Merge pull request 'feat/impl-2' (#5) from feat/impl-2 into master

Reviewed-on: https://gitlab-gepasp.in.tum.de/gra22s/team199/pulls/5
Reviewed-by: Thomas Florian <thomas.florian@tum.de>

Implementierung/Makefile

@@ -1,6 +1,6 @@
 
 
-SRC = src/main.c src/helper.c src/io.c src/md2.c src/md2_impls/md2_common.c src/md2_impls/md2_0.c
+SRC = src/main.c src/helper.c src/io.c src/md2.c src/md2_impls/md2_common.c src/md2_impls/md2_0.c src/md2_impls/md2_2.c
 OBJ = ${subst src,build,${SRC:.c=.o}}
 CC = gcc
 CFLAGS = -Ilib -ggdb -std=c11 -g -Wall -Wextra -no-pie -O3

Implementierung/lib/io.h

@@ -10,6 +10,17 @@
 #include <stdlib.h>
 #include <sys/stat.h>
 
+/**
+ * @brief Open a file and load its stats
+ *
+ * @param path the filepath
+ * @param file where the pointer of the file handle should be stored
+ * @param file_stat pointer to a stat struct
+ * @return true it worked
+ * @return false there was an error
+ */
+bool open_file(const char* path, FILE** file, struct stat* file_stat);
+
 /**
  * @brief reads a file at a path
  *

Implementierung/lib/md2_impls/md2_2.h

@@ -0,0 +1,23 @@
+#ifndef MD2_2_H
+#define MD2_2_H
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+
+#include "../io.h"
+
+/**
+ * @brief This implementation loads the file in bits and not at once
+ *
+ * @param _ unused
+ * @param filename name of the file to load
+ * @param out
+ */
+void md2_hash_2(size_t len, const uint8_t buf[len], uint8_t out[16]);
+void md2_checksum_2(size_t len, uint8_t* buf);
+
+#endif  // MD2_2_H

Implementierung/src/io.c

@@ -1,26 +1,35 @@
 #include "../lib/io.h"
 
+bool open_file(const char* path, FILE** file, struct stat* file_stat) {
+  (*file) = fopen(path, "r");
+  if ((*file) == NULL) {
+    if (errno == 0) errno = EIO;
+    return false;
+  }
+
+  int status = fstat(fileno((*file)), file_stat);
+  if (status == -1) {
+    if (errno == 0) errno = EIO;
+    fclose((*file));
+    return false;
+  };
+
+  if ((file_stat->st_mode & S_IFMT) != S_IFREG) {
+    printf("File is not a regular file!\n");
+    errno = ENOENT;
+    fclose((*file));
+    return false;
+  }
+
+  return true;
+}
+
 uint8_t* read_file(const char* path, size_t* size) {
   // Read the contents of the file specified by path into a heap-allocated
   // buffer and return a pointer to that buffer.
-  FILE* f = fopen(path, "r");
-  if (f == NULL) {
-    printf("Fopen error: %d\n", errno);
-    fclose(f);
-    return NULL;
-  }
-
+  FILE* f;
   struct stat statOfFile;
-  int status = fstat(fileno(f), &statOfFile);
-  if (status == -1) {
-    printf("Fstat error: %d\n", errno);
-    fclose(f);
-    return NULL;
-  };
-
-  if ((statOfFile.st_mode & S_IFMT) != S_IFREG) {
-    printf("File is not a regular file!\n");
-    fclose(f);
+  if (!open_file(path, &f, &statOfFile)) {
     return NULL;
   }
 
@@ -30,8 +39,8 @@ uint8_t* read_file(const char* path, size_t* size) {
       fread(data, statOfFile.st_blksize, statOfFile.st_blocks, f);
   // size_t bytesRead = fread(data, sizeof(uint8_t), statOfFile.st_size, f);
   if (bytesRead != 0 && !feof(f)) {
-    printf("Error reading file!\n");
     fclose(f);
+    if (errno == 0) errno = EIO;
     return NULL;
   }
 

Implementierung/src/main.c

@@ -62,6 +62,43 @@ unsigned runTests(struct configuration* c) {
   return failed;
 }
 
+bool calculate_hash(struct configuration c, char* hash) {
+  size_t len;
+  uint8_t* data;
+
+  if (c.implementationToUse != 2) {
+    data = read_file(c.filename, &len);
+  } else {
+    data = (uint8_t*)c.filename;
+    len = 0;
+  }
+
+  if (data == NULL) {
+    printf("Error reading file %s!\n", c.filename);
+    return false;
+  }
+
+  errno = 0;
+  uint8_t out[16];
+  if (c.doBenchmark) {
+    double duration =
+        run_benchmark(c.benchmarkingCycles, md2_hash, len, data, out);
+    printf("Running %d cycles took %f seconds\n", c.benchmarkingCycles,
+           duration);
+  } else {
+    md2_hash(len, data, out);
+  }
+
+  if (errno != 0) {
+    return false;
+  }
+
+  md2_encode_hash(out, hash);
+
+  if (c.implementationToUse != 2) free(data);
+  return true;
+}
+
 int main(int argc, char** argv) {
   struct configuration c;
   enum argumentParseResult result = parseArguments(argc, argv, &c);
@@ -87,33 +124,27 @@ int main(int argc, char** argv) {
       "benchmark cycles: %d\n",
       c.implementationToUse, c.doBenchmark, c.benchmarkingCycles);
 
