[PATCH 0/2] wireguard-linux-compat: grsecurity compat patches

[Mathias Krause]

Hi Jason,

Am 03.12.21 um 23:20 schrieb Jason A. Donenfeld:
> This resulted in kind of an interesting regression with old compilers
> on old kernel versions when I backported this to
> wireguard-linux-compat:
> https://git.zx2c4.com/wireguard-linux-compat/commit/?id=8118c247a75ae95169f0a9a539dfc661ffda8bc5
> 
> The 25519 tests fail for 4.8.17, 4.7.10, 4.6.7, 4.5.7 with gcc 6:
> 
> https://build.wireguard.com/wireguard-linux-compat/e8db181d62467da6c476cf4ac21e13dd477612c8/4.8.17-x86_64.log
> https://build.wireguard.com/wireguard-linux-compat/e8db181d62467da6c476cf4ac21e13dd477612c8/4.7.10-x86_64.log
> https://build.wireguard.com/wireguard-linux-compat/e8db181d62467da6c476cf4ac21e13dd477612c8/4.6.7-x86_64.log
> https://build.wireguard.com/wireguard-linux-compat/e8db181d62467da6c476cf4ac21e13dd477612c8/4.5.7-x86_64.log
> 
> But then they crash for 4.0.9, 3.19.8, 3.17.8 with gcc 5:
> 
> https://build.wireguard.com/wireguard-linux-compat/e8db181d62467da6c476cf4ac21e13dd477612c8/4.0.9-x86_64.log
> https://build.wireguard.com/wireguard-linux-compat/e8db181d62467da6c476cf4ac21e13dd477612c8/3.19.8-x86_64.log
> https://build.wireguard.com/wireguard-linux-compat/e8db181d62467da6c476cf4ac21e13dd477612c8/3.17.8-x86_64.log
> 
> And also crash with 3.16.85, 3.15.10, 3.14.79, 3.12.74, 3.11.10 with gcc 4:
> 
> https://build.wireguard.com/wireguard-linux-compat/e8db181d62467da6c476cf4ac21e13dd477612c8/3.16.85-x86_64.log
> https://build.wireguard.com/wireguard-linux-compat/e8db181d62467da6c476cf4ac21e13dd477612c8/3.15.10-x86_64.log
> https://build.wireguard.com/wireguard-linux-compat/e8db181d62467da6c476cf4ac21e13dd477612c8/3.14.79-x86_64.log
> https://build.wireguard.com/wireguard-linux-compat/e8db181d62467da6c476cf4ac21e13dd477612c8/3.13.11-x86_64.log
> https://build.wireguard.com/wireguard-linux-compat/e8db181d62467da6c476cf4ac21e13dd477612c8/3.12.74-x86_64.log
> https://build.wireguard.com/wireguard-linux-compat/e8db181d62467da6c476cf4ac21e13dd477612c8/3.11.10-x86_64.log
> 
> Any intuition about what might have happened?

Sorry to hear that. I didn't ran into such issues when doing the
backport and, in fact, trying to reproduce the selftest errors / crashes
failed so far on v4.8.17 with gcc 6.3 and 4.6.3:

[    0.137871] wireguard: chacha20 self-tests: pass
[    0.141106] wireguard: poly1305 self-tests: pass
[    0.141604] wireguard: chacha20poly1305 self-tests: pass
[    0.142309] wireguard: blake2s self-tests: pass
[    0.157012] wireguard: curve25519 self-tests: pass
[    0.157430] wireguard: allowedips self-tests: pass
[    0.158354] wireguard: nonce counter self-tests: pass
[    0.388426] wireguard: ratelimiter self-tests: pass
[    0.389045] wireguard: WireGuard 1.0.20210606 loaded. See
www.wireguard.com for information.
[    0.389874] wireguard: Copyright (C) 2015-2019 Jason A. Donenfeld
<Jason at zx2c4.com>. All Rights Reserved.

I'll try older kernels and see if they trigger. In case not, can you
send me the object files of a failing kernel?

Thanks,
Mathias