Add support for AES-CCM to the crypto library.
This will be used to provide a streamlined implementation of the
"ccm(aes)" crypto_aead algorithm. Most users of "ccm(aes)" will also be
able to switch to the library, which as usual will be faster and
simpler, e.g.:
- fs/smb/client/
- fs/smb/server/
- net/mac80211/
- net/mac802154/
(I've already written proof-of-concept patches for all the above, and
they helped inform the API design.)
As in the AES-GCM API, incremental operation is supported. It has to be
used carefully, especially when decrypting, but it makes the API general
enough to work well for all users.
The AES-CCM library code calls aes_cbcmac_blocks() directly, bypassing
the higher-level aes_cbcmac_init(), aes_cbcmac_update(), and
aes_cbcmac_final(). The latter set of functions is useful only for
AES-CCM, so they don't make sense to keep around and will be removed
once the "ccm(aes)" crypto_aead starts using the AES-CCM library.
Initial test coverage is provided by the crypto_aead support added in a
later commit. I'm planning a KUnit test suite as well.
Link: https://patch.msgid.link/20260715221153.246410-8-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Add support for AES-GCM to the crypto library.
This will be used to provide streamlined implementations of the
"gcm(aes)" and "rfc4106(gcm(aes))" crypto_aead algorithms. Most users
of these will also be able to switch to the library, which as usual will
be faster and simpler, e.g.:
- drivers/net/macsec.c
- fs/smb/client/
- fs/smb/server/
- net/ceph/messenger_v2.c
- net/mac80211/ (for both GMAC and GCMP)
- net/tipc/crypto.c
- security/keys/trusted-keys/trusted_dcp.c
(I've already written proof-of-concept patches for all the above, and
they helped inform the API design.)
As usual, the architecture-optimized AES-GCM code will be migrated into
the library as well (using the hooks provided in this commit as well as
the GHASH ones), eliminating lots of repetitive boilerplate code.
Incremental en/decryption is supported. Incremental operation is a bit
controversial in AEAD APIs because users have to be careful not to
consume any decrypted data that hasn't been authenticated yet. But I do
think it's the right choice here. It's not fundamentally different from
the existing incremental MAC APIs, and it's the only approach that's
general enough to work well for all users in the kernel:
- An array of virtually-addressed buffers (like that used by
BoringSSL's EVP_AEAD_CTX_sealv() and EVP_AEAD_CTX_openv()) doesn't
work in the kernel in general, since in some cases the data for a
single AES-GCM message is contained in a large number of highmem
pages that each need to be mapped into memory individually. That
can be done efficiently only by using CPU-local mappings, but there
is a limited number of those.
Ceph messenger v2 is a great example, as it can send or receive up
to 32 MiB in a single AES-GCM message. And it needs the
en/decrypted data to go into a (potentially large) number of bvecs
provided by a custom iterator, as well as into four
virtually-addressed buffers, two of which can be large buffers in
the vmalloc region.
Even just allocating an array big enough to store all the pointers
can be problematic in the kernel. There are cases in which
decryption runs in GFP_NOIO context or even in softirq context,
where memory allocations are not as reliable as they normally are.
- Meanwhile, 'struct scatterlist' (the choice of crypto_aead) has
turned out to be really inconvenient for anyone who *does* just have
virtually-addressed buffers. This is especially true if they can be
in the vmalloc region, including the stack, as in that case the
conversion to a scatterlist has to be done page-by-page.
And even for users who have all of their data in bare 'struct page',
none of them actually use 'struct scatterlist' as their native data
structure anyway. They actually use skbs, bvecs, or other formats.
- iov_iter is attractive, but ultimately not general enough either
(considering the Ceph case for example), but also too general in
some ways (like having support for userspace addresses). Additional
iter types like ITER_SKB would help a bit, but bloating iov_iter
with more types would reduce performance elsewhere in the kernel.
Initial test coverage is provided by the crypto_aead support added in a
later commit. I'm planning a KUnit test suite as well.
Link: https://patch.msgid.link/20260715221153.246410-7-ebiggers@kernel.org
Link: https://patch.msgid.link/20260722021730.16897-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Add support for AES-XTS to the crypto library.
This will be used to provide a streamlined implementation of the
"xts(aes)" crypto_skcipher algorithm. I'm also planning to use this
directly in fscrypt and blk-crypto-fallback.
As usual, the architecture-optimized AES-XTS code will be migrated into
the library as well (using the hooks provided in this commit),
eliminating lots of repetitive boilerplate code. Compared to direct
implementation of "xts(aes)", I've also eliminated the requirement for
architectures to implement ciphertext stealing, as the library just
handles it portably instead. That will simplify things considerably.
