Lense · June 29, 2016 15:55
diff --git a/challenge.md b/challenge.md
diff --git a/key.jpg b/key.jpg
diff --git a/read.c b/read.c
 #include<stdint.h>
 #include<stdio.h>
 #include<stdlib.h>
 #include<string.h>

 typedef struct _hdr {
    uint8_t magic[8];
    uint32_t version;
    uint32_t num_files;
 } hdr;

 typedef struct _entry {
    uint32_t magic;
    uint32_t compressed_size;
    uint32_t uncompressed_size;
    uint8_t filename[32];
 } entry;

 int main()
 {
 	int entryNum, uncompressedLen, compressedOffset, compressedIndex, uncompressedIndex, replaceIndex, numReplaced, replaceLen;
 	char* compressedBuf;
 	char* uncompressedBuf;
 	hdr head;
 	entry entry;
 	FILE* fUncompressed;
 	FILE* f = fopen("weissman.csawlz", "rb");
 	fread(&head, sizeof(hdr), 1, f);
 	for(entryNum=0; entryNum<head.num_files; entryNum++)
 	{
 		fread(&entry, sizeof(entry), 1, f);
 		printf("%s\n", entry.filename);
 		printf("0x%x %u %u\n",
 				entry.magic, entry.compressed_size, entry.uncompressed_size);
 		compressedBuf = calloc(entry.compressed_size, sizeof (char));
 		fread(compressedBuf, sizeof (char), entry.compressed_size, f);

 		switch(entryNum)
 		{
 			case 1:
 				free(compressedBuf);
 				continue;
 			case 0:
 				fUncompressed = fopen("index.html", "rb");
 				break;
 			case 2:
 				fUncompressed = fopen("alice.txt", "rb");
 		}
 		fseek(fUncompressed, 0, SEEK_END);
 		uncompressedLen = ftell(fUncompressed)*8;
 		fseek(fUncompressed, 0, SEEK_SET);
 		uncompressedBuf = calloc(uncompressedLen, sizeof (char));
 		fread(uncompressedBuf, sizeof (char), uncompressedLen, fUncompressed);

 		compressedIndex = 0;
 		uncompressedIndex = 0;
 		compressedOffset = 0;
 		while(compressedIndex < entry.compressed_size)
 		{
 			if((compressedIndex-compressedOffset)%10 == 0)
 			{
 				// Weird compression thing here
 				uncompressedIndex--;
 				if(compressedBuf[compressedIndex] != 0x13)
 				{
 					printf("//{");
 					replaceLen = 0;
 					do
 					{
 						replaceLen += compressedBuf[compressedIndex] >> 1;
 						printf("<len:0x%02x>", compressedBuf[compressedIndex] >> 1);
 						printf("<0x%08x>", 
 								((compressedBuf[compressedIndex+1]&0xff)<<8) +
 								(compressedBuf[compressedIndex+2]&0xff));
 						compressedIndex += 3;
 						compressedOffset += 3;
 					}
 					while(compressedBuf[compressedIndex] != 0x13);

 					printf("}={");

 					for(replaceIndex=0; replaceIndex<replaceLen; replaceIndex++)
 					{
 							uncompressedIndex++;
 							printf("%c", uncompressedBuf[uncompressedIndex]);
 					}
 					printf("}");
 					compressedIndex--;
 				}
 				printf("|");
 			}
 			else
 			{
 				// I commented this out for input into Python script to do
 				// some frequency analysis. It didn't help.
 				if(uncompressedIndex < entry.uncompressed_size)
 					printf("%c", compressedBuf[compressedIndex]);
 			}
 			compressedIndex++;
 			uncompressedIndex++;
 		}
 		// Guess whether or not these were in the code I wrote during the ctf
 		fclose(fUncompressed);
 		free(compressedBuf);
 		free(uncompressedBuf);
 	}
 	fclose(f);
 	return 0;
 }
diff --git a/weissman.csawlz b/weissman.csawlz
diff --git a/write.c b/write.c
 #include<stdint.h>
 #include<stdio.h>
 #include<stdlib.h>
 #include<string.h>

 typedef struct _hdr {
    uint8_t magic[8];
    uint32_t version;
    uint32_t num_files;
 } hdr;

 typedef struct _entry {
    uint32_t magic;
    uint32_t compressed_size;
    uint32_t uncompressed_size;
    uint8_t filename[32];
 } entry;

 int main()
 {
 	int entryNum, compressedOffset, compressedIndex, replaceIndex, numReplaced;
 	int* replaceSizes = calloc(100, sizeof (int));
 	int* replaceHashes = calloc(100, sizeof (int));
 	char* compressedBuf;
 	char* replaceBuf = calloc(9, sizeof (char));
 	hdr head;
 	entry entry;
 	FILE* f = fopen("weissman.csawlz", "rb");
 	fread(&head, sizeof(hdr), 1, f);
 	for(entryNum=0; entryNum<head.num_files; entryNum++)
 	{
 		fread(&entry, sizeof(entry), 1, f);
 		compressedBuf = calloc(entry.compressed_size, sizeof (char));
 		fread(compressedBuf, sizeof (char), entry.compressed_size, f);
 		switch(entryNum)
 		{
 			case 1:
 				break;
 			case 0:
 			case 2:
 				free(compressedBuf);
 				continue;
 		}

