imer_setup() is not compatible with PaX's RAP

[PaX Team]

On 13 Nov 2017 at 20:34, Jason A. Donenfeld wrote:

> I've fixed this all up here:
> https://git.zx2c4.com/WireGuard/commit/?id=e4bf02b833f99f4dcc2ab685d92517ccf8cc4766
> 
> I think it _should_ work now. Thanks for the suggestions. I just
> monkey patched the signatures of each of those functions. Ugly, but it
> works.

oh boy, can't disagree with ugly ;). it needed a few tweaks:

--- WireGuard-0.0.20171111.orig/src/compat/compat.h       2017-11-11 04:35:06.000000000 +0100
+++ WireGuard-0.0.20171111/src/compat/compat.h    2017-11-13 23:21:17.967716768 +0100
@@ -562,4 +562,23 @@ static inline void new_icmpv6_send(struc
 #define __read_mostly
 #endif

+#ifdef RAP_PLUGIN
+#include <linux/timer.h>
+#ifndef TIMER_DATA_TYPE
+#define TIMER_DATA_TYPE unsigned long
+#endif
+
+#define expired_retransmit_handshake(a) expired_retransmit_handshake(TIMER_DATA_TYPE timer)
+#define expired_send_keepalive(a) expired_send_keepalive(TIMER_DATA_TYPE timer)
+#define expired_new_handshake(a) expired_new_handshake(TIMER_DATA_TYPE timer)
+#define expired_zero_key_material(a) expired_zero_key_material(TIMER_DATA_TYPE timer)
+#define expired_send_persistent_keepalive(a) expired_send_persistent_keepalive(TIMER_DATA_TYPE timer)
+
+#undef timer_setup
+#define timer_setup(a, b, c) setup_timer(a, ((void (*)(TIMER_DATA_TYPE))b), ((TIMER_DATA_TYPE)a))
+
+#undef from_timer
+#define from_timer(var, callback_timer, timer_fieldname) container_of((struct timer_list *)callback_timer, typeof(*var), timer_fieldname)
+#endif
+
 #endif /* _WG_COMPAT_H */

the KERNEXEC block isn't needed as it was removing KERNEXEC's own define and
pre 4.14 kernels don't define TIMER_DATA_TYPE so it has to be defined for them.
also this whole block should probably depend on 4.15 if it ends up converting
all old prototypes and removes TIMER_DATA_TYPE itself.

> By the way, if you ever find yourself having to revert things to run
> WireGuard, don't hesitate to send a patch or just poke me, and I'll
> fix things. I'd definitely like to support PaX for as long as I can
> manage to do so.

thanks, will keep you posted if i see anything.