Initial test coverage is provided by the crypto_skcipher support added
in a later commit. I'm planning a KUnit test suite as well.
Link: https://patch.msgid.link/20260715221153.246410-6-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Add support for AES-CTR and AES-XCTR to the crypto library.
These will be used to provide streamlined implementations of the
"ctr(aes)" and "xctr(aes)" crypto_skcipher algorithms. Most users of
"ctr(aes)" will also be able to switch to the library, which as usual
will be simpler and faster, e.g.:
- net/mac80211/fils_aead.c
- net/mac802154/llsec.c
As usual, the architecture-optimized AES-CTR and AES-XCTR code will be
migrated into the library as well (using the hooks provided in this
commit), eliminating lots of repetitive boilerplate code.
This is also a prerequisite for supporting AES-GCM, AES-CCM, and
AES-HCTR2 in the crypto library.
Initial test coverage is provided by the crypto_skcipher support added
in a later commit. I'm planning a KUnit test suite as well.
Reviewed-by: Thomas Huth <thuth@redhat.com>
Link: https://patch.msgid.link/20260715221153.246410-5-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Add support for AES-CBC and AES-CBC-CTS to the crypto library.
These will be used to provide streamlined implementations of the
"cbc(aes)" and "cts(cbc(aes))" crypto_skcipher algorithms. Most users
of these crypto_skcipher algorithms will also be able to switch to the
library, which as usual will be simpler and faster, e.g.:
- block/blk-crypto-fallback.c (for AES-128-CBC-ESSIV)
- fs/crypto/crypto.c (for AES-128-CBC-ESSIV)
- fs/crypto/fname.c (for AES-256-CTS and AES-128-CBC)
- kernel/bpf/crypto.c
- net/ceph/crypto.c
- security/keys/encrypted-keys/encrypted.c
As usual, the architecture-optimized AES-CBC and AES-CBC-CTS code will
be migrated into the library as well (using the hooks provided in this
commit), eliminating lots of repetitive boilerplate code.
Initial test coverage is provided by the crypto_skcipher support added
in a later commit. I'm planning a KUnit test suite as well.
Reviewed-by: Thomas Huth <thuth@redhat.com>
Link: https://patch.msgid.link/20260715221153.246410-4-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Add support for AES-ECB to the crypto library.
This will be used to provide a streamlined implementation of the
"ecb(aes)" crypto_skcipher algorithm. fs/crypto/keysetup_v1.c will also
use aes_ecb_encrypt() directly.
As usual, the architecture-optimized AES-ECB code will be migrated into
the library as well (using the hooks provided in this commit),
eliminating lots of repetitive boilerplate code.
ECB is obsolete of course, but we need this for parity with the
traditional API and to support some odd users of ECB in the kernel.
Initial test coverage is provided by the crypto_skcipher support added
in a later commit. I'm planning a KUnit test suite as well.
Create a documentation file libcrypto-unauth-encryption.rst to hold the
documentation for this and other unauthenticated encryption modes.
Reviewed-by: Thomas Huth <thuth@redhat.com>
Link: https://patch.msgid.link/20260715221153.246410-3-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
AF_ALG is a frequent source of vulnerabilities and a maintenance
nightmare. It exposes far more functionality to userspace than ever
should have been exposed, especially to unprivileged processes. Recent
exploits have targeted kernel internal implementation details like
"authencesn" that have zero use case for userspace access.
Fortunately, AF_ALG is rarely used in practice, as userspace crypto
libraries exist. And when it is used, only some functionality is known
to be used, and many users are known to hold capabilities already.
iwd for example requires CAP_NET_ADMIN and has a known algorithm list
(https://lore.kernel.org/linux-crypto/bcbbef00-5881-421b-8892-7be6c04b832d@gmail.com/).
Thus, let's restrict the set of allowed algorithms by default, depending
on the capabilities held.
Add a sysctl /proc/sys/crypto/af_alg_restrict with meaning:
0: unrestricted
1: limited functionality
2: completely disabled
Set the default value to 1, which enables an algorithm allowlist for
unprivileged processes and a slightly longer allowlist for privileged
processes.
Note that the list may be tweaked in the future. However, the common
use cases such as iwd and bluez are taken into account already. I've
tested that iwd still works with the default value of 1.
