crypto: testmgr - reinstate kconfig control over full self-tests

Commit 698de822780f ("crypto: testmgr - make it easier to enable the
full set of tests") removed support for building kernels that run only
the "fast" set of crypto self-tests by default.  This assumed that
nearly everyone actually wanted the full set of tests, *if* they had
already chosen to enable the tests at all.

Unfortunately, it turns out that both Debian and Fedora intentionally
have the crypto self-tests enabled in their production kernels.  And for
production kernels we do need to keep the testing time down, which
implies just running the "fast" tests, not the full set of tests.

For Fedora, a reason for enabling the tests in production is that they
are being (mis)used to meet the FIPS 140-3 pre-operational testing
requirement.

However, the other reason for enabling the tests in production, which
applies to both distros, is that they provide some value in protecting
users from buggy drivers.  Unfortunately, the crypto/ subsystem has many
buggy and untested drivers for off-CPU hardware accelerators on rare
platforms.  These broken drivers get shipped to users, and there have
been multiple examples of the tests preventing these buggy drivers from
being used.  So effectively, the tests are being relied on in production
kernels.  I think this is kind of crazy (untested drivers should just
not be enabled at all), but that seems to be how things work currently.

Thus, reintroduce a kconfig option that controls the level of testing.
Call it CRYPTO_SELFTESTS_FULL instead of the original name
CRYPTO_MANAGER_EXTRA_TESTS, which was slightly misleading.

Moreover, given the "production kernel" use case, make CRYPTO_SELFTESTS
depend on EXPERT instead of DEBUG_KERNEL.

I also haven't reinstated all the #ifdefs in crypto/testmgr.c.  Instead,
just rely on the compiler to optimize out unused code.

Fixes: 40b9969796bf ("crypto: testmgr - replace CRYPTO_MANAGER_DISABLE_TESTS with CRYPTO_SELFTESTS")
Fixes: 698de822780f ("crypto: testmgr - make it easier to enable the full set of tests")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 12 insertions, 3 deletions

diff --git a/crypto/testmgr.c b/crypto/testmgr.c
index 72005074a5c2..32f753d6c430 100644
--- a/crypto/testmgr.c
+++ b/crypto/testmgr.c
@@ -45,6 +45,7 @@ static bool notests;
 module_param(notests, bool, 0644);
 MODULE_PARM_DESC(notests, "disable all crypto self-tests");
 
+#ifdef CONFIG_CRYPTO_SELFTESTS_FULL
 static bool noslowtests;
 module_param(noslowtests, bool, 0644);
 MODULE_PARM_DESC(noslowtests, "disable slow crypto self-tests");
@@ -52,6 +53,10 @@ MODULE_PARM_DESC(noslowtests, "disable slow crypto self-tests");
 static unsigned int fuzz_iterations = 100;
 module_param(fuzz_iterations, uint, 0644);
 MODULE_PARM_DESC(fuzz_iterations, "number of fuzz test iterations");
+#else
+#define noslowtests 1
+#define fuzz_iterations 0
+#endif
 
 #ifndef CONFIG_CRYPTO_SELFTESTS
 
@@ -319,9 +324,9 @@ struct testvec_config {
 
 /*
  * The following are the lists of testvec_configs to test for each algorithm
- * type when the fast crypto self-tests are enabled.  They aim to provide good
- * test coverage, while keeping the test time much shorter than the full tests
- * so that the fast tests can be used to fulfill FIPS 140 testing requirements.
+ * type when the "fast" crypto self-tests are enabled.  They aim to provide good
+ * test coverage, while keeping the test time much shorter than the "full" tests
+ * so that the "fast" tests can be enabled in a wider range of circumstances.
  */
 
 /* Configs for skciphers and aeads */
@@ -1183,14 +1188,18 @@ static void generate_random_testvec_config(struct rnd_state *rng,
 
 static void crypto_disable_simd_for_test(void)
 {
+#ifdef CONFIG_CRYPTO_SELFTESTS_FULL
 	migrate_disable();
 	__this_cpu_write(crypto_simd_disabled_for_test, true);
+#endif
 }
 
 static void crypto_reenable_simd_for_test(void)
 {
+#ifdef CONFIG_CRYPTO_SELFTESTS_FULL
 	__this_cpu_write(crypto_simd_disabled_for_test, false);
 	migrate_enable();
+#endif
 }
 
 /*