Re: auth-policy crashing
On 07/08/2019 11:19, James via dovecot wrote: My more simplistic policy does not need both. I perform whitelist, blacklist, geo and greylist ...and DNSBL which where I started with the policyserver, "Can dovecot do DNSBL?", only indirectly via a policyserver. This is better as most pass white list or fail geo local checks before doing the external DNS lookup.
Re: auth-policy crashing
On 07/08/2019 11:02, Aki Tuomi via dovecot wrote: before and after auth? roundcube webmail reports an error with only auth_policy_check_before_auth. I cannot see why. The simple and lazy solution is to use double auth_policy_check_! ... The double-check is for places which want to implement something like COS or want to perform validations in policy server *after* we know the user identity. The first check is done before we even know if the user or the credential(s) are valid. I can see why both before and after are options. My more simplistic policy does not need both. I perform whitelist, blacklist, geo and greylist and do not cross reference these with the user. I can't see why roundcubemail fails without both. The IMAP exchange with roundcubemail should not be aware of the policy server. I was spending [wasting] too much time on looking for an answer and gave up.
Re: auth-policy crashing
On 7.8.2019 11.51, James via dovecot wrote: > On 06/08/2019 06:46, Aki Tuomi via dovecot wrote: >> >> On 2.8.2019 13.45, James via dovecot wrote: >>> My auth process is dumping core. This happens several times per day > ... > >> There is an easy fix for this, attached. > > Patch applied; no core dump in 24 hours. > > This appears to have fixed the problem. I found that it crashed when > the policy server responded too quickly. As the before and after auth > command=allow request are the same I cache the first, leading to a > fast second response. Removing the cache (nginx proxy_cache ...) must > change the timings and circumvented the crash. Why use both check > before and after auth? roundcube webmail reports an error with only > auth_policy_check_before_auth. I cannot see why. The simple and lazy > solution is to use double auth_policy_check_! > > Thank you Aki for looking at this and finding a solution so quickly. The double-check is for places which want to implement something like COS or want to perform validations in policy server *after* we know the user identity. The first check is done before we even know if the user or the credential(s) are valid. Aki
Re: auth-policy crashing
On 06/08/2019 06:46, Aki Tuomi via dovecot wrote: On 2.8.2019 13.45, James via dovecot wrote: My auth process is dumping core. This happens several times per day ... There is an easy fix for this, attached. Patch applied; no core dump in 24 hours. This appears to have fixed the problem. I found that it crashed when the policy server responded too quickly. As the before and after auth command=allow request are the same I cache the first, leading to a fast second response. Removing the cache (nginx proxy_cache ...) must change the timings and circumvented the crash. Why use both check before and after auth? roundcube webmail reports an error with only auth_policy_check_before_auth. I cannot see why. The simple and lazy solution is to use double auth_policy_check_! Thank you Aki for looking at this and finding a solution so quickly.
Re: auth-policy crashing
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@1 (l@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,
> " context->request == NULL\n");
> i_stream_unref(>payload);
>
> if (context->request == NULL) fprintf(stderr,
> " context->request == NULL\n");
> if (context->parse_error) {
> context->result = (context->set->policy_reject_on_fail ? -1 : 0);
> }
>
> if (context->request == NULL) fprintf(stderr,
> " 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:
> context->request == NULL
> Aug 1 14:25:44 mailhost dovecot: [ID 702911 mail.error] auth: Error:
> 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
>From 760452dacb6da1209c79765ed8ad51144e9d9dcf Mon Sep 17 00:00:00 2001
From: Aki Tuomi
Date: Tue, 6 Aug 2019 08:44:18 +0300
Subject: [PATCH] auth: Do not unref policy payload too early
This can cause the context to be free'd too early leading
to crashes.
---
src/auth/auth-policy.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/auth/auth-policy.c b/src/auth/auth-policy.c
index 9efc81330..6318db8bf 100644
--- a/src/auth/auth-policy.c
+++ b/src/auth/auth-policy.c
@@ -347,7 +347,6 @@ void auth_policy_parse_response(struct policy_lookup_ctx *context)
else if (context->parse_state == POLICY_RESULT)
context->parse_error = FALSE;
}
- i_stream_unref(>payload);
if (context->parse_error) {
context->result = (context->set->policy_reject_on_fail ? -1 : 0);
@@ -376,6 +375,7 @@ void auth_policy_parse_response(struct policy_lookup_ctx *context)
}
auth_policy_callback(context);
+ i_stream_unref(>payload);
}
static
--
2.11.0
Re: auth-policy crashing
On 02/08/2019 11:45, 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@1 (l@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; Further tracking shows this sets context->request to NULL: "src/lib/iostream.c" line 54 array_foreach(>destroy_callbacks, dc) dc->callback(dc->context); Very occasionally I see: Aug 3 11:00:35 mailhost dovecot: [ID 702911 mail.crit] auth: Panic: file http-client-request.c: line 283 (http_client_request_unref): assertion failed: (req->refcount > 0) Swapping keep-alive on/off changes crashing from very approximately once per day to some per hour. I guess there is some fundamental thread clash or keep alive time out clean-up failure. James.
