed.
Cc: stable@vger.kernel.org
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Modify crypto drivers to use the generic SG helper since
both of them are equivalent and the one from crypto is redundant.
See also:
468577abe3 reverted in
b2ab4a57b0
Signed-off-by: Cristian Stoica <cristian.stoica@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Fixed style error identified by checkpatch.
WARNING: Missing a blank line after declarations
+ unsigned int unaligned = alignmask + 1 - (offset & alignmask);
+ if (nbytes > unaligned)
Signed-off-by: Joshua I. James <joshua@cybercrimetech.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
For the special case when we have a null input string, we want
to initialize the entry len to 0 for the hash/ahash walk, so
cyrpto_hash_walk_last will return the correct result indicating
that we have completed the scatter list walk. Otherwise we may
keep walking the sg list and access bogus memory address.
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Although the existing hash walk interface has already been used
by a number of ahash crypto drivers, it turns out that none of
them were really asynchronous. They were all essentially polling
for completion.
That's why nobody has noticed until now that the walk interface
couldn't work with a real asynchronous driver since the memory
is mapped using kmap_atomic.
As we now have a use-case for a real ahash implementation on x86,
this patch creates a minimal ahash walk interface. Basically it
just calls kmap instead of kmap_atomic and does away with the
crypto_yield call. Real ahash crypto drivers don't need to yield
since by definition they won't be hogging the CPU.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The ahash_def_finup() can make use of the request save/restore functions,
thus make it so. This simplifies the code a little and unifies the code
paths.
Note that the same remark about free()ing the req->priv applies here, the
req->priv can only be free()'d after the original request was restored.
Finally, squash a bug in the invocation of completion in the ASYNC path.
In both ahash_def_finup_done{1,2}, the function areq->base.complete(X, err);
was called with X=areq->base.data . This is incorrect , as X=&areq->base
is the correct value. By analysis of the data structures, we see the areq is
of type 'struct ahash_request' , areq->base is of type 'struct crypto_async_request'
and areq->base.completion is of type crypto_completion_t, which is defined in
include/linux/crypto.h as:
typedef void (*crypto_completion_t)(struct crypto_async_request *req, int err);
This is one lead that the X should be &areq->base . Next up, we can inspect
other code which calls the completion callback to give us kind-of statistical
idea of how this callback is used. We can try:
$ git grep base\.complete\( drivers/crypto/
Finally, by inspecting ahash_request_set_callback() implementation defined
in include/crypto/hash.h , we observe that the .data entry of 'struct
crypto_async_request' is intended for arbitrary data, not for completion
argument.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The functions to save original request within a newly adjusted request
and it's counterpart to restore the original request can be re-used by
more code in the crypto/ahash.c file. Pull these functions out from the
code so they're available.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Add documentation for the pointer voodoo that is happening in crypto/ahash.c
in ahash_op_unaligned(). This code is quite confusing, so add a beefy chunk
of documentation.
Moreover, make sure the mangled request is completely restored after finishing
this unaligned operation. This means restoring all of .result, .base.data
and .base.complete .
Also, remove the crypto_completion_t complete = ... line present in the
ahash_op_unaligned_done() function. This type actually declares a function
pointer, which is very confusing.
Finally, yet very important nonetheless, make sure the req->priv is free()'d
only after the original request is restored in ahash_op_unaligned_done().
The req->priv data must not be free()'d before that in ahash_op_unaligned_finish(),
since we would be accessing previously free()'d data in ahash_op_unaligned_done()
and cause corruption.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
When finishing the ahash request, the ahash_op_unaligned_done() will
call complete() on the request. Yet, this will not call the correct
complete callback. The correct complete callback was previously stored
in the requests' private data, as seen in ahash_op_unaligned(). This
patch restores the correct complete callback and .data field of the
request before calling complete() on it.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Three errors resulting in kernel memory disclosure:
1/ The structures used for the netlink based crypto algorithm report API
are located on the stack. As snprintf() does not fill the remainder of
the buffer with null bytes, those stack bytes will be disclosed to users
of the API. Switch to strncpy() to fix this.
2/ crypto_report_one() does not initialize all field of struct
crypto_user_alg. Fix this to fix the heap info leak.
3/ For the module name we should copy only as many bytes as
module_name() returns -- not as much as the destination buffer could
hold. But the current code does not and therefore copies random data
from behind the end of the module name, as the module name is always
shorter than CRYPTO_MAX_ALG_NAME.
