/*
* RSA implementation just sufficient for ssh client-side
* initialisation step
+ *
+ * Rewritten for more speed by Joris van Rantwijk, Jun 1999.
*/
-/*#include <windows.h>
-#define RSADEBUG
-#define DLVL 2
-#include "stel.h"*/
-
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "ssh.h"
-typedef unsigned short *Bignum;
-
-static unsigned short Zero[1] = { 0 };
-
-#if defined TESTMODE || defined RSADEBUG
-#ifndef DLVL
-#define DLVL 10000
-#endif
-#define debug(x) bndebug(#x,x)
-static int level = 0;
-static void bndebug(char *name, Bignum b) {
- int i;
- int w = 50-level-strlen(name)-5*b[0];
- if (level >= DLVL)
- return;
- if (w < 0) w = 0;
- dprintf("%*s%s%*s", level, "", name, w, "");
- for (i=b[0]; i>0; i--)
- dprintf(" %04x", b[i]);
- dprintf("\n");
-}
-#define dmsg(x) do {if(level<DLVL){dprintf("%*s",level,"");printf x;}} while(0)
-#define enter(x) do { dmsg(x); level += 4; } while(0)
-#define leave(x) do { level -= 4; dmsg(x); } while(0)
-#else
-#define debug(x)
-#define dmsg(x)
-#define enter(x)
-#define leave(x)
-#endif
-
-static Bignum newbn(int length) {
- Bignum b = malloc((length+1)*sizeof(unsigned short));
- if (!b)
- abort(); /* FIXME */
- b[0] = length;
- return b;
-}
-
-static void freebn(Bignum b) {
- free(b);
-}
-
-static int msb(Bignum r) {
- int i;
- int j;
- unsigned short n;
-
- for (i=r[0]; i>0; i--)
- if (r[i])
- break;
-
- j = (i-1)*16;
- n = r[i];
- if (n & 0xFF00) j += 8, n >>= 8;
- if (n & 0x00F0) j += 4, n >>= 4;
- if (n & 0x000C) j += 2, n >>= 2;
- if (n & 0x0002) j += 1, n >>= 1;
-
- return j;
-}
-
-static void add(Bignum r1, Bignum r2, Bignum result) {
- int i;
- long stuff = 0;
-
- enter((">add\n"));
- debug(r1);
- debug(r2);
-
- for (i = 1 ;; i++) {
- if (i <= r1[0])
- stuff += r1[i];
- if (i <= r2[0])
- stuff += r2[i];
- if (i <= result[0])
- result[i] = stuff & 0xFFFFU;
- if (i > r1[0] && i > r2[0] && i >= result[0])
- break;
- stuff >>= 16;
- }
-
- debug(result);
- leave(("<add\n"));
-}
-
-static void sub(Bignum r1, Bignum r2, Bignum result) {
- int i;
- long stuff = 0;
-
- enter((">sub\n"));
- debug(r1);
- debug(r2);
-
- for (i = 1 ;; i++) {
- if (i <= r1[0])
- stuff += r1[i];
- if (i <= r2[0])
- stuff -= r2[i];
- if (i <= result[0])
- result[i] = stuff & 0xFFFFU;
- if (i > r1[0] && i > r2[0] && i >= result[0])
- break;
- stuff = stuff<0 ? -1 : 0;
- }
-
- debug(result);
- leave(("<sub\n"));
-}
-
-static int ge(Bignum r1, Bignum r2) {
- int i;
-
- enter((">ge\n"));
- debug(r1);
- debug(r2);
-
- if (r1[0] < r2[0])
- i = r2[0];
- else
- i = r1[0];
-
- while (i > 0) {
- unsigned short n1 = (i > r1[0] ? 0 : r1[i]);
- unsigned short n2 = (i > r2[0] ? 0 : r2[i]);
-
- if (n1 > n2) {
- dmsg(("greater\n"));
- leave(("<ge\n"));
- return 1; /* r1 > r2 */
- } else if (n1 < n2) {
- dmsg(("less\n"));
- leave(("<ge\n"));
- return 0; /* r1 < r2 */
- }
-
- i--;
- }
-
- dmsg(("equal\n"));
- leave(("<ge\n"));
- return 1; /* r1 = r2 */
-}
-
-static void modmult(Bignum r1, Bignum r2, Bignum modulus, Bignum result) {
- Bignum temp = newbn(modulus[0]+1);
- Bignum tmp2 = newbn(modulus[0]+1);
- int i;
- int bit, bits, digit, smallbit;
-
- enter((">modmult\n"));
- debug(r1);
- debug(r2);
- debug(modulus);
-
- for (i=1; i<=result[0]; i++)
- result[i] = 0; /* result := 0 */
- for (i=1; i<=temp[0]; i++)
- temp[i] = (i > r2[0] ? 0 : r2[i]); /* temp := r2 */
-
- bits = 1+msb(r1);
-
- for (bit = 0; bit < bits; bit++) {
- digit = 1 + bit / 16;
- smallbit = bit % 16;
-
- debug(temp);
