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Fix an unaligned access on OpenBSD/sparc64

The pointer to the packet content doesn't seem to be word-aligned,
resulting in a SIGBUS when accessing it as a pointer to struct ip that
contains bit fields.

Replace with struct openvpn_iphdr and OPENVPN_IPH_GET_VER, which only
does a one byte access and thus isn't affected by alignement.
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <87ink3vpcs.fsf@ritchie.wxcvbn.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg14769.html

Signed-off-by: Gert Doering <gert@greenie.muc.de>

Jérémie Courrèges-Anglas authored on 2017/06/10 23:48:44
Showing 1 changed files

src/openvpn/tun.c

History View file @ 3e4e300

@@ -1654,11 +1654,11 @@ write_tun_header(struct tuntap *tt, uint8_t *buf, int len)
     {
         u_int32_t type;
         struct iovec iv[2];
-        struct ip *iph;
+        struct openvpn_iphdr *iph;
 
-        iph = (struct ip *) buf;
+        iph = (struct openvpn_iphdr *) buf;
 
-        if (iph->ip_v == 6)
+        if (OPENVPN_IPH_GET_VER(iph->version_len) == 6)
         {
             type = htonl(AF_INET6);
         }

...	...	@@ -1654,11 +1654,11 @@ write_tun_header(struct tuntap tt, uint8_t buf, int len)
1654	1654	{
1655	1655	u_int32_t type;
1656	1656	struct iovec iv[2];
1657		- struct ip *iph;
	1657	+ struct openvpn_iphdr *iph;
1658	1658
1659		- iph = (struct ip *) buf;
	1659	+ iph = (struct openvpn_iphdr *) buf;
1660	1660
1661		- if (iph->ip_v == 6)
	1661	+ if (OPENVPN_IPH_GET_VER(iph->version_len) == 6)
1662	1662	{
1663	1663	type = htonl(AF_INET6);
1664	1664	}