X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/e557416818242c2e8b14ec03d321740fd83619e4..8b8cf871e5471e658dda0836db678e0d68027e8c:/sshrsa.c diff --git a/sshrsa.c b/sshrsa.c index bf54e409..d39f8462 100644 --- a/sshrsa.c +++ b/sshrsa.c @@ -9,86 +9,48 @@ #include #include -#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(levelbits = 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=b; i-- ;) { - unsigned char byte = *p++; - if (i & 1) - bn[j][1+i/2] |= byte<<8; - else - bn[j][1+i/2] |= byte; - } - - 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; @@ -116,12 +78,8 @@ void rsaencrypt(unsigned char *data, int length, struct RSAKey *key) { b1[1+i/2] |= byte; } - debug(b1); - modpow(b1, key->exponent, key->modulus, b2); - debug(b2); - p = data; for (i=key->bytes; i-- ;) { unsigned char b; @@ -136,69 +94,82 @@ void rsaencrypt(unsigned char *data, int length, struct RSAKey *key) { 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); +}