Rewrite the patcher in C (but properly this time)

patcher/patcher.c

@@ -0,0 +1,119 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <stdlib.h>
+
+#define INPUT_EXE_HASH              (uint32_t)(0xE220C635)
+#define OUTPUT_EXE_HASH             (uint32_t)(0xE5E5AF0C)
+#define OUTPUT_EXE_SUFFIX           (const char*)".patched.exe"
+#define OUTPUT_EXE_SUFFIX_SIZE      strlen(OUTPUT_EXE_SUFFIX)
+
+#define PATCH_BLOB_SIZE             (sizeof(PATCH_BLOB_INFO))
+#define PATCH_BLOB_INFO_SIZE        (sizeof(blobs))
+#define PATCH_GET_COUNT(b)          (PATCH_BLOB_INFO_SIZE/PATCH_BLOB_SIZE)
+#define PATCH_APPLY_BLOB(b,d,pb)    memcpy(&d[b.offset], &pb[b.pos], b.size)
+
+typedef struct
+{
+    uint32_t offset;
+    uint32_t pos;
+    uint32_t size;
+} PATCH_BLOB_INFO;
+
+const uint8_t patch_blob[] = {
+    0xC3,
+    0x48,0x89,0x5C,0x24,0x08,0x48,0x89,0x74,0x24,0x10,0x48,0x89,0x7C,0x24,0x18,0x65,0x48,0x8B,0x04,0x25,0x60,
+    0x00,0x00,0x48,0x8B,0x40,0x18,0x48,0x8B,0x40,0x10,0x48,0x8B,0x48,0x60,0x41,0xBA,0xDB,0xB2,0x46,0xA1,0x0F,0xB7,0x50,0x58,0x48,0xD1,0xEA,0x4C,0x8D,0x1C,0x51,0x49,0x3B,0xCB,0x74,0x39,0x66,0x0F,0x1F,0x44,0x00,0x00,0x0F,0xBE,0x11,0x44,0x8B,0xC2,0x80,0xEA,0x41,0x45,0x8B,0xC8,0x41,0x83,0xC9,0x20,0x80,0xFA,0x19,0x45,0x0F,0x47,0xC8,0x48,0x83,0xC1,0x02,0x45,0x33,0xCA,0x45,0x69,0xD1,0x93,0x01,0x00,0x01,0x49,0x3B,0xCB,0x75,0xD6,0x41,0x81,0xFA,0x39,0x48,0xEF,0xAA,0x74,0x05,
+    0x8B,0x00,0xEB,0xA8,0x4C,0x8B,0x58,0x30,0x45,0x33,0xD2,0x49,0x63,0x43,0x3C,0x42,0x8B,0xBC,0x18,0x88,0x00,0x00,0x00,0x42,0x8B,0x74,0x1F,0x20,0x4A,0x8D,0x04,0x96,0x41,0xB9,0x48,0xB1,0x46,0xA0,0x42,0x8B,0x14,0x18,0x49,0x03,0xD3,0x44,0x0F,0xB6,0x02,0x48,0xFF,0xC2,
+    0x84,0xC0,0x74,0x38,0x0F,0x1F,0x00,0x41,0x0F,0xBE,0xC0,0x48,0x8D,0x52,0x01,0x41,0x80,0xE8,0x41,0x8B,0xC8,0x83,0xC9,0x20,0x41,0x80,0xF8,0x19,0x44,0x0F,0xB6,0x42,0xFF,0x0F,0x47,0xC8,0x41,0x33,0xC9,0x44,0x69,0xC9,0x93,0x01,
+    0x01,0x45,0x84,0xC0,0x75,0xD4,0x41,0x81,0xF9,0x0A,0x55,0xC7,0x64,0x74,0x05,0x41,0xFF,0xC2,0xEB,0xA6,0x42,0x8B,0x4C,
+    0x24,0x48,0x8B,0x5C,0x24,0x08,
+    0x03,0xCB,0x48,0x8B,0x74,0x24,0x10,0x42,0x0F,0xB7,0x14,0x51,0x42,0x8B,0x4C,0x1F,0x1C,0x48,0x8B,0x7C,0x24,0x18,0x49,0x03,0xCB,
+    0x04,0x91,0x49,0x03,0xC3,0x48,0x8D,0x0D,0x02,0x00,0x00,
+    0xFF,0xE0,0x69,0x6E,0x6A,0x65,0x63,0x74,0x2E,0x64,0x6C,0x6C,0x00
+};
+
+PATCH_BLOB_INFO blobs[] = {
+    {0x113C110, 0, 1},
+    {0x137E000, 1, 21},
+    {0x137E016, 22, 93},
+    {0x137E074, 115, 52},
+    {0x137E0A9, 167, 44},
+    {0x137E0D6, 211, 23},
+    {0x137E0EE, 234, 6},
+    {0x137E0F5, 240, 25},
+    {0x137E10F, 265, 11},
+    {0x137E11B, 276, 13}
+};
+
+void print_usage(char* program_name)
+{
+    printf("Usage:\n");
+    printf("    %s <path/to/GameClientApp.exe>\n", program_name);
+    printf("    CRC32 of unpatched exe: %08x\n", INPUT_EXE_HASH);
+    printf("    CRC32 of patched exe: %08x\n", OUTPUT_EXE_HASH);
+}
+
+int main(int argc, char** argv)
+{
+    if(argc == 1)
+    {
+        print_usage(argv[0]);
+        return 0;
+    }
+
+    /* Read the file */
+    FILE* fog = fopen(argv[1], "rb");
+
+    if(fog == NULL)
+    {
+        print_usage(argv[0]);
+        return 0;
+    }
+
+    uint32_t inexe_size = 0;
+    uint8_t* inexe_data = NULL;
+
+    fseek(fog, 0, SEEK_END);
+    inexe_size = ftell(fog);
+    fseek(fog, 0, SEEK_SET);
+    inexe_data = (uint8_t*)malloc(inexe_size);
+    fread(inexe_data, inexe_size, 1, fog);
+    fclose(fog);
+
+    /* Name */
+    uint32_t og_name_size = strlen(argv[1]);
+    uint32_t new_name_size = og_name_size - 4;
+
+    if(strncmp(&argv[1][new_name_size], ".exe", 4) == 0)
+    {
+        og_name_size -= 4;
+        new_name_size += OUTPUT_EXE_SUFFIX_SIZE + 1;
+    }
+    else
+    {
+        new_name_size = og_name_size + OUTPUT_EXE_SUFFIX_SIZE + 1;
+    }
+
+    char* new_name = (char*)calloc(new_name_size+1, 1);
+    memcpy(new_name, argv[1], og_name_size);
+    memcpy(&new_name[og_name_size], OUTPUT_EXE_SUFFIX, OUTPUT_EXE_SUFFIX_SIZE);
+    printf("New name: %s\n", new_name);
+
+    /* Patch */
+    const uint32_t blobs_count = PATCH_GET_COUNT(blobs);
+
+    for(uint32_t i = 0; i != blobs_count; ++i)
+    {
+        PATCH_APPLY_BLOB(blobs[i], inexe_data, patch_blob);
+    }
+
+    /* Save */
+    FILE* fout = fopen(new_name, "wb");
+    fwrite(inexe_data, inexe_size, 1, fout);
+    fclose(fout);
+
+    /* Cleanup */
+    free(new_name);
+    free(inexe_data);
+}