From 26c013108c12b94bc023bf19198a4300596c98b1 Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Fri, 16 Sep 2022 15:37:40 +0100 Subject: [PATCH] wireguard: netlink: avoid variable-sized memcpy on sockaddr Doing a variable-sized memcpy is slower, and the compiler isn't smart enough to turn this into a constant-size assignment. Further, Kees' latest fortified memcpy will actually bark, because the destination pointer is type sockaddr, not explicitly sockaddr_in or sockaddr_in6, so it thinks there's an overflow: memcpy: detected field-spanning write (size 28) of single field "&endpoint.addr" at drivers/net/wireguard/netlink.c:446 (size 16) Fix this by just assigning by using explicit casts for each checked case. Fixes: e7096c131e51 ("net: WireGuard secure network tunnel") Signed-off-by: Jason A. Donenfeld Reviewed-by: Kees Cook Reported-by: syzbot+a448cda4dba2dac50de5@syzkaller.appspotmail.com Signed-off-by: Jakub Kicinski --- drivers/net/wireguard/netlink.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/drivers/net/wireguard/netlink.c b/drivers/net/wireguard/netlink.c index d0f3b6d..5c804bc 100644 --- a/drivers/net/wireguard/netlink.c +++ b/drivers/net/wireguard/netlink.c @@ -436,14 +436,13 @@ static int set_peer(struct wg_device *wg, struct nlattr **attrs) if (attrs[WGPEER_A_ENDPOINT]) { struct sockaddr *addr = nla_data(attrs[WGPEER_A_ENDPOINT]); size_t len = nla_len(attrs[WGPEER_A_ENDPOINT]); + struct endpoint endpoint = { { { 0 } } }; - if ((len == sizeof(struct sockaddr_in) && - addr->sa_family == AF_INET) || - (len == sizeof(struct sockaddr_in6) && - addr->sa_family == AF_INET6)) { - struct endpoint endpoint = { { { 0 } } }; - - memcpy(&endpoint.addr, addr, len); + if (len == sizeof(struct sockaddr_in) && addr->sa_family == AF_INET) { + endpoint.addr4 = *(struct sockaddr_in *)addr; + wg_socket_set_peer_endpoint(peer, &endpoint); + } else if (len == sizeof(struct sockaddr_in6) && addr->sa_family == AF_INET6) { + endpoint.addr6 = *(struct sockaddr_in6 *)addr; wg_socket_set_peer_endpoint(peer, &endpoint); } } -- 2.7.4