auth-policy crashing

[Aki Tuomi]

On 2.8.2019 13.45, James via dovecot wrote:
> My auth process is dumping core.  This happens several times per day
> but dovecot can operate normally for hours between errors.
>
> The crash occurs in src/auth/auth-policy.c, line 356:
>
> t at 1 (l at 1) program terminated by signal SEGV (no mapping at the fault
> address)
> Current function is auth_policy_parse_response
>   356           context->request->policy_refusal = FALSE;
>
> ...context->request is null.  Add markers to the code...
>
>     }
>     if (context->request == NULL) fprintf(stderr,
> "2222222222222222222222222222 context->request == NULL\n");
>     i_stream_unref(&context->payload);
>
>     if (context->request == NULL) fprintf(stderr,
> "1111111111111111111111111111 context->request == NULL\n");
>     if (context->parse_error) {
>         context->result = (context->set->policy_reject_on_fail ? -1 : 0);
>     }
>
>     if (context->request == NULL) fprintf(stderr,
> "AAAAAAAAAAAAAAAAAAAAAAAAAAAA context->request == NULL\n");
>     context->request->policy_refusal = FALSE;
>
>     if (context->result < 0) {
>
> ...gives at the time of the crash...
>
> Aug  1 14:25:44 mailhost dovecot: [ID 702911 mail.error] auth: Error:
> 1111111111111111111111111111 context->request == NULL
> Aug  1 14:25:44 mailhost dovecot: [ID 702911 mail.error] auth: Error:
> AAAAAAAAAAAAAAAAAAAAAAAAAAAA context->request == NULL
>
> ...so context->result is not null before the call (no 222) to
> i_stream_unref but is after.
>
>
>
> dovecot.conf has:
>
> auth_policy_server_url = http://policyserver.lan/
> auth_policy_server_timeout_msecs = 3000
> auth_policy_hash_nonce = Ohr9phaeSeip2Pahaez2raiGohxoo5Ia
> auth_policy_request_attributes = remote=%{rip}
> auth_policy_check_before_auth = yes
> auth_policy_check_after_auth = yes
> auth_policy_report_after_auth = yes
>
>
> To simplify the problem I used a dummy policy server, in nginx.conf:
>
>     location / {
>         default_type  application/json;
>         return 200 "{\"status\":0,\"msg\":\"accepted\"}";
>     }
>
> however no matter what rubbish a policy server sends back it should
> not cause dovecot to crash.
>
> I've tried 32 and 64 bit and two compilers (gcc and SunStudio), all
> result in crashes.  Adding:
>     keepalive_timeout 0;
> ...to nginx.conf appears to reduce the crashes.  It happens with a
> variety of users and with debug output I see no pattern.
>
>
>
> James.
>

Hi!

There is an easy fix for this, attached.

Aki

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