#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);
-}
-
-/*
- * Compute c = a * b.
- * Input is in the first len words of a and b.
- * Result is returned in the first 2*len words of c.
- */
-static void bigmul(unsigned short *a, unsigned short *b, unsigned short *c,
- int len)
-{
- int i, j;
- unsigned long ai, t;
-
- for (j = len - 1; j >= 0; j--)
- c[j+len] = 0;
-
- for (i = len - 1; i >= 0; i--) {
- ai = a[i];
- t = 0;
- for (j = len - 1; j >= 0; j--) {
- t += ai * (unsigned long) b[j];
- t += (unsigned long) c[i+j+1];
- c[i+j+1] = (unsigned short)t;
- t = t >> 16;
- }
- c[i] = (unsigned short)t;
- }
-}
-
-/*
- * Compute a = a % m.
- * Input in first 2*len words of a and first len words of m.
- * Output in first 2*len words of a (of which first len words will be zero).
- * The MSW of m MUST have its high bit set.
- */
-static void bigmod(unsigned short *a, unsigned short *m, int len)
-{
- unsigned short m0, m1;
- unsigned int h;
- int i, k;
-
- /* Special case for len == 1 */
- if (len == 1) {
- a[1] = (((long) a[0] << 16) + a[1]) % m[0];
- a[0] = 0;
- return;
- }
-
- m0 = m[0];
- m1 = m[1];
-
- for (i = 0; i <= len; i++) {
- unsigned long t;
- unsigned int q, r, c;
-
- if (i == 0) {
- h = 0;
- } else {
- h = a[i-1];
- a[i-1] = 0;
- }
-
- /* Find q = h:a[i] / m0 */
- t = ((unsigned long) h << 16) + a[i];
- q = t / m0;
- r = t % m0;
-
- /* Refine our estimate of q by looking at
- h:a[i]:a[i+1] / m0:m1 */
- t = (long) m1 * (long) q;
- if (t > ((unsigned long) r << 16) + a[i+1]) {
- q--;
- t -= m1;
- r = (r + m0) & 0xffff; /* overflow? */
- if (r >= (unsigned long)m0 &&
- t > ((unsigned long) r << 16) + a[i+1])
- q--;
- }
-
- /* Substract q * m from a[i...] */
- c = 0;
- for (k = len - 1; k >= 0; k--) {
- t = (long) q * (long) m[k];
- t += c;
- c = t >> 16;
- if ((unsigned short) t > a[i+k]) c++;
- a[i+k] -= (unsigned short) t;
- }
-
- /* Add back m in case of borrow */
- if (c != h) {
- t = 0;
- for (k = len - 1; k >= 0; k--) {
- t += m[k];
- t += a[i+k];
- a[i+k] = (unsigned short)t;
- t = t >> 16;
- }
- }
- }
-}
-
-/*
- * Compute (base ^ exp) % mod.
- * The base MUST be smaller than the modulus.
- * The most significant word of mod MUST be non-zero.
- * We assume that the result array is the same size as the mod array.
- */
-static void modpow(Bignum base, Bignum exp, Bignum mod, Bignum result)
-{
- unsigned short *a, *b, *n, *m;
- int mshift;
- int mlen, i, j;
-
- /* Allocate m of size mlen, copy mod to m */
- /* We use big endian internally */
- mlen = mod[0];
- m = malloc(mlen * sizeof(unsigned short));
- for (j = 0; j < mlen; j++) m[j] = mod[mod[0] - j];
-
- /* Shift m left to make msb bit set */
- for (mshift = 0; mshift < 15; mshift++)
- if ((m[0] << mshift) & 0x8000) break;
- if (mshift) {
- for (i = 0; i < mlen - 1; i++)
- m[i] = (m[i] << mshift) | (m[i+1] >> (16-mshift));
- m[mlen-1] = m[mlen-1] << mshift;
- }
-
- /* Allocate n of size mlen, copy base to n */
- n = malloc(mlen * sizeof(unsigned short));
- i = mlen - base[0];
- for (j = 0; j < i; j++) n[j] = 0;
- for (j = 0; j < base[0]; j++) n[i+j] = base[base[0] - j];
-
- /* Allocate a and b of size 2*mlen. Set a = 1 */
- a = malloc(2 * mlen * sizeof(unsigned short));
- b = malloc(2 * mlen * sizeof(unsigned short));
- for (i = 0; i < 2*mlen; i++) a[i] = 0;
- a[2*mlen-1] = 1;
-
- /* Skip leading zero bits of exp. */
- i = 0; j = 15;
- while (i < exp[0] && (exp[exp[0] - i] & (1 << j)) == 0) {
- j--;
- if (j < 0) { i++; j = 15; }
- }
-
- /* Main computation */
- while (i < exp[0]) {
- while (j >= 0) {
- bigmul(a + mlen, a + mlen, b, mlen);
- bigmod(b, m, mlen);
- if ((exp[exp[0] - i] & (1 << j)) != 0) {
- bigmul(b + mlen, n, a, mlen);
- bigmod(a, m, mlen);
- } else {
- unsigned short *t;
- t = a; a = b; b = t;
- }
- j--;
- }
- i++; j = 15;
- }
-
- /* Fixup result in case the modulus was shifted */
- if (mshift) {
- for (i = mlen - 1; i < 2*mlen - 1; i++)
- a[i] = (a[i] << mshift) | (a[i+1] >> (16-mshift));
- a[2*mlen-1] = a[2*mlen-1] << mshift;
- bigmod(a, m, mlen);
- for (i = 2*mlen - 1; i >= mlen; i--)
- a[i] = (a[i] >> mshift) | (a[i-1] << (16-mshift));
- }
-
- /* Copy result to buffer */
- for (i = 0; i < mlen; i++)
- result[result[0] - i] = a[i+mlen];
-
- /* Free temporary arrays */
- for (i = 0; i < 2*mlen; i++) a[i] = 0; free(a);
- for (i = 0; i < 2*mlen; i++) b[i] = 0; free(b);
- for (i = 0; i < mlen; i++) m[i] = 0; free(m);
- for (i = 0; i < mlen; i++) n[i] = 0; free(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