From: Tim Duesterhus <tim@bastelstu.be>
Date: Sat, 18 Jan 2020 01:04:12 +0000 (+0100)
Subject: BUG/MINOR: dns: Make dns_query_id_seed unsigned
X-Git-Tag: v2.2-dev1~80
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=fcac33d0c1138ef22914c3b36518c1df105c9b72;p=thirdparty%2Fhaproxy.git

BUG/MINOR: dns: Make dns_query_id_seed unsigned

Left shifting of large signed values and negative values is undefined.

In a test script clang's ubsan rightfully complains:

> runtime error: left shift of 1934242336581872173 by 13 places cannot be represented in type 'int64_t' (aka 'long')

This bug was introduced in the initial version of the DNS resolver
in 325137d603aa81bd24cbd8c99d816dd42291daa7. The fix must be backported
to HAProxy 1.6+.
---

diff --git a/src/dns.c b/src/dns.c
index bc68a81c06..64bb0d15f1 100644
--- a/src/dns.c
+++ b/src/dns.c
@@ -54,7 +54,7 @@
 struct list dns_resolvers  = LIST_HEAD_INIT(dns_resolvers);
 struct list dns_srvrq_list = LIST_HEAD_INIT(dns_srvrq_list);
 
-static THREAD_LOCAL int64_t dns_query_id_seed = 0; /* random seed */
+static THREAD_LOCAL uint64_t dns_query_id_seed = 0; /* random seed */
 
 DECLARE_STATIC_POOL(dns_answer_item_pool, "dns_answer_item", sizeof(struct dns_answer_item));
 DECLARE_STATIC_POOL(dns_resolution_pool,  "dns_resolution",  sizeof(struct dns_resolution));