(cp)[3] = (unsigned char)(value); }
#if 0
-/*
- * Condition this section in for debugging of DSS.
- */
-static void diagbn(char *prefix, Bignum md) {
- int i, nibbles, morenibbles;
- static const char hex[] = "0123456789ABCDEF";
-
- printf("%s0x", prefix ? prefix : "");
-
- nibbles = (3 + ssh1_bignum_bitcount(md))/4; if (nibbles<1) nibbles=1;
- morenibbles = 4*md[0] - nibbles;
- for (i=0; i<morenibbles; i++) putchar('-');
- for (i=nibbles; i-- ;)
- putchar(hex[(bignum_byte(md, i/2) >> (4*(i%2))) & 0xF]);
-
- if (prefix) putchar('\n');
-}
#define DEBUG_DSS
#else
#define diagbn(x,y)
}
static Bignum getmp(char **data, int *datalen) {
char *p;
- int i, j, length;
+ int length;
Bignum b;
getstring(data, datalen, &p, &length);
return NULL;
if (p[0] & 0x80)
return NULL; /* negative mp */
- b = newbn((length+1)/2);
- for (i = 0; i < length; i++) {
- j = length - 1 - i;
- if (j & 1)
- b[j/2+1] |= ((unsigned char)p[i]) << 8;
- else
- b[j/2+1] |= ((unsigned char)p[i]);
- }
- while (b[0] > 1 && b[b[0]] == 0) b[0]--;
+ b = bignum_from_bytes(p, length);
return b;
}
static Bignum get160(char **data, int *datalen) {
- char *p;
- int i, j, length;
Bignum b;
- p = *data;
+ b = bignum_from_bytes(*data, 20);
*data += 20; *datalen -= 20;
- length = 20;
- while (length > 0 && !p[0])
- p++, length--;
- b = newbn((length+1)/2);
- for (i = 0; i < length; i++) {
- j = length - 1 - i;
- if (j & 1)
- b[j/2+1] |= ((unsigned char)p[i]) << 8;
- else
- b[j/2+1] |= ((unsigned char)p[i]);
- }
return b;
}
-static Bignum dss_p, dss_q, dss_g, dss_y;
+struct dss_key {
+ Bignum p, q, g, y;
+};
-static void dss_setkey(char *data, int len) {
+static void *dss_newkey(char *data, int len) {
char *p;
int slen;
+ struct dss_key *dss;
+
+ dss = smalloc(sizeof(struct dss_key));
+ if (!dss) return NULL;
getstring(&data, &len, &p, &slen);
#ifdef DEBUG_DSS
#endif
if (!p || memcmp(p, "ssh-dss", 7)) {
- dss_p = NULL;
- return;
+ sfree(dss);
+ return NULL;
}
- dss_p = getmp(&data, &len);
- dss_q = getmp(&data, &len);
- dss_g = getmp(&data, &len);
- dss_y = getmp(&data, &len);
+ dss->p = getmp(&data, &len);
+ dss->q = getmp(&data, &len);
+ dss->g = getmp(&data, &len);
+ dss->y = getmp(&data, &len);
+
+ return dss;
}
-static char *dss_fmtkey(void) {
+static void dss_freekey(void *key) {
+ struct dss_key *dss = (struct dss_key *)key;
+ freebn(dss->p);
+ freebn(dss->q);
+ freebn(dss->g);
+ freebn(dss->y);
+ sfree(dss);
+}
+
+static char *dss_fmtkey(void *key) {
+ struct dss_key *dss = (struct dss_key *)key;
char *p;
int len, i, pos, nibbles;
static const char hex[] = "0123456789abcdef";
- if (!dss_p)
+ if (!dss->p)
return NULL;
len = 8 + 4 + 1; /* 4 x "0x", punctuation, \0 */
- len += 4 * (dss_p[0] + dss_q[0] + dss_g[0] + dss_y[0]); /* digits */
- p = malloc(len);
+ len += 4 * (ssh1_bignum_bitcount(dss->p)+15)/16;
+ len += 4 * (ssh1_bignum_bitcount(dss->q)+15)/16;
+ len += 4 * (ssh1_bignum_bitcount(dss->g)+15)/16;
+ len += 4 * (ssh1_bignum_bitcount(dss->y)+15)/16;
+ p = smalloc(len);
if (!p) return NULL;
pos = 0;
pos += sprintf(p+pos, "0x");
- nibbles = (3 + ssh1_bignum_bitcount(dss_p))/4; if (nibbles<1) nibbles=1;
+ nibbles = (3 + ssh1_bignum_bitcount(dss->p))/4; if (nibbles<1) nibbles=1;
for (i=nibbles; i-- ;)
- p[pos++] = hex[(bignum_byte(dss_p, i/2) >> (4*(i%2))) & 0xF];
+ p[pos++] = hex[(bignum_byte(dss->p, i/2) >> (4*(i%2))) & 0xF];
pos += sprintf(p+pos, ",0x");
- nibbles = (3 + ssh1_bignum_bitcount(dss_q))/4; if (nibbles<1) nibbles=1;
+ nibbles = (3 + ssh1_bignum_bitcount(dss->q))/4; if (nibbles<1) nibbles=1;
for (i=nibbles; i-- ;)
- p[pos++] = hex[(bignum_byte(dss_q, i/2) >> (4*(i%2))) & 0xF];
+ p[pos++] = hex[(bignum_byte(dss->q, i/2) >> (4*(i%2))) & 0xF];
pos += sprintf(p+pos, ",0x");
