Initial code.

src/lib/crypto/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 "scrypt_platform.h"
+
+#include <sys/types.h>
+
+#include <stdint.h>
+#include <string.h>
+
+#include "sysendian.h"
+
+#include "sha256.h"
+
+/*
+ * 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));
+}