Remove use of redc_helper in fuzzers

This runs into the same weird UbSan issue as in #1370

6 files changed, 48 insertions, 54 deletions

diff --git a/src/fuzzer/redc_helper.h b/src/fuzzer/redc_helper.h
deleted file mode 100644
index f08df3656..000000000
--- a/src/fuzzer/redc_helper.h
+++ /dev/null
@@ -1,34 +0,0 @@
-/*
-* (C) 2015,2016 Jack Lloyd
-*
-* Botan is released under the Simplified BSD License (see license.txt)
-*/
-
-#ifndef BOTAN_FUZZ_REDC_HELPERS_H_
-#define BOTAN_FUZZ_REDC_HELPERS_H_
-
-#include "fuzzers.h"
-#include <botan/reducer.h>
-#include <functional>
-
-namespace {
-
-void check_redc(std::function<void (Botan::BigInt&, Botan::secure_vector<Botan::word>&)> redc_fn,
-                const Botan::Modular_Reducer& redc,
-                const Botan::BigInt& prime,
-                const Botan::BigInt& x)
-   {
-   const Botan::BigInt v1 = x % prime;
-   const Botan::BigInt v2 = redc.reduce(x);
-
-   Botan::secure_vector<Botan::word> ws;
-   Botan::BigInt v3 = x;
-   redc_fn(v3, ws);
-
-   FUZZER_ASSERT_EQUAL(v1, v2);
-   FUZZER_ASSERT_EQUAL(v2, v3);
-   }
-
-}
-
-#endif
diff --git a/src/fuzzer/redc_p192.cpp b/src/fuzzer/redc_p192.cpp
index e1f7c753f..6898cdbb9 100644
--- a/src/fuzzer/redc_p192.cpp
+++ b/src/fuzzer/redc_p192.cpp
@@ -5,7 +5,7 @@
 */
 
 #include "fuzzers.h"
-#include "redc_helper.h"
+#include <botan/reducer.h>
 #include <botan/curve_nistp.h>
 
 void fuzz(const uint8_t in[], size_t len)
@@ -17,10 +17,15 @@ void fuzz(const uint8_t in[], size_t len)
    static const Botan::BigInt prime_2 = prime * prime;
    static Botan::Modular_Reducer prime_redc(prime);
 
-   Botan::BigInt x = Botan::BigInt::decode(in, len);
+   Botan::BigInt input = Botan::BigInt::decode(in, len);
 
-   if(x < prime_2)
+   if(input < prime_2)
       {
-      check_redc(Botan::redc_p192, prime_redc, prime, x);
+      const Botan::BigInt ref = prime_redc.reduce(input);
+
+      Botan::secure_vector<Botan::word> ws;
+      Botan::redc_p192(input, ws);
+
+      FUZZER_ASSERT_EQUAL(ref, input);
       }
    }
diff --git a/src/fuzzer/redc_p224.cpp b/src/fuzzer/redc_p224.cpp
index a8a4d5d72..b2dbac16e 100644
--- a/src/fuzzer/redc_p224.cpp
+++ b/src/fuzzer/redc_p224.cpp
@@ -5,19 +5,27 @@
 */
 
 #include "fuzzers.h"
-#include "redc_helper.h"
+#include <botan/reducer.h>
 #include <botan/curve_nistp.h>
 
 void fuzz(const uint8_t in[], size_t len)
    {
+   if(len > 2*224/8)
+      return;
+
    static const Botan::BigInt& prime = Botan::prime_p224();
    static const Botan::BigInt prime_2 = prime * prime;
    static Botan::Modular_Reducer prime_redc(prime);
 
-   Botan::BigInt x = Botan::BigInt::decode(in, len);
+   Botan::BigInt input = Botan::BigInt::decode(in, len);
 
