Sylpheed

/* md5.c - MD5 Message-Digest Algorithm

 *        Copyright (C) 1995, 1996, 1998, 1999 Free Software Foundation, Inc.

 *

 * according to the definition of MD5 in RFC 1321 from April 1992.

 * NOTE: This is *not* the same file as the one from glibc.

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License as published by the

 * Free Software Foundation; either version 2, or (at your option) any

 * later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software Foundation,

 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

 */

/* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995.  */

/* heavily modified for GnuPG by <werner.koch@guug.de> */

/* modified again for Sylpheed by <wk@gnupg.org> 2001-02-11 */

/* Test values:

 * ""                  D4 1D 8C D9 8F 00 B2 04  E9 80 09 98 EC F8 42 7E

 * "a"                 0C C1 75 B9 C0 F1 B6 A8  31 C3 99 E2 69 77 26 61

 * "abc                90 01 50 98 3C D2 4F B0  D6 96 3F 7D 28 E1 7F 72

 * "message digest"    F9 6B 69 7D 7C B7 93 8D  52 5A 2F 31 AA F1 61 D0

 */

#include <config.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <assert.h>

#include "utils.h"

#include "md5.h"

/****************

 * Rotate a 32 bit integer by n bytes

 */

#if defined(__GNUC__) && defined(__i386__)

static inline u32

rol( u32 x, int n)

{

        __asm__("roll %%cl,%0"

                :"=r" (x)

                :"0" (x),"c" (n));

        return x;

}

#else

#define rol(x,n) ( ((x) << (n)) | ((x) >> (32-(n))) )

#endif

void

md5_init(MD5_CONTEXT *ctx)

{

        ctx->A = 0x67452301;

        ctx->B = 0xefcdab89;

        ctx->C = 0x98badcfe;

        ctx->D = 0x10325476;

        ctx->nblocks = 0;

        ctx->count = 0;

        ctx->finalized = 0;

}

/* These are the four functions used in the four steps of the MD5 algorithm

   and defined in the RFC 1321.  The first function is a little bit optimized

   (as found in Colin Plumbs public domain implementation).  */

/* #define FF(b, c, d) ((b & c) | (~b & d)) */

#define FF(b, c, d) (d ^ (b & (c ^ d)))

#define FG(b, c, d) FF (d, b, c)

#define FH(b, c, d) (b ^ c ^ d)

#define FI(b, c, d) (c ^ (b | ~d))

/****************

 * transform n*64 bytes

 */

static void

transform(MD5_CONTEXT *ctx, const unsigned char *data)

{

        u32 correct_words[16];

        u32 A = ctx->A;

        u32 B = ctx->B;

        u32 C = ctx->C;

        u32 D = ctx->D;

        u32 *cwp = correct_words;

#ifdef BIG_ENDIAN_HOST

        {

                int i;

                unsigned char *p2, *p1;

                for (i = 0, p1 = data, p2 = (unsigned char*)correct_words;

                     i < 16; i++, p2 += 4) {

                        p2[3] = *p1++;

                        p2[2] = *p1++;

                        p2[1] = *p1++;

                        p2[0] = *p1++;

                }

        }

#else

        memcpy(correct_words, data, 64);

#endif

#define OP(a, b, c, d, s, T)                                \

        do {                                                \

                a += FF (b, c, d) + (*cwp++) + T;         \

                a = rol(a, s);                                \

                a += b;                                        \

        } while (0)

        /* Before we start, one word about the strange constants.

           They are defined in RFC 1321 as

           T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64

         */

        /* Round 1.  */

        OP (A, B, C, D,  7, 0xd76aa478);

        OP (D, A, B, C, 12, 0xe8c7b756);

        OP (C, D, A, B, 17, 0x242070db);

        OP (B, C, D, A, 22, 0xc1bdceee);

        OP (A, B, C, D,  7, 0xf57c0faf);

        OP (D, A, B, C, 12, 0x4787c62a);

        OP (C, D, A, B, 17, 0xa8304613);

        OP (B, C, D, A, 22, 0xfd469501);

        OP (A, B, C, D,  7, 0x698098d8);

        OP (D, A, B, C, 12, 0x8b44f7af);

        OP (C, D, A, B, 17, 0xffff5bb1);

        OP (B, C, D, A, 22, 0x895cd7be);

        OP (A, B, C, D,  7, 0x6b901122);

        OP (D, A, B, C, 12, 0xfd987193);

        OP (C, D, A, B, 17, 0xa679438e);

        OP (B, C, D, A, 22, 0x49b40821);

#undef OP

#define OP(f, a, b, c, d, k, s, T)  \

        do {                                                        \

                a += f (b, c, d) + correct_words[k] + T;        \

                a = rol(a, s);                                        \

                a += b;                                         \

        } while (0)

        /* Round 2.  */

        OP (FG, A, B, C, D,  1,  5, 0xf61e2562);

        OP (FG, D, A, B, C,  6,  9, 0xc040b340);

        OP (FG, C, D, A, B, 11, 14, 0x265e5a51);

