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];
- pos += sprintf(p+pos, "0x");
+ pos += sprintf(p+pos, ",0x");
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];
- pos += sprintf(p+pos, "0x");
+ pos += sprintf(p+pos, ",0x");
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];
- pos += sprintf(p+pos, "0x");
+ pos += sprintf(p+pos, ",0x");
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];
if (!dss_p)
return 0;
- getstring(&sig, &siglen, &p, &slen);
- if (!p || memcmp(p, "ssh-dss", 7)) {
- return 0;
+ /*
+ * Commercial SSH (2.0.13) and OpenSSH disagree over the format
+ * of a DSA signature. OpenSSH is in line with the IETF drafts:
+ * it uses a string "ssh-dss", followed by a 40-byte string
+ * containing two 160-bit integers end-to-end. Commercial SSH
+ * can't be bothered with the header bit, and considers a DSA
+ * signature blob to be _just_ the 40-byte string containing
+ * the two 160-bit integers. We tell them apart by measuring
+ * the length: length 40 means the commercial-SSH bug, anything
+ * else is assumed to be IETF-compliant.
+ */
+ if (siglen != 40) { /* bug not present; read admin fields */
+ getstring(&sig, &siglen, &p, &slen);
+ if (!p || memcmp(p, "ssh-dss", 7)) {
+ return 0;
+ }
+ sig += 4, siglen -= 4; /* skip yet another length field */
}
- sig += 4, siglen -= 4; /* skip yet another length field */
r = get160(&sig, &siglen);
s = get160(&sig, &siglen);
if (!r || !s)