md5.c

snmp up 2

    ii(A, B, C, D, 4, is1, Uns(4149444226));
    ii(D, A, B, C, 11, is2, Uns(3174756917));
    ii(C, D, A, B, 2, is3, Uns(718787259));
    ii(B, C, D, A, 9, is4, Uns(3951481745));

    MDp->buffer[0] += A;
    MDp->buffer[1] += B;
    MDp->buffer[2] += C;
    MDp->buffer[3] += D;
#ifdef WORDS_BIGENDIAN
    MDreverse(X);
#endif
}

/*
 * MDupdate(MDp,X,count)
 * ** Input: MDp -- an MDptr
 * **        X -- a pointer to an array of unsigned characters.
 * **        count -- the number of bits of X to use.
 * **                 (if not a multiple of 8, uses high bits of last byte.)
 * ** Update MDp using the number of bits of X given by count.
 * ** This is the basic input routine for an MD5 user.
 * ** The routine completes the MD computation when count < 512, so
 * ** every MD computation should end with one call to MDupdate with a
 * ** count less than 512.  A call with count 0 will be ignored if the
 * ** MD has already been terminated (done != 0), so an extra call with count
 * ** 0 can be given as a ``courtesy close'' to force termination if desired.
 * ** Returns : 0 if processing succeeds or was already done;
 * **          -1 if processing was already done
 * **          -2 if count was too large
 */
int
MDupdate(MDptr MDp, unsigned char *X, unsigned int count)
{
    unsigned int    i, tmp, bit, byte, mask;
    unsigned char   XX[64];
    unsigned char  *p;
    /*
     * return with no error if this is a courtesy close with count
     * ** zero and MDp->done is true.
     */
    if (count == 0 && MDp->done)
        return 0;
    /*
     * check to see if MD is already done and report error 
     */
    if (MDp->done) {
        return -1;
    }
    /*
     * if (MDp->done) { fprintf(stderr,"\nError: MDupdate MD already done."); return; }
     */
    /*
     * Add count to MDp->count 
     */
    tmp = count;
    p = MDp->count;
    while (tmp) {
        tmp += *p;
        *p++ = tmp;
        tmp = tmp >> 8;
    }
    /*
     * Process data 
     */
    if (count == 512) {         /* Full block of data to handle */
        MDblock(MDp, (unsigned int *) X);
    } else if (count > 512)     /* Check for count too large */
        return -2;
    /*
     * { fprintf(stderr,"\nError: MDupdate called with illegal count value %d.",count);
     * return;
     * }
     */
    else {                      /* partial block -- must be last block so finish up */
        /*
         * Find out how many bytes and residual bits there are 
         */
        int             copycount;
        byte = count >> 3;
        bit = count & 7;
        copycount = byte;
        if (bit)
            copycount++;
        /*
         * Copy X into XX since we need to modify it 
         */
        memset(XX, 0, sizeof(XX));
        memcpy(XX, X, copycount);

        /*
         * Add padding '1' bit and low-order zeros in last byte 
         */
        mask = ((unsigned long) 1) << (7 - bit);
        XX[byte] = (XX[byte] | mask) & ~(mask - 1);
        /*
         * If room for bit count, finish up with this block 
         */
        if (byte <= 55) {
            for (i = 0; i < 8; i++)
                XX[56 + i] = MDp->count[i];
            MDblock(MDp, (unsigned int *) XX);
        } else {                /* need to do two blocks to finish up */
            MDblock(MDp, (unsigned int *) XX);
            for (i = 0; i < 56; i++)
                XX[i] = 0;
            for (i = 0; i < 8; i++)
                XX[56 + i] = MDp->count[i];
            MDblock(MDp, (unsigned int *) XX);
        }
        /*
         * Set flag saying we're done with MD computation 
         */
        MDp->done = 1;
    }
    return 0;
}

/*
 * MDchecksum(data, len, MD5): do a checksum on an arbirtrary amount of data 
 */
int
MDchecksum(u_char * data, size_t len, u_char * mac, size_t maclen)
{
    MDstruct        md;
    MDstruct       *MD = &md;
    int             rc = 0;

