gecko-dev/mozglue/android/pbkdf2_sha256.c

/*-
 * Copyright 2005,2007,2009 Colin Percival
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
#include <sys/types.h>

#include <stdint.h>
#include <string.h>

#include <sys/endian.h>

#include "pbkdf2_sha256.h"

static inline uint32_t be32dec(const void* pp) {
  const uint8_t* p = (uint8_t const*)pp;

  return ((uint32_t)(p[3]) + ((uint32_t)(p[2]) << 8) +
          ((uint32_t)(p[1]) << 16) + ((uint32_t)(p[0]) << 24));
}

static inline void be32enc(void* pp, uint32_t x) {
  uint8_t* p = (uint8_t*)pp;

  p[3] = x & 0xff;
  p[2] = (x >> 8) & 0xff;
  p[1] = (x >> 16) & 0xff;
  p[0] = (x >> 24) & 0xff;
}

/*
 * Encode a length len/4 vector of (uint32_t) into a length len vector of
 * (unsigned char) in big-endian form.  Assumes len is a multiple of 4.
 */
static void be32enc_vect(unsigned char* dst, const uint32_t* src, size_t len) {
  size_t i;

  for (i = 0; i < len / 4; i++) be32enc(dst + i * 4, src[i]);
}

/*
 * Decode a big-endian length len vector of (unsigned char) into a length
 * len/4 vector of (uint32_t).  Assumes len is a multiple of 4.
 */
static void be32dec_vect(uint32_t* dst, const unsigned char* src, size_t len) {
  size_t i;

  for (i = 0; i < len / 4; i++) dst[i] = be32dec(src + i * 4);
}

/* Elementary functions used by SHA256 */
#define Ch(x, y, z) ((x & (y ^ z)) ^ z)
#define Maj(x, y, z) ((x & (y | z)) | (y & z))
#define SHR(x, n) (x >> n)
#define ROTR(x, n) ((x >> n) | (x << (32 - n)))
#define S0(x) (ROTR(x, 2) ^ ROTR(x, 13) ^ ROTR(x, 22))
#define S1(x) (ROTR(x, 6) ^ ROTR(x, 11) ^ ROTR(x, 25))
#define s0(x) (ROTR(x, 7) ^ ROTR(x, 18) ^ SHR(x, 3))
#define s1(x) (ROTR(x, 17) ^ ROTR(x, 19) ^ SHR(x, 10))

/* SHA256 round function */
#define RND(a, b, c, d, e, f, g, h, k) \
  t0 = h + S1(e) + Ch(e, f, g) + k;    \
  t1 = S0(a) + Maj(a, b, c);           \
  d += t0;                             \
  h = t0 + t1;

/* Adjusted round function for rotating state */
#define RNDr(S, W, i, k)                                                  \
  RND(S[(64 - i) % 8], S[(65 - i) % 8], S[(66 - i) % 8], S[(67 - i) % 8], \
      S[(68 - i) % 8], S[(69 - i) % 8], S[(70 - i) % 8], S[(71 - i) % 8], \
      W[i] + k)

/*
 * SHA256 block compression function.  The 256-bit state is transformed via
 * the 512-bit input block to produce a new state.
 */
static void SHA256_Transform(uint32_t* state, const unsigned char block[64]) {
  uint32_t W[64];
  uint32_t S[8];
  uint32_t t0, t1;
  int i;

  /* 1. Prepare message schedule W. */
  be32dec_vect(W, block, 64);
  for (i = 16; i < 64; i++)
    W[i] = s1(W[i - 2]) + W[i - 7] + s0(W[i - 15]) + W[i - 16];

  /* 2. Initialize working variables. */
  memcpy(S, state, 32);