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Pull non-MM updates from Andrew Morton:
- "taskstats: fix TGID dead-thread stat retention" (Yiyang Chen)
Fix a taskstats TGID aggregation bug where fields added in the TGID
query path were not preserved after thread exit, and adds a kselftest
covering the regression.
- "lib/tests: string_helpers: Slight improvements" (Andy Shevchenko)
Improve lib/tests/string_helpers_kunit.c a little
- "lib/base64: decode fixes" (Josh Law)
Address minor issues in lib/base64.c
- "selftests/filelock: Make output more kselftestish" (Mark Brown)
Make the output from the ofdlocks test a bit easier for tooling to
work with. Also ignore the generated file
- "uaccess: unify inline vs outline copy_{from,to}_user() selection"
(Yury Norov)
Simplify the usercopy code by removing the selectability of inlining
copy_{from,to}_user().
- "ocfs2: validate inline xattr header consumers" (ZhengYuan Huang)
Fix a number of possible issues in the ocfs2 xattr code
- "lib and lib/cmdline enhancements" (Dmitry Antipov)
Provide additional robustness checking in the cmdline handling code
and its in-kernel testing and selftests
- "cleanup the RAID6 P/Q library" (Christoph Hellwig)
Clean up the RAID6 P/Q library to match the recent updates to the
RAID 5 XOR library and other CRC/crypto libraries
- "ocfs2: harden inode validators against forged metadata" (Michael
Bommarito)
Add three structural checks to OCFS2 dinode validation so malformed
on-disk fields are rejected before ocfs2_populate_inode() copies them
into the in-core inode
- "lib/raid: replace __get_free_pages() call with kmalloc()" (Mike
Rapoport)
Clean up the lib/raid code by using kmalloc() in more places
* tag 'mm-nonmm-stable-2026-06-21-10-22' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (108 commits)
ocfs2: fix circular locking dependency in ocfs2_dio_end_io_write
ocfs2: fix NULL h_transaction deref in ocfs2_assure_trans_credits
lib: interval_tree_test: validate benchmark parameters
ocfs2: avoid moving extents to occupied clusters
treewide: fix transposed "sign" typos and update spelling.txt
ocfs2: fix UBSAN array-index-out-of-bounds in ocfs2_sum_rightmost_rec
fat: reject BPB volumes whose data area starts beyond total sectors
selftests/uevent: increase __UEVENT_BUFFER_SIZE to avoid ENOBUFS on busy systems
lib/test_firmware: allocate the configured into_buf size
fs: efs: remove unneeded debug prints
checkpatch: cuppress warnings when Reported-by: is followed by Link:
MAINTAINERS: add Alexander as a kcov reviewer
mailmap: update Alexander Sverdlin's Email addresses
fs: fat: inode: replace sprintf() with scnprintf()
ocfs2: fix out-of-bounds write in ocfs2_remove_refcount_extent
ocfs2: fix race between ocfs2_control_install_private() and ocfs2_control_release()
ocfs2/dlm: require a ref for locking_state debugfs open
ocfs2: reject FITRIM ranges shorter than a cluster
ocfs2: validate fast symlink target during inode read
ocfs2: add journal NULL check in ocfs2_checkpoint_inode()
...
Pull crypto updates from Herbert Xu:
"API:
- Drop support for off-CPU cryptography in af_alg
- Document that af_alg is *always* slower
- Document the deprecation of af_alg
- Remove zero-copy support from skcipher and aead in af_alg
- Cap AEAD AD length to 0x80000000 in af_alg
- Free default RNG on module exit
Algorithms:
- Fix vli multiplication carry overflow in ecc
- Drop unused cipher_null crypto_alg
- Remove unused variants of drbg
- Use lib/crypto in drbg
- Use memcpy_from/to_sglist in authencesn
- Allow authenc(hmac(sha{256,384}),cts(cbc(aes))) in FIPS mode
- Disallow RSA PKCS#1 SHA-1 sig algs in FIPS mode
- Filter out async aead implementations at alloc in krb5
- Fix non-parallel fallback by rstoring callback in pcrypt
- Validate poly1305 template argument in chacha20poly1305
Drivers:
- Add sysfs PCI reset support to qat
- Add KPT support for GEN6 devices to qat
- Remove unused character device and ioctls from qat
- Add support for hw access via SMCC to mtk
- Remove prng support from crypto4xx
- Remove prng support from hisi-trng
- Remove prng support from sun4i-ss
- Remove prng support from xilinx-trng
- Remove loongson-rng
- Remove exynos-rng
Others:
- Remove support for AIO on sockets"
* tag 'v7.2-p1' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (196 commits)
crypto: tegra - fix refcount leak in tegra_se_host1x_submit()
crypto: rng - Free default RNG on module exit
crypto: testmgr - allow authenc(hmac(sha{256,384}),cts(cbc(aes))) in FIPS mode
hwrng: jh7110 - fix refcount leak in starfive_trng_read()
