From: Tim Duesterhus <tim@bastelstu.be>
Date: Sun, 14 Jun 2020 15:27:36 +0000 (+0200)
Subject: BUG/MAJOR: vars: Fix bogus free() during deinit() for http-request rules
X-Git-Tag: v2.2-dev10~44
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=01a0ce39e28e1056d4dd513a9ef8734c5545c184;p=thirdparty%2Fhaproxy.git

BUG/MAJOR: vars: Fix bogus free() during deinit() for http-request rules

We cannot simply `release_sample_expr(rule->arg.vars.expr)` for a
`struct act_rule`, because `rule->arg` is a union that might not
contain valid `vars`. This leads to a crash on a configuration using
`http-request redirect` and possibly others:

    frontend http
    	mode http
    	bind 127.0.0.1:80
    	http-request redirect scheme https

Instead a `struct act_rule` has a `release_ptr` that must be used
to properly free any additional storage allocated.

This patch fixes a regression in commit ff78fcdd7f15c8626c7e70add7a935221ee2920c.
It must be backported to whereever that patch is backported.

It has be verified that the configuration above no longer crashes.
It has also been verified that the configuration in ff78fcdd7f15c8626c7e70add7a935221ee2920c
does not leak.
---

diff --git a/src/haproxy.c b/src/haproxy.c
index 6a8c13e6dd..215c68a303 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -2555,7 +2555,6 @@ static void deinit_act_rules(struct list *rules)
 	list_for_each_entry_safe(rule, ruleb, rules, list) {
 		LIST_DEL(&rule->list);
 		deinit_acl_cond(rule->cond);
-		release_sample_expr(rule->arg.vars.expr);
 		if (rule->release_ptr)
 			rule->release_ptr(rule);
 		free(rule);
diff --git a/src/vars.c b/src/vars.c
index b154c529d3..fd95eed5d7 100644
--- a/src/vars.c
+++ b/src/vars.c
@@ -689,6 +689,11 @@ static enum act_return action_clear(struct act_rule *rule, struct proxy *px,
 	return ACT_RET_CONT;
 }
 
+static void release_store_rule(struct act_rule *rule)
+{
+	release_sample_expr(rule->arg.vars.expr);
+}
+
 /* This two function checks the variable name and replace the
  * configuration string name by the global string name. its
  * the same string, but the global pointer can be easy to
@@ -758,6 +763,7 @@ static enum act_parse_ret parse_store(const char **args, int *arg, struct proxy
 	if (!set_var) {
 		rule->action     = ACT_CUSTOM;
 		rule->action_ptr = action_clear;
+		rule->release_ptr = release_store_rule;
 		return ACT_RET_PRS_OK;
 	}
 
@@ -791,6 +797,7 @@ static enum act_parse_ret parse_store(const char **args, int *arg, struct proxy
 
 	rule->action     = ACT_CUSTOM;
 	rule->action_ptr = action_store;
+	rule->release_ptr = release_store_rule;
 	return ACT_RET_PRS_OK;
 }