    MDbegin(MD);
    while (len >= 64) {
        rc = MDupdate(MD, data, 64 * 8);
        if (rc)
            goto check_end;
        data += 64;
        len -= 64;
    }
    rc = MDupdate(MD, data, len * 8);
    if (rc)
        goto check_end;

    /*
     * copy the checksum to the outgoing data (all of it that is requested). 
     */
    MDget(MD, mac, maclen);

  check_end:
    memset(&md, 0, sizeof(md));
    return rc;
}


/*
 * MDsign(data, len, MD5): do a checksum on an arbirtrary amount
 * of data, and prepended with a secret in the standard fashion 
 */
int
MDsign(u_char * data, size_t len, u_char * mac, size_t maclen,
       u_char * secret, size_t secretlen)
{
#define HASHKEYLEN 64

    MDstruct        MD;
    u_char          K1[HASHKEYLEN];
    u_char          K2[HASHKEYLEN];
    u_char          extendedAuthKey[HASHKEYLEN];
    u_char          buf[HASHKEYLEN];
    size_t          i;
    u_char         *cp, *newdata = 0;
    int             rc = 0;

    /*
     * memset(K1,0,HASHKEYLEN);
     * memset(K2,0,HASHKEYLEN);
     * memset(buf,0,HASHKEYLEN);
     * memset(extendedAuthKey,0,HASHKEYLEN);
     */

    if (secretlen != 16 || secret == NULL || mac == NULL || data == NULL ||
        len <= 0 || maclen <= 0) {
        /*
         * DEBUGMSGTL(("md5","MD5 signing not properly initialized")); 
         */
        return -1;
    }

    memset(extendedAuthKey, 0, HASHKEYLEN);
    memcpy(extendedAuthKey, secret, secretlen);
    for (i = 0; i < HASHKEYLEN; i++) {
        K1[i] = extendedAuthKey[i] ^ 0x36;
        K2[i] = extendedAuthKey[i] ^ 0x5c;
    }

    MDbegin(&MD);
    rc = MDupdate(&MD, K1, HASHKEYLEN * 8);
    if (rc)
        goto update_end;

    i = len;
    if (((unsigned int) data) % 32 != 0) {
        /*
         * this relies on the ability to use integer math and thus we
         * must rely on data that aligns on 32-bit-word-boundries 
         */
        memdup(&newdata, data, len);
        cp = newdata;
    } else {
        cp = data;
    }

    while (i >= 64) {
        rc = MDupdate(&MD, cp, 64 * 8);
        if (rc)
            goto update_end;
        cp += 64;
        i -= 64;
    }

    rc = MDupdate(&MD, cp, i * 8);
    if (rc)
        goto update_end;

    memset(buf, 0, HASHKEYLEN);
    MDget(&MD, buf, HASHKEYLEN);

    MDbegin(&MD);
    rc = MDupdate(&MD, K2, HASHKEYLEN * 8);
    if (rc)
        goto update_end;
    rc = MDupdate(&MD, buf, 16 * 8);
    if (rc)
        goto update_end;

    /*
     * copy the sign checksum to the outgoing pointer 
     */
    MDget(&MD, mac, maclen);

  update_end:
    memset(buf, 0, HASHKEYLEN);
    memset(K1, 0, HASHKEYLEN);
    memset(K2, 0, HASHKEYLEN);
    memset(extendedAuthKey, 0, HASHKEYLEN);
    memset(&MD, 0, sizeof(MD));

    if (newdata)
        free(newdata);
    return rc;
}

void
MDget(MDstruct * MD, u_char * buf, size_t buflen)
{
    int             i, j;

    /*
     * copy the checksum to the outgoing data (all of it that is requested). 
     */
    for (i = 0; i < 4 && i * 4 < (int) buflen; i++)
        for (j = 0; j < 4 && i * 4 + j < (int) buflen; j++)
            buf[i * 4 + j] = (MD->buffer[i] >> j * 8) & 0xff;
}

/*
 * ** End of md5.c
 * ****************************(cut)****************************************
 */