linux/crypto/api.c

742 lines
17 KiB

crypto: api - Fix generic algorithm self-test races On Fri, Aug 30, 2024 at 10:51:54AM -0700, Eric Biggers wrote: > > Given below in defconfig form, use 'make olddefconfig' to apply. The failures > are nondeterministic and sometimes there are different ones, for example: > > [ 0.358017] alg: skcipher: failed to allocate transform for cbc(twofish-generic): -2 > [ 0.358365] alg: self-tests for cbc(twofish) using cbc(twofish-generic) failed (rc=-2) > [ 0.358535] alg: skcipher: failed to allocate transform for cbc(camellia-generic): -2 > [ 0.358918] alg: self-tests for cbc(camellia) using cbc(camellia-generic) failed (rc=-2) > [ 0.371533] alg: skcipher: failed to allocate transform for xts(ecb(aes-generic)): -2 > [ 0.371922] alg: self-tests for xts(aes) using xts(ecb(aes-generic)) failed (rc=-2) > > Modules are not enabled, maybe that matters (I haven't checked yet). Yes I think that was the key. This triggers a massive self-test run which executes in parallel and reveals a few race conditions in the system. I think it boils down to the following scenario: Base algorithm X-generic, X-optimised Template Y Optimised algorithm Y-X-optimised Everything gets registered, and then the self-tests are started. When Y-X-optimised gets tested, it requests the creation of the generic Y(X-generic). Which then itself undergoes testing. The race is that after Y(X-generic) gets registered, but just before it gets tested, X-optimised finally finishes self-testing which then causes all spawns of X-generic to be destroyed. So by the time the self-test for Y(X-generic) comes along, it can no longer find the algorithm. This error then bubbles up all the way up to the self-test of Y-X-optimised which then fails. Note that there is some complexity that I've omitted here because when the generic self-test fails to find Y(X-generic) it actually triggers the construction of it again which then fails for various other reasons (these are not important because the construction should *not* be triggered at this point). So in a way the error is expected, and we should probably remove the pr_err for the case where ENOENT is returned for the algorithm that we're currently testing. The solution is two-fold. First when an algorithm undergoes self-testing it should not trigger its construction. Secondly if an instance larval fails to materialise due to it being destroyed by a more optimised algorithm coming along, it should obviously retry the construction. Remove the check in __crypto_alg_lookup that stops a larval from matching new requests based on differences in the mask. It is better to block new requests even if it is wrong and then simply retry the lookup. If this ends up being the wrong larval it will sort iself out during the retry. Reduce the CRYPTO_ALG_TYPE_MASK bits in type during larval creation as otherwise LSKCIPHER algorithms may not match SKCIPHER larvals. Also block the instance creation during self-testing in the function crypto_larval_lookup by checking for CRYPTO_ALG_TESTED in the mask field. Finally change the return value when crypto_alg_lookup fails in crypto_larval_wait to EAGAIN to redo the lookup. Fixes: 37da5d0ffa7b ("crypto: api - Do not wait for tests during registration") Reported-by: Eric Biggers <ebiggers@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2024-09-01 16:05:40 +08:00
crypto: api - allow algs only in specific constructions in FIPS mode Currently we do not distinguish between algorithms that fail on the self-test vs. those which are disabled in FIPS mode (not allowed). Both are marked as having failed the self-test. Recently the need arose to allow the usage of certain algorithms only as arguments to specific template instantiations in FIPS mode. For example, standalone "dh" must be blocked, but e.g. "ffdhe2048(dh)" is allowed. Other potential use cases include "cbcmac(aes)", which must only be used with ccm(), or "ghash", which must be used only for gcm(). This patch allows this scenario by adding a new flag FIPS_INTERNAL to indicate those algorithms that are not FIPS-allowed. They can then be used as template arguments only, i.e. when looked up via crypto_grab_spawn() to be more specific. The FIPS_INTERNAL bit gets propagated upwards recursively into the surrounding template instances, until the construction eventually matches an explicit testmgr entry with ->fips_allowed being set, if any. The behaviour to skip !->fips_allowed self-test executions in FIPS mode will be retained. Note that this effectively means that FIPS_INTERNAL algorithms are handled very similarly to the INTERNAL ones in this regard. It is expected that the FIPS_INTERNAL algorithms will receive sufficient testing when the larger constructions they're a part of, if any, get exercised by testmgr. Note that as a side-effect of this patch algorithms which are not FIPS-allowed will now return ENOENT instead of ELIBBAD. Hopefully this is not an issue as some people were relying on this already. Link: https://lore.kernel.org/r/YeEVSaMEVJb3cQkq@gondor.apana.org.au Originally-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Nicolai Stange <nstange@suse.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-02-21 13:10:58 +01:00
