From: Willy Tarreau <w@1wt.eu>
Date: Tue, 25 Feb 2020 08:43:22 +0000 (+0100)
Subject: CLEANUP: sample: use read_u64() in ipmask() to apply an IPv6 mask
X-Git-Tag: v2.2-dev3~15
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=a8b7ecd4dcb2b11d418ff57484c41ae62d1766ce;p=thirdparty%2Fhaproxy.git

CLEANUP: sample: use read_u64() in ipmask() to apply an IPv6 mask

There were 8 strict aliasing warnings there due to the dereferences
casting to uint32_t of input and output. We can achieve the same using
two write_u64() and four read_u64() which do not cause this issue and
even let the compiler use 64-bit operations.
---

diff --git a/src/sample.c b/src/sample.c
index 0fb5f9aa79..3c61112240 100644
--- a/src/sample.c
+++ b/src/sample.c
@@ -22,6 +22,7 @@
 #include <common/hash.h>
 #include <common/http.h>
 #include <common/initcall.h>
+#include <common/net_helper.h>
 #include <common/standard.h>
 #include <common/uri_auth.h>
 #include <common/base64.h>
@@ -1750,10 +1751,10 @@ static int sample_conv_ipmask(const struct arg *args, struct sample *smp, void *
 		if (args[1].type != ARGT_IPV6)
 			return 0;
 
-		*(uint32_t*)&smp->data.u.ipv6.s6_addr[0]  &= *(uint32_t*)&args[1].data.ipv6.s6_addr[0];
-		*(uint32_t*)&smp->data.u.ipv6.s6_addr[4]  &= *(uint32_t*)&args[1].data.ipv6.s6_addr[4];
-		*(uint32_t*)&smp->data.u.ipv6.s6_addr[8]  &= *(uint32_t*)&args[1].data.ipv6.s6_addr[8];
-		*(uint32_t*)&smp->data.u.ipv6.s6_addr[12] &= *(uint32_t*)&args[1].data.ipv6.s6_addr[12];
+		write_u64(&smp->data.u.ipv6.s6_addr[0],
+			  read_u64(&smp->data.u.ipv6.s6_addr[0]) & read_u64(&args[1].data.ipv6.s6_addr[0]));
+		write_u64(&smp->data.u.ipv6.s6_addr[8],
+			  read_u64(&smp->data.u.ipv6.s6_addr[8]) & read_u64(&args[1].data.ipv6.s6_addr[8]));
 		smp->data.type = SMP_T_IPV6;
 	}