#include <stdio.h>
#include <stdlib.h>
#include <string.h>
-
-#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
+#include <assert.h>
#include "ssh.h"
+
int makekey(unsigned char *data, struct RSAKey *result,
unsigned char **keystr, int order) {
unsigned char *p = data;
int i;
- result->bits = 0;
- for (i=0; i<4; i++)
- result->bits = (result->bits << 8) + *p++;
+ 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
*/
if (order == 0)
- p += ssh1_read_bignum(p, &result->exponent);
- result->bytes = (((p[0] << 8) + p[1]) + 7) / 8;
+ 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->modulus);
+ p += ssh1_read_bignum(p, result ? &result->modulus : NULL);
if (order == 1)
- p += ssh1_read_bignum(p, &result->exponent);
+ p += ssh1_read_bignum(p, result ? &result->exponent : NULL);
return p - data;
}
void rsaencrypt(unsigned char *data, int length, struct RSAKey *key) {
Bignum b1, b2;
- int w, i;
+ int i;
unsigned char *p;
- debug(key->exponent);
-
memmove(data+key->bytes-length, data, length);
data[0] = 0;
data[1] = 2;
}
data[key->bytes-length-1] = 0;
- w = (key->bytes+1)/2;
+ b1 = bignum_from_bytes(data, key->bytes);
- b1 = newbn(w);
- b2 = newbn(w);
+ b2 = modpow(b1, key->exponent, key->modulus);
p = data;
- for (i=1; i<=w; i++)
- b1[i] = 0;
for (i=key->bytes; i-- ;) {
- unsigned char byte = *p++;
- if (i & 1)
- b1[1+i/2] |= byte<<8;
- else
- 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;
- if (i & 1)
- b = b2[1+i/2] >> 8;
- else
- b = b2[1+i/2] & 0xFF;
- *p++ = b;
+ *p++ = bignum_byte(b2, i);
}
freebn(b1);
Bignum rsadecrypt(Bignum input, struct RSAKey *key) {
Bignum ret;
- ret = newbn(key->modulus[0]);
- modpow(input, key->private_exponent, key->modulus, ret);
+ ret = modpow(input, key->private_exponent, key->modulus);
return ret;
}
int rsastr_len(struct RSAKey *key) {
Bignum md, ex;
+ int mdlen, exlen;
md = key->modulus;
ex = key->exponent;
- return 4 * (ex[0]+md[0]) + 10;
+ mdlen = (ssh1_bignum_bitcount(md)+15) / 16;
+ exlen = (ssh1_bignum_bitcount(ex)+15) / 16;
+ return 4 * (mdlen+exlen) + 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);
+ 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';
+}
+
+/*
+ * 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);
}
- str[len++] = '/';
- for (i=1; i<=md[0]; i++) {
- sprintf(str+len, "%04x", md[i]);
- len += strlen(str+len);
+ 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';
}
- str[len] = '\0';
}
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);
+ if (key->comment) sfree(key->comment);
+}
+
+/* ----------------------------------------------------------------------
+ * Implementation of the ssh-rsa signing key type.
+ */
+
+#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;
+}
+
+static void *rsa2_newkey(char *data, int len) {
+ char *p;
+ int slen;
+ struct RSAKey *rsa;
+
+ 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;
+ }
+ rsa->exponent = getmp(&data, &len);
+ rsa->modulus = getmp(&data, &len);
+ rsa->private_exponent = NULL;
+ rsa->comment = NULL;
+
+ return rsa;
}
-#ifdef TESTMODE
+static void rsa2_freekey(void *key) {
+ struct RSAKey *rsa = (struct RSAKey *)key;
+ freersakey(rsa);
+ sfree(rsa);
+}
-#ifndef NODDY
-#define p1 10007
-#define p2 10069
-#define p3 10177
-#else
-#define p1 3
-#define p2 7
-#define p3 13
-#endif
+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;
+}
-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 };
+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;
-int main(void) {
- modmult(P1, P2, bigmod, a); debug(a);
- modmult(a, P3, bigmod, mod); debug(mod);
+ elen = (ssh1_bignum_bitcount(rsa->exponent)+8)/8;
+ mlen = (ssh1_bignum_bitcount(rsa->modulus)+8)/8;
- 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);
+ /*
+ * 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;
+}
+
+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;
- modpow(Two, b, mod, a); debug(a);
+ 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;
+}
+
+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;
+}
+
+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;
+ }
+
+ return rsa;
+}
+
+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;
+}
+
+/*
+ * 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;
+ }
+ 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;
+ }
+ /* 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;
+}
- 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"
+};
projects / u / mdw / putty / blobdiff