crypto: atmel-ecc - drop dead code in atmel_ecdh_max_size
crypto: cavium/cpt - fix DMA cleanup using wrong loop index
crypto: marvell/octeontx - fix DMA cleanup using wrong loop index
MAINTAINERS: make myself the maintainer of the Qualcomm QCE driver
crypto: amcc - convert irq_of_parse_and_map to platform_get_irq
crypto: sun4i-ss - Remove insecure and unused rng_alg
hwrng: xilinx - Move xilinx-rng into drivers/char/hw_random/
crypto: xilinx-trng - Replace crypto_drbg_ctr_df() with HMAC-SHA512
crypto: xilinx-trng - Fix return value of xtrng_hwrng_trng_read()
crypto: xilinx-trng - Remove crypto_rng interface
crypto: exynos-rng - Remove exynos-rng driver
hwrng: hisi-trng - Move hisi-trng into drivers/char/hw_random/
crypto: hisi-trng - Remove crypto_rng interface
crypto: loongson - Remove broken and unused loongson-rng
crypto: crypto4xx - Remove insecure and unused rng_alg
crypto: qat - validate RSA CRT component lengths
...
Without support for zero-copy or off-CPU offloads, AF_ALG is always
slower than software cryptography. Its only advantage is that it might
save code size. However, this is largely mitigated by lightweight
userspace cryptographic libraries.
Signed-off-by: Demi Marie Obenour <demiobenour@gmail.com>
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 zero-copy support is one of the riskiest aspects of AF_ALG. It
allows userspace to request cryptographic operations directly on
pagecache pages of files like the 'su' binary. It also allows userspace
to concurrently modify the memory which is being operated on, a recipe
for TOCTOU vulnerabilities.
While zero-copy support is more valuable in other areas of the kernel
like the frequently used networking and file I/O code, it has far less
value in AF_ALG, which is a niche UAPI. AF_ALG primarily just exists
for backwards compatibility with a small set of userspace programs such
as 'iwd' that haven't yet been fixed to use userspace crypto code.
Originally AF_ALG was intended to be used to access hardware crypto
accelerators. However, it isn't an efficient interface for that anyway,
and it turned out to be rarely used in this way in practice.
Thus, the risks of the zero-copy support in AF_ALG vastly outweigh its
benefits. Let's just remove it.
This commit removes it from the "skcipher" and "aead" algorithm types.
"hash" will be handled separately.
This is a soft break, not a hard break. Even after this commit, it
still works to use splice() or sendfile() to transfer data to an AF_ALG
request socket from a pipe or any file, respectively. What changes is
just that the kernel now makes an internal, stable copy of the data
before doing the crypto operation. So performance is slightly reduced,
but the UAPI isn't broken. And, very importantly, it's much safer.
Tested with libkcapi/test.sh. All its test cases still pass. I also
verified that this would have prevented the copy.fail exploit as well.
I also used a custom test program to verify that sendfile() still works.
Fixes: 8ff590903d ("crypto: algif_skcipher - User-space interface for skcipher operations")
Fixes: 400c40cf78 ("crypto: algif - add AEAD support")
Reported-by: Taeyang Lee <0wn@theori.io>
Link: https://copy.fail/
Reported-by: Feng Ning <feng@innora.ai>
Closes: https://lore.kernel.org/r/afYcc-tZFwvZZo76@ans-MacBook-Pro.local
Reviewed-by: Demi Marie Obenour <demiobenour@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
AF_ALG is almost completely unnecessary, and it exposes a massive attack
surface that hasn't been standing up to modern vulnerability discovery
tools. The latest one even has its own website, providing a small
Python script that reliably roots most Linux distros: https://copy.fail/
This isn't sustainable, especially as LLMs have accelerated the rate the
vulnerabilities are coming in. The effort that is being put into this
thing is vastly disproportional to the few programs that actually use
it, and those programs would be better served by userspace code anyway.
These issues have been noted in many mailing list discussions already.
But until now they haven't been reflected in the documentation or
kconfig menu itself, and the vulnerabilities are still coming in.
Let's go ahead and document the deprecation.
This isn't intended to change anything overnight. After all, most Linux
distros won't be able to disable the kconfig options quite yet, mainly
because of iwd. But this should create a bit more impetus for these
userspace programs to be fixed, and the documentation update should also
help prevent more users from appearing.