Also switch to use strncpy() to copy the algorithm's name and
driver_name. They are strings, after all.
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
These macros contain a hidden goto, and are thus extremely error
prone and make code hard to audit.
Signed-off-by: David S. Miller <davem@davemloft.net>
The report functions use NLA_PUT so we need to ensure that NET
is enabled.
Reported-by: Luis Henriques <henrix@camandro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
If a scatterwalk chain contains an entry with an unaligned offset then
hash_walk_next() will cut off the next step at the next alignment point.
However, if the entry ends before the next alignment point then we a loop,
which leads to a kernel oops.
Fix this by checking whether the next aligment point is before the end of the
current entry.
Signed-off-by: Szilveszter Ördög <slipszi@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The correct way to calculate the start of the aligned part of an
unaligned buffer is:
offset = ALIGN(offset, alignmask + 1);
However, crypto_hash_walk_done() has:
offset += alignmask - 1;
offset = ALIGN(offset, alignmask + 1);
which actually skips a whole block unless offset % (alignmask + 1) == 1.
This patch fixes the problem.
Signed-off-by: Szilveszter Ördög <slipszi@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
ahash_op_unaligned() and ahash_def_finup() allocate memory atomically,
regardless whether the request can sleep or not. This patch changes
this to use GFP_KERNEL if the request can sleep.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
When the alignment check was made unconditional for ahash we
may end up crashing on shash algorithms because we're always
calling alg->setkey instead of tfm->setkey.
This patch fixes it.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch exports the finup operation where available and adds
a default finup operation for ahash. The operations final, finup
and digest also will now deal with unaligned result pointers by
copying it. Finally export/import operations are will now be
exported too.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
We currently use GFP_ATOMIC in the unaligned setkey function
to allocate the temporary aligned buffer. Since setkey must
be called in a sleepable context, we can use GFP_KERNEL instead.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Some unaligned buffers on the stack weren't zapped properly which
may cause secret data to be leaked. This patch fixes them by doing
a zero memset.
It is also possible for us to place random kernel stack contents
in the digest buffer if a digest operation fails. This is fixed
by only copying if the operation succeeded.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Now that all ahash implementations have been converted to the new
ahash type, we can remove old_ahash_alg and its associated support.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch converts crypto_ahash to the new style. The old ahash
algorithm type is retained until the existing ahash implementations
are also converted. All ahash users will automatically get the
new crypto_ahash type.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
A quirk that we've always supported is having an sg entry that's
bigger than a page, or more generally an sg entry that crosses
page boundaries. Even though it would be better to explicitly have
to sg entries for this, we need to support it for the existing users,
in particular, IPsec.
The new ahash sg walking code did try to handle this, but there was
a bug where we didn't increment the page so kept on walking on the
first page over an dover again.
This patch fixes it.
Tested-by: Martin Willi <martin@strongswan.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
crypto_ahash_show changed to use cra_ahash for digestsize reference.
Signed-off-by: Lee Nipper <lee.nipper@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Since most cryptographic hash algorithms have no keys, this patch
makes the setkey function optional for ahash and shash.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch allows shash algorithms to be used through the old hash
interface. This is a transitional measure so we can convert the
underlying algorithms to shash before converting the users across.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
It is often useful to save the partial state of a hash function
so that it can be used as a base for two or more computations.
The most prominent example is HMAC where all hashes start from
a base determined by the key. Having an import/export interface
means that we only have to compute that base once rather than
for each message.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch adds the walking helpers for hash algorithms akin to
those of block ciphers. This is a necessary step before we can
reimplement existing hash algorithms using the new ahash interface.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The base field in ahash_tfm appears to have been cut-n-pasted from
ablkcipher. It isn't needed here at all. Similarly, the info field
in ahash_request also appears to have originated from its cipher
counter-part and is vestigial.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The digest size check on hash algorithms is incorrect. It's
perfectly valid for hash algorithms to have a digest length
longer than their block size. For example crc32c has a block
size of 1 and a digest size of 4. Rather than having it lie
about its block size, this patch fixes the checks to do what
they really should which is to bound the digest size so that
code placing the digest on the stack continue to work.
HMAC however still needs to check this as it's only defined
for such algorithms.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
