/*
SHA-1 in C
By Steve Reid <steve@edmweb.com>
100% Public Domain

Test Vectors (from FIPS PUB 180-1)
"abc"
  A9993E36 4706816A BA3E2571 7850C26C 9CD0D89D
"abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq"
  84983E44 1C3BD26E BAAE4AA1 F95129E5 E54670F1
A million repetitions of "a"
  34AA973C D4C4DAA4 F61EEB2B DBAD2731 6534016F
*/

/* #define LITTLE_ENDIAN * This should be #define'd if true. */
/* #define SHA1HANDSOFF * Copies data before messing with it. */

#include "module.h"
#include <stdio.h>
#include <string.h>

typedef struct {
	uint32 state[5];
	uint32 count[2];
	unsigned char buffer[64];
} SHA1_CTX;

void SHA1Transform(uint32 state[5], unsigned char const buffer[64]);
void SHA1Init(SHA1_CTX* context);
void SHA1Update(SHA1_CTX* context, unsigned char const * data, uint32 len);
void SHA1Final(unsigned char digest[20], SHA1_CTX* context);

#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))

/* blk0() and blk() perform the initial expand. */
/* I got the idea of expanding during the round function from SSLeay */
#ifdef LITTLE_ENDIAN
#define blk0(i) (block->l[i] = (rol(block->l[i],24)&0xFF00FF00) \
	|(rol(block->l[i],8)&0x00FF00FF))
#else
#define blk0(i) block->l[i]
#endif
#define blk(i) (block->l[i&15] = rol(block->l[(i+13)&15]^block->l[(i+8)&15] \
	^block->l[(i+2)&15]^block->l[i&15],1))

/* (R0+R1), R2, R3, R4 are the different operations used in SHA1 */
#define R0(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk0(i)+0x5A827999+rol(v,5);w=rol(w,30);
#define R1(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk(i)+0x5A827999+rol(v,5);w=rol(w,30);
#define R2(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0x6ED9EBA1+rol(v,5);w=rol(w,30);
#define R3(v,w,x,y,z,i) z+=(((w|x)&y)|(w&x))+blk(i)+0x8F1BBCDC+rol(v,5);w=rol(w,30);
#define R4(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0xCA62C1D6+rol(v,5);w=rol(w,30);


/* Hash a single 512-bit block. This is the core of the algorithm. */

void SHA1Transform(uint32 state[5], unsigned char const buffer[64])
{
uint32 a, b, c, d, e;
typedef union {
	unsigned char c[64];
	uint32 l[16];
} CHAR64LONG16;
CHAR64LONG16* block;
#ifdef SHA1HANDSOFF
static unsigned char workspace[64];
	block = (CHAR64LONG16*)workspace;
	memcpy(block, buffer, 64);
#else
	block = (CHAR64LONG16*)buffer;
#endif
	/* Copy context->state[] to working vars */
	a = state[0];
	b = state[1];
	c = state[2];
	d = state[3];
	e = state[4];
	/* 4 rounds of 20 operations each. Loop unrolled. */
	R0(a,b,c,d,e, 0); R0(e,a,b,c,d, 1); R0(d,e,a,b,c, 2); R0(c,d,e,a,b, 3);
	R0(b,c,d,e,a, 4); R0(a,b,c,d,e, 5); R0(e,a,b,c,d, 6); R0(d,e,a,b,c, 7);
	R0(c,d,e,a,b, 8); R0(b,c,d,e,a, 9); R0(a,b,c,d,e,10); R0(e,a,b,c,d,11);
	R0(d,e,a,b,c,12); R0(c,d,e,a,b,13); R0(b,c,d,e,a,14); R0(a,b,c,d,e,15);
	R1(e,a,b,c,d,16); R1(d,e,a,b,c,17); R1(c,d,e,a,b,18); R1(b,c,d,e,a,19);
	R2(a,b,c,d,e,20); R2(e,a,b,c,d,21); R2(d,e,a,b,c,22); R2(c,d,e,a,b,23);
	R2(b,c,d,e,a,24); R2(a,b,c,d,e,25); R2(e,a,b,c,d,26); R2(d,e,a,b,c,27);
	R2(c,d,e,a,b,28); R2(b,c,d,e,a,29); R2(a,b,c,d,e,30); R2(e,a,b,c,d,31);
	R2(d,e,a,b,c,32); R2(c,d,e,a,b,33); R2(b,c,d,e,a,34); R2(a,b,c,d,e,35);
	R2(e,a,b,c,d,36); R2(d,e,a,b,c,37); R2(c,d,e,a,b,38); R2(b,c,d,e,a,39);
	R3(a,b,c,d,e,40); R3(e,a,b,c,d,41); R3(d,e,a,b,c,42); R3(c,d,e,a,b,43);
	R3(b,c,d,e,a,44); R3(a,b,c,d,e,45); R3(e,a,b,c,d,46); R3(d,e,a,b,c,47);
	R3(c,d,e,a,b,48); R3(b,c,d,e,a,49); R3(a,b,c,d,e,50); R3(e,a,b,c,d,51);
	R3(d,e,a,b,c,52); R3(c,d,e,a,b,53); R3(b,c,d,e,a,54); R3(a,b,c,d,e,55);
	R3(e,a,b,c,d,56); R3(d,e,a,b,c,57); R3(c,d,e,a,b,58); R3(b,c,d,e,a,59);
	R4(a,b,c,d,e,60); R4(e,a,b,c,d,61); R4(d,e,a,b,c,62); R4(c,d,e,a,b,63);
	R4(b,c,d,e,a,64); R4(a,b,c,d,e,65); R4(e,a,b,c,d,66); R4(d,e,a,b,c,67);
	R4(c,d,e,a,b,68); R4(b,c,d,e,a,69); R4(a,b,c,d,e,70); R4(e,a,b,c,d,71);
	R4(d,e,a,b,c,72); R4(c,d,e,a,b,73); R4(b,c,d,e,a,74); R4(a,b,c,d,e,75);
	R4(e,a,b,c,d,76); R4(d,e,a,b,c,77); R4(c,d,e,a,b,78); R4(b,c,d,e,a,79);
	/* Add the working vars back into context.state[] */
	state[0] += a;
	state[1] += b;
	state[2] += c;
	state[3] += d;
	state[4] += e;
	/* Wipe variables */
	a = b = c = d = e = 0;
}


