From 8d171fe0c6a981e8829a72dbb4802c36f43096c4 Mon Sep 17 00:00:00 2001
From: Thomas Florian <thomas.florian@tum.de>
Date: Tue, 19 Jul 2022 23:07:05 +0200
Subject: [PATCH] fix: correct hash calculation on V3

---
 Implementierung/src/md2_impls/md2_3.c | 97 +++++++++++----------------
 1 file changed, 38 insertions(+), 59 deletions(-)

diff --git a/Implementierung/src/md2_impls/md2_3.c b/Implementierung/src/md2_impls/md2_3.c
index d3c332f..c8334be 100644
--- a/Implementierung/src/md2_impls/md2_3.c
+++ b/Implementierung/src/md2_impls/md2_3.c
@@ -2,16 +2,9 @@
 
 #include "../../lib/md2_impls/md2_common.h"
 
-struct arg_hash {
+struct thread_args {
   size_t len;
   const uint8_t* buf;
-  uint8_t messageDigestBuf[48];
-};
-
-struct arg_checksum {
-  size_t len;
-  uint8_t* buf;
-  uint8_t checksum[16];
 };
 
 void process_nothread_hash(size_t len, uint8_t buf[len],
@@ -34,49 +27,57 @@ void process_nothread_hash(size_t len, uint8_t buf[len],
   }
 }
 
-void* process_hash(void* args) {
-  struct arg_hash* arg = (struct arg_hash*)args;
-  printf("process_hash: %zu\n", arg->len);
-  for (size_t i = 0; i < (arg->len + 16) / 16 - 1; i++) {
+void* process_hash(void* threadArgs) {
+  struct thread_args* args = (struct thread_args*)threadArgs;
+
+  uint8_t* messageDigestBuf = calloc(48, sizeof(uint8_t));
+  if (messageDigestBuf == NULL) {
+    return;
+  }
+
+  for (size_t i = 0; i < (args->len + 16) / 16 - 1; i++) {
     for (int j = 0; j < 16; j++) {
-      arg->messageDigestBuf[16 + j] = arg->buf[i * 16 + j];
-      arg->messageDigestBuf[32 + j] =
-          (arg->messageDigestBuf[16 + j] ^ arg->messageDigestBuf[j]);
+      messageDigestBuf[16 + j] = args->buf[i * 16 + j];
+      messageDigestBuf[32 + j] =
+          (messageDigestBuf[16 + j] ^ messageDigestBuf[j]);
     }
 
     u_int8_t t = 0;
 
     for (int j = 0; j < 18; j++) {
       for (int k = 0; k < 48; k++) {
-        t = arg->messageDigestBuf[k] =
-            arg->messageDigestBuf[k] ^ MD2_PI_SUBST[t];
+        t = messageDigestBuf[k] = messageDigestBuf[k] ^ MD2_PI_SUBST[t];
       }
       t = (t + j) % 256;
     }
   }
-  md2_print_buf(48, arg->messageDigestBuf);
-  pthread_exit(NULL);
+  pthread_exit(messageDigestBuf);
 }
 
-void* process_checksum(void* args) {
-  struct arg_checksum* arg = (struct arg_checksum*)args;
+void* process_checksum(void* threasdArgs) {
+  struct thread_args* args = (struct thread_args*)threasdArgs;
+
+  uint8_t* checksum = calloc(16, sizeof(uint8_t));
+  if (checksum == NULL) {
+    return;
+  }
+
   uint8_t l = 0;
 
-  for (size_t i = 0; i < arg->len / 16; i++) {
+  for (size_t i = 0; i < args->len / 16; i++) {
     for (int j = 0; j < 16; j++) {
-      u_int8_t c = arg->buf[i * 16 + j];
+      u_int8_t c = args->buf[i * 16 + j];
       // reference is wrong. It says: Set C[j] to S[c xor L]. But it should be:
-      l = arg->checksum[j] ^= MD2_PI_SUBST[c ^ l];
+      l = checksum[j] ^= MD2_PI_SUBST[c ^ l];
     }
   }
-  pthread_exit(&arg->checksum);
+  pthread_exit(checksum);
 }
 
 // unused!
 void md2_checksum_3(size_t _, uint8_t* __) {}
 
 void md2_hash_3(size_t len, const uint8_t buf[len], uint8_t out[16]) {
-  // === step 1 ===
   int paddingNeeded = 16 - (len % 16);
   uint8_t originalPadding = paddingNeeded;
   len += paddingNeeded;
@@ -93,57 +94,35 @@ void md2_hash_3(size_t len, const uint8_t buf[len], uint8_t out[16]) {
     paddingNeeded--;
   }
 
-  // === step 3 ===
-  uint8_t* messageDigestBuf = calloc(48, sizeof(uint8_t));
-  if (messageDigestBuf == NULL) {
-    return;
-  }
-
-  // === step 4 ===
-  uint8_t* checksum = calloc(16, sizeof(uint8_t));
-  if (checksum == NULL) {
-    return;
-  }
-
   pthread_t thread_1, thread_2;
 
-  struct arg_hash arg_1 = {len, newBuf, messageDigestBuf};
-  struct arg_checksum arg_2 = {len, newBuf, checksum};
+  struct thread_args thread_args = {len, newBuf};
 
-  if (pthread_create(&thread_1, NULL, process_hash, (void*)&arg_1) != 0) {
+  if (pthread_create(&thread_1, NULL, process_hash, (void*)&thread_args) != 0) {
     printf("Error creating thread 1\n");
     exit(EXIT_FAILURE);
   }
-  if (pthread_create(&thread_2, NULL, process_checksum, (void*)&arg_2) != 0) {
+  if (pthread_create(&thread_2, NULL, process_checksum, (void*)&thread_args) !=
+      0) {
     printf("Error creating thread 2\n");
     exit(EXIT_FAILURE);
   }
 
-  if (pthread_join(thread_1, NULL) != 0) {
+  u_int8_t* messageDigestBuf;
+  u_int8_t* checksum;
+
+  if (pthread_join(thread_1, (void**)&messageDigestBuf) != 0) {
     printf("Error joining thread 1\n");
     exit(EXIT_FAILURE);
   }
-  if (pthread_join(thread_2, NULL) != 0) {
+  if (pthread_join(thread_2, (void**)&checksum) != 0) {
     printf("Error joining thread 2\n");
     exit(EXIT_FAILURE);
   }
 
-  md2_print_buf(48, arg_1.messageDigestBuf);
-  // md2_print_buf(16, checksum);
+  process_nothread_hash(16, checksum, messageDigestBuf);
+  memcpy(out, messageDigestBuf, 16);
 
-  // struct arg_hash arg_last = {16, checksum, messageDigestBuf};
-
-  process_nothread_hash(16, arg_2.checksum, arg_1.messageDigestBuf);
-  // md2_print_buf(16, messageDigestBuf);
-  memcpy(out, arg_1.messageDigestBuf, 16);
-
-  // free(data);
   free(messageDigestBuf);
   free(checksum);
-
-  // process_block_checksum(data, checksum, &l);
-  // process_block_hash(data, messageDigestBuf);
-
-  // process_block_checksum(data, checksum, &l);
-  // process_block_hash(data, messageDigestBuf);
 }