- nibbles = (3 + ssh1_bignum_bitcount(dss_g))/4; if (nibbles<1) nibbles=1;
+ nibbles = (3 + ssh1_bignum_bitcount(dss->g))/4; if (nibbles<1) nibbles=1;
for (i=nibbles; i-- ;)
- p[pos++] = hex[(bignum_byte(dss_g, i/2) >> (4*(i%2))) & 0xF];
+ p[pos++] = hex[(bignum_byte(dss->g, i/2) >> (4*(i%2))) & 0xF];
pos += sprintf(p+pos, ",0x");
- nibbles = (3 + ssh1_bignum_bitcount(dss_y))/4; if (nibbles<1) nibbles=1;
+ nibbles = (3 + ssh1_bignum_bitcount(dss->y))/4; if (nibbles<1) nibbles=1;
for (i=nibbles; i-- ;)
- p[pos++] = hex[(bignum_byte(dss_y, i/2) >> (4*(i%2))) & 0xF];
+ p[pos++] = hex[(bignum_byte(dss->y, i/2) >> (4*(i%2))) & 0xF];
p[pos] = '\0';
return p;
}
-static char *dss_fingerprint(void) {
+static char *dss_fingerprint(void *key) {
+ struct dss_key *dss = (struct dss_key *)key;
struct MD5Context md5c;
unsigned char digest[16], lenbuf[4];
char buffer[16*3+40];
unsigned char c = bignum_byte(bignum, i); \
MD5Update(&md5c, &c, 1); \
}
- ADD_BIGNUM(dss_p);
- ADD_BIGNUM(dss_q);
- ADD_BIGNUM(dss_g);
- ADD_BIGNUM(dss_y);
+ ADD_BIGNUM(dss->p);
+ ADD_BIGNUM(dss->q);
+ ADD_BIGNUM(dss->g);
+ ADD_BIGNUM(dss->y);
#undef ADD_BIGNUM
MD5Final(digest, &md5c);
- sprintf(buffer, "%d ", ssh1_bignum_bitcount(dss_p));
+ sprintf(buffer, "ssh-dss %d ", ssh1_bignum_bitcount(dss->p));
for (i = 0; i < 16; i++)
sprintf(buffer+strlen(buffer), "%s%02x", i?":":"", digest[i]);
- ret = malloc(strlen(buffer)+1);
+ ret = smalloc(strlen(buffer)+1);
if (ret)
strcpy(ret, buffer);
return ret;
}
-static int dss_verifysig(char *sig, int siglen, char *data, int datalen) {
+static int dss_verifysig(void *key, char *sig, int siglen,
+ char *data, int datalen) {
+ struct dss_key *dss = (struct dss_key *)key;
char *p;
int slen;
char hash[20];
Bignum r, s, w, gu1p, yu2p, gu1yu2p, u1, u2, sha, v;
int ret;
- if (!dss_p)
+ if (!dss->p)
return 0;
#ifdef DEBUG_DSS
int i;
printf("sig:");
for (i=0;i<siglen;i++)
- printf(" %02xf", (unsigned char)(sig[i]));
+ printf(" %02x", (unsigned char)(sig[i]));
printf("\n");
}
#endif
*/
if (siglen != 40) { /* bug not present; read admin fields */
getstring(&sig, &siglen, &p, &slen);
- if (!p || memcmp(p, "ssh-dss", 7)) {
+ if (!p || slen != 7 || memcmp(p, "ssh-dss", 7)) {
return 0;
}
sig += 4, siglen -= 4; /* skip yet another length field */
}
- diagbn("p=", dss_p);
- diagbn("q=", dss_q);
- diagbn("g=", dss_g);
- diagbn("y=", dss_y);
+ diagbn("p=", dss->p);
+ diagbn("q=", dss->q);
+ diagbn("g=", dss->g);
+ diagbn("y=", dss->y);
r = get160(&sig, &siglen);
diagbn("r=", r);
s = get160(&sig, &siglen);
/*
* Step 1. w <- s^-1 mod q.
*/
- w = modinv(s, dss_q);
+ w = modinv(s, dss->q);
diagbn("w=", w);
/*
SHA_Simple(data, datalen, hash);
p = hash; slen = 20; sha = get160(&p, &slen);
diagbn("sha=", sha);
- u1 = modmul(sha, w, dss_q);
+ u1 = modmul(sha, w, dss->q);
diagbn("u1=", u1);
/*
* Step 3. u2 <- r * w mod q.
*/
- u2 = modmul(r, w, dss_q);
+ u2 = modmul(r, w, dss->q);
diagbn("u2=", u2);
/*
* Step 4. v <- (g^u1 * y^u2 mod p) mod q.
*/
- gu1p = modpow(dss_g, u1, dss_p);
+ gu1p = modpow(dss->g, u1, dss->p);
diagbn("gu1p=", gu1p);
- yu2p = modpow(dss_y, u2, dss_p);
+ yu2p = modpow(dss->y, u2, dss->p);
diagbn("yu2p=", yu2p);
- gu1yu2p = modmul(gu1p, yu2p, dss_p);
+ gu1yu2p = modmul(gu1p, yu2p, dss->p);
diagbn("gu1yu2p=", gu1yu2p);
- v = modmul(gu1yu2p, One, dss_q);
+ v = modmul(gu1yu2p, One, dss->q);
diagbn("gu1yu2q=v=", v);
diagbn("r=", r);
return ret;
}
-struct ssh_hostkey ssh_dss = {
- dss_setkey,
+int dss_sign(void *key, char *sig, int siglen,
+ char *data, int datalen) {
+ return 0; /* do nothing */
+}
+
+struct ssh_signkey ssh_dss = {
+ dss_newkey,
+ dss_freekey,
dss_fmtkey,
dss_fingerprint,
dss_verifysig,
+ dss_sign,
"ssh-dss",
"dss"
};