X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/4644b0ce3adad5efe574dc125bc3b0cd8f6c2aa7..d8770b1245ff0acd81f581c5667563e0d127104a:/sshrsa.c diff --git a/sshrsa.c b/sshrsa.c index 71e1d634..36069ad7 100644 --- a/sshrsa.c +++ b/sshrsa.c @@ -8,396 +8,487 @@ #include #include #include +#include #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 makekey(unsigned char *data, struct RSAKey *result, + unsigned char **keystr, int order) { + unsigned char *p = data; 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(levelbits = 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; } -/* - * 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; - } +int makeprivate(unsigned char *data, struct RSAKey *result) { + return ssh1_read_bignum(data, &result->private_exponent); } -/* - * 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; - } +void rsaencrypt(unsigned char *data, int length, struct RSAKey *key) { + Bignum b1, b2; + int i; + unsigned char *p; - 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 >= 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; - } - } - } -} + memmove(data+key->bytes-length, data, length); + data[0] = 0; + data[1] = 2; -/* - * 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; + for (i = 2; i < key->bytes-length-1; i++) { + do { + data[i] = random_byte(); + } while (data[i] == 0); } + data[key->bytes-length-1] = 0; - /* 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; } - } + b1 = bignum_from_bytes(data, key->bytes); - /* 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; - } + b2 = modpow(b1, key->exponent, key->modulus); - /* 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)); + p = data; + for (i=key->bytes; i-- ;) { + *p++ = bignum_byte(b2, i); } - /* Copy result to buffer */ - for (i = 0; i < mlen; i++) - result[result[0] - i] = a[i+mlen]; + freebn(b1); + freebn(b2); +} - /* 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); +Bignum rsadecrypt(Bignum input, struct RSAKey *key) { + Bignum ret; + ret = modpow(input, key->private_exponent, key->modulus); + return ret; } -int makekey(unsigned char *data, struct RSAKey *result, - unsigned char **keystr) { - unsigned char *p = data; - Bignum bn[2]; - int i, j; - int w, b; +int rsastr_len(struct RSAKey *key) { + Bignum md, ex; + int mdlen, exlen; - result->bits = 0; - for (i=0; i<4; i++) - result->bits = (result->bits << 8) + *p++; + md = key->modulus; + ex = key->exponent; + mdlen = (ssh1_bignum_bitcount(md)+15) / 16; + exlen = (ssh1_bignum_bitcount(ex)+15) / 16; + return 4 * (mdlen+exlen) + 20; +} - for (j=0; j<2; j++) { +void rsastr_fmt(char *str, struct RSAKey *key) { + Bignum md, ex; + int len = 0, i, nibbles; + static const char hex[] = "0123456789abcdef"; - w = 0; - for (i=0; i<2; i++) - w = (w << 8) + *p++; + md = key->modulus; + ex = key->exponent; - result->bytes = b = (w+7)/8; /* bits -> bytes */ - w = (w+15)/16; /* bits -> words */ + len += sprintf(str+len, "0x"); - bn[j] = newbn(w); + 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]; - if (keystr) *keystr = p; /* point at key string, second time */ + len += sprintf(str+len, ",0x"); - for (i=1; i<=w; i++) - bn[j][i] = 0; - for (i=0; i> (4*(i%2))) & 0xF]; - debug(bn[j]); + str[len] = '\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'; + } +} - result->exponent = bn[0]; - result->modulus = bn[1]; - - return p - data; +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) sfree(key->comment); } -void rsaencrypt(unsigned char *data, int length, struct RSAKey *key) { - Bignum b1, b2; - int w, i; - unsigned char *p; +/* ---------------------------------------------------------------------- + * Implementation of the ssh-rsa signing key type. + */ - debug(key->exponent); +#define GET_32BIT(cp) \ + (((unsigned long)(unsigned char)(cp)[0] << 24) | \ + ((unsigned long)(unsigned char)(cp)[1] << 16) | \ + ((unsigned long)(unsigned char)(cp)[2] << 8) | \ + ((unsigned long)(unsigned char)(cp)[3])) + +#define PUT_32BIT(cp, value) { \ + (cp)[0] = (unsigned char)((value) >> 24); \ + (cp)[1] = (unsigned char)((value) >> 16); \ + (cp)[2] = (unsigned char)((value) >> 8); \ + (cp)[3] = (unsigned char)(value); } + +static void getstring(char **data, int *datalen, char **p, int *length) { + *p = NULL; + if (*datalen < 4) + return; + *length = GET_32BIT(*data); + *datalen -= 4; *data += 4; + if (*datalen < *length) + return; + *p = *data; + *data += *length; *datalen -= *length; +} +static Bignum getmp(char **data, int *datalen) { + char *p; + int length; + Bignum b; + + getstring(data, datalen, &p, &length); + if (!p) + return NULL; + b = bignum_from_bytes(p, length); + return b; +} - memmove(data+key->bytes-length, data, length); - data[0] = 0; - data[1] = 2; +static void *rsa2_newkey(char *data, int len) { + char *p; + int slen; + struct RSAKey *rsa; - for (i = 2; i < key->bytes-length-1; i++) { - do { - data[i] = random_byte(); - } while (data[i] == 0); + rsa = smalloc(sizeof(struct RSAKey)); + if (!rsa) return NULL; + getstring(&data, &len, &p, &slen); + + if (!p || slen != 7 || memcmp(p, "ssh-rsa", 7)) { + sfree(rsa); + return NULL; } - data[key->bytes-length-1] = 0; + rsa->exponent = getmp(&data, &len); + rsa->modulus = getmp(&data, &len); + rsa->private_exponent = NULL; + rsa->comment = NULL; - w = (key->bytes+1)/2; + return rsa; +} - b1 = newbn(w); - b2 = newbn(w); +static void rsa2_freekey(void *key) { + struct RSAKey *rsa = (struct RSAKey *)key; + freersakey(rsa); + sfree(rsa); +} - p = data; - for (i=1; i<=w; i++) - b1[i] = 0; - for (i=0; ibytes; i++) { - unsigned char byte = *p++; - if ((key->bytes-i) & 1) - b1[w-i/2] |= byte; - else - b1[w-i/2] |= byte<<8; - } +static char *rsa2_fmtkey(void *key) { + struct RSAKey *rsa = (struct RSAKey *)key; + char *p; + int len; + + len = rsastr_len(rsa); + p = smalloc(len); + rsastr_fmt(p, rsa); + return p; +} - debug(b1); +static unsigned char *rsa2_public_blob(void *key, int *len) { + struct RSAKey *rsa = (struct RSAKey *)key; + int elen, mlen, bloblen; + int i; + unsigned char *blob, *p; + + elen = (ssh1_bignum_bitcount(rsa->exponent)+8)/8; + mlen = (ssh1_bignum_bitcount(rsa->modulus)+8)/8; + + /* + * string "ssh-rsa", mpint exp, mpint mod. Total 19+elen+mlen. + * (three length fields, 12+7=19). + */ + bloblen = 19+elen+mlen; + blob = smalloc(bloblen); + p = blob; + PUT_32BIT(p, 7); p += 4; + memcpy(p, "ssh-rsa", 7); p += 7; + PUT_32BIT(p, elen); p += 4; + for (i = elen; i-- ;) *p++ = bignum_byte(rsa->exponent, i); + PUT_32BIT(p, mlen); p += 4; + for (i = mlen; i-- ;) *p++ = bignum_byte(rsa->modulus, i); + assert(p == blob + bloblen); + *len = bloblen; + return blob; +} - modpow(b1, key->exponent, key->modulus, b2); +static unsigned char *rsa2_private_blob(void *key, int *len) { + struct RSAKey *rsa = (struct RSAKey *)key; + int dlen, plen, qlen, ulen, bloblen; + int i; + unsigned char *blob, *p; + + dlen = (ssh1_bignum_bitcount(rsa->private_exponent)+8)/8; + plen = (ssh1_bignum_bitcount(rsa->p)+8)/8; + qlen = (ssh1_bignum_bitcount(rsa->q)+8)/8; + ulen = (ssh1_bignum_bitcount(rsa->iqmp)+8)/8; + + /* + * mpint private_exp, mpint p, mpint q, mpint iqmp. Total 16 + + * sum of lengths. + */ + bloblen = 16+dlen+plen+qlen+ulen; + blob = smalloc(bloblen); + p = blob; + PUT_32BIT(p, dlen); p += 4; + for (i = dlen; i-- ;) *p++ = bignum_byte(rsa->private_exponent, i); + PUT_32BIT(p, plen); p += 4; + for (i = plen; i-- ;) *p++ = bignum_byte(rsa->p, i); + PUT_32BIT(p, qlen); p += 4; + for (i = qlen; i-- ;) *p++ = bignum_byte(rsa->q, i); + PUT_32BIT(p, ulen); p += 4; + for (i = ulen; i-- ;) *p++ = bignum_byte(rsa->iqmp, i); + assert(p == blob + bloblen); + *len = bloblen; + return blob; +} - debug(b2); +static void *rsa2_createkey(unsigned char *pub_blob, int pub_len, + unsigned char *priv_blob, int priv_len) { + struct RSAKey *rsa; + char *pb = (char *)priv_blob; + + rsa = rsa2_newkey((char *)pub_blob, pub_len); + rsa->private_exponent = getmp(&pb, &priv_len); + rsa->p = getmp(&pb, &priv_len); + rsa->q = getmp(&pb, &priv_len); + rsa->iqmp = getmp(&pb, &priv_len); + + return rsa; +} - p = data; - for (i=0; ibytes; i++) { - unsigned char b; - if (i & 1) - b = b2[w-i/2] & 0xFF; - else - b = b2[w-i/2] >> 8; - *p++ = b; +static void *rsa2_openssh_createkey(unsigned char **blob, int *len) { + char **b = (char **)blob; + struct RSAKey *rsa; + + rsa = smalloc(sizeof(struct RSAKey)); + if (!rsa) return NULL; + rsa->comment = NULL; + + rsa->modulus = getmp(b, len); + rsa->exponent = getmp(b, len); + rsa->private_exponent = getmp(b, len); + rsa->iqmp = getmp(b, len); + rsa->p = getmp(b, len); + rsa->q = getmp(b, len); + + if (!rsa->modulus || !rsa->exponent || !rsa->private_exponent || + !rsa->iqmp || !rsa->p || !rsa->q) { + sfree(rsa->modulus); + sfree(rsa->exponent); + sfree(rsa->private_exponent); + sfree(rsa->iqmp); + sfree(rsa->p); + sfree(rsa->q); + sfree(rsa); + return NULL; } - freebn(b1); - freebn(b2); + return rsa; } -int rsastr_len(struct RSAKey *key) { - Bignum md, ex; - - md = key->modulus; - ex = key->exponent; - return 4 * (ex[0]+md[0]) + 10; +static char *rsa2_fingerprint(void *key) { + struct RSAKey *rsa = (struct RSAKey *)key; + struct MD5Context md5c; + unsigned char digest[16], lenbuf[4]; + char buffer[16*3+40]; + char *ret; + int numlen, i; + + MD5Init(&md5c); + MD5Update(&md5c, "\0\0\0\7ssh-rsa", 11); + +#define ADD_BIGNUM(bignum) \ + numlen = (ssh1_bignum_bitcount(bignum)+8)/8; \ + PUT_32BIT(lenbuf, numlen); MD5Update(&md5c, lenbuf, 4); \ + for (i = numlen; i-- ;) { \ + unsigned char c = bignum_byte(bignum, i); \ + MD5Update(&md5c, &c, 1); \ + } + ADD_BIGNUM(rsa->exponent); + ADD_BIGNUM(rsa->modulus); +#undef ADD_BIGNUM + + MD5Final(digest, &md5c); + + sprintf(buffer, "ssh-rsa %d ", ssh1_bignum_bitcount(rsa->modulus)); + for (i = 0; i < 16; i++) + sprintf(buffer+strlen(buffer), "%s%02x", i?":":"", digest[i]); + ret = smalloc(strlen(buffer)+1); + if (ret) + strcpy(ret, buffer); + return ret; } -void rsastr_fmt(char *str, struct RSAKey *key) { - Bignum md, ex; - int len = 0, i; - - md = key->modulus; - ex = key->exponent; - - for (i=1; i<=ex[0]; i++) { - sprintf(str+len, "%04x", ex[i]); - len += strlen(str+len); +/* + * This is