- if (digit <= r1[0] && (r1[digit] & (1<<smallbit))) {
- dmsg(("bit %d\n", bit));
- add(temp, result, tmp2);
- if (ge(tmp2, modulus))
- sub(tmp2, modulus, result);
- else
- add(tmp2, Zero, result);
- debug(result);
- }
-
- add(temp, temp, tmp2);
- if (ge(tmp2, modulus))
- sub(tmp2, modulus, temp);
- else
- add(tmp2, Zero, temp);
- }
-
- freebn(temp);
- freebn(tmp2);
-
- debug(result);
- leave(("<modmult\n"));
-}
-
-static void modpow(Bignum r1, Bignum r2, Bignum modulus, Bignum result) {
- Bignum temp = newbn(modulus[0]+1);
- Bignum tmp2 = newbn(modulus[0]+1);
- int i;
- int bit, bits, digit, smallbit;
-
- enter((">modpow\n"));
- debug(r1);
- debug(r2);
- debug(modulus);
-
- for (i=1; i<=result[0]; i++)
- result[i] = (i==1); /* result := 1 */
- for (i=1; i<=temp[0]; i++)
- temp[i] = (i > r1[0] ? 0 : r1[i]); /* temp := r1 */
-
- bits = 1+msb(r2);
-
- for (bit = 0; bit < bits; bit++) {
- digit = 1 + bit / 16;
- smallbit = bit % 16;
-
- debug(temp);
- if (digit <= r2[0] && (r2[digit] & (1<<smallbit))) {
- dmsg(("bit %d\n", bit));
- modmult(temp, result, modulus, tmp2);
- add(tmp2, Zero, result);
- debug(result);
- }
-
- modmult(temp, temp, modulus, tmp2);
- add(tmp2, Zero, temp);
- }
-
- freebn(temp);
- freebn(tmp2);
-
- debug(result);
- leave(("<modpow\n"));
-}
int makekey(unsigned char *data, struct RSAKey *result,
- unsigned char **keystr) {
+ unsigned char **keystr, int order) {
unsigned char *p = data;
- Bignum bn[2];
- int i, j;
- int w, b;
-
- result->bits = 0;
- for (i=0; i<4; i++)
- result->bits = (result->bits << 8) + *p++;
-
- for (j=0; j<2; j++) {
-
- w = 0;
- for (i=0; i<2; i++)
- w = (w << 8) + *p++;
-
- result->bytes = b = (w+7)/8; /* bits -> bytes */
- w = (w+15)/16; /* bits -> words */
-
- bn[j] = newbn(w);
-
- if (keystr) *keystr = p; /* point at key string, second time */
-
- for (i=1; i<=w; i++)
- bn[j][i] = 0;
- for (i=0; i<b; i++) {
- unsigned char byte = *p++;
- if ((b-i) & 1)
- bn[j][w-i/2] |= byte;
- else
- bn[j][w-i/2] |= byte<<8;
- }
-
- debug(bn[j]);
-
- }
+ int i;
- result->exponent = bn[0];
- result->modulus = bn[1];
+ if (result) {
+ result->bits = 0;
+ for (i=0; i<4; i++)
+ result->bits = (result->bits << 8) + *p++;
+ } else
+ p += 4;
+
+ /*
+ * order=0 means exponent then modulus (the keys sent by the
+ * server). order=1 means modulus then exponent (the keys
+ * stored in a keyfile).
+ */
+
+ if (order == 0)
+ p += ssh1_read_bignum(p, result ? &result->exponent : NULL);
+ if (result)
+ result->bytes = (((p[0] << 8) + p[1]) + 7) / 8;
+ if (keystr) *keystr = p+2;
+ p += ssh1_read_bignum(p, result ? &result->modulus : NULL);
+ if (order == 1)
+ p += ssh1_read_bignum(p, result ? &result->exponent : NULL);
return p - data;
}
+int makeprivate(unsigned char *data, struct RSAKey *result) {
+ return ssh1_read_bignum(data, &result->private_exponent);
+}
+
void rsaencrypt(unsigned char *data, int length, struct RSAKey *key) {
Bignum b1, b2;
int w, i;
unsigned char *p;
- debug(key->exponent);
-
memmove(data+key->bytes-length, data, length);
data[0] = 0;
data[1] = 2;
p = data;
for (i=1; i<=w; i++)
b1[i] = 0;
- for (i=0; i<key->bytes; i++) {
+ for (i=key->bytes; i-- ;) {
unsigned char byte = *p++;
- if ((key->bytes-i) & 1)
- b1[w-i/2] |= byte;
+ if (i & 1)
+ b1[1+i/2] |= byte<<8;
else
- b1[w-i/2] |= byte<<8;
+ b1[1+i/2] |= byte;
}
- debug(b1);
-
modpow(b1, key->exponent, key->modulus, b2);
- debug(b2);
-
p = data;
- for (i=0; i<key->bytes; i++) {
+ for (i=key->bytes; i-- ;) {