 		compressedIndex = 0;
 		compressedOffset = 0;
 		while(compressedIndex < entry.compressed_size)
 		{
 			if((compressedIndex-compressedOffset)%10 == 0)
 			{
 				// Weird compression thing here
 				if(compressedBuf[compressedIndex] != 0x13)
 				{
 					memset(replaceSizes, 0, 100*sizeof (int));
 					memset(replaceHashes, 0, 100*sizeof (int));
 					numReplaced = 0;
 					do
 					{
 						replaceSizes[numReplaced] = compressedBuf[compressedIndex] >> 1;
 						replaceHashes[numReplaced] = 
 								((compressedBuf[compressedIndex+1]&0xff)<<8) +
 								(compressedBuf[compressedIndex+2]&0xff);
 						compressedIndex += 3;
 						compressedOffset += 3;
 						numReplaced++;
 					}
 					while(compressedBuf[compressedIndex] != 0x13);

 					for(replaceIndex=0; replaceIndex<numReplaced; replaceIndex++)
 					{
 						switch(replaceHashes[replaceIndex])
 						{
 							case 0x4f9a:
 								strncpy(replaceBuf, "DDDDDDDDD", 9);
 								break;
 							case 0x4ce3:
 								strncpy(replaceBuf,
 										"\x00\x00\x00\x00\x00\x00\x00\x01\x02", 9);
 								break;
 							default:
 								strncpy(replaceBuf, "AAAAAAAAA", 9);
 						}
 						while(replaceSizes[replaceIndex]--)
 						{
 							printf("%c", replaceBuf[replaceIndex%9]);
 						}
 					}
 					compressedIndex--;
 				}
 			}
 			else
 			{
 				printf("%c", compressedBuf[compressedIndex]);
 			}
 			compressedIndex++;
 		}
 		// Guess whether or not these were in the code I wrote during the ctf
 		free(compressedBuf);
 	}
 	free(replaceSizes);
 	free(replaceHashes);
 	fclose(f);
 	free(replaceBuf);
 	return 0;
 }
diff --git a/writeup.md b/writeup.md
	#include<stdint.h>
	#include<stdio.h>
	#include<stdlib.h>
	#include<string.h>

	typedef struct _hdr {
	uint8_t magic[8];
	uint32_t version;
	uint32_t num_files;
	} hdr;

	typedef struct _entry {
	uint32_t magic;
	uint32_t compressed_size;
	uint32_t uncompressed_size;
	uint8_t filename[32];
	} entry;

	int main()
	{
	int entryNum, uncompressedLen, compressedOffset, compressedIndex, uncompressedIndex, replaceIndex, numReplaced, replaceLen;
	char* compressedBuf;
	char* uncompressedBuf;
	hdr head;
	entry entry;
	FILE* fUncompressed;
	FILE* f = fopen("weissman.csawlz", "rb");
	fread(&head, sizeof(hdr), 1, f);
	for(entryNum=0; entryNum<head.num_files; entryNum++)
	{
	fread(&entry, sizeof(entry), 1, f);
	printf("%s\n", entry.filename);
	printf("0x%x %u %u\n",
	entry.magic, entry.compressed_size, entry.uncompressed_size);
	compressedBuf = calloc(entry.compressed_size, sizeof (char));
	fread(compressedBuf, sizeof (char), entry.compressed_size, f);

	switch(entryNum)
	{
	case 1:
	free(compressedBuf);
	continue;
	case 0:
	fUncompressed = fopen("index.html", "rb");
	break;
	case 2:
	fUncompressed = fopen("alice.txt", "rb");
	}
	fseek(fUncompressed, 0, SEEK_END);
	uncompressedLen = ftell(fUncompressed)*8;
	fseek(fUncompressed, 0, SEEK_SET);
	uncompressedBuf = calloc(uncompressedLen, sizeof (char));
	fread(uncompressedBuf, sizeof (char), uncompressedLen, fUncompressed);

	compressedIndex = 0;
	uncompressedIndex = 0;
	compressedOffset = 0;
	while(compressedIndex < entry.compressed_size)
	{
	if((compressedIndex-compressedOffset)%10 == 0)
	{
	// Weird compression thing here
	uncompressedIndex--;
	if(compressedBuf[compressedIndex] != 0x13)
	{
	printf("//{");
	replaceLen = 0;
	do
	{
	replaceLen += compressedBuf[compressedIndex] >> 1;
	printf("<len:0x%02x>", compressedBuf[compressedIndex] >> 1);
	printf("<0x%08x>",
	((compressedBuf[compressedIndex+1]&0xff)<<8) +
	(compressedBuf[compressedIndex+2]&0xff));
	compressedIndex += 3;
	compressedOffset += 3;
	}
	while(compressedBuf[compressedIndex] != 0x13);

	printf("}={");

	for(replaceIndex=0; replaceIndex<replaceLen; replaceIndex++)
	{
	uncompressedIndex++;
	printf("%c", uncompressedBuf[uncompressedIndex]);
	}
	printf("}");
	compressedIndex--;
	}
	printf("\|");
	}
	else
	{
	// I commented this out for input into Python script to do
	// some frequency analysis. It didn't help.
	if(uncompressedIndex < entry.uncompressed_size)
	printf("%c", compressedBuf[compressedIndex]);
	}
	compressedIndex++;
	uncompressedIndex++;
	}
	// Guess whether or not these were in the code I wrote during the ctf
	fclose(fUncompressed);
	free(compressedBuf);
	free(uncompressedBuf);
	}
	fclose(f);
	return 0;
	}