+  if (c.runTests && c.implementationToUse == 2) {
+    fprintf(stderr, "Cannot run tests on implementation 2!\n");
+    return EXIT_FAILURE;
+  }
+
   if (c.runTests) {
     printf("Running tests...\n\n");
     return runTests(&c);
   }
 
   printf("Hashing file %s...\n\n", c.filename);
-  size_t len;
-  uint8_t* data = read_file(c.filename, &len);
-  if (data == NULL) {
-    printf("Error reading file %s!", c.filename);
+
+  char hash[32];
+  if (!calculate_hash(c, hash)) {
+    if (errno != 0) {
+      fprintf(stderr, "\n\033[0;31mAn error occured: %s\033[0m\n",
+              strerror(errno));
+    }
     return EXIT_FAILURE;
   }
-
-  uint8_t out[16];
-  char hash[32];
-  if (c.doBenchmark) {
-    double duration =
-        run_benchmark(c.benchmarkingCycles, md2_hash, len, data, out);
-    printf("Running %d cycles took %f seconds\n", c.benchmarkingCycles,
-           duration);
-  } else {
-    md2_hash(len, data, out);
-  }
-  md2_encode_hash(out, hash);
   printf("Hash: %s\n", hash);
 
-  free(data);
-
-  return 0;
+  return EXIT_SUCCESS;
 }

Implementierung/src/md2.c

@@ -2,6 +2,7 @@
 
 // include all implementations
 #include "../lib/md2_impls/md2_0.h"
+#include "../lib/md2_impls/md2_2.h"
 
 md2_hash_func md2_hash;
 md2_checksum_func md2_checksum;
@@ -22,6 +23,11 @@ bool md2_choose_implementation(int i) {
       md2_checksum = md2_checksum_0;
       return true;
 
+    case 2:
+      md2_hash = md2_hash_2;
+      md2_checksum = md2_checksum_2;
+      return true;
+
     default:
       return false;
   }

Implementierung/src/md2_impls/md2_2.c

@@ -0,0 +1,89 @@
+#include "../../lib/md2_impls/md2_2.h"
+
+#include "../../lib/md2_impls/md2_common.h"
+
+void process_block_hash(uint8_t block[16], uint8_t messageDigestBuf[48]) {
+  for (int j = 0; j < 16; j++) {
+    messageDigestBuf[16 + j] = block[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 = messageDigestBuf[k] = messageDigestBuf[k] ^ MD2_PI_SUBST[t];
+    }
+    t = (t + j) % 256;
+  }
+}
+
+void process_block_checksum(uint8_t block[16], uint8_t checksum[16],
+                            uint8_t* l) {
+  for (int j = 0; j < 16; j++) {
+    u_int8_t c = block[j];
+    // reference is wrong. It says: Set C[j] to S[c xor L]. But it should be:
+    (*l) = checksum[j] ^= MD2_PI_SUBST[c ^ (*l)];
+  }
+}
+
+void apply_padding(size_t len, uint8_t buf[16]) {
+  int paddingNeeded = 16 - (len % 16);
+  uint8_t originalPadding = paddingNeeded;
+  len += paddingNeeded;
+
+  while (paddingNeeded > 0) {
+    buf[len - paddingNeeded] = originalPadding;
+    paddingNeeded--;
+  }
+}
+
+// unused!
+void md2_checksum_2(size_t, uint8_t*) {}
+
+void md2_hash_2(size_t len, const uint8_t buf[len], uint8_t out[16]) {
+  FILE* file;
+  struct stat file_stat;
+  if (!open_file((char*)buf, &file, &file_stat)) {
+    return;
+  }
+
+  // === step 3 ===
+  uint8_t* messageDigestBuf = calloc(48, sizeof(uint8_t));
+
+  // === step 4 ===
+  uint8_t l = 0;
+  uint8_t* checksum = calloc(16, sizeof(uint8_t));
+
+  uint8_t* data = malloc(16);
+  size_t bytes_left_to_read = file_stat.st_size;
+  size_t bytes_left_to_process = 0;
+
+  while (bytes_left_to_read != 0) {
+    bytes_left_to_process = bytes_left_to_read >= 16 ? 16 : bytes_left_to_read;
+
+    fread(data, 1, bytes_left_to_process, file);
+    if (ferror(file) || feof(file)) {
+      if (errno == 0) errno = EIO;
+      return;
+    }
+
+    process_block_checksum(data, checksum, &l);
+    process_block_hash(data, messageDigestBuf);
+
+    bytes_left_to_read -= bytes_left_to_process;
+  };
+
+  fclose(file);
+
+  apply_padding(bytes_left_to_process % 16, data);
+  process_block_checksum(data, checksum, &l);
+  process_block_hash(data, messageDigestBuf);
+
+  process_block_hash(checksum, messageDigestBuf);
+  memcpy(out, messageDigestBuf, 16);
+
+  free(data);
+  free(messageDigestBuf);
+  free(checksum);
+}