unsigned char b;
if (i & 1)
- b = b2[w-i/2] & 0xFF;
+ b = b2[1+i/2] >> 8;
else
- b = b2[w-i/2] >> 8;
+ b = b2[1+i/2] & 0xFF;
*p++ = b;
}
freebn(b2);
}
+Bignum rsadecrypt(Bignum input, struct RSAKey *key) {
+ Bignum ret;
+ ret = newbn(key->modulus[0]);
+ modpow(input, key->private_exponent, key->modulus, ret);
+ return ret;
+}
+
int rsastr_len(struct RSAKey *key) {
Bignum md, ex;
md = key->modulus;
ex = key->exponent;
- return 4 * (ex[0]+md[0]) + 10;
+ return 4 * (ex[0]+md[0]) + 20;
}
void rsastr_fmt(char *str, struct RSAKey *key) {
Bignum md, ex;
- int len = 0, i;
+ int len = 0, i, nibbles;
+ static const char hex[] = "0123456789abcdef";
md = key->modulus;
ex = key->exponent;
- for (i=1; i<=ex[0]; i++) {
- sprintf(str+len, "%04x", ex[i]);
- len += strlen(str+len);
- }
- str[len++] = '/';
- for (i=1; i<=md[0]; i++) {
- sprintf(str+len, "%04x", md[i]);
- len += strlen(str+len);
- }
+ len += sprintf(str+len, "0x");
+
+ nibbles = (3 + ssh1_bignum_bitcount(ex))/4; if (nibbles<1) nibbles=1;
+ for (i=nibbles; i-- ;)
+ str[len++] = hex[(bignum_byte(ex, i/2) >> (4*(i%2))) & 0xF];
+
+ len += sprintf(str+len, ",0x");
+
+ nibbles = (3 + ssh1_bignum_bitcount(md))/4; if (nibbles<1) nibbles=1;
+ for (i=nibbles; i-- ;)
+ str[len++] = hex[(bignum_byte(md, i/2) >> (4*(i%2))) & 0xF];
+
str[len] = '\0';
}
-#ifdef TESTMODE
-
-#ifndef NODDY
-#define p1 10007
-#define p2 10069
-#define p3 10177
-#else
-#define p1 3
-#define p2 7
-#define p3 13
-#endif
-
-unsigned short P1[2] = { 1, p1 };
-unsigned short P2[2] = { 1, p2 };
-unsigned short P3[2] = { 1, p3 };
-unsigned short bigmod[5] = { 4, 0, 0, 0, 32768U };
-unsigned short mod[5] = { 4, 0, 0, 0, 0 };
-unsigned short a[5] = { 4, 0, 0, 0, 0 };
-unsigned short b[5] = { 4, 0, 0, 0, 0 };
-unsigned short c[5] = { 4, 0, 0, 0, 0 };
-unsigned short One[2] = { 1, 1 };
-unsigned short Two[2] = { 1, 2 };
-
-int main(void) {
- modmult(P1, P2, bigmod, a); debug(a);
- modmult(a, P3, bigmod, mod); debug(mod);
-
- sub(P1, One, a); debug(a);
- sub(P2, One, b); debug(b);
- modmult(a, b, bigmod, c); debug(c);
- sub(P3, One, a); debug(a);
- modmult(a, c, bigmod, b); debug(b);
-
- modpow(Two, b, mod, a); debug(a);
-
- return 0;
+/*
+ * Generate a fingerprint string for the key. Compatible with the
+ * OpenSSH fingerprint code.
+ */
+void rsa_fingerprint(char *str, int len, struct RSAKey *key) {
+ struct MD5Context md5c;
+ unsigned char digest[16];
+ char buffer[16*3+40];
+ int numlen, slen, i;
+
+ MD5Init(&md5c);
+ numlen = ssh1_bignum_length(key->modulus) - 2;
+ for (i = numlen; i-- ;) {
+ unsigned char c = bignum_byte(key->modulus, i);
+ MD5Update(&md5c, &c, 1);
+ }
+ numlen = ssh1_bignum_length(key->exponent) - 2;
+ for (i = numlen; i-- ;) {
+ unsigned char c = bignum_byte(key->exponent, i);
+ MD5Update(&md5c, &c, 1);
+ }
+ MD5Final(digest, &md5c);
+
+ sprintf(buffer, "%d ", ssh1_bignum_bitcount(key->modulus));
+ for (i = 0; i < 16; i++)
+ sprintf(buffer+strlen(buffer), "%s%02x", i?":":"", digest[i]);
+ strncpy(str, buffer, len); str[len-1] = '\0';
+ slen = strlen(str);
+ if (key->comment && slen < len-1) {
+ str[slen] = ' ';
+ strncpy(str+slen+1, key->comment, len-slen-1);
+ str[len-1] = '\0';
+ }
}
-#endif
+void freersakey(struct RSAKey *key) {
+ if (key->modulus) freebn(key->modulus);
+ if (key->exponent) freebn(key->exponent);
+ if (key->private_exponent) freebn(key->private_exponent);
+ if (key->comment) free(key->comment);
+}
projects / u / mdw / putty / blobdiff