ffc/ffc_params_generate.c: Add the check for the EVP_MD_get_size()

Add the check for the EVP_MD_get_size() to avoid invalid negative numbers.

Fixes: 4f2271d ("Add ACVP fips module tests")
Signed-off-by: Jiasheng Jiang <jiasheng@purdue.edu>

Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from #23970)

crypto/ffc/ffc_params_generate.c

@@ -814,6 +814,7 @@ int ossl_ffc_params_FIPS186_2_gen_verify(OSSL_LIB_CTX *libctx,
     BIGNUM *r0, *test, *tmp, *g = NULL, *q = NULL, *p = NULL;
     BN_MONT_CTX *mont = NULL;
     EVP_MD *md = NULL;
+    int md_size;
     size_t qsize;
     int n = 0, m = 0;
     int counter = 0, pcounter = 0, use_random_seed;
@@ -842,8 +843,11 @@ int ossl_ffc_params_FIPS186_2_gen_verify(OSSL_LIB_CTX *libctx,
     }
     if (md == NULL)
         goto err;
+    md_size = EVP_MD_get_size(md);
+    if (md_size <= 0)
+        goto err;
     if (N == 0)
-        N = EVP_MD_get_size(md) * 8;
+        N = md_size * 8;
     qsize = N >> 3;
 
     /*