kernel/linux.git/crypto/akcipher.c, branch v6.18.21

crypto: api - Add support for duplicating algorithms before registration

2025-04-16T07:36:24+00:00

If the bit CRYPTO_ALG_DUP_FIRST is set, an algorithm will be duplicated by kmemdup before registration. This is inteded for hardware-based algorithms that may be unplugged at will. Do not use this if the algorithm data structure is embedded in a bigger data structure. Perform the duplication in the driver instead. Signed-off-by: Herbert Xu

crypto: akcipher - Drop sign/verify operations

2024-10-05T05:22:04+00:00

A sig_alg backend has just been introduced and all asymmetric sign/verify algorithms have been migrated to it. The sign/verify operations can thus be dropped from akcipher_alg. It is now purely for asymmetric encrypt/decrypt. Move struct crypto_akcipher_sync_data from internal.h to akcipher.c and unexport crypto_akcipher_sync_{prep,post}(): They're no longer used by sig.c but only locally in akcipher.c. In crypto_akcipher_sync_{prep,post}(), drop various NULL pointer checks for data->dst as they were only necessary for the verify operation. In the crypto_sig_*() API calls, remove the forks that were necessary while algorithms were converted from crypto_akcipher to crypto_sig one by one. In struct akcipher_testvec, remove the "params", "param_len" and "algo" elements as they were only needed for the ecrdsa verify operation. Remove corresponding dead code from test_akcipher_one() as well. Signed-off-by: Lukas Wunner Signed-off-by: Herbert Xu

crypto: remove CONFIG_CRYPTO_STATS

2024-04-02T02:49:38+00:00

Remove support for the "Crypto usage statistics" feature (CONFIG_CRYPTO_STATS). This feature does not appear to have ever been used, and it is harmful because it significantly reduces performance and is a large maintenance burden. Covering each of these points in detail: 1. Feature is not being used Since these generic crypto statistics are only readable using netlink, it's fairly straightforward to look for programs that use them. I'm unable to find any evidence that any such programs exist. For example, Debian Code Search returns no hits except the kernel header and kernel code itself and translations of the kernel header: https://codesearch.debian.net/search?q=CRYPTOCFGA_STAT&literal=1&perpkg=1 The patch series that added this feature in 2018 (https://lore.kernel.org/linux-crypto/1537351855-16618-1-git-send-email-clabbe@baylibre.com/) said "The goal is to have an ifconfig for crypto device." This doesn't appear to have happened. It's not clear that there is real demand for crypto statistics. Just because the kernel provides other types of statistics such as I/O and networking statistics and some people find those useful does not mean that crypto statistics are useful too. Further evidence that programs are not using CONFIG_CRYPTO_STATS is that it was able to be disabled in RHEL and Fedora as a bug fix (https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/2947). Even further evidence comes from the fact that there are and have been bugs in how the stats work, but they were never reported. For example, before Linux v6.7 hash stats were double-counted in most cases. There has also never been any documentation for this feature, so it might be hard to use even if someone wanted to. 2. CONFIG_CRYPTO_STATS significantly reduces performance Enabling CONFIG_CRYPTO_STATS significantly reduces the performance of the crypto API, even if no program ever retrieves the statistics. This primarily affects systems with a large number of CPUs. For example, https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2039576 reported that Lustre client encryption performance improved from 21.7GB/s to 48.2GB/s by disabling CONFIG_CRYPTO_STATS. It can be argued that this means that CONFIG_CRYPTO_STATS should be optimized with per-cpu counters similar to many of the networking counters. But no one has done this in 5+ years. This is consistent with the fact that the feature appears to be unused, so there seems to be little interest in improving it as opposed to just disabling it. It can be argued that because CONFIG_CRYPTO_STATS is off by default, performance doesn't matter. But Linux distros tend to error on the side of enabling options. The option is enabled in Ubuntu and Arch Linux, and until recently was enabled in RHEL and Fedora (see above). So, even just having the option available is harmful to users. 3. CONFIG_CRYPTO_STATS is a large maintenance burden There are over 1000 lines of code associated with CONFIG_CRYPTO_STATS, spread among 32 files. It significantly complicates much of the implementation of the crypto API. After the initial submission, many fixes and refactorings have consumed effort of multiple people to keep this feature "working". We should be spending this effort elsewhere. Acked-by: Ard Biesheuvel Acked-by: Corentin Labbe Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu

crypto: akcipher - Do not copy dst if it is NULL

2023-06-27T09:59:52+00:00

As signature verification has a NULL destination buffer, the pointer needs to be checked before the memcpy is done. Fixes: addde1f2c966 ("crypto: akcipher - Add sync interface without SG lists") Signed-off-by: Herbert Xu

crypto: sig - Fix verify call

2023-06-27T07:40:24+00:00

The dst SG list needs to be set to NULL for verify calls. Do this as otherwise the underlying algorithm may fail. Furthermore the digest needs to be copied just like the source. Fixes: 6cb8815f41a9 ("crypto: sig - Add interface for sign/verify") Signed-off-by: Herbert Xu

crypto: akcipher - Set request tfm on sync path

2023-06-27T07:40:24+00:00

The request tfm needs to be set. Fixes: addde1f2c966 ("crypto: akcipher - Add sync interface without SG lists") Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202306261421.2ac744fa-oliver.sang@intel.com Signed-off-by: Herbert Xu

crypto: sig - Add interface for sign/verify

2023-06-23T08:15:36+00:00

Split out the sign/verify functionality from the existing akcipher interface. Most algorithms in akcipher either support encryption and decryption, or signing and verify. Only one supports both. As a signature algorithm may not support encryption at all, these two should be spearated. For now sig is simply a wrapper around akcipher as all algorithms remain unchanged. This is a first step and allows users to start allocating sig instead of akcipher. Signed-off-by: Herbert Xu

crypto: akcipher - Add sync interface without SG lists

2023-06-23T08:15:36+00:00

The only user of akcipher does not use SG lists. Therefore forcing users to use SG lists only results unnecessary overhead. Add a new interface that supports arbitrary kernel pointers. For the time being the copy will be performed unconditionally. But this will go away once the underlying interface is updated. Note also that only encryption and decryption is addressed by this patch as sign/verify will go into a new interface (sig). Signed-off-by: Herbert Xu

crypto: api - Fix CRYPTO_USER checks for report function

2023-05-02T10:22:24+00:00

Checking the config via ifdef incorrectly compiles out the report functions when CRYPTO_USER is set to =m. Fix it by using IS_ENABLED() instead. Fixes: c0f9e01dd266 ("crypto: api - Check CRYPTO_USER instead of NET for report") Signed-off-by: Ondrej Mosnacek Signed-off-by: Herbert Xu

crypto: api - Check CRYPTO_USER instead of NET for report

2023-03-14T09:06:42+00:00

The report function is currently conditionalised on CONFIG_NET. As it's only used by CONFIG_CRYPTO_USER, conditionalising on that instead of CONFIG_NET makes more sense. This gets rid of a rarely used code-path. Signed-off-by: Herbert Xu