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Remove the support for HASH_DRBG. It's likely unused code, seeing as
HMAC_DRBG is always enabled and prioritized over it unless
NETLINK_CRYPTO is used to change the algorithm priorities.
There's also no compelling reason to support more than one of
[HMAC_DRBG, HASH_DRBG, CTR_DRBG]. By definition, callers cannot tell
any difference in their outputs. And all are FIPS-certifiable, which is
the only point of the kernel's NIST DRBGs anyway.
Switching to HASH_DRBG doesn't seem all that compelling, either. For
one, it's more complex than HMAC_DRBG.
Thus, let's just drop HASH_DRBG support and focus on HMAC_DRBG.
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> # m68k
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Pull more crypto library updates from Eric Biggers:
"Crypto library fix and documentation update:
- Fix an integer underflow in the mpi library
- Improve the crypto library documentation"
* tag 'libcrypto-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux:
lib/crypto: docs: Add rst documentation to Documentation/crypto/
docs: kdoc: Expand 'at_least' when creating parameter list
lib/crypto: mpi: Fix integer underflow in mpi_read_raw_from_sgl()
Add a documentation file Documentation/crypto/libcrypto.rst which
provides a high-level overview of lib/crypto/.
Also add several sub-pages which include the kernel-doc for the
algorithms that have it. This makes the existing, quite extensive
kernel-doc start being included in the HTML and PDF documentation.
Note that the intent is very much *not* that everyone has to read these
Documentation/ files. The library is intended to be straightforward and
use familiar conventions; generally it should be possible to dive right
into the kernel-doc. You shouldn't need to read a lot of documentation
to just call `sha256()`, for example, or to run the unit tests if you're
already familiar with KUnit. (This differs from the traditional crypto
API which has a larger barrier to entry.)
Nevertheless, this seems worth adding. Hopefully it is useful and makes
LWN no longer consider the library to be "meticulously undocumented".
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20260418192138.15556-3-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
According to archive.org the site threw HTTP errors 404 since early 2024.
The last snapshot in the archive having actual content was from late 2023.
The page behind the new URL has more or less the same content as the
archived page from 2023, so it probably was just moved without setting
up a redirect.
Signed-off-by: Alexander Dahl <ada@thorsis.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Pull crypto updates from Herbert Xu:
"API:
- Rewrite memcpy_sglist from scratch
- Add on-stack AEAD request allocation
- Fix partial block processing in ahash
Algorithms:
- Remove ansi_cprng
- Remove tcrypt tests for poly1305
- Fix EINPROGRESS processing in authenc
- Fix double-free in zstd
Drivers:
- Use drbg ctr helper when reseeding xilinx-trng
- Add support for PCI device 0x115A to ccp
- Add support of paes in caam
- Add support for aes-xts in dthev2
Others:
- Use likely in rhashtable lookup
- Fix lockdep false-positive in padata by removing a helper"
* tag 'v6.19-p1' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (71 commits)
crypto: zstd - fix double-free in per-CPU stream cleanup
crypto: ahash - Zero positive err value in ahash_update_finish
crypto: ahash - Fix crypto_ahash_import with partial block data
crypto: lib/mpi - use min() instead of min_t()
crypto: ccp - use min() instead of min_t()
hwrng: core - use min3() instead of nested min_t()
crypto: aesni - ctr_crypt() use min() instead of min_t()
crypto: drbg - Delete unused ctx from struct sdesc
crypto: testmgr - Add missing DES weak and semi-weak key tests
Revert "crypto: scatterwalk - Move skcipher walk and use it for memcpy_sglist"
crypto: scatterwalk - Fix memcpy_sglist() to always succeed
crypto: iaa - Request to add Kanchana P Sridhar to Maintainers.
crypto: tcrypt - Remove unused poly1305 support
crypto: ansi_cprng - Remove unused ansi_cprng algorithm
crypto: asymmetric_keys - fix uninitialized pointers with free attribute
KEYS: Avoid -Wflex-array-member-not-at-end warning
crypto: ccree - Correctly handle return of sg_nents_for_len
crypto: starfive - Correctly handle return of sg_nents_for_len
crypto: iaa - Fix incorrect return value in save_iaa_wq()
crypto: zstd - Remove unnecessary size_t cast
...
Mark Brown
Eric Biggers
Manuel Ebner
Linus Torvalds
Demi Marie Obenour
Christoph Hellwig
David Howells
Alexander Dahl