Remove the insecure FCrypt block cipher from the crypto API. Its only
user was net/rxrpc/, but now net/rxrpc/ implements it locally. The
crypto API implementation is no longer needed.
For some additional context: FCrypt was designed in 1988 and is
essentially a weakened version of DES. It has the same 56-bit key size
as DES, which is easily brute forced. Moreover, it's cryptographically
weak and doesn't even provide the intended 56-bit security level. Its
author considers it to be a mistake, as well
(https://lists.openafs.org/pipermail/openafs-devel/2000-December/005320.html).
But fortunately this 1980s-era homebrew block cipher was never adopted
outside of net/rxrpc/. So its code can just be kept there.
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> # m68k
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Tested-by: Marc Dionne <marc.dionne@auristor.com>
Link: https://patch.msgid.link/20260522050740.84561-5-ebiggers@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
chachapoly_create() still accepts the compatibility poly1305 parameter
in the template name, but it assumes the second template argument is
always present and immediately passes it to strcmp().
When the argument is missing, crypto_attr_alg_name() returns an error
pointer. Check for that before comparing the name so malformed template
instantiations fail with an error instead of dereferencing the error
pointer in strcmp().
This matches the surrounding Crypto API template pattern where
crypto_attr_alg_name() results are validated before string-specific use.
Fixes: a298765e28 ("crypto: chacha20poly1305 - Use lib/crypto poly1305")
Cc: stable@kernel.org
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Zhengchuan Liang <zcliangcn@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Co-developed-by: Luxing Yin <tr0jan@lzu.edu.cn>
Signed-off-by: Luxing Yin <tr0jan@lzu.edu.cn>
Signed-off-by: Xiaonan Zhao <ngochuongbui67@gmail.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
pcrypt installs pcrypt_aead_done() on the child AEAD request before
trying to submit it through padata. If padata_do_parallel() returns
-EBUSY, pcrypt falls back to calling the child AEAD directly.
That fallback must not keep the padata completion callback. Otherwise
an asynchronous completion runs pcrypt_aead_done() even though the
request was never enrolled in padata.
Restore the original request callback and callback data before calling
the child AEAD directly. This keeps the fallback path aligned with a
direct AEAD request while leaving the parallel path unchanged.
Fixes: 662f2f13e6 ("crypto: pcrypt - Call crypto layer directly when padata_do_parallel() return -EBUSY")
Cc: stable@kernel.org
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Reported-by: Zhengchuan Liang <zcliangcn@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Assisted-by: Codex:gpt-5.4
Signed-off-by: Ruijie Li <ruijieli51@gmail.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
AF_ALG is deprecated and exposed to unprivileged userspace. Only
use the least buggy algorithm implementations: the pure software ones.
This removes one of the main advantages of AF_ALG, which is the
ability to use it with off-CPU accelerators. However, using off-CPU
accelerators has huge overheads, both in performance and attack surface.
I have yet to see real-world, performance-critical workloads where using
an accelerator via AF_ALG is actually a win over doing cryptography in
userspace.
If using an off-CPU accelerator really does turn out to be a win, a new
API should be developed that is actually a good fit for it.
Signed-off-by: Demi Marie Obenour <demiobenour@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The only user of msg->msg_iocb was AF_ALG, but that's deprecated.
It can be removed entirely at the cost of only supporting synchronous
operations. This doesn't break userspace, which will silently block
(for a bounded amount of time) in io_submit instead of operating
asynchronously.
This also makes struct msghdr smaller, helping every other caller of
sendmsg().
Signed-off-by: Demi Marie Obenour <demiobenour@gmail.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
ecrdsa_exit_tfm() is empty, and sig_alg .exit is optional. The
corresponding .init callback is not set either, so there is nothing to
release in .exit.
Remove the empty function and leave .exit unset.
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This reverts commit ae131f4970 ("crypto: api - Add crypto_tfm_get").
The refcount in struct crypto_tfm was added solely to support
crypto_clone_tfm(). Before then it was a simple non-refcounted object.
Since crypto_clone_tfm() has been removed, remove the refcount as well.
Note that this eliminates an expensive atomic operation from every tfm
freeing operation. So this revert doesn't just remove unused code, but
it also fixes a performance regression.
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Link: https://patch.msgid.link/20260522053028.91165-5-ebiggers@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The last MIPS crypto code was moved to lib/crypto/mips in
commit c9e5ac0ab9 ("lib/crypto: mips/md5: Migrate optimized code into
library"). However, arch/mips/crypto still contains stub Kconfig,
Makefile, and .gitignore files. Remove these unnecessary files.
Signed-off-by: Ethan Nelson-Moore <enelsonmoore@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
All LoongArch crypto code was moved to arch/loongarch/lib in
commit 72f51a4f4b ("loongarch/crc32: expose CRC32 functions through
lib"). However, arch/loongarch/crypto still contains stub Kconfig and
Makefile files. Remove these unnecessary files.
Signed-off-by: Ethan Nelson-Moore <enelsonmoore@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The carry flag calculation fails when r01.m_high is saturated
(0xFFFFFFFFFFFFFFFF) and addition of lower bits overflows.
The condition (r01.m_high < product.m_high) doesn't handle the case
where r01.m_high == product.m_high and an additional carry exists
from lower-bit overflow.
When commit 3c4b23901a ("crypto: ecdh - Add ECDH software support")
introduced crypto/ecc.c, it split the muladd() function in the
micro-ecc library into separate mul_64_64() and add_128_128() helpers.
It seems the check got lost in translation.
Add proper handling for this boundary by accounting for the carry
from the lower addition.
