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pki: Add mbedTLS ECDSA key comparison support

Signed-off-by: Juraj Vijtiuk <juraj.vijtiuk@sartura.hr>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
This commit is contained in:
Juraj Vijtiuk 2018-02-22 15:56:05 +01:00 committed by Andreas Schneider
parent 81847bf513
commit d11869bdb6
3 changed files with 28 additions and 24 deletions

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@ -1,15 +1,3 @@
libssh mbedTLS ECDSA support
=============================
When built with mbedTLS, libssh currently does not support ECDSA key comparison.
Since the comparison function is used during the verification of publickey
authentication requests a libssh server will not be able to deal with ECDSA
keys.
In general, if the ssh_key_cmp function is used with mbedTLS, ECDSA key
comparison won't work.
mbedTLS and libssh in multithreaded applications
==================================================

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@ -451,15 +451,34 @@ int pki_key_compare(const ssh_key k1, const ssh_key k2, enum ssh_keycmp_e what)
}
break;
}
case SSH_KEYTYPE_ECDSA:
/* TODO: mbedTLS can't compare ecdsa keys.
mbedtls_ecdsa_context is actually a mbedtls_ecp_keypair,
so the private and public points and the group can be accessed
through the keypair. However, mbedtls has no method corresponding
to OpenSSL's EC_GROUP_cmp and EC_POITN_cmp, so the comparison
would have to be done manually.
*/
return 1;
case SSH_KEYTYPE_ECDSA: {
mbedtls_ecp_keypair *ecdsa1 = k1->ecdsa;
mbedtls_ecp_keypair *ecdsa2 = k2->ecdsa;
if (ecdsa1->grp.id != ecdsa2->grp.id) {
return 1;
}
if (mbedtls_mpi_cmp_mpi(&ecdsa1->Q.X, &ecdsa2->Q.X)) {
return 1;
}
if (mbedtls_mpi_cmp_mpi(&ecdsa1->Q.Y, &ecdsa2->Q.Y)) {
return 1;
}
if (mbedtls_mpi_cmp_mpi(&ecdsa1->Q.Z, &ecdsa2->Q.Z)) {
return 1;
}
if (what == SSH_KEY_CMP_PRIVATE) {
if (mbedtls_mpi_cmp_mpi(&ecdsa1->d, &ecdsa2->d)) {
return 1;
}
}
break;
}
case SSH_KEYTYPE_ED25519:
/* ed25519 keys handled globally */
return 0;

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@ -227,11 +227,8 @@ static void torture_pki_ecdsa_duplicate_key(void **state)
assert_string_equal(b64_key, b64_key_gen);
#ifndef HAVE_LIBMBEDCRYPTO
/* libmbedcrypto can't compare ecdsa keys */
rc = ssh_key_cmp(privkey, privkey_dup, SSH_KEY_CMP_PRIVATE);
assert_true(rc == 0);
#endif
ssh_key_free(pubkey);
ssh_key_free(privkey);