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

crypto: rng - Ensure set_ent is always present

2025-10-06T02:17:07+00:00

Ensure that set_ent is always set since only drbg provides it. Fixes: 77ebdabe8de7 ("crypto: af_alg - add extra parameters for DRBG interface") Reported-by: Yiqi Sun Signed-off-by: Herbert Xu

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: 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: 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

crypto: rng - Count error stats differently

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

Move all stat code specific to rng into the rng code. While we're at it, change the stats so that bytes and counts are always incremented even in case of error. This allows the reference counting to be removed as we can now increment the counters prior to the operation. After the operation we simply increase the error count if necessary. This is safe as errors can only occur synchronously (or rather, the existing code already ignored asynchronous errors which are only visible to the callback function). Signed-off-by: Herbert Xu

crypto: rng - fix crypto_rng_reset() refcounting when !CRYPTO_STATS

2021-04-02T07:28:12+00:00

crypto_stats_get() is a no-op when the kernel is compiled without CONFIG_CRYPTO_STATS, so pairing it with crypto_alg_put() unconditionally (as crypto_rng_reset() does) is wrong. Fix this by moving the call to crypto_stats_get() to just before the actual algorithm operation which might need it. This makes it always paired with crypto_stats_rng_seed(). Fixes: eed74b3eba9e ("crypto: rng - Fix a refcounting bug in crypto_rng_reset()") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu

mm, treewide: rename kzfree() to kfree_sensitive()

2020-08-07T18:33:22+00:00

As said by Linus: A symmetric naming is only helpful if it implies symmetries in use. Otherwise it's actively misleading. In "kzalloc()", the z is meaningful and an important part of what the caller wants. In "kzfree()", the z is actively detrimental, because maybe in the future we really _might_ want to use that "memfill(0xdeadbeef)" or something. The "zero" part of the interface isn't even _relevant_. The main reason that kzfree() exists is to clear sensitive information that should not be leaked to other future users of the same memory objects. Rename kzfree() to kfree_sensitive() to follow the example of the recently added kvfree_sensitive() and make the intention of the API more explicit. In addition, memzero_explicit() is used to clear the memory to make sure that it won't get optimized away by the compiler. The renaming is done by using the command sequence: git grep -w --name-only kzfree |\ xargs sed -i 's/kzfree/kfree_sensitive/' followed by some editing of the kfree_sensitive() kerneldoc and adding a kzfree backward compatibility macro in slab.h. [akpm@linux-foundation.org: fs/crypto/inline_crypt.c needs linux/slab.h] [akpm@linux-foundation.org: fix fs/crypto/inline_crypt.c some more] Suggested-by: Joe Perches Signed-off-by: Waiman Long Signed-off-by: Andrew Morton Acked-by: David Howells Acked-by: Michal Hocko Acked-by: Johannes Weiner Cc: Jarkko Sakkinen Cc: James Morris Cc: "Serge E. Hallyn" Cc: Joe Perches Cc: Matthew Wilcox Cc: David Rientjes Cc: Dan Carpenter Cc: "Jason A . Donenfeld" Link: http://lkml.kernel.org/r/20200616154311.12314-3-longman@redhat.com Signed-off-by: Linus Torvalds

crypto: rng - Fix a refcounting bug in crypto_rng_reset()

2020-02-13T08:58:09+00:00

We need to decrement this refcounter on these error paths. Fixes: f7d76e05d058 ("crypto: user - fix use_after_free of struct xxx_request") Cc: Signed-off-by: Dan Carpenter Acked-by: Neil Horman Signed-off-by: Herbert Xu

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

2019-05-30T18:26:32+00:00

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman