From 965daa1df3ba55af0851257364c9ea488f8ef2af Mon Sep 17 00:00:00 2001 From: Tobias Brunner Date: Fri, 4 Nov 2016 10:14:30 +0100 Subject: [PATCH] kernel-netlink: Use correct 4 byte alignment for AH with IPv4 By default, the kernel incorrectly uses an 8 byte alignment, which is mandatory for IPv6 but prohibited for IPv4. For many algorithms this doesn't matter but that's not the case for HMAC_SHA2_256_128. Since 2.6.39 the kernel can be explicitly configured to use a 4 byte alignment. --- src/libcharon/plugins/kernel_netlink/kernel_netlink_ipsec.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/src/libcharon/plugins/kernel_netlink/kernel_netlink_ipsec.c b/src/libcharon/plugins/kernel_netlink/kernel_netlink_ipsec.c index b2ccbe0419..1d5e3b2bd2 100644 --- a/src/libcharon/plugins/kernel_netlink/kernel_netlink_ipsec.c +++ b/src/libcharon/plugins/kernel_netlink/kernel_netlink_ipsec.c @@ -1369,6 +1369,11 @@ METHOD(kernel_ipsec_t, add_sa, status_t, default: break; } + if (id->proto == IPPROTO_AH && sa->family == AF_INET) + { /* use alignment to 4 bytes for IPv4 instead of the incorrect 8 byte + * alignment that's used by default but is only valid for IPv6 */ + sa->flags |= XFRM_STATE_ALIGN4; + } sa->reqid = data->reqid; sa->lft.soft_byte_limit = XFRM_LIMIT(data->lifetime->bytes.rekey); -- 2.39.2