/* SHA1Init - Initialize new context */

void SHA1Init(SHA1_CTX* context)
{
	/* SHA1 initialization constants */
	context->state[0] = 0x67452301;
	context->state[1] = 0xEFCDAB89;
	context->state[2] = 0x98BADCFE;
	context->state[3] = 0x10325476;
	context->state[4] = 0xC3D2E1F0;
	context->count[0] = context->count[1] = 0;
}


/* Run your data through this. */

void SHA1Update(SHA1_CTX* context, unsigned char const * data, uint32 len)
{
	uint32 i, j;

	j = (context->count[0] >> 3) & 63;
	if ((context->count[0] += len << 3) < (len << 3)) context->count[1]++;
	context->count[1] += (len >> 29);
	if ((j + len) > 63) {
		memcpy(&context->buffer[j], data, (i = 64-j));
		SHA1Transform(context->state, context->buffer);
		for ( ; i + 63 < len; i += 64) {
			SHA1Transform(context->state, &data[i]);
		}
		j = 0;
	}
	else i = 0;
		memcpy(&context->buffer[j], &data[i], len - i);
}


/* Add padding and return the message digest. */

void SHA1Final(unsigned char digest[20], SHA1_CTX* context)
{
	uint32 i;
	unsigned char finalcount[8];

	for (i = 0; i < 8; i++) {
		finalcount[i] = (unsigned char)((context->count[(i >= 4 ? 0 : 1)]
		 >> ((3-(i & 3)) * 8) ) & 255);  /* Endian independent */
	}
	SHA1Update(context, (unsigned char *)"\200", 1);
	while ((context->count[0] & 504) != 448) {
		SHA1Update(context, (unsigned char *)"\0", 1);
	}
	SHA1Update(context, finalcount, 8);  /* Should cause a SHA1Transform() */
	for (i = 0; i < 20; i++) {
		digest[i] = (unsigned char)
		 ((context->state[i>>2] >> ((3-(i & 3)) * 8) ) & 255);
	}
	/* Wipe variables */
	i = 0;
	memset(context->buffer, 0, 64);
	memset(context->state, 0, 20);
	memset(context->count, 0, 8);
	memset(&finalcount, 0, 8);
#ifdef SHA1HANDSOFF  /* make SHA1Transform overwrite it's own static vars */
	SHA1Transform(context->state, context->buffer);
#endif
}

/*****************************************************************************/
/*****************************************************************************/

/* Module stuff. */

class ESHA1 : public Module
{
 public:
	ESHA1(const std::string &modname, const std::string &creator) : Module(modname, creator)
	{
		this->SetAuthor("Anope");
		this->SetVersion("$Id$");
		this->SetType(ENCRYPTION);

		ModuleManager::Attach(I_OnEncrypt, this);
		ModuleManager::Attach(I_OnEncryptInPlace, this);
		ModuleManager::Attach(I_OnEncryptCheckLen, this);
		ModuleManager::Attach(I_OnDecrypt, this);
		ModuleManager::Attach(I_OnCheckPassword, this);

	}


	EventReturn OnEncrypt(const std::string &src, std::string &dest)
	{
		SHA1_CTX context;
		char *digest = new char[Config.PassLen];
		std::string buf = "sha1:";
		char cpass[1000];

		memset(digest,0,32);

		SHA1Init(&context);
		SHA1Update(&context, (unsigned char *)src.c_str(), src.size());
		SHA1Final((unsigned char *)digest, &context);

		b64_encode(digest, 20, cpass, 1000);
		buf.append(cpass);
		Alog(LOG_DEBUG_2) << "(enc_sha1) hashed password from [" << src << "] to [" << buf << "]";
		dest.assign(buf);
		delete [] digest;
		return EVENT_ALLOW;
	}


	EventReturn OnEncryptInPlace(std::string &buf)
	{
		return this->OnEncrypt(buf, buf);
	}

	EventReturn OnDecrypt(const std::string &hashm, std::string &src, std::string &dest)
	{
		if (hashm != "sha1")
			return EVENT_CONTINUE;
		return EVENT_STOP;
	}


	EventReturn OnCheckPassword(const std::string &hashm, std::string &plaintext, std::string &password)
	{
		if (hashm != "sha1")
			return EVENT_CONTINUE;
		std::string buf;
		this->OnEncrypt(plaintext, buf);
		if (!password.compare(buf))
		{
			/* when we are NOT the first module in the list, 
			 * we want to re-encrypt the pass with the new encryption
			 */
			if (Config.EncModuleList.front().compare(this->name))
			{
				enc_encrypt(plaintext, password);
			}
			return EVENT_ALLOW;
		}
		return EVENT_STOP;
	}

};


MODULE_INIT(ESHA1)