From b2f369e56e13dc135d57c53210ea7ab38b239e94 Mon Sep 17 00:00:00 2001
From: Marco Elver <elver@google.com>
Date: Fri, 4 Oct 2019 13:43:02 +0200
Subject: executor, host, csource: Add support to enable KCSAN

By default, the current KCSAN .config does not enable KCSAN during boot,
since we encounter races during boot which would prevent syzkaller from
ever executing.

This adds support to detect if KCSAN is available, and enables it on the
fuzzer host.
---
 pkg/csource/common.go    |  1 +
 pkg/csource/generated.go | 11 +++++++++++
 pkg/csource/options.go   |  6 +++++-
 3 files changed, 17 insertions(+), 1 deletion(-)

(limited to 'pkg/csource')

diff --git a/pkg/csource/common.go b/pkg/csource/common.go
index f4da50b85..e537ed724 100644
--- a/pkg/csource/common.go
+++ b/pkg/csource/common.go
@@ -94,6 +94,7 @@ func defineList(p, mmapProg *prog.Prog, opts Options) (defines []string) {
 		"SYZ_RESET_NET_NAMESPACE":           opts.EnableNetReset,
 		"SYZ_ENABLE_BINFMT_MISC":            opts.EnableBinfmtMisc,
 		"SYZ_ENABLE_CLOSE_FDS":              opts.EnableCloseFds,
+		"SYZ_ENABLE_KCSAN":                  opts.EnableKCSAN,
 		"SYZ_USE_TMP_DIR":                   opts.UseTmpDir,
 		"SYZ_HANDLE_SEGV":                   opts.HandleSegv,
 		"SYZ_REPRO":                         opts.Repro,
diff --git a/pkg/csource/generated.go b/pkg/csource/generated.go
index a8bebb9a9..c216e0973 100644
--- a/pkg/csource/generated.go
+++ b/pkg/csource/generated.go
@@ -5193,6 +5193,14 @@ static void setup_binfmt_misc()
 }
 #endif
 
+#if SYZ_EXECUTOR || SYZ_ENABLE_KCSAN
+static void setup_kcsan()
+{
+	if (!write_file("/proc/kcsaninfo", "on"))
+		fail("failed to enable KCSAN");
+}
+#endif
+
 #elif GOOS_test
 
 #include <stdlib.h>
@@ -5671,6 +5679,9 @@ int main(void)
 #if SYZ_FAULT_INJECTION
 	setup_fault();
 #endif
+#if SYZ_ENABLE_KCSAN
+	setup_kcsan();
+#endif
 
 #if SYZ_HANDLE_SEGV
 	install_segv_handler();
diff --git a/pkg/csource/options.go b/pkg/csource/options.go
index 2eda3acc6..7ad8c1d9c 100644
--- a/pkg/csource/options.go
+++ b/pkg/csource/options.go
@@ -37,6 +37,7 @@ type Options struct {
 	EnableCgroups    bool `json:"cgroups,omitempty"`
 	EnableBinfmtMisc bool `json:"binfmt_misc,omitempty"`
 	EnableCloseFds   bool `json:"close_fds"`
+