DNM: force jitter

[xnox]

• Force use jitter entropy in the FIPS 3.0.9 provider callback
  FIPS 3.0.9 provider does not honor runtime seed configuration, thus if
  one desires to use JITTER entropy source with FIPS 3.0.9 provider
  something like this needs to be applied to the core (libcrypto) build.

  Not sure if this is at all suitable for upstream.

This is backport of #25930 to codebase pre fips-jitter config option

[Sashan]

Thank you for PR and detailed analysis. To be honest I think @paulidale can provide better insight here. I could spot just few nits. But change seems to make sense to me.

[Sashan]

Thank you for PR. I wonder if should raise some error like we do in similar situation in ossl_rand_get_entropy().

[xnox]

True.

[paulidale]

This is an improvement, but we don't back port features which this is.

OTC: back port or not?

[Sashan]

I gave a try this pull request for 3.4 branch. It looks like some work is needed here, because the relevant changes delivered here are not being compiled. The compile time option which enables jitrer entroy is controlled by enable-fips-jitter compile time option. The option is adhered in master branch only, it is not recognized as compile time flag in 3.4 branch. So the code which delivers desired functionality is dead. see my test diff here:

diff --git a/crypto/provider_core.c b/crypto/provider_core.c
index e5e40d5e82..f4fc4104e8 100644
--- a/crypto/provider_core.c
+++ b/crypto/provider_core.c
@@ -2141,6 +2141,7 @@ static size_t rand_get_entropy(const OSSL_CORE_HANDLE *handle,
                                unsigned char **pout, int entropy,
                                size_t min_len, size_t max_len)
 {
+#error "We have some jitter"
     return ossl_rand_jitter_get_seed(pout, entropy, min_len, max_len);
 }
 # endif

compilation of 3.4 branch just succeeds with change above in.

[xnox]

@Sashan the conditional in this PR is OPENSSL_NO_JITTER

The conditional in the #25930 PR targetting master/3.5 is OPENSSL_NO_FIPS_JITTER

Are you reviewing matching code with matching PRs as they are indeed different and use different conditionals. Depending on the version of the core being compiled and the configure settings of the core.

[xnox]

I gave a try this pull request for 3.4 branch. It looks like some work is needed here, because the relevant changes delivered here are not being compiled. The compile time option which enables jitrer entroy is controlled by enable-fips-jitter compile time option. The option is adhered in master branch only, it is not recognized as compile time flag in 3.4 branch. So the code which delivers desired functionality is dead. see my test diff here:

diff --git a/crypto/provider_core.c b/crypto/provider_core.c
index e5e40d5e82..f4fc4104e8 100644
--- a/crypto/provider_core.c
+++ b/crypto/provider_core.c
@@ -2141,6 +2141,7 @@ static size_t rand_get_entropy(const OSSL_CORE_HANDLE *handle,
                                unsigned char **pout, int entropy,
                                size_t min_len, size_t max_len)
 {
+#error "We have some jitter"
     return ossl_rand_jitter_get_seed(pout, entropy, min_len, max_len);
 }
 # endif

compilation of 3.4 branch just succeeds with change above in.

Please see https://github.com/openssl/openssl/pull/25929/files#r1840610093

The exact test cases I use to test this functionality is gdb batch scripts that break on syscall_random function and jitter ones. Like so

  pipeline:
    - name: Verify only jitter entropy source is in use
      runs: |
        # Possibly python gdb would be easier to read
        cat <<EOF >openssl.gdb
        set pagination off
        set logging file gdb.log
        set logging on
        set width 0
        set height 0
        set verbose off
        set breakpoint pending on
        break get_jitter_random_value
        commands 1
          continue
        end
        break syscall_random
        commands 2
          continue
        end
        run rand -hex 8
        run genrsa -out /dev/null
        run ecparam -name prime256v1 -genkey
        run genpkey -algorithm ed25519
        EOF
        gdb --batch --command ./openssl.gdb openssl
        # Assert that jitter entropy is used
        grep -q 'Breakpoint 1,' gdb.log || exit 1
        # Assert that getrandom syscall wrapper is not used
        grep -q 'Breakpoint 2,' gdb.log && exit 1

[levitte]

OTC: no backport