crypto: api - allow algs only in specific constructions in FIPS mode Currently we do not distinguish between algorithms that fail on the self-test vs. those which are disabled in FIPS mode (not allowed). Both are marked as having failed the self-test. Recently the need arose to allow the usage of certain algorithms only as arguments to specific template instantiations in FIPS mode. For example, standalone "dh" must be blocked, but e.g. "ffdhe2048(dh)" is allowed. Other potential use cases include "cbcmac(aes)", which must only be used with ccm(), or "ghash", which must be used only for gcm(). This patch allows this scenario by adding a new flag FIPS_INTERNAL to indicate those algorithms that are not FIPS-allowed. They can then be used as template arguments only, i.e. when looked up via crypto_grab_spawn() to be more specific. The FIPS_INTERNAL bit gets propagated upwards recursively into the surrounding template instances, until the construction eventually matches an explicit testmgr entry with ->fips_allowed being set, if any. The behaviour to skip !->fips_allowed self-test executions in FIPS mode will be retained. Note that this effectively means that FIPS_INTERNAL algorithms are handled very similarly to the INTERNAL ones in this regard. It is expected that the FIPS_INTERNAL algorithms will receive sufficient testing when the larger constructions they're a part of, if any, get exercised by testmgr. Note that as a side-effect of this patch algorithms which are not FIPS-allowed will now return ENOENT instead of ELIBBAD. Hopefully this is not an issue as some people were relying on this already. Link: https://lore.kernel.org/r/YeEVSaMEVJb3cQkq@gondor.apana.org.au Originally-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Nicolai Stange <nstange@suse.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-02-21 13:10:58 +01:00
crypto: api - allow algs only in specific constructions in FIPS mode Currently we do not distinguish between algorithms that fail on the self-test vs. those which are disabled in FIPS mode (not allowed). Both are marked as having failed the self-test. Recently the need arose to allow the usage of certain algorithms only as arguments to specific template instantiations in FIPS mode. For example, standalone "dh" must be blocked, but e.g. "ffdhe2048(dh)" is allowed. Other potential use cases include "cbcmac(aes)", which must only be used with ccm(), or "ghash", which must be used only for gcm(). This patch allows this scenario by adding a new flag FIPS_INTERNAL to indicate those algorithms that are not FIPS-allowed. They can then be used as template arguments only, i.e. when looked up via crypto_grab_spawn() to be more specific. The FIPS_INTERNAL bit gets propagated upwards recursively into the surrounding template instances, until the construction eventually matches an explicit testmgr entry with ->fips_allowed being set, if any. The behaviour to skip !->fips_allowed self-test executions in FIPS mode will be retained. Note that this effectively means that FIPS_INTERNAL algorithms are handled very similarly to the INTERNAL ones in this regard. It is expected that the FIPS_INTERNAL algorithms will receive sufficient testing when the larger constructions they're a part of, if any, get exercised by testmgr. Note that as a side-effect of this patch algorithms which are not FIPS-allowed will now return ENOENT instead of ELIBBAD. Hopefully this is not an issue as some people were relying on this already. Link: https://lore.kernel.org/r/YeEVSaMEVJb3cQkq@gondor.apana.org.au Originally-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Nicolai Stange <nstange@suse.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-02-21 13:10:58 +01:00
crypto: api - Fix generic algorithm self-test races On Fri, Aug 30, 2024 at 10:51:54AM -0700, Eric Biggers wrote: > > Given below in defconfig form, use 'make olddefconfig' to apply. The failures > are nondeterministic and sometimes there are different ones, for example: > > [ 0.358017] alg: skcipher: failed to allocate transform for cbc(twofish-generic): -2 > [ 0.358365] alg: self-tests for cbc(twofish) using cbc(twofish-generic) failed (rc=-2) > [ 0.358535] alg: skcipher: failed to allocate transform for cbc(camellia-generic): -2 > [ 0.358918] alg: self-tests for cbc(camellia) using cbc(camellia-generic) failed (rc=-2) > [ 0.371533] alg: skcipher: failed to allocate transform for xts(ecb(aes-generic)): -2 > [ 0.371922] alg: self-tests for xts(aes) using xts(ecb(aes-generic)) failed (rc=-2) > > Modules are not enabled, maybe that matters (I haven't checked yet). Yes I think that was the key. This triggers a massive self-test run which executes in parallel and reveals a few race conditions in the system. I think it boils down to the following scenario: Base algorithm X-generic, X-optimised Template Y Optimised algorithm Y-X-optimised Everything gets registered, and then the self-tests are started. When Y-X-optimised gets tested, it requests the creation of the generic Y(X-generic). Which then itself undergoes testing. The race is that after Y(X-generic) gets registered, but just before it gets tested, X-optimised finally finishes self-testing which then causes all spawns of X-generic to be destroyed. So by the time the self-test for Y(X-generic) comes along, it can no longer find the algorithm. This error then bubbles up all the way up to the self-test of Y-X-optimised which then fails. Note that there is some complexity that I've omitted here because when the generic self-test fails to find Y(X-generic) it actually triggers the