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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 <ardb@kernel.org>
Acked-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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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 <herbert@gondor.apana.org.au>
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Move all stat code specific to skcipher into the skcipher 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 <herbert@gondor.apana.org.au>
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Move all stat code specific to kpp into the kpp 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 <herbert@gondor.apana.org.au>
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Move all stat code specific to acomp into the acomp 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 <herbert@gondor.apana.org.au>
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Move all stat code specific to hash into the hash 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 <herbert@gondor.apana.org.au>
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Move all stat code specific to akcipher into the akcipher 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 <herbert@gondor.apana.org.au>
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Move all stat code specific to aead into the aead 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 <herbert@gondor.apana.org.au>
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The stats code resurrected the unions from the early days of
kernel crypto. This patch starts the process of moving them
out to the individual type structures as we do for everything
else.
In particular, add a report_stat function to cra_type and call
that from the stats code if available. This allows us to move
the actual code over one-by-one.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Now that all "blkcipher" algorithms have been converted to "skcipher",
remove the blkcipher algorithm type.
The skcipher (symmetric key cipher) algorithm type was introduced a few
years ago to replace both blkcipher and ablkcipher (synchronous and
asynchronous block cipher). The advantages of skcipher include:
- A much less confusing name, since none of these algorithm types have
ever actually been for raw block ciphers, but rather for all
length-preserving encryption modes including block cipher modes of
operation, stream ciphers, and other length-preserving modes.
- It unified blkcipher and ablkcipher into a single algorithm type
which supports both synchronous and asynchronous implementations.
Note, blkcipher already operated only on scatterlists, so the fact
that skcipher does too isn't a regression in functionality.
- Better type safety by using struct skcipher_alg, struct
crypto_skcipher, etc. instead of crypto_alg, crypto_tfm, etc.
- It sometimes simplifies the implementations of algorithms.
Also, the blkcipher API was no longer being tested.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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In crypto_reportstat, a new skb is created by nlmsg_new(). This skb is
leaked if crypto_reportstat_alg() fails. Required release for skb is
added.
Fixes: cac5818c25d0 ("crypto: user - Implement a generic crypto statistics")
Cc: <stable@vger.kernel.org>
Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Currently, NETLINK_CRYPTO works only in the init network namespace. It
doesn't make much sense to cut it out of the other network namespaces,
so do the minor plumbing work necessary to make it work in any network
namespace. Code inspired by net/core/sock_diag.c.
Tested using kcapi-dgst from libkcapi [1]:
Before:
# unshare -n kcapi-dgst -c sha256 </dev/null | wc -c
libkcapi - Error: Netlink error: sendmsg failed
libkcapi - Error: Netlink error: sendmsg failed
libkcapi - Error: NETLINK_CRYPTO: cannot obtain cipher information for hmac(sha512) (is required crypto_user.c patch missing? see documentation)
0
After:
# unshare -n kcapi-dgst -c sha256 </dev/null | wc -c
32
[1] https://github.com/smuellerDD/libkcapi
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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crypto_cfg_mutex in crypto_user_stat.c is unused. Remove it.
Cc: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Move the declaration of crypto_nlsk into internal/cryptouser.h. This
fixes the following sparse warning:
crypto/crypto_user_base.c:41:13: warning: symbol 'crypto_nlsk' was not declared. Should it be static?
Cc: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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This patch removes unused dump functions for crypto_user_stats.
There are remains of the copy/paste of crypto_user_base to
crypto_user_stat and I forgot to remove them.
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Since now all crypto stats are on their own structures, it is now
useless to have the algorithm name in the err_cnt member.
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Like for userspace, this patch splits stats into multiple structures,
one for each algorithm class.
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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The use of the v64 intermediate variable is useless, and removing it
bring to much readable code.
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Some error count use the wrong name for getting this data.
But this had not caused any reporting problem, since all error count are shared in the same
union.
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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It is cleaner to have each stat in their own structures.
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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All the 32-bit fields need to be 64-bit. In some cases, UINT32_MAX crypto
operations can be done in seconds.
Reported-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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There have been a pretty ridiculous number of issues with initializing
the report structures that are copied to userspace by NETLINK_CRYPTO.
Commit 4473710df1f8 ("crypto: user - Prepare for CRYPTO_MAX_ALG_NAME
expansion") replaced some strncpy()s with strlcpy()s, thereby
introducing information leaks. Later two other people tried to replace
other strncpy()s with strlcpy() too, which would have introduced even
more information leaks:
- https://lore.kernel.org/patchwork/patch/954991/
- https://patchwork.kernel.org/patch/10434351/
Commit cac5818c25d0 ("crypto: user - Implement a generic crypto
statistics") also uses the buggy strlcpy() approach and therefore leaks
uninitialized memory to userspace. A fix was proposed, but it was
originally incomplete.
Seeing as how apparently no one can get this right with the current
approach, change all the reporting functions to:
- Start by memsetting the report structure to 0. This guarantees it's
always initialized, regardless of what happens later.
- Initialize all strings using strscpy(). This is safe after the
memset, ensures null termination of long strings, avoids unnecessary
work, and avoids the -Wstringop-truncation warnings from gcc.
- Use sizeof(var) instead of sizeof(type). This is more robust against
copy+paste errors.
For simplicity, also reuse the -EMSGSIZE return value from nla_put().
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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For preventing uninitialized data to be given to user-space (and so leak
potential useful data), the crypto_stat structure must be correctly
initialized.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: cac5818c25d0 ("crypto: user - Implement a generic crypto statistics")
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
[EB: also fix it in crypto_reportstat_one()]
[EB: use sizeof(var) rather than sizeof(type)]
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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This patch implement a generic way to get statistics about all crypto
usages.
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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