        OP (FG, B, C, D, A,  0, 20, 0xe9b6c7aa);

        OP (FG, A, B, C, D,  5,  5, 0xd62f105d);

        OP (FG, D, A, B, C, 10,  9, 0x02441453);

        OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);

        OP (FG, B, C, D, A,  4, 20, 0xe7d3fbc8);

        OP (FG, A, B, C, D,  9,  5, 0x21e1cde6);

        OP (FG, D, A, B, C, 14,  9, 0xc33707d6);

        OP (FG, C, D, A, B,  3, 14, 0xf4d50d87);

        OP (FG, B, C, D, A,  8, 20, 0x455a14ed);

        OP (FG, A, B, C, D, 13,  5, 0xa9e3e905);

        OP (FG, D, A, B, C,  2,  9, 0xfcefa3f8);

        OP (FG, C, D, A, B,  7, 14, 0x676f02d9);

        OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);

        /* Round 3.  */

        OP (FH, A, B, C, D,  5,  4, 0xfffa3942);

        OP (FH, D, A, B, C,  8, 11, 0x8771f681);

        OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);

        OP (FH, B, C, D, A, 14, 23, 0xfde5380c);

        OP (FH, A, B, C, D,  1,  4, 0xa4beea44);

        OP (FH, D, A, B, C,  4, 11, 0x4bdecfa9);

        OP (FH, C, D, A, B,  7, 16, 0xf6bb4b60);

        OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);

        OP (FH, A, B, C, D, 13,  4, 0x289b7ec6);

        OP (FH, D, A, B, C,  0, 11, 0xeaa127fa);

        OP (FH, C, D, A, B,  3, 16, 0xd4ef3085);

        OP (FH, B, C, D, A,  6, 23, 0x04881d05);

        OP (FH, A, B, C, D,  9,  4, 0xd9d4d039);

        OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);

        OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);

        OP (FH, B, C, D, A,  2, 23, 0xc4ac5665);

        /* Round 4.  */

        OP (FI, A, B, C, D,  0,  6, 0xf4292244);

        OP (FI, D, A, B, C,  7, 10, 0x432aff97);

        OP (FI, C, D, A, B, 14, 15, 0xab9423a7);

        OP (FI, B, C, D, A,  5, 21, 0xfc93a039);

        OP (FI, A, B, C, D, 12,  6, 0x655b59c3);

        OP (FI, D, A, B, C,  3, 10, 0x8f0ccc92);

        OP (FI, C, D, A, B, 10, 15, 0xffeff47d);

        OP (FI, B, C, D, A,  1, 21, 0x85845dd1);

        OP (FI, A, B, C, D,  8,  6, 0x6fa87e4f);

        OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);

        OP (FI, C, D, A, B,  6, 15, 0xa3014314);

        OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);

        OP (FI, A, B, C, D,  4,  6, 0xf7537e82);

        OP (FI, D, A, B, C, 11, 10, 0xbd3af235);

        OP (FI, C, D, A, B,  2, 15, 0x2ad7d2bb);

        OP (FI, B, C, D, A,  9, 21, 0xeb86d391);

        /* Put checksum in context given as argument.  */

        ctx->A += A;

        ctx->B += B;

        ctx->C += C;

        ctx->D += D;

}

/* The routine updates the message-digest context to

 * account for the presence of each of the characters inBuf[0..inLen-1]

 * in the message whose digest is being computed.

 */

void

md5_update(MD5_CONTEXT *hd, const unsigned char *inbuf, size_t inlen)

{

        if (hd->count == 64) { /* flush the buffer */

                transform( hd, hd->buf );

                hd->count = 0;

                hd->nblocks++;

        }

        if (!inbuf)

                return;

        if (hd->count) {

                for (; inlen && hd->count < 64; inlen--)

                        hd->buf[hd->count++] = *inbuf++;

                md5_update(hd, NULL, 0);

                if (!inlen)

                        return;

        }

        while (inlen >= 64) {

                transform(hd, inbuf);

                hd->count = 0;

                hd->nblocks++;

                inlen -= 64;

                inbuf += 64;

        }

        for (; inlen && hd->count < 64; inlen--)

                hd->buf[hd->count++] = *inbuf++;

}

/* The routine final terminates the message-digest computation and

 * ends with the desired message digest in mdContext->digest[0...15].

 * The handle is prepared for a new MD5 cycle.

 * Returns 16 bytes representing the digest.

