server: Use really the negotiated signature type

Generally, when the extension negotiation is enabled and client supports
SHA2 algorithms for RSA, they are supposed to be prioritized against the
old SHA1. If it is not (ssh-rsa is listed in front of rsa-sha2-* hostkey
algorithms during negotiation), the server wrongly tries to provide the
new typo of signature, ignoring the negotiated algirithm

This commit propagates the digest algorithm from negotiation to the actual
signature functions, which were previously responsible for decision
about the hash algorithm based just on the negotiated extensions.

Fixes T191

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
(cherry picked from commit 1ebf506913)
This commit is contained in:
Jakub Jelen
2019-10-31 13:03:21 +01:00
committed by Andreas Schneider
parent f0b676a9f0
commit 54cf7b92ed
12 changed files with 41 additions and 29 deletions

View File

@@ -264,7 +264,11 @@ SSH_PACKET_CALLBACK(ssh_packet_kexdh_init){
return SSH_PACKET_NOT_USED;
}
int ssh_get_key_params(ssh_session session, ssh_key *privkey){
int
ssh_get_key_params(ssh_session session,
ssh_key *privkey,
enum ssh_digest_e *digest)
{
ssh_key pubkey;
ssh_string pubkey_blob;
int rc;
@@ -290,6 +294,7 @@ int ssh_get_key_params(ssh_session session, ssh_key *privkey){
*privkey = NULL;
}
*digest = session->srv.hostkey_digest;
rc = ssh_pki_export_privkey_to_pubkey(*privkey, &pubkey);
if (rc < 0) {
ssh_set_error(session, SSH_FATAL,