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BUG/MEDIUM: dns: Don't yield in do-resolve action on a final evaluation

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When an action is evaluated, flags are passed to know if it is the first call
(ACT_OPT_FIRST) and if it must be the last one (ACT_OPT_FINAL). For the
do-resolve DNS action, the ACT_OPT_FINAL flag must be handled because the
action may yield. It must never yield when this flag is set. Otherwise, it may
lead to a wakeup loop of the stream because the inspected-delay of a tcp-request
content ruleset was reached without stopping the rules evaluation.

This patch is related to the issue #222. It must be backported as far as 2.0.
This commit is contained in:
Christopher Faulet 2020-07-28 10:21:54 +02:00
parent 08ed98fd79
commit 385101e538
1 changed files with 21 additions and 18 deletions
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39
src/dns.c
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@ -2456,10 +2456,8 @@ enum act_return dns_action_do_resolve(struct act_rule *rule, struct proxy *px,
locked = 1;
}
if (resolution->step == RSLV_STEP_RUNNING) {
ret = ACT_RET_YIELD;
goto end;
}
if (resolution->step == RSLV_STEP_RUNNING)
goto yield;
if (resolution->step == RSLV_STEP_NONE) {
/* We update the variable only if we have a valid response. */
if (resolution->status == RSLV_STATUS_VALID) {
@ -2493,14 +2491,7 @@ enum act_return dns_action_do_resolve(struct act_rule *rule, struct proxy *px,
}
}
free(s->dns_ctx.hostname_dn); s->dns_ctx.hostname_dn = NULL;
s->dns_ctx.hostname_dn_len = 0;
dns_unlink_resolution(s->dns_ctx.dns_requester);
pool_free(dns_requester_pool, s->dns_ctx.dns_requester);
s->dns_ctx.dns_requester = NULL;
goto end;
goto release_requester;
}
/* need to configure and start a new DNS resolution */
@ -2521,26 +2512,38 @@ enum act_return dns_action_do_resolve(struct act_rule *rule, struct proxy *px,
/* Check if there is a fresh enough response in the cache of our associated resolution */
req = s->dns_ctx.dns_requester;
if (!req || !req->resolution) {
dns_trigger_resolution(s->dns_ctx.dns_requester);
ret = ACT_RET_YIELD;
goto end;
}
if (!req || !req->resolution)
goto release_requester; /* on error, ignore the action */
res = req->resolution;
exp = tick_add(res->last_resolution, resolvers->hold.valid);
if (resolvers->t && res->status == RSLV_STATUS_VALID && tick_isset(res->last_resolution)
&& !tick_is_expired(exp, now_ms)) {
&& !tick_is_expired(exp, now_ms)) {
goto use_cache;
}
dns_trigger_resolution(s->dns_ctx.dns_requester);
yield:
if (flags & ACT_OPT_FINAL)
goto release_requester;
ret = ACT_RET_YIELD;
end:
if (locked)
HA_SPIN_UNLOCK(DNS_LOCK, &resolvers->lock);
return ret;
release_requester:
free(s->dns_ctx.hostname_dn);
s->dns_ctx.hostname_dn = NULL;
s->dns_ctx.hostname_dn_len = 0;
if (s->dns_ctx.dns_requester) {
dns_unlink_resolution(s->dns_ctx.dns_requester);
pool_free(dns_requester_pool, s->dns_ctx.dns_requester);
s->dns_ctx.dns_requester = NULL;
}
goto end;
}
static void release_dns_action(struct act_rule *rule)