  /* 3. Mix. */
  RNDr(S, W, 0, 0x428a2f98);
  RNDr(S, W, 1, 0x71374491);
  RNDr(S, W, 2, 0xb5c0fbcf);
  RNDr(S, W, 3, 0xe9b5dba5);
  RNDr(S, W, 4, 0x3956c25b);
  RNDr(S, W, 5, 0x59f111f1);
  RNDr(S, W, 6, 0x923f82a4);
  RNDr(S, W, 7, 0xab1c5ed5);
  RNDr(S, W, 8, 0xd807aa98);
  RNDr(S, W, 9, 0x12835b01);
  RNDr(S, W, 10, 0x243185be);
  RNDr(S, W, 11, 0x550c7dc3);
  RNDr(S, W, 12, 0x72be5d74);
  RNDr(S, W, 13, 0x80deb1fe);
  RNDr(S, W, 14, 0x9bdc06a7);
  RNDr(S, W, 15, 0xc19bf174);
  RNDr(S, W, 16, 0xe49b69c1);
  RNDr(S, W, 17, 0xefbe4786);
  RNDr(S, W, 18, 0x0fc19dc6);
  RNDr(S, W, 19, 0x240ca1cc);
  RNDr(S, W, 20, 0x2de92c6f);
  RNDr(S, W, 21, 0x4a7484aa);
  RNDr(S, W, 22, 0x5cb0a9dc);
  RNDr(S, W, 23, 0x76f988da);
  RNDr(S, W, 24, 0x983e5152);
  RNDr(S, W, 25, 0xa831c66d);
  RNDr(S, W, 26, 0xb00327c8);
  RNDr(S, W, 27, 0xbf597fc7);
  RNDr(S, W, 28, 0xc6e00bf3);
  RNDr(S, W, 29, 0xd5a79147);
  RNDr(S, W, 30, 0x06ca6351);
  RNDr(S, W, 31, 0x14292967);
  RNDr(S, W, 32, 0x27b70a85);
  RNDr(S, W, 33, 0x2e1b2138);
  RNDr(S, W, 34, 0x4d2c6dfc);
  RNDr(S, W, 35, 0x53380d13);
  RNDr(S, W, 36, 0x650a7354);
  RNDr(S, W, 37, 0x766a0abb);
  RNDr(S, W, 38, 0x81c2c92e);
  RNDr(S, W, 39, 0x92722c85);
  RNDr(S, W, 40, 0xa2bfe8a1);
  RNDr(S, W, 41, 0xa81a664b);
  RNDr(S, W, 42, 0xc24b8b70);
  RNDr(S, W, 43, 0xc76c51a3);
  RNDr(S, W, 44, 0xd192e819);
  RNDr(S, W, 45, 0xd6990624);
  RNDr(S, W, 46, 0xf40e3585);
  RNDr(S, W, 47, 0x106aa070);
  RNDr(S, W, 48, 0x19a4c116);
  RNDr(S, W, 49, 0x1e376c08);
  RNDr(S, W, 50, 0x2748774c);
  RNDr(S, W, 51, 0x34b0bcb5);
  RNDr(S, W, 52, 0x391c0cb3);
  RNDr(S, W, 53, 0x4ed8aa4a);
  RNDr(S, W, 54, 0x5b9cca4f);
  RNDr(S, W, 55, 0x682e6ff3);
  RNDr(S, W, 56, 0x748f82ee);
  RNDr(S, W, 57, 0x78a5636f);
  RNDr(S, W, 58, 0x84c87814);
  RNDr(S, W, 59, 0x8cc70208);
  RNDr(S, W, 60, 0x90befffa);
  RNDr(S, W, 61, 0xa4506ceb);
  RNDr(S, W, 62, 0xbef9a3f7);
  RNDr(S, W, 63, 0xc67178f2);

  /* 4. Mix local working variables into global state. */
  for (i = 0; i < 8; i++) state[i] += S[i];

  /* Clean the stack. */
  memset(W, 0, 256);
  memset(S, 0, 32);
  t0 = t1 = 0;
}

static unsigned char PAD[64] = {
    0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};

/* Add padding and terminating bit-count. */
static void SHA256_Pad(SHA256_CTX* ctx) {
  unsigned char len[8];
  uint32_t r, plen;

  /*
   * Convert length to a vector of bytes -- we do this now rather
   * than later because the length will change after we pad.
   */
  be32enc_vect(len, ctx->count, 8);

  /* Add 1--64 bytes so that the resulting length is 56 mod 64. */
  r = (ctx->count[1] >> 3) & 0x3f;
  plen = (r < 56) ? (56 - r) : (120 - r);
  SHA256_Update(ctx, PAD, (size_t)plen);

  /* Add the terminating bit-count. */
  SHA256_Update(ctx, len, 8);
}

/* SHA-256 initialization.  Begins a SHA-256 operation. */
void SHA256_Init(SHA256_CTX* ctx) {
  /* Zero bits processed so far. */
  ctx->count[0] = ctx->count[1] = 0;

  /* Magic initialization constants. */
  ctx->state[0] = 0x6A09E667;
  ctx->state[1] = 0xBB67AE85;
  ctx->state[2] = 0x3C6EF372;
  ctx->state[3] = 0xA54FF53A;
  ctx->state[4] = 0x510E527F;
  ctx->state[5] = 0x9B05688C;
  ctx->state[6] = 0x1F83D9AB;
  ctx->state[7] = 0x5BE0CD19;
}

/* Add bytes into the hash. */
void SHA256_Update(SHA256_CTX* ctx, const void* in, size_t len) {
  uint32_t bitlen[2];
  uint32_t r;
  const unsigned char* src = in;

  /* Number of bytes left in the buffer from previous updates. */
  r = (ctx->count[1] >> 3) & 0x3f;

  /* Convert the length into a number of bits. */
  bitlen[1] = ((uint32_t)len) << 3;
  bitlen[0] = (uint32_t)(len >> 29);

  /* Update number of bits. */
  if ((ctx->count[1] += bitlen[1]) < bitlen[1]) ctx->count[0]++;
  ctx->count[0] += bitlen[0];

  /* Handle the case where we don't need to perform any transforms. */
  if (len < 64 - r) {
    memcpy(&ctx->buf[r], src, len);
    return;
  }

  /* Finish the current block. */
  memcpy(&ctx->buf[r], src, 64 - r);
  SHA256_Transform(ctx->state, ctx->buf);
  src += 64 - r;
  len -= 64 - r;

