tor-browser

sha1.c (12804B)

---

/*
* sha1.c
*
* an implementation of the Secure Hash Algorithm v.1 (SHA-1),
* specified in FIPS 180-1
*
* David A. McGrew
* Cisco Systems, Inc.
*/

/*
*
* Copyright (c) 2001-2017, Cisco Systems, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
*   Redistributions of source code must retain the above copyright
*   notice, this list of conditions and the following disclaimer.
*
*   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.
*
*   Neither the name of the Cisco Systems, Inc. nor the names of its
*   contributors may be used to endorse or promote products derived
*   from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
* COPYRIGHT HOLDERS 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.
*
*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "sha1.h"

srtp_debug_module_t srtp_mod_sha1 = {
   0,      /* debugging is off by default */
   "sha-1" /* printable module name       */
};

/* SN == Rotate left N bits */
#define S1(X) ((X << 1) | (X >> 31))
#define S5(X) ((X << 5) | (X >> 27))
#define S30(X) ((X << 30) | (X >> 2))

#define f0(B, C, D) ((B & C) | (~B & D))
#define f1(B, C, D) (B ^ C ^ D)
#define f2(B, C, D) ((B & C) | (B & D) | (C & D))
#define f3(B, C, D) (B ^ C ^ D)

/*
* nota bene: the variable K0 appears in the curses library, so we
* give longer names to these variables to avoid spurious warnings
* on systems that uses curses
*/

uint32_t SHA_K0 = 0x5A827999; /* Kt for 0  <= t <= 19 */
uint32_t SHA_K1 = 0x6ED9EBA1; /* Kt for 20 <= t <= 39 */
uint32_t SHA_K2 = 0x8F1BBCDC; /* Kt for 40 <= t <= 59 */
uint32_t SHA_K3 = 0xCA62C1D6; /* Kt for 60 <= t <= 79 */

/*
*  srtp_sha1_core(M, H) computes the core compression function, where M is
*  the next part of the message (in network byte order) and H is the
*  intermediate state { H0, H1, ...} (in host byte order)
*
*  this function does not do any of the padding required in the
*  complete SHA1 function
*
*  this function is used in the SEAL 3.0 key setup routines
*  (crypto/cipher/seal.c)
*/

void srtp_sha1_core(const uint32_t M[16], uint32_t hash_value[5])
{
   uint32_t H0;
   uint32_t H1;
   uint32_t H2;
   uint32_t H3;
   uint32_t H4;
   uint32_t W[80];
   uint32_t A, B, C, D, E, TEMP;
   int t;

   /* copy hash_value into H0, H1, H2, H3, H4 */
   H0 = hash_value[0];
   H1 = hash_value[1];
   H2 = hash_value[2];
   H3 = hash_value[3];
   H4 = hash_value[4];

   /* copy/xor message into array */

   W[0] = be32_to_cpu(M[0]);
   W[1] = be32_to_cpu(M[1]);
   W[2] = be32_to_cpu(M[2]);
   W[3] = be32_to_cpu(M[3]);
   W[4] = be32_to_cpu(M[4]);
   W[5] = be32_to_cpu(M[5]);
   W[6] = be32_to_cpu(M[6]);
   W[7] = be32_to_cpu(M[7]);
   W[8] = be32_to_cpu(M[8]);
   W[9] = be32_to_cpu(M[9]);
   W[10] = be32_to_cpu(M[10]);
   W[11] = be32_to_cpu(M[11]);
   W[12] = be32_to_cpu(M[12]);
   W[13] = be32_to_cpu(M[13]);
   W[14] = be32_to_cpu(M[14]);
   W[15] = be32_to_cpu(M[15]);
   TEMP = W[13] ^ W[8] ^ W[2] ^ W[0];
   W[16] = S1(TEMP);
   TEMP = W[14] ^ W[9] ^ W[3] ^ W[1];
   W[17] = S1(TEMP);
   TEMP = W[15] ^ W[10] ^ W[4] ^ W[2];
   W[18] = S1(TEMP);
   TEMP = W[16] ^ W[11] ^ W[5] ^ W[3];
   W[19] = S1(TEMP);
   TEMP = W[17] ^ W[12] ^ W[6] ^ W[4];
   W[20] = S1(TEMP);
   TEMP = W[18] ^ W[13] ^ W[7] ^ W[5];
   W[21] = S1(TEMP);
   TEMP = W[19] ^ W[14] ^ W[8] ^ W[6];
   W[22] = S1(TEMP);
   TEMP = W[20] ^ W[15] ^ W[9] ^ W[7];
   W[23] = S1(TEMP);
   TEMP = W[21] ^ W[16] ^ W[10] ^ W[8];
   W[24] = S1(TEMP);
   TEMP = W[22] ^ W[17] ^ W[11] ^ W[9];
   W[25] = S1(TEMP);
   TEMP = W[23] ^ W[18] ^ W[12] ^ W[10];
   W[26] = S1(TEMP);
   TEMP = W[24] ^ W[19] ^ W[13] ^ W[11];
   W[27] = S1(TEMP);
   TEMP = W[25] ^ W[20] ^ W[14] ^ W[12];
   W[28] = S1(TEMP);
   TEMP = W[26] ^ W[21] ^ W[15] ^ W[13];
   W[29] = S1(TEMP);
   TEMP = W[27] ^ W[22] ^ W[16] ^ W[14];
   W[30] = S1(TEMP);
   TEMP = W[28] ^ W[23] ^ W[17] ^ W[15];
   W[31] = S1(TEMP);

