/*
 *
 * Modified for Anope.
 * (C) 2006-2022 Anope Team
 * Contact us at team@anope.org

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. */

#include "module.h"
#include "modules/encryption.h"

union CHAR64LONG16
{
	unsigned char c[64];
	uint32_t l[16];
};

inline static uint32_t rol(uint32_t value, uint32_t bits) { return (value << bits) | (value >> (32 - bits)); }

/* blk0() and blk() perform the initial expand. */
/* I got the idea of expanding during the round function from SSLeay */
inline static uint32_t blk0(CHAR64LONG16 &block, uint32_t i)
{
#ifdef LITTLE_ENDIAN
	return block.l[i] = (rol(block.l[i], 24) & 0xFF00FF00) | (rol(block.l[i], 8) & 0x00FF00FF);
#else
	return block.l[i];
#endif
}
inline static uint32_t blk(CHAR64LONG16 &block, uint32_t i) { return 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 */
inline static void R0(CHAR64LONG16 &block, uint32_t v, uint32_t &w, uint32_t x, uint32_t y, uint32_t &z, uint32_t i) { z += ((w & (x ^ y)) ^ y) + blk0(block, i) + 0x5A827999 + rol(v, 5); w = rol(w, 30); }
inline static void R1(CHAR64LONG16 &block, uint32_t v, uint32_t &w, uint32_t x, uint32_t y, uint32_t &z, uint32_t i) { z += ((w & (x ^ y)) ^ y) + blk(block, i) + 0x5A827999 + rol(v, 5); w = rol(w, 30); }
inline static void R2(CHAR64LONG16 &block, uint32_t v, uint32_t &w, uint32_t x, uint32_t y, uint32_t &z, uint32_t i) { z += (w ^ x ^ y) + blk(block, i) + 0x6ED9EBA1 + rol(v, 5); w = rol(w, 30); }
inline static void R3(CHAR64LONG16 &block, uint32_t v, uint32_t &w, uint32_t x, uint32_t y, uint32_t &z, uint32_t i) { z += (((w | x) & y) | (w & x)) + blk(block, i) + 0x8F1BBCDC + rol(v, 5); w = rol(w, 30); }
inline static void R4(CHAR64LONG16 &block, uint32_t v, uint32_t &w, uint32_t x, uint32_t y, uint32_t &z, uint32_t i) { z += (w ^ x ^ y) + blk(block, i) + 0xCA62C1D6 + rol(v, 5); w = rol(w, 30); }

static const uint32_t sha1_iv[5] =
{
	0x67452301, 0xEFCDAB89, 0x98BADCFE, 0x10325476, 0xC3D2E1F0
};

class SHA1Context : public Encryption::Context
{
	uint32_t state[5];
	uint32_t count[2];
	unsigned char buffer[64];
	unsigned char digest[20];

	void Transform(const unsigned char buf[64])
	{
		uint32_t a, b, c, d, e;

		CHAR64LONG16 block;
		memcpy(block.c, buf, 64);

		/* Copy context->state[] to working vars */
		a = this->state[0];
		b = this->state[1];
		c = this->state[2];
		d = this->state[3];
		e = this->state[4];

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

 public:
	SHA1Context(Encryption::IV *iv = NULL)
	{
		if (iv != NULL)
		{
			if (iv->second != 5)
				throw CoreException("Invalid IV size");
			for (int i = 0; i < 5; ++i)
				this->state[i] = iv->first[i];
		}
		else
			for (int i = 0; i < 5; ++i)
				this->state[i] = sha1_iv[i];

		this->count[0] = this->count[1] = 0;
		memset(this->buffer, 0, sizeof(this->buffer));
		memset(this->digest, 0, sizeof(this->digest));
	}

	void Update(const unsigned char *data, size_t len) anope_override
	{
		uint32_t i, j;

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

	void Finalize() anope_override
	{
		uint32_t i;
		unsigned char finalcount[8];

		for (i = 0; i < 8; ++i)
			finalcount[i] = static_cast<unsigned char>((this->count[i >= 4 ? 0 : 1] >> ((3 - (i & 3)) * 8)) & 255); /* Endian independent */
		this->Update(reinterpret_cast<const unsigned char *>("\200"), 1);
		while ((this->count[0] & 504) != 448)
			this->Update(reinterpret_cast<const unsigned char *>("\0"), 1);
		this->Update(finalcount, 8); /* Should cause a SHA1Transform() */
		for (i = 0; i < 20; ++i)
			this->digest[i] = static_cast<unsigned char>((this->state[i>>2] >> ((3 - (i & 3)) * 8)) & 255);

		/* Wipe variables */
		memset(this->buffer, 0, sizeof(this->buffer));
		memset(this->state, 0, sizeof(this->state));
		memset(this->count, 0, sizeof(this->count));
		memset(&finalcount, 0, sizeof(finalcount));

		this->Transform(this->buffer);
	}

	Encryption::Hash GetFinalizedHash() anope_override
	{
		Encryption::Hash hash;
		hash.first = this->digest;
		hash.second = sizeof(this->digest);
		return hash;
	}
};

class SHA1Provider : public Encryption::Provider
{
 public:
	SHA1Provider(Module *creator) : Encryption::Provider(creator, "sha1") { }

	Encryption::Context *CreateContext(Encryption::IV *iv) anope_override
	{
		return new SHA1Context(iv);
	}

	Encryption::IV GetDefaultIV() anope_override
	{
		Encryption::IV iv;
		iv.first = sha1_iv;
		iv.second = sizeof(sha1_iv) / sizeof(uint32_t);
		return iv;
	}
};

class ESHA1 : public Module
{
	SHA1Provider sha1provider;

 public:
	ESHA1(const Anope::string &modname, const Anope::string &creator) : Module(modname, creator, ENCRYPTION | VENDOR),
		sha1provider(this)
	{

	}

	EventReturn OnEncrypt(const Anope::string &src, Anope::string &dest) anope_override
	{
		SHA1Context context;

		context.Update(reinterpret_cast<const unsigned char *>(src.c_str()), src.length());
		context.Finalize();

		Encryption::Hash hash = context.GetFinalizedHash();

		Anope::string buf = "sha1:" + Anope::Hex(reinterpret_cast<const char *>(hash.first), hash.second);

		Log(LOG_DEBUG_2) << "(enc_sha1) hashed password from [" << src << "] to [" << buf << "]";
		dest = buf;
		return EVENT_ALLOW;
	}

	void OnCheckAuthentication(User *, IdentifyRequest *req) anope_override
	{
		const NickAlias *na = NickAlias::Find(req->GetAccount());
		if (na == NULL)
			return;
		NickCore *nc = na->nc;

		size_t pos = nc->pass.find(':');
		if (pos == Anope::string::npos)
			return;
		Anope::string hash_method(nc->pass.begin(), nc->pass.begin() + pos);
		if (!hash_method.equals_cs("sha1"))
			return;

		Anope::string buf;
		this->OnEncrypt(req->GetPassword(), buf);
		if (nc->pass.equals_cs(buf))
		{
			if (ModuleManager::FindFirstOf(ENCRYPTION) != this)
				Anope::Encrypt(req->GetPassword(), nc->pass);
			req->Success(this);
		}
	}
};

MODULE_INIT(ESHA1)