submisssion-login: Fix segfault occuring at proxy AUTH upon relay connection failure

Fixed by halting server input once proxy authentication succeeds. This prevents
race conditions between input from proxy server and command output, which causes
a segfault when the current server command is already cleared when more input
(beyond AUTH success) from the proxy server comes in.

diff --git a/src/submission-login/submission-proxy.c b/src/submission-login/submission-proxy.c
index c239040b6c3f6f6b7bc3b572330e9313ec343acb..47e4994e1623c25f08c80fa96c3f0aae021e211b 100644 (file)
--- a/src/submission-login/submission-proxy.c
+++ b/src/submission-login/submission-proxy.c
@@ -651,6 +651,7 @@ int submission_proxy_parse_line(struct client *client, const char *line)
                        command, SMTP_SERVER_COMMAND_HOOK_DESTROY,
                        submission_proxy_success_reply_sent, subm_client);
 
+               login_proxy_input_halt(client->login_proxy);
                subm_client->auth_cmd = NULL;
 
                /* Login successful. Send this reply to client. */