   /* process the remainder of the array */
   for (t = 32; t < 80; t++) {
       TEMP = W[t - 3] ^ W[t - 8] ^ W[t - 14] ^ W[t - 16];
       W[t] = S1(TEMP);
   }

   A = H0;
   B = H1;
   C = H2;
   D = H3;
   E = H4;

   for (t = 0; t < 20; t++) {
       TEMP = S5(A) + f0(B, C, D) + E + W[t] + SHA_K0;
       E = D;
       D = C;
       C = S30(B);
       B = A;
       A = TEMP;
   }
   for (; t < 40; t++) {
       TEMP = S5(A) + f1(B, C, D) + E + W[t] + SHA_K1;
       E = D;
       D = C;
       C = S30(B);
       B = A;
       A = TEMP;
   }
   for (; t < 60; t++) {
       TEMP = S5(A) + f2(B, C, D) + E + W[t] + SHA_K2;
       E = D;
       D = C;
       C = S30(B);
       B = A;
       A = TEMP;
   }
   for (; t < 80; t++) {
       TEMP = S5(A) + f3(B, C, D) + E + W[t] + SHA_K3;
       E = D;
       D = C;
       C = S30(B);
       B = A;
       A = TEMP;
   }

   hash_value[0] = H0 + A;
   hash_value[1] = H1 + B;
   hash_value[2] = H2 + C;
   hash_value[3] = H3 + D;
   hash_value[4] = H4 + E;

   return;
}

void srtp_sha1_init(srtp_sha1_ctx_t *ctx)
{
   /* initialize state vector */
   ctx->H[0] = 0x67452301;
   ctx->H[1] = 0xefcdab89;
   ctx->H[2] = 0x98badcfe;
   ctx->H[3] = 0x10325476;
   ctx->H[4] = 0xc3d2e1f0;

   /* indicate that message buffer is empty */
   ctx->octets_in_buffer = 0;

   /* reset message bit-count to zero */
   ctx->num_bits_in_msg = 0;
}

void srtp_sha1_update(srtp_sha1_ctx_t *ctx,
                     const uint8_t *msg,
                     int octets_in_msg)
{
   int i;
   uint8_t *buf = (uint8_t *)ctx->M;

   /* update message bit-count */
   ctx->num_bits_in_msg += octets_in_msg * 8;

   /* loop over 16-word blocks of M */
   while (octets_in_msg > 0) {
       if (octets_in_msg + ctx->octets_in_buffer >= 64) {
           /*
            * copy words of M into msg buffer until that buffer is full,
            * converting them into host byte order as needed
            */
           octets_in_msg -= (64 - ctx->octets_in_buffer);
           for (i = ctx->octets_in_buffer; i < 64; i++) {
               buf[i] = *msg++;
           }
           ctx->octets_in_buffer = 0;

           /* process a whole block */

           debug_print0(srtp_mod_sha1, "(update) running srtp_sha1_core()");

           srtp_sha1_core(ctx->M, ctx->H);

       } else {
           debug_print0(srtp_mod_sha1,
                        "(update) not running srtp_sha1_core()");

           for (i = ctx->octets_in_buffer;
                i < (ctx->octets_in_buffer + octets_in_msg); i++) {
               buf[i] = *msg++;
           }
           ctx->octets_in_buffer += octets_in_msg;
           octets_in_msg = 0;
       }
   }
}

/*
* srtp_sha1_final(ctx, output) computes the result for ctx and copies it
* into the twenty octets located at *output
*/

void srtp_sha1_final(srtp_sha1_ctx_t *ctx, uint32_t output[5])
{
   uint32_t A, B, C, D, E, TEMP;
   uint32_t W[80];
   int i, t;

   /*
    * process the remaining octets_in_buffer, padding and terminating as
    * necessary
    */
   {
       int tail = ctx->octets_in_buffer % 4;

       /* copy/xor message into array */
       for (i = 0; i < (ctx->octets_in_buffer + 3) / 4; i++) {
           W[i] = be32_to_cpu(ctx->M[i]);
       }

