Hi, thank you for the patch. Can you submit it as a merge request in gitlab?
https://gitlab.com/libssh/libssh-mirror/-/merge_requests On 5/7/21 12:29 AM, Jeremy Cross wrote:
[#48/T22] Added missing server reply on auth-agent-req when a reply was requested by the client. PuTTY for Windows chokes without this reply if "Allow agent forwarding" is enabled. Reply will be successful if channel_auth_agent_req_function callback is defined. Based on an unmerged patch by Jon Simons. Signed-off-by: Jeremy Cross <jcr...@beyondtrust.com> -- diff --git a/src/channels.c b/src/channels.c index 4eea885b..663dbcaf 100644 --- a/src/channels.c +++ b/src/channels.c @@ -692,7 +692,7 @@ SSH_PACKET_CALLBACK(channel_rcv_close) { SSH_PACKET_CALLBACK(channel_rcv_request) { ssh_channel channel; char *request=NULL; - uint8_t status; + uint8_t want_reply; int rc; (void)user; (void)type; @@ -705,7 +705,7 @@ SSH_PACKET_CALLBACK(channel_rcv_request) {rc = ssh_buffer_unpack(packet, "sb",&request, - &status); + &want_reply); if (rc != SSH_OK) { SSH_LOG(SSH_LOG_PACKET, "Invalid MSG_CHANNEL_REQUEST"); return SSH_PACKET_USED; @@ -815,11 +815,29 @@ SSH_PACKET_CALLBACK(channel_rcv_request) { if (strcmp(request, "auth-agent-...@openssh.com") == 0) { SAFE_FREE(request); SSH_LOG(SSH_LOG_PROTOCOL, "Received an auth-agent-req request"); - ssh_callbacks_execute_list(channel->callbacks, - ssh_channel_callbacks, - channel_auth_agent_req_function, - channel->session, - channel); + + int status = SSH2_MSG_CHANNEL_FAILURE;
Please, keep the variables declaration in the beginning of blocks. I think it is not explicitly stated anywhere, but some older C standards and compiler implementation have issues with this.
+ ssh_callbacks_iterate(channel->callbacks, ssh_channel_callbacks, + channel_auth_agent_req_function){ + ssh_callbacks_iterate_exec(channel_auth_agent_req_function, + channel->session, + channel); + /* in lieu of a return value, if the callback exists it's supported */ + status = SSH2_MSG_CHANNEL_SUCCESS; + break; + } + ssh_callbacks_iterate_end(); + + if (want_reply) { + rc = ssh_buffer_pack(session->out_buffer, + "bd", + status, + channel->remote_channel); + if (rc != SSH_OK) { + return SSH_PACKET_USED; + } + ssh_packet_send(session); + }return SSH_PACKET_USED;} @@ -828,7 +846,7 @@ SSH_PACKET_CALLBACK(channel_rcv_request) { * client requests. That means we need to create a ssh message to be passed * to the user code handling ssh messages */ - ssh_message_handle_channel_request(session,channel,packet,request,status); + ssh_message_handle_channel_request(session,channel,packet,request,want_reply); #else SSH_LOG(SSH_LOG_WARNING, "Unhandled channel request %s", request); #endif
Otherwise it looks fine. Thanks, -- Jakub Jelen Senior Software Engineer Crypto Team, Security Engineering Red Hat, Inc.
