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Centralise SSH-2 key fingerprinting into sshpubk.c.

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There were ad-hoc functions for fingerprinting a bare key blob in both
cmdgen.c and pageant.c, not quite doing the same thing. Also, every
SSH-2 public key algorithm in the code base included a dedicated
fingerprint() method, which is completely pointless since SSH-2 key
fingerprints are computed in an algorithm-independent way (just hash
the standard-format public key blob), so each of those methods was
just duplicating the work of the public_blob() method with a less
general output mechanism.

Now sshpubk.c centrally provides an ssh2_fingerprint_blob() function
that does all the real work, plus an ssh2_fingerprint() function that
wraps it and deals with calling public_blob() to get something to
fingerprint. And the fingerprint() method has been completely removed
from ssh_signkey and all its implementations, and good riddance.
This commit is contained in:
Simon Tatham
2015-05-12 14:35:44 +01:00
parent eef0235a0f
commit 8682246d33
10 changed files with 71 additions and 213 deletions
Download Patch File Download Diff File Expand all files Collapse all files

85
sshecc.c
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@ -3082,87 +3082,6 @@ static int ecdsa_pubkey_bits(const void *blob, int len)
return ret;
}
static char *ecdsa_fingerprint(void *key)
{
struct ec_key *ec = (struct ec_key *) key;
struct MD5Context md5c;
unsigned char digest[16], lenbuf[4];
char *ret;
unsigned char *name, *fullname;
int pointlen, namelen, fullnamelen, i, j;
MD5Init(&md5c);
namelen = ec_curve_to_name(EC_TYPE_DSA, ec->publicKey.curve, NULL, 0);
name = snewn(namelen, unsigned char);
ec_curve_to_name(EC_TYPE_DSA, ec->publicKey.curve, name, namelen);
if (ec->publicKey.curve->type == EC_EDWARDS) {
unsigned char b;
/* Do it with the weird encoding */
PUT_32BIT(lenbuf, namelen);
MD5Update(&md5c, lenbuf, 4);
MD5Update(&md5c, name, namelen);
pointlen = ec->publicKey.curve->fieldBits / 8;
PUT_32BIT(lenbuf, pointlen);
MD5Update(&md5c, lenbuf, 4);
for (i = 0; i < pointlen - 1; ++i) {
b = bignum_byte(ec->publicKey.y, i);
MD5Update(&md5c, &b, 1);
}
/* Unset last bit of y and set first bit of x in its place */
b = bignum_byte(ec->publicKey.y, i) & 0x7f;
b |= bignum_bit(ec->publicKey.x, 0) << 7;
MD5Update(&md5c, &b, 1);
} else if (ec->publicKey.curve->type == EC_WEIERSTRASS) {
fullnamelen = ec_curve_to_name(EC_TYPE_CURVE, ec->publicKey.curve, NULL, 0);
fullname = snewn(namelen, unsigned char);
ec_curve_to_name(EC_TYPE_DSA, ec->publicKey.curve, fullname, fullnamelen);
PUT_32BIT(lenbuf, fullnamelen);
MD5Update(&md5c, lenbuf, 4);
MD5Update(&md5c, fullname, fullnamelen);
sfree(fullname);
PUT_32BIT(lenbuf, namelen);
MD5Update(&md5c, lenbuf, 4);
MD5Update(&md5c, name, namelen);
pointlen = (bignum_bitcount(ec->publicKey.curve->p) + 7) / 8;
PUT_32BIT(lenbuf, 1 + (pointlen * 2));
MD5Update(&md5c, lenbuf, 4);
MD5Update(&md5c, (const unsigned char *)"\x04", 1);
for (i = pointlen; i--; ) {
unsigned char c = bignum_byte(ec->publicKey.x, i);
MD5Update(&md5c, &c, 1);
}
for (i = pointlen; i--; ) {
unsigned char c = bignum_byte(ec->publicKey.y, i);
MD5Update(&md5c, &c, 1);
}
} else {
sfree(name);
return NULL;
}
MD5Final(digest, &md5c);
ret = snewn(namelen + 1 + (16 * 3), char);
i = 0;
memcpy(ret, name, namelen);
i += namelen;
sfree(name);
ret[i++] = ' ';
for (j = 0; j < 16; j++) {
i += sprintf(ret + i, "%s%02x", j ? ":" : "", digest[j]);
}
return ret;
}
static int ecdsa_verifysig(void *key, const char *sig, int siglen,
const char *data, int datalen)
{
@ -3545,7 +3464,6 @@ const struct ssh_signkey ssh_ecdsa_ed25519 = {
ed25519_openssh_fmtkey,
2 /* point, private exponent */,
ecdsa_pubkey_bits,
ecdsa_fingerprint,
ecdsa_verifysig,
ecdsa_sign,
"ssh-ed25519",
@ -3563,7 +3481,6 @@ const struct ssh_signkey ssh_ecdsa_nistp256 = {
ecdsa_openssh_fmtkey,
3 /* curve name, point, private exponent */,
ecdsa_pubkey_bits,
ecdsa_fingerprint,
ecdsa_verifysig,
ecdsa_sign,
"ecdsa-sha2-nistp256",
@ -3581,7 +3498,6 @@ const struct ssh_signkey ssh_ecdsa_nistp384 = {
ecdsa_openssh_fmtkey,
3 /* curve name, point, private exponent */,
ecdsa_pubkey_bits,
ecdsa_fingerprint,
ecdsa_verifysig,
ecdsa_sign,
"ecdsa-sha2-nistp384",
@ -3599,7 +3515,6 @@ const struct ssh_signkey ssh_ecdsa_nistp521 = {
ecdsa_openssh_fmtkey,
3 /* curve name, point, private exponent */,
ecdsa_pubkey_bits,
ecdsa_fingerprint,
ecdsa_verifysig,
ecdsa_sign,
"ecdsa-sha2-nistp521",