       /* set the high bit of the octet immediately following the message */
       switch (tail) {
       case (3):
           W[i - 1] = (be32_to_cpu(ctx->M[i - 1]) & 0xffffff00) | 0x80;
           W[i] = 0x0;
           break;
       case (2):
           W[i - 1] = (be32_to_cpu(ctx->M[i - 1]) & 0xffff0000) | 0x8000;
           W[i] = 0x0;
           break;
       case (1):
           W[i - 1] = (be32_to_cpu(ctx->M[i - 1]) & 0xff000000) | 0x800000;
           W[i] = 0x0;
           break;
       case (0):
           W[i] = 0x80000000;
           break;
       }

       /* zeroize remaining words */
       for (i++; i < 15; i++) {
           W[i] = 0x0;
       }

       /*
        * if there is room at the end of the word array, then set the
        * last word to the bit-length of the message; otherwise, set that
        * word to zero and then we need to do one more run of the
        * compression algo.
        */
       if (ctx->octets_in_buffer < 56) {
           W[15] = ctx->num_bits_in_msg;
       } else if (ctx->octets_in_buffer < 60) {
           W[15] = 0x0;
       }

       /* process the word array */
       for (t = 16; t < 80; t++) {
           TEMP = W[t - 3] ^ W[t - 8] ^ W[t - 14] ^ W[t - 16];
           W[t] = S1(TEMP);
       }

       A = ctx->H[0];
       B = ctx->H[1];
       C = ctx->H[2];
       D = ctx->H[3];
       E = ctx->H[4];

       for (t = 0; t < 20; t++) {
           TEMP = S5(A) + f0(B, C, D) + E + W[t] + SHA_K0;
           E = D;
           D = C;
           C = S30(B);
           B = A;
           A = TEMP;
       }
       for (; t < 40; t++) {
           TEMP = S5(A) + f1(B, C, D) + E + W[t] + SHA_K1;
           E = D;
           D = C;
           C = S30(B);
           B = A;
           A = TEMP;
       }
       for (; t < 60; t++) {
           TEMP = S5(A) + f2(B, C, D) + E + W[t] + SHA_K2;
           E = D;
           D = C;
           C = S30(B);
           B = A;
           A = TEMP;
       }
       for (; t < 80; t++) {
           TEMP = S5(A) + f3(B, C, D) + E + W[t] + SHA_K3;
           E = D;
           D = C;
           C = S30(B);
           B = A;
           A = TEMP;
       }

       ctx->H[0] += A;
       ctx->H[1] += B;
       ctx->H[2] += C;
       ctx->H[3] += D;
       ctx->H[4] += E;
   }

   debug_print0(srtp_mod_sha1, "(final) running srtp_sha1_core()");

   if (ctx->octets_in_buffer >= 56) {
       debug_print0(srtp_mod_sha1, "(final) running srtp_sha1_core() again");

       /* we need to do one final run of the compression algo */

       /*
        * set initial part of word array to zeros, and set the
        * final part to the number of bits in the message
        */
       for (i = 0; i < 15; i++) {
           W[i] = 0x0;
       }
       W[15] = ctx->num_bits_in_msg;

       /* process the word array */
       for (t = 16; t < 80; t++) {
           TEMP = W[t - 3] ^ W[t - 8] ^ W[t - 14] ^ W[t - 16];
           W[t] = S1(TEMP);
       }

       A = ctx->H[0];
       B = ctx->H[1];
       C = ctx->H[2];
       D = ctx->H[3];
       E = ctx->H[4];

       for (t = 0; t < 20; t++) {
           TEMP = S5(A) + f0(B, C, D) + E + W[t] + SHA_K0;
           E = D;
           D = C;
           C = S30(B);
           B = A;
           A = TEMP;
       }
       for (; t < 40; t++) {
           TEMP = S5(A) + f1(B, C, D) + E + W[t] + SHA_K1;
           E = D;
           D = C;
           C = S30(B);
           B = A;
           A = TEMP;
       }
       for (; t < 60; t++) {
           TEMP = S5(A) + f2(B, C, D) + E + W[t] + SHA_K2;
           E = D;
           D = C;
           C = S30(B);
           B = A;
           A = TEMP;
       }
       for (; t < 80; t++) {
           TEMP = S5(A) + f3(B, C, D) + E + W[t] + SHA_K3;
           E = D;
           D = C;
           C = S30(B);
           B = A;
           A = TEMP;
       }

       ctx->H[0] += A;
       ctx->H[1] += B;
       ctx->H[2] += C;
       ctx->H[3] += D;
       ctx->H[4] += E;
   }

   /* copy result into output buffer */
   output[0] = be32_to_cpu(ctx->H[0]);
   output[1] = be32_to_cpu(ctx->H[1]);
   output[2] = be32_to_cpu(ctx->H[2]);
   output[3] = be32_to_cpu(ctx->H[3]);
   output[4] = be32_to_cpu(ctx->H[4]);

   /* indicate that message buffer in context is empty */
   ctx->octets_in_buffer = 0;

   return;
}