wireguard: selftests: set fake real time in init

Not all platforms have an RTC, and rather than trying to force one into
each, it's much easier to just set a fixed time. This is necessary
because WireGuard's latest handshakes parameter is returned in wallclock
time, and if the system time isn't set, and the system is really fast,
then this returns 0, which trips the test.

Turning this on requires setting CONFIG_COMPAT_32BIT_TIME=y, as musl
doesn't support settimeofday without it.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/wireguard/qemu/arch/arm.config

@@ -7,6 +7,7 @@ CONFIG_SERIAL_AMBA_PL011_CONSOLE=y
 CONFIG_VIRTIO_MENU=y
 CONFIG_VIRTIO_MMIO=y
 CONFIG_VIRTIO_CONSOLE=y
+CONFIG_COMPAT_32BIT_TIME=y
 CONFIG_CMDLINE_BOOL=y
 CONFIG_CMDLINE="console=ttyAMA0 wg.success=vport0p1 panic_on_warn=1"
 CONFIG_FRAME_WARN=1024

tools/testing/selftests/wireguard/qemu/arch/armeb.config

@@ -7,6 +7,7 @@ CONFIG_SERIAL_AMBA_PL011_CONSOLE=y
 CONFIG_VIRTIO_MENU=y
 CONFIG_VIRTIO_MMIO=y
 CONFIG_VIRTIO_CONSOLE=y
+CONFIG_COMPAT_32BIT_TIME=y
 CONFIG_CMDLINE_BOOL=y
 CONFIG_CMDLINE="console=ttyAMA0 wg.success=vport0p1 panic_on_warn=1"
 CONFIG_CPU_BIG_ENDIAN=y

tools/testing/selftests/wireguard/qemu/arch/i686.config

 CONFIG_ACPI=y
 CONFIG_SERIAL_8250=y
 CONFIG_SERIAL_8250_CONSOLE=y
+CONFIG_COMPAT_32BIT_TIME=y
 CONFIG_CMDLINE_BOOL=y
 CONFIG_CMDLINE="console=ttyS0 wg.success=ttyS1 panic_on_warn=1"
 CONFIG_FRAME_WARN=1024

tools/testing/selftests/wireguard/qemu/arch/m68k.config

@@ -5,5 +5,6 @@ CONFIG_MAC=y
 CONFIG_SERIAL_PMACZILOG=y
 CONFIG_SERIAL_PMACZILOG_TTYS=y
 CONFIG_SERIAL_PMACZILOG_CONSOLE=y
+CONFIG_COMPAT_32BIT_TIME=y
 CONFIG_CMDLINE="console=ttyS0 wg.success=ttyS1 panic_on_warn=1"
 CONFIG_FRAME_WARN=1024

tools/testing/selftests/wireguard/qemu/arch/mips.config

@@ -6,6 +6,7 @@ CONFIG_POWER_RESET=y
 CONFIG_POWER_RESET_SYSCON=y
 CONFIG_SERIAL_8250=y
 CONFIG_SERIAL_8250_CONSOLE=y
+CONFIG_COMPAT_32BIT_TIME=y
 CONFIG_CMDLINE_BOOL=y
 CONFIG_CMDLINE="console=ttyS0 wg.success=ttyS1 panic_on_warn=1"
 CONFIG_FRAME_WARN=1024

tools/testing/selftests/wireguard/qemu/arch/mipsel.config

@@ -7,6 +7,7 @@ CONFIG_POWER_RESET=y
 CONFIG_POWER_RESET_SYSCON=y
 CONFIG_SERIAL_8250=y
 CONFIG_SERIAL_8250_CONSOLE=y
+CONFIG_COMPAT_32BIT_TIME=y
 CONFIG_CMDLINE_BOOL=y
 CONFIG_CMDLINE="console=ttyS0 wg.success=ttyS1 panic_on_warn=1"
 CONFIG_FRAME_WARN=1024

tools/testing/selftests/wireguard/qemu/arch/powerpc.config

@@ -4,6 +4,7 @@ CONFIG_PPC_85xx=y
 CONFIG_PHYS_64BIT=y
 CONFIG_SERIAL_8250=y
 CONFIG_SERIAL_8250_CONSOLE=y
+CONFIG_COMPAT_32BIT_TIME=y
 CONFIG_MATH_EMULATION=y
 CONFIG_CMDLINE_BOOL=y
 CONFIG_CMDLINE="console=ttyS0 wg.success=ttyS1 panic_on_warn=1"

tools/testing/selftests/wireguard/qemu/init.c

@@ -11,6 +11,7 @@
 #include <stdlib.h>
 #include <stdbool.h>
 #include <fcntl.h>
+#include <time.h>
 #include <sys/wait.h>
 #include <sys/mount.h>
 #include <sys/stat.h>
@@ -70,6 +71,15 @@ static void seed_rng(void)
 	close(fd);
 }
 
+static void set_time(void)
+{
+	if (time(NULL))
+		return;
+	pretty_message("[+] Setting fake time...");
+	if (stime(&(time_t){1433512680}) < 0)
+		panic("settimeofday()");
+}
+
 static void mount_filesystems(void)
 {
 	pretty_message("[+] Mounting filesystems...");
@@ -259,6 +269,7 @@ int main(int argc, char *argv[])
 	print_banner();
 	mount_filesystems();
 	seed_rng();
+	set_time();
 	kmod_selftests();
 	enable_logging();
 	clear_leaks();