Fixes: 3c4b23901a ("crypto: ecdh - Add ECDH software support")
Signed-off-by: Anastasia Tishchenko <sv3iry@gmail.com>
Cc: stable@vger.kernel.org # v4.8+
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
krb5_aead_encrypt(), krb5_aead_decrypt() in rfc3961_simplified.c and
rfc8009_encrypt(), rfc8009_decrypt() in rfc8009_aes2.c set a NULL
completion callback and treat any negative return from
crypto_aead_{encrypt,decrypt}() as terminal, falling through to
kfree_sensitive(buffer). When the encrypt_name resolves to an
async AEAD instance the request returns -EINPROGRESS, the buffer
is freed while the backend's worker still holds a pointer, and the
worker dereferences the freed slab on completion.
KASAN report under UML+SLUB with a synthetic async aead backend
bound to krb5->encrypt_name:
BUG: KASAN: slab-use-after-free in t5_stub_complete+0x7d/0xc7
The helpers were written synchronously, so filter the async
instances out at allocation time instead of plumbing
crypto_wait_req() through every call site.
Reachable via net/rxrpc/rxgk.c, fs/afs/cm_security.c and
net/ceph/crypto.c on systems with an async AEAD provider bound to
the krb5 enctype name.
Fixes: 00244da40f ("crypto/krb5: Implement the Kerberos5 rfc3961 encrypt and decrypt functions")
Fixes: 6c3c0e86c2 ("crypto/krb5: Implement the AES enctypes from rfc8009")
Cc: stable@vger.kernel.org
Suggested-by: Herbert Xu <herbert@gondor.apana.org.au>
Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Use designated initializers for the report structs instead of clearing
the struct with memset() and then copying fixed strings with strscpy()
at runtime.
This keeps the structs zero-initialized, lets the compiler diagnose
oversized string literals, and makes the code easier to read.
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Andrew reports build breakage of arm allmodconfig, reproducible with gcc
14.2.0 and 15.2.0:
crypto/ecc.c: In function 'ecc_point_mult':
crypto/ecc.c:1380:1: error: the frame size of 1360 bytes is larger than 1280 bytes [-Werror=frame-larger-than=]
gcc aggressively inlines functions called by ecc_point_mult() (without
there being any explicit inline declarations), which pushes stack usage
close to the limit imposed by CONFIG_FRAME_WARN. allmodconfig implies
CONFIG_KASAN_STACK=y, which increases the stack above that limit.
In the bugzilla entry linked below, gcc maintainers explain that gcc
estimates extra stack usage caused by inlining, but ASAN instrumentation
is added in post-IPA passes and thus the inlining heuristics cannot
account for it.
It could be argued that -Werror=frame-larger-than=1280 instructs the
compiler to avoid inlining beyond that limit lest the build breaks,
which would imply gcc behaves incorrectly. But gcc maintainers reject
this notion and believe that a warning switch should never affect code
generation, even if it is promoted to an error.
One way to unbreak the build is to limit inlining via -finline-limit=100
or by explicitly declaring some functions noinline. However while it
does keep stack usage of individual functions below the limit, *total*
stack usage increases.
A longterm solution is to refactor ecc.c for reduced stack usage. It
currently performs ECC point multiplication with a Montgomery ladder
which uses co-Z (conjugate) addition to trade off memory for speed.
The algorithm is susceptible to timing attacks and needs to be replaced
with a constant time Montgomery ladder, which should consume less memory
and thus resolve the stack usage issue as a side effect.
In the interim, raise the limit for ecc.c, as is already done for
several other files in the source tree.
Constrain to gcc because clang 19.1.7 does not exhibit the issue. It
makes do with a 724 bytes stack frame even though it inlines almost the
same functions as gcc.
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124949
Reported-by: Andrew Morton <akpm@linux-foundation.org> # off-list
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
"Prediction resistance", i.e. the property that the RNG's output is
unpredictable even after a state compromise, might sound like a nice
property to have. In reality, it's not very practical, as it requires
that fresh entropy be pulled on every request. (The normal Linux RNG
doesn't provide prediction resistance.) In the case of drbg.c, that
means pulling from "jitterentropy", which is extremely slow.
For some perspective, running a simple benchmark, generating 32 random
bytes takes the following amount of time:
get_random_bytes(): 90 ns
drbg_nopr_hmac_sha512: 3707 ns
drbg_pr_hmac_sha512: 773082 ns
So at least in this case, the "pr" (prediction-resistant) DRBG is over
200 times slower than the "nopr" (non-prediction-resistant) DRBG, or
over 8000 times slower than the normal Linux RNG. While anyone using
drbg.c has always had to tolerate that it's slower than the normal Linux
RNG, the "pr" DRBG is clearly at another level of slowness.
Thus, the following is also entirely unsurprising:
- FIPS 140-3 doesn't actually require that SP800-90A DRBG
implementations support prediction resistance. The non-prediction
resistant DRBGs can be, and have been, certified.
- drbg.c registers "drbg_nopr_hmac_sha512" with a higher cra_priority
than "drbg_pr_hmac_sha512". So "drbg_nopr_hmac_sha512" is already
the one actually being used in practice.
Given these considerations, it's clear that "drbg_pr_hmac_sha512" isn't
actually useful, and it essentially just existed as another curiosity in
the museum of crypto algorithms. Remove it to simplify the code.
Suggested-by: Joachim Vandersmissen <joachim@jvdsn.com>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Eric Biggers
Xiaonan Zhao
Ruijie Li
Demi Marie Obenour
Thorsten Blum
Christoph Hellwig
Ard Biesheuvel
Ethan Nelson-Moore
Lukas Wunner
Anastasia Tishchenko
David Howells
Michael Bommarito