the magic ASN.1/DER prefix that goes in the decoded + * signature, between the string of FFs and the actual SHA hash + * value. As closely as I can tell, the meaning of it is: + * + * 00 -- this marks the end of the FFs; not part of the ASN.1 bit itself + * + * 30 21 -- a constructed SEQUENCE of length 0x21 + * 30 09 -- a constructed sub-SEQUENCE of length 9 + * 06 05 -- an object identifier, length 5 + * 2B 0E 03 02 1A -- + * 05 00 -- NULL + * 04 14 -- a primitive OCTET STRING of length 0x14 + * [0x14 bytes of hash data follows] + */ +static unsigned char asn1_weird_stuff[] = { + 0x00,0x30,0x21,0x30,0x09,0x06,0x05,0x2B, + 0x0E,0x03,0x02,0x1A,0x05,0x00,0x04,0x14, +}; + +#define ASN1_LEN ( (int) sizeof(asn1_weird_stuff) ) + +static int rsa2_verifysig(void *key, char *sig, int siglen, + char *data, int datalen) { + struct RSAKey *rsa = (struct RSAKey *)key; + Bignum in, out; + char *p; + int slen; + int bytes, i, j, ret; + unsigned char hash[20]; + + getstring(&sig, &siglen, &p, &slen); + if (!p || slen != 7 || memcmp(p, "ssh-rsa", 7)) { + return 0; } - str[len++] = '/'; - for (i=1; i<=md[0]; i++) { - sprintf(str+len, "%04x", md[i]); - len += strlen(str+len); + in = getmp(&sig, &siglen); + out = modpow(in, rsa->exponent, rsa->modulus); + freebn(in); + + ret = 1; + + bytes = ssh1_bignum_bitcount(rsa->modulus) / 8; + /* Top (partial) byte should be zero. */ + if (bignum_byte(out, bytes-1) != 0) + ret = 0; + /* First whole byte should be 1. */ + if (bignum_byte(out, bytes-2) != 1) + ret = 0; + /* Most of the rest should be FF. */ + for (i = bytes-3; i >= 20 + ASN1_LEN; i--) { + if (bignum_byte(out, i) != 0xFF) + ret = 0; } - str[len] = '\0'; + /* Then we expect to see the asn1_weird_stuff. */ + for (i = 20 + ASN1_LEN - 1, j=0; i >= 20; i--,j++) { + if (bignum_byte(out, i) != asn1_weird_stuff[j]) + ret = 0; + } + /* Finally, we expect to see the SHA-1 hash of the signed data. */ + SHA_Simple(data, datalen, hash); + for (i = 19, j=0; i >= 0; i--,j++) { + if (bignum_byte(out, i) != hash[j]) + ret = 0; + } + + return ret; } -#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; +unsigned char *rsa2_sign(void *key, char *data, int datalen, int *siglen) { + struct RSAKey *rsa = (struct RSAKey *)key; + unsigned char *bytes; + int nbytes; + unsigned char hash[20]; + Bignum in, out; + int i, j; + + SHA_Simple(data, datalen, hash); + + nbytes = (ssh1_bignum_bitcount(rsa->modulus)-1) / 8; + bytes = smalloc(nbytes); + + bytes[0] = 1; + for (i = 1; i < nbytes-20-ASN1_LEN; i++) + bytes[i] = 0xFF; + for (i = nbytes-20-ASN1_LEN, j=0; i < nbytes-20; i++,j++) + bytes[i] = asn1_weird_stuff[j]; + for (i = nbytes-20, j=0; i < nbytes; i++,j++) + bytes[i] = hash[j]; + + in = bignum_from_bytes(bytes, nbytes); + sfree(bytes); + + out = modpow(in, rsa->private_exponent, rsa->modulus); + freebn(in); + + nbytes = (ssh1_bignum_bitcount(out)+7)/8; + bytes = smalloc(4+7+4+nbytes); + PUT_32BIT(bytes, 7); + memcpy(bytes+4, "ssh-rsa", 7); + PUT_32BIT(bytes+4+7, nbytes); + for (i = 0; i < nbytes; i++) + bytes[4+7+4+i] = bignum_byte(out, nbytes-1-i); + freebn(out); + + *siglen = 4+7+4+nbytes; + return bytes; } -#endif +const struct ssh_signkey ssh_rsa = { + rsa2_newkey, + rsa2_freekey, + rsa2_fmtkey, + rsa2_public_blob, + rsa2_private_blob, + rsa2_createkey, + rsa2_openssh_createkey, + rsa2_fingerprint, + rsa2_verifysig, + rsa2_sign, + "ssh-rsa", + "rsa2" +};