  /* Perform complete blocks. */
  while (len >= 64) {
    SHA256_Transform(ctx->state, src);
    src += 64;
    len -= 64;
  }

  /* Copy left over data into buffer. */
  memcpy(ctx->buf, src, len);
}

/*
 * SHA-256 finalization.  Pads the input data, exports the hash value,
 * and clears the context state.
 */
void SHA256_Final(unsigned char digest[32], SHA256_CTX* ctx) {
  /* Add padding. */
  SHA256_Pad(ctx);

  /* Write the hash. */
  be32enc_vect(digest, ctx->state, 32);

  /* Clear the context state. */
  memset((void*)ctx, 0, sizeof(*ctx));
}

/* Initialize an HMAC-SHA256 operation with the given key. */
void HMAC_SHA256_Init(HMAC_SHA256_CTX* ctx, const void* _K, size_t Klen) {
  unsigned char pad[64];
  unsigned char khash[32];
  const unsigned char* K = _K;
  size_t i;

  /* If Klen > 64, the key is really SHA256(K). */
  if (Klen > 64) {
    SHA256_Init(&ctx->ictx);
    SHA256_Update(&ctx->ictx, K, Klen);
    SHA256_Final(khash, &ctx->ictx);
    K = khash;
    Klen = 32;
  }

  /* Inner SHA256 operation is SHA256(K xor [block of 0x36] || data). */
  SHA256_Init(&ctx->ictx);
  memset(pad, 0x36, 64);
  for (i = 0; i < Klen; i++) pad[i] ^= K[i];
  SHA256_Update(&ctx->ictx, pad, 64);

  /* Outer SHA256 operation is SHA256(K xor [block of 0x5c] || hash). */
  SHA256_Init(&ctx->octx);
  memset(pad, 0x5c, 64);
  for (i = 0; i < Klen; i++) pad[i] ^= K[i];
  SHA256_Update(&ctx->octx, pad, 64);

  /* Clean the stack. */
  memset(khash, 0, 32);
}

/* Add bytes to the HMAC-SHA256 operation. */
void HMAC_SHA256_Update(HMAC_SHA256_CTX* ctx, const void* in, size_t len) {
  /* Feed data to the inner SHA256 operation. */
  SHA256_Update(&ctx->ictx, in, len);
}

/* Finish an HMAC-SHA256 operation. */
void HMAC_SHA256_Final(unsigned char digest[32], HMAC_SHA256_CTX* ctx) {
  unsigned char ihash[32];

  /* Finish the inner SHA256 operation. */
  SHA256_Final(ihash, &ctx->ictx);

  /* Feed the inner hash to the outer SHA256 operation. */
  SHA256_Update(&ctx->octx, ihash, 32);

  /* Finish the outer SHA256 operation. */
  SHA256_Final(digest, &ctx->octx);

  /* Clean the stack. */
  memset(ihash, 0, 32);
}

/**
 * PBKDF2_SHA256(passwd, passwdlen, salt, saltlen, c, buf, dkLen):
 * Compute PBKDF2(passwd, salt, c, dkLen) using HMAC-SHA256 as the PRF, and
 * write the output to buf.  The value dkLen must be at most 32 * (2^32 - 1).
 */
void PBKDF2_SHA256(const uint8_t* passwd, size_t passwdlen, const uint8_t* salt,
                   size_t saltlen, uint64_t c, uint8_t* buf, size_t dkLen) {
  HMAC_SHA256_CTX PShctx, hctx;
  size_t i;
  uint8_t ivec[4];
  uint8_t U[32];
  uint8_t T[32];
  uint64_t j;
  int k;
  size_t clen;

  /* Compute HMAC state after processing P and S. */
  HMAC_SHA256_Init(&PShctx, passwd, passwdlen);
  HMAC_SHA256_Update(&PShctx, salt, saltlen);

  /* Iterate through the blocks. */
  for (i = 0; i * 32 < dkLen; i++) {
    /* Generate INT(i + 1). */
    be32enc(ivec, (uint32_t)(i + 1));

    /* Compute U_1 = PRF(P, S || INT(i)). */
    memcpy(&hctx, &PShctx, sizeof(HMAC_SHA256_CTX));
    HMAC_SHA256_Update(&hctx, ivec, 4);
    HMAC_SHA256_Final(U, &hctx);

    /* T_i = U_1 ... */
    memcpy(T, U, 32);

    for (j = 2; j <= c; j++) {
      /* Compute U_j. */
      HMAC_SHA256_Init(&hctx, passwd, passwdlen);
      HMAC_SHA256_Update(&hctx, U, 32);
      HMAC_SHA256_Final(U, &hctx);

      /* ... xor U_j ... */
      for (k = 0; k < 32; k++) T[k] ^= U[k];
    }

    /* Copy as many bytes as necessary into buf. */
    clen = dkLen - i * 32;
    if (clen > 32) clen = 32;
    memcpy(&buf[i * 32], T, clen);
  }

  /* Clean PShctx, since we never called _Final on it. */
  memset(&PShctx, 0, sizeof(HMAC_SHA256_CTX));
}