construction of it again which then fails for various other reasons (these are not important because the construction should *not* be triggered at this point). So in a way the error is expected, and we should probably remove the pr_err for the case where ENOENT is returned for the algorithm that we're currently testing. The solution is two-fold. First when an algorithm undergoes self-testing it should not trigger its construction. Secondly if an instance larval fails to materialise due to it being destroyed by a more optimised algorithm coming along, it should obviously retry the construction. Remove the check in __crypto_alg_lookup that stops a larval from matching new requests based on differences in the mask. It is better to block new requests even if it is wrong and then simply retry the lookup. If this ends up being the wrong larval it will sort iself out during the retry. Reduce the CRYPTO_ALG_TYPE_MASK bits in type during larval creation as otherwise LSKCIPHER algorithms may not match SKCIPHER larvals. Also block the instance creation during self-testing in the function crypto_larval_lookup by checking for CRYPTO_ALG_TESTED in the mask field. Finally change the return value when crypto_alg_lookup fails in crypto_larval_wait to EAGAIN to redo the lookup. Fixes: 37da5d0ffa7b ("crypto: api - Do not wait for tests during registration") Reported-by: Eric Biggers <ebiggers@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2024-09-01 16:05:40 +08:00
crypto: api - Fix generic algorithm self-test races On Fri, Aug 30, 2024 at 10:51:54AM -0700, Eric Biggers wrote: > > Given below in defconfig form, use 'make olddefconfig' to apply. The failures > are nondeterministic and sometimes there are different ones, for example: > > [ 0.358017] alg: skcipher: failed to allocate transform for cbc(twofish-generic): -2 > [ 0.358365] alg: self-tests for cbc(twofish) using cbc(twofish-generic) failed (rc=-2) > [ 0.358535] alg: skcipher: failed to allocate transform for cbc(camellia-generic): -2 > [ 0.358918] alg: self-tests for cbc(camellia) using cbc(camellia-generic) failed (rc=-2) > [ 0.371533] alg: skcipher: failed to allocate transform for xts(ecb(aes-generic)): -2 > [ 0.371922] alg: self-tests for xts(aes) using xts(ecb(aes-generic)) failed (rc=-2) > > Modules are not enabled, maybe that matters (I haven't checked yet). Yes I think that was the key. This triggers a massive self-test run which executes in parallel and reveals a few race conditions in the system. I think it boils down to the following scenario: Base algorithm X-generic, X-optimised Template Y Optimised algorithm Y-X-optimised Everything gets registered, and then the self-tests are started. When Y-X-optimised gets tested, it requests the creation of the generic Y(X-generic). Which then itself undergoes testing. The race is that after Y(X-generic) gets registered, but just before it gets tested, X-optimised finally finishes self-testing which then causes all spawns of X-generic to be destroyed. So by the time the self-test for Y(X-generic) comes along, it can no longer find the algorithm. This error then bubbles up all the way up to the self-test of Y-X-optimised which then fails. Note that there is some complexity that I've omitted here because when the generic self-test fails to find Y(X-generic) it actually triggers the construction of it again which then fails for various other reasons (these are not important because the construction should *not* be triggered at this point). So in a way the error is expected, and we should probably remove the pr_err for the case where ENOENT is returned for the algorithm that we're currently testing. The solution is two-fold. First when an algorithm undergoes self-testing it should not trigger its construction. Secondly if an instance larval fails to materialise due to it being destroyed by a more optimised algorithm coming along, it should obviously retry the construction. Remove the check in __crypto_alg_lookup that stops a larval from matching new requests based on differences in the mask. It is better to block new requests even if it is wrong and then simply retry the lookup. If this ends up being the wrong larval it will sort iself out during the retry. Reduce the CRYPTO_ALG_TYPE_MASK bits in type during larval creation as otherwise LSKCIPHER algorithms may not match SKCIPHER larvals. Also block the instance creation during self-testing in the function crypto_larval_lookup by checking for CRYPTO_ALG_TESTED in the mask field. Finally change the return value when crypto_alg_lookup fails in crypto_larval_wait to EAGAIN to redo the lookup. Fixes: 37da5d0ffa7b ("crypto: api - Do not wait for tests during registration") Reported-by: Eric Biggers <ebiggers@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2024-09-01 16:05:40 +08:00
mm, treewide: rename kzfree() to kfree_sensitive() 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 <joe@perches.com> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: David Howells <dhowells@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Joe Perches <joe@perches.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: David Rientjes <rientjes@google.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: "Jason A . Donenfeld" <Jason@zx2c4.com> Link: http://lkml.kernel.org/r/20200616154311.12314-3-longman@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-06 23:18:13 -07:00