From 0f23e882fa8ef33d4f44a3fc0a5bba7a32889801 Mon Sep 17 00:00:00 2001
From: m00nbsd <42475391+m00nbsd@users.noreply.github.com>
Date: Thu, 11 Jun 2020 23:16:52 +0200
Subject: [PATCH] sys/netbsd: add support for fault injection (#1817)

---
 executor/common.h        |  2 +-
 executor/common_bsd.h    | 49 ++++++++++++++++++++++++++++++++++++++
 executor/executor_bsd.h  |  1 +
 pkg/csource/generated.go | 51 +++++++++++++++++++++++++++++++++++++++-
 pkg/host/host_netbsd.go  |  8 +++++++
 5 files changed, 109 insertions(+), 2 deletions(-)

diff --git a/executor/common.h b/executor/common.h
index 9e1c94c0..cb409e76 100644
--- a/executor/common.h
+++ b/executor/common.h
@@ -221,7 +221,7 @@ static void remove_dir(const char* dir)
 #endif
 #endif
 
-#if !GOOS_linux
+#if !GOOS_linux && !GOOS_netbsd
 #if SYZ_EXECUTOR
 static int inject_fault(int nth)
 {
diff --git a/executor/common_bsd.h b/executor/common_bsd.h
index a04d86a9..82aef421 100644
--- a/executor/common_bsd.h
+++ b/executor/common_bsd.h
@@ -12,6 +12,7 @@
 #include <sys/syscall.h>
 
 #if GOOS_netbsd
+
 #if SYZ_EXECUTOR || __NR_syz_usb_connect
 #include "common_usb_netbsd.h"
 #endif
@@ -22,6 +23,54 @@ static void setup_usb(void)
 		fail("failed to chmod /dev/vhci");
 }
 #endif
+
+#if SYZ_EXECUTOR || SYZ_FAULT
+#include <fcntl.h>
+#include <sys/fault.h>
+static void setup_fault(void)
+{
+	if (chmod("/dev/fault", 0666))
+		fail("failed to chmod /dev/fault");
+}
+static int inject_fault(int nth)
+{
+	struct fault_ioc_enable en;
+	int fd;
+
+	fd = open("/dev/fault", O_RDWR);
+	if (fd == -1)
+		fail("failed to open /dev/fault");
+
+	en.scope = FAULT_SCOPE_LWP;
+	en.mode = FAULT_MODE_NTH;
+	en.nth = nth;
+	if (ioctl(fd, FAULT_IOC_ENABLE, &en) != 0)
+		fail("FAULT_IOC_ENABLE failed with nth=%d", nth);
+
+	return fd;
+}
+#endif
+#if SYZ_EXECUTOR
+static int fault_injected(int fd)
+{
+	struct fault_ioc_getinfo info;
+	struct fault_ioc_disable dis;
+	int res;
+
+	if (ioctl(fd, FAULT_IOC_GETINFO, &info) != 0)
+		fail("FAULT_IOC_GETINFO failed");
+	res = (info.nfaults > 0);
+
+	dis.scope = FAULT_SCOPE_LWP;
+	if (ioctl(fd, FAULT_IOC_DISABLE, &dis) != 0)
+		fail("FAULT_IOC_DISABLE failed");
+
+	close(fd);
+
+	return res;
+}
+#endif
+
 #endif
 
 #if GOOS_openbsd
diff --git a/executor/executor_bsd.h b/executor/executor_bsd.h
index c17f3796..a9440ace 100644
--- a/executor/executor_bsd.h
+++ b/executor/executor_bsd.h
@@ -172,6 +172,7 @@ static bool cover_check(uint64 pc)
 #define SYZ_HAVE_FEATURES 1
 static feature_t features[] = {
     {"usb", setup_usb},
+    {"fault", setup_fault},
 };
 
 static void setup_machine(void)
diff --git a/pkg/csource/generated.go b/pkg/csource/generated.go
index 6f81981a..eaa2b714 100644
--- a/pkg/csource/generated.go
+++ b/pkg/csource/generated.go
@@ -206,7 +206,7 @@ static void remove_dir(const char* dir)
 #endif
 #endif
 
-#if !GOOS_linux
+#if !GOOS_linux && !GOOS_netbsd
 #if SYZ_EXECUTOR
 static int inject_fault(int nth)
 {
@@ -410,6 +410,7 @@ void child()
 #include <sys/syscall.h>
 
 #if GOOS_netbsd
+
 #if SYZ_EXECUTOR || __NR_syz_usb_connect
 
 #include <dev/usb/usb.h>
@@ -1568,6 +1569,54 @@ static void setup_usb(void)
 		fail("failed to chmod /dev/vhci");
 }
 #endif
+
+#if SYZ_EXECUTOR || SYZ_FAULT
+#include <fcntl.h>
+#include <sys/fault.h>
+static void setup_fault(void)
+{
+	if (chmod("/dev/fault", 0666))
+		fail("failed to chmod /dev/fault");
+}
+static int inject_fault(int nth)
+{
+	struct fault_ioc_enable en;
+	int fd;
+
+	fd = open("/dev/fault", O_RDWR);
+	if (fd == -1)
+		fail("failed to open /dev/fault");
+
+	en.scope = FAULT_SCOPE_LWP;
+	en.mode = FAULT_MODE_NTH;
+	en.nth = nth;
+	if (ioctl(fd, FAULT_IOC_ENABLE, &en) != 0)
+		fail("FAULT_IOC_ENABLE failed with nth=%d", nth);
+
+	return fd;
+}
+#endif
+#if SYZ_EXECUTOR
+static int fault_injected(int fd)
+{
+	struct fault_ioc_getinfo info;
+	struct fault_ioc_disable dis;
+	int res;
+
+	if (ioctl(fd, FAULT_IOC_GETINFO, &info) != 0)
+		fail("FAULT_IOC_GETINFO failed");
+	res = (info.nfaults > 0);
+
+	dis.scope = FAULT_SCOPE_LWP;
+	if (ioctl(fd, FAULT_IOC_DISABLE, &dis) != 0)
+		fail("FAULT_IOC_DISABLE failed");
+
+	close(fd);
+
+	return res;
+}
+#endif
+
 #endif
 
 #if GOOS_openbsd
diff --git a/pkg/host/host_netbsd.go b/pkg/host/host_netbsd.go
index 16092919..dffdec5d 100644
--- a/pkg/host/host_netbsd.go
+++ b/pkg/host/host_netbsd.go
@@ -23,6 +23,7 @@ func init() {
 	checkFeature[FeatureComparisons] = unconditionallyEnabled
 	checkFeature[FeatureUSBEmulation] = checkUSBEmulation
 	checkFeature[FeatureExtraCoverage] = checkUSBEmulation
+	checkFeature[FeatureFault] = checkFault
 }
 
 func checkUSBEmulation() string {
@@ -31,3 +32,10 @@ func checkUSBEmulation() string {
 	}
 	return ""
 }
+
+func checkFault() string {
+	if err := osutil.IsAccessible("/dev/fault"); err != nil {
+		return err.Error()
+	}
+	return ""
+}