-   if(x < prime_2)
+   if(input < prime_2)
       {
-      check_redc(Botan::redc_p224, prime_redc, prime, x);
+      const Botan::BigInt ref = prime_redc.reduce(input);
+
+      Botan::secure_vector<Botan::word> ws;
+      Botan::redc_p224(input, ws);
+
+      FUZZER_ASSERT_EQUAL(ref, input);
       }
    }
diff --git a/src/fuzzer/redc_p256.cpp b/src/fuzzer/redc_p256.cpp
index b8d78e7bb..4c3809f08 100644
--- a/src/fuzzer/redc_p256.cpp
+++ b/src/fuzzer/redc_p256.cpp
@@ -5,7 +5,7 @@
 */
 
 #include "fuzzers.h"
-#include "redc_helper.h"
+#include <botan/reducer.h>
 #include <botan/curve_nistp.h>
 
 void fuzz(const uint8_t in[], size_t len)
@@ -17,10 +17,15 @@ void fuzz(const uint8_t in[], size_t len)
    static const Botan::BigInt prime_2 = prime * prime;
    static Botan::Modular_Reducer prime_redc(prime);
 
-   Botan::BigInt x = Botan::BigInt::decode(in, len);
+   Botan::BigInt input = Botan::BigInt::decode(in, len);
 
-   if(x < prime_2)
+   if(input < prime_2)
       {
-      check_redc(Botan::redc_p256, prime_redc, prime, x);
+      const Botan::BigInt ref = prime_redc.reduce(input);
+
+      Botan::secure_vector<Botan::word> ws;
+      Botan::redc_p256(input, ws);
+
+      FUZZER_ASSERT_EQUAL(ref, input);
       }
    }
diff --git a/src/fuzzer/redc_p384.cpp b/src/fuzzer/redc_p384.cpp
index 35e3ccfee..1c3a777a0 100644
--- a/src/fuzzer/redc_p384.cpp
+++ b/src/fuzzer/redc_p384.cpp
@@ -5,7 +5,7 @@
 */
 
 #include "fuzzers.h"
-#include "redc_helper.h"
+#include <botan/reducer.h>
 #include <botan/curve_nistp.h>
 
 void fuzz(const uint8_t in[], size_t len)
@@ -17,10 +17,15 @@ void fuzz(const uint8_t in[], size_t len)
    static const Botan::BigInt prime_2 = prime * prime;
    static Botan::Modular_Reducer prime_redc(prime);
 
-   Botan::BigInt x = Botan::BigInt::decode(in, len);
+   Botan::BigInt input = Botan::BigInt::decode(in, len);
 
-   if(x < prime_2)
+   if(input < prime_2)
       {
-      check_redc(Botan::redc_p384, prime_redc, prime, x);
+      const Botan::BigInt ref = prime_redc.reduce(input);
+
+      Botan::secure_vector<Botan::word> ws;
+      Botan::redc_p384(input, ws);
+
+      FUZZER_ASSERT_EQUAL(ref, input);
       }
    }
diff --git a/src/fuzzer/redc_p521.cpp b/src/fuzzer/redc_p521.cpp
index c6c5d262b..e148c94bb 100644
--- a/src/fuzzer/redc_p521.cpp
+++ b/src/fuzzer/redc_p521.cpp
@@ -5,7 +5,7 @@
 */
 
 #include "fuzzers.h"
-#include "redc_helper.h"
+#include <botan/reducer.h>
 #include <botan/curve_nistp.h>
 
 void fuzz(const uint8_t in[], size_t len)
@@ -17,10 +17,15 @@ void fuzz(const uint8_t in[], size_t len)
    static const Botan::BigInt prime_2 = prime * prime;
    static Botan::Modular_Reducer prime_redc(prime);
 
-   Botan::BigInt x = Botan::BigInt::decode(in, len);
+   Botan::BigInt input = Botan::BigInt::decode(in, len);
 
-   if(x < prime_2)
+   if(input < prime_2)
       {
-      check_redc(Botan::redc_p521, prime_redc, prime, x);
+      const Botan::BigInt ref = prime_redc.reduce(input);
+
+      Botan::secure_vector<Botan::word> ws;
+      Botan::redc_p521(input, ws);
+
+      FUZZER_ASSERT_EQUAL(ref, input);
       }
    }