FreeBSD/Linux Kernel Cross Reference
sys/crypto/sha2/sha256c.c

     /*-
      * Copyright 2005 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/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include <sys/endian.h>
    #include <sys/types.h>
    
    #ifdef _KERNEL
    #include <sys/systm.h>
    #else
    #include <string.h>
    #endif
    
    #include "sha256.h"
    
    #if BYTE_ORDER == BIG_ENDIAN
    
    /* Copy a vector of big-endian uint32_t into a vector of bytes */
    #define be32enc_vect(dst, src, len)     \
            memcpy((void *)dst, (const void *)src, (size_t)len)
    
    /* Copy a vector of bytes into a vector of big-endian uint32_t */
    #define be32dec_vect(dst, src, len)     \
            memcpy((void *)dst, (const void *)src, (size_t)len)
    
    #else /* BYTE_ORDER != BIG_ENDIAN */
    
    /*
     * 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);
    }
    
    #endif /* BYTE_ORDER != BIG_ENDIAN */
    
    /* SHA256 round constants. */
    static const uint32_t K[64] = {
            0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
            0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
            0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
            0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
            0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
            0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
            0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
            0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
            0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
            0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
            0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
            0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
            0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
            0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
            0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
            0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
    };
   
   /* 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)                  \
           h += S1(e) + Ch(e, f, g) + k;                   \
           d += h;                                         \
           h += S0(a) + Maj(a, b, c);
   
   /* Adjusted round function for rotating state */
   #define RNDr(S, W, i, ii)                       \
           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 + ii] + K[i + ii])
   
   /* Message schedule computation */
   #define MSCH(W, ii, i)                          \
           W[i + ii + 16] = s1(W[i + ii + 14]) + W[i + ii + 9] + s0(W[i + ii + 1]) + W[i + ii]
   
   /*
    * 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];
           int i;
   
           /* 1. Prepare the first part of the message schedule W. */
           be32dec_vect(W, block, 64);
   
           /* 2. Initialize working variables. */
           memcpy(S, state, 32);
   
           /* 3. Mix. */
           for (i = 0; i < 64; i += 16) {
                   RNDr(S, W, 0, i);
                   RNDr(S, W, 1, i);
                   RNDr(S, W, 2, i);
                   RNDr(S, W, 3, i);
                   RNDr(S, W, 4, i);
                   RNDr(S, W, 5, i);
                   RNDr(S, W, 6, i);
                   RNDr(S, W, 7, i);
                   RNDr(S, W, 8, i);
                   RNDr(S, W, 9, i);
                   RNDr(S, W, 10, i);
                   RNDr(S, W, 11, i);
                   RNDr(S, W, 12, i);
                   RNDr(S, W, 13, i);
                   RNDr(S, W, 14, i);
                   RNDr(S, W, 15, i);
   
                   if (i == 48)
                           break;
                   MSCH(W, 0, i);
                   MSCH(W, 1, i);
                   MSCH(W, 2, i);
                   MSCH(W, 3, i);
                   MSCH(W, 4, i);
                   MSCH(W, 5, i);
                   MSCH(W, 6, i);
                   MSCH(W, 7, i);
                   MSCH(W, 8, i);
                   MSCH(W, 9, i);
                   MSCH(W, 10, i);
                   MSCH(W, 11, i);
                   MSCH(W, 12, i);
                   MSCH(W, 13, i);
                   MSCH(W, 14, i);
                   MSCH(W, 15, i);
           }
   
           /* 4. Mix local working variables into global state */
           for (i = 0; i < 8; i++)
                   state[i] += S[i];
   }
   
   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)
   {
           size_t r;
   
           /* Figure out how many bytes we have buffered. */
           r = (ctx->count >> 3) & 0x3f;
   
           /* Pad to 56 mod 64, transforming if we finish a block en route. */
           if (r < 56) {
                   /* Pad to 56 mod 64. */
                   memcpy(&ctx->buf[r], PAD, 56 - r);
           } else {
                   /* Finish the current block and mix. */
                   memcpy(&ctx->buf[r], PAD, 64 - r);
                   SHA256_Transform(ctx->state, ctx->buf);
   
                   /* The start of the final block is all zeroes. */
                   memset(&ctx->buf[0], 0, 56);
           }
   
           /* Add the terminating bit-count. */
           be64enc(&ctx->buf[56], ctx->count);
   
           /* Mix in the final block. */
           SHA256_Transform(ctx->state, ctx->buf);
   }
   
   /* SHA-256 initialization.  Begins a SHA-256 operation. */
   void
   SHA256_Init(SHA256_CTX * ctx)
   {
   
           /* Zero bits processed so far */
           ctx->count = 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)
   {
           uint64_t bitlen;
           uint32_t r;
           const unsigned char *src = in;
   
           /* Number of bytes left in the buffer from previous updates */
           r = (ctx->count >> 3) & 0x3f;
   
           /* Convert the length into a number of bits */
           bitlen = len << 3;
   
           /* Update number of bits */
           ctx->count += bitlen;
   
           /* 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));
   }
   
   #ifdef WEAK_REFS
   /* When building libmd, provide weak references. Note: this is not
      activated in the context of compiling these sources for internal
      use in libcrypt.
    */
   #undef SHA256_Init
   __weak_reference(_libmd_SHA256_Init, SHA256_Init);
   #undef SHA256_Update
   __weak_reference(_libmd_SHA256_Update, SHA256_Update);
   #undef SHA256_Final
   __weak_reference(_libmd_SHA256_Final, SHA256_Final);
   #undef SHA256_Transform
   __weak_reference(_libmd_SHA256_Transform, SHA256_Transform);
   #endif

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