Commit 26c01310 authored by Jason A. Donenfeld's avatar Jason A. Donenfeld Committed by Jakub Kicinski

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: e7096c13 ("net: WireGuard secure network tunnel")
Signed-off-by: default avatarJason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Reported-by: syzbot+a448cda4dba2dac50de5@syzkaller.appspotmail.com
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 8e25c02b
...@@ -436,14 +436,13 @@ static int set_peer(struct wg_device *wg, struct nlattr **attrs) ...@@ -436,14 +436,13 @@ static int set_peer(struct wg_device *wg, struct nlattr **attrs)
if (attrs[WGPEER_A_ENDPOINT]) { if (attrs[WGPEER_A_ENDPOINT]) {
struct sockaddr *addr = nla_data(attrs[WGPEER_A_ENDPOINT]); struct sockaddr *addr = nla_data(attrs[WGPEER_A_ENDPOINT]);
size_t len = nla_len(attrs[WGPEER_A_ENDPOINT]); size_t len = nla_len(attrs[WGPEER_A_ENDPOINT]);
struct endpoint endpoint = { { { 0 } } };
if ((len == sizeof(struct sockaddr_in) && if (len == sizeof(struct sockaddr_in) && addr->sa_family == AF_INET) {
addr->sa_family == AF_INET) || endpoint.addr4 = *(struct sockaddr_in *)addr;
(len == sizeof(struct sockaddr_in6) && wg_socket_set_peer_endpoint(peer, &endpoint);
addr->sa_family == AF_INET6)) { } else if (len == sizeof(struct sockaddr_in6) && addr->sa_family == AF_INET6) {
struct endpoint endpoint = { { { 0 } } }; endpoint.addr6 = *(struct sockaddr_in6 *)addr;
memcpy(&endpoint.addr, addr, len);
wg_socket_set_peer_endpoint(peer, &endpoint); wg_socket_set_peer_endpoint(peer, &endpoint);
} }
} }
......
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