fips-jitter: 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.

With fips-jitter (3.5+) config, also ensure that core<->provider
callback for entropy uses jitter entropy source, rather than os seed
(getrandom syscall).

Reviewed-by: Neil Horman <nhorman@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Paul Dale <ppzgs1@gmail.com>
(Merged from https://github.com/openssl/openssl/pull/25930)

crypto/provider_core.c

@@ -2421,6 +2421,7 @@ static void core_self_test_get_callback(OPENSSL_CORE_CTX *libctx,
     OSSL_SELF_TEST_get_callback((OSSL_LIB_CTX *)libctx, cb, cbarg);
 }
 
+# ifdef OPENSSL_NO_FIPS_JITTER
 static size_t rand_get_entropy(const OSSL_CORE_HANDLE *handle,
                                unsigned char **pout, int entropy,
                                size_t min_len, size_t max_len)
@@ -2428,6 +2429,31 @@ static size_t rand_get_entropy(const OSSL_CORE_HANDLE *handle,
     return ossl_rand_get_entropy((OSSL_LIB_CTX *)core_get_libctx(handle),
                                  pout, entropy, min_len, max_len);
 }
+# else
+/*
+ * OpenSSL FIPS providers prior to 3.2 call rand_get_entropy API from
+ * core, instead of the newer get_user_entropy. Newer API call honors
+ * runtime configuration of random seed source and can be configured
+ * to use os getranom() or another seed source, such as
+ * JITTER. However, 3.0.9 only calls this API. Note that no other
+ * providers known to use this, and it is core <-> provider only
+ * API. Public facing EVP and getrandom bytes already correctly honor
+ * runtime configuration for seed source. There are no other providers
+ * packaged in Wolfi, or even known to exist that use this api. Thus
+ * it is safe to say any caller of this API is in fact 3.0.9 FIPS
+ * provider. Also note that the passed in handle is invalid and cannot
+ * be safely dereferences in such cases. Due to a bug in FIPS
+ * providers 3.0.0, 3.0.8 and 3.0.9. See
+ * https://github.com/openssl/openssl/blob/master/doc/internal/man3/ossl_rand_get_entropy.pod#notes
+ */
+size_t ossl_rand_jitter_get_seed(unsigned char **, int, size_t, size_t);
+static size_t rand_get_entropy(const OSSL_CORE_HANDLE *handle,
+                               unsigned char **pout, int entropy,
+                               size_t min_len, size_t max_len)
+{
+    return ossl_rand_jitter_get_seed(pout, entropy, min_len, max_len);
+}
+# endif
 
 static size_t rand_get_user_entropy(const OSSL_CORE_HANDLE *handle,
                                     unsigned char **pout, int entropy,

providers/implementations/rands/seed_src_jitter.c

@@ -295,6 +295,22 @@ static size_t jitter_get_seed(void *vseed, unsigned char **pout,
     return ret;
 }
 
+size_t ossl_rand_jitter_get_seed(unsigned char **pout, int entropy, size_t min_len, size_t max_len)
+{
+    size_t ret = 0;
+    OSSL_PARAM params[1] = { OSSL_PARAM_END };
+    PROV_JITTER *s = jitter_new(NULL, NULL, NULL);
+
+    if (s == NULL)
+        return ret;
+    if (!jitter_instantiate(s, 0, 0, NULL, 0, params))
+        goto end;
+    ret = jitter_get_seed(s, pout, entropy, min_len, max_len, 0, NULL, 0);
+ end:
+    jitter_free(s);
+    return ret;
+}
+
 static void jitter_clear_seed(ossl_unused void *vdrbg,
                               unsigned char *out, size_t outlen)
 {