 */

static void

do_final(MD5_CONTEXT *hd)

{

        u32 t, msb, lsb;

        unsigned char *p;

        md5_update(hd, NULL, 0); /* flush */

        msb = 0;

        t = hd->nblocks;

        if ((lsb = t << 6) < t) /* multiply by 64 to make a byte count */

                msb++;

        msb += t >> 26;

        t = lsb;

        if ((lsb = t + hd->count) < t) /* add the count */

                msb++;

        t = lsb;

        if ((lsb = t << 3) < t) /* multiply by 8 to make a bit count */

                msb++;

        msb += t >> 29;

        if (hd->count < 56) { /* enough room */

                hd->buf[hd->count++] = 0x80; /* pad */

                while(hd->count < 56)

                        hd->buf[hd->count++] = 0;  /* pad */

        } else { /* need one extra block */

                hd->buf[hd->count++] = 0x80; /* pad character */

                while (hd->count < 64)

                        hd->buf[hd->count++] = 0;

                md5_update(hd, NULL, 0);  /* flush */

                memset(hd->buf, 0, 56); /* fill next block with zeroes */

        }

        /* append the 64 bit count */

        hd->buf[56] = lsb      ;

        hd->buf[57] = lsb >>  8;

        hd->buf[58] = lsb >> 16;

        hd->buf[59] = lsb >> 24;

        hd->buf[60] = msb      ;

        hd->buf[61] = msb >>  8;

        hd->buf[62] = msb >> 16;

        hd->buf[63] = msb >> 24;

        transform(hd, hd->buf);

        p = hd->buf;

#ifdef BIG_ENDIAN_HOST

#define X(a) do { *p++ = hd->a      ; *p++ = hd->a >> 8;      \

                  *p++ = hd->a >> 16; *p++ = hd->a >> 24; } while(0)

#else /* little endian */

        /*#define X(a) do { *(u32*)p = hd->##a ; p += 4; } while(0)*/

        /* Unixware's cpp doesn't like the above construct so we do it his way:

         * (reported by Allan Clark) */

#define X(a) do { *(u32*)p = (*hd).a ; p += 4; } while(0)

#endif

        X(A);

        X(B);

        X(C);

        X(D);

#undef X

        hd->finalized = 1;

}

void

md5_final(unsigned char *digest, MD5_CONTEXT *ctx)

{

        if (!ctx->finalized)

                do_final(ctx);

        memcpy(digest, ctx->buf, 16);

}

/*

 * Creates a MD5 digest in hex fomrat (lowercase letters) from the

 * string S.  hextdigest but be buffer of at lease 33 bytes!

 */

void

md5_hex_digest(char *hexdigest, const unsigned char *s)

{

        int i;

        MD5_CONTEXT context;

        unsigned char digest[16];

        md5_init(&context);

        md5_update(&context, s, strlen(s));

        md5_final(digest, &context);

        for (i = 0; i < 16; i++)

                sprintf(hexdigest + 2 * i, "%02x", digest[i]);

}

/*

** Function: md5_hmac

** taken from the file rfc2104.txt

** written by Martin Schaaf <mascha@ma-scha.de>

*/

void

md5_hmac(unsigned char *digest,

         const unsigned char* text, int text_len,

         const unsigned char* key, int key_len)

{

        MD5_CONTEXT context;

        unsigned char k_ipad[64];    /* inner padding -

                                      * key XORd with ipad

                                      */

        unsigned char k_opad[64];    /* outer padding -

                                      * key XORd with opad

                                      */

        /* unsigned char tk[16]; */

        int i;

        /* start out by storing key in pads */

        memset(k_ipad, 0, sizeof k_ipad);

        memset(k_opad, 0, sizeof k_opad);

        if (key_len > 64) {

                /* if key is longer than 64 bytes reset it to key=MD5(key) */

                MD5_CONTEXT tctx;

                md5_init(&tctx);

                md5_update(&tctx, key, key_len);

                md5_final(k_ipad, &tctx);

                md5_final(k_opad, &tctx);

        } else {

                memcpy(k_ipad, key, key_len);

                memcpy(k_opad, key, key_len);

        }

        /*

         * the HMAC_MD5 transform looks like:

         *

         * MD5(K XOR opad, MD5(K XOR ipad, text))

         *

         * where K is an n byte key

         * ipad is the byte 0x36 repeated 64 times

         * opad is the byte 0x5c repeated 64 times

         * and text is the data being protected

         */

        /* XOR key with ipad and opad values */

        for (i = 0; i < 64; i++) {

                k_ipad[i] ^= 0x36;

                k_opad[i] ^= 0x5c;

        }

        /*

         * perform inner MD5

         */

        md5_init(&context);                      /* init context for 1st

                                               * pass */

        md5_update(&context, k_ipad, 64);     /* start with inner pad */

        md5_update(&context, text, text_len); /* then text of datagram */

        md5_final(digest, &context);              /* finish up 1st pass */

        /*

         * perform outer MD5

         */

        md5_init(&context);                      /* init context for 2nd

                                               * pass */

        md5_update(&context, k_opad, 64);     /* start with outer pad */

        md5_update(&context, digest, 16);     /* then results of 1st

                                               * hash */

        md5_final(digest, &context);              /* finish up 2nd pass */

}

void

md5_hex_hmac(char *hexdigest,

             const unsigned char* text, int text_len,

             const unsigned char* key, int key_len)

{

        unsigned char digest[16];

        int i;

        md5_hmac(digest, text, text_len, key, key_len);

        for (i = 0; i < 16; i++)

                sprintf(hexdigest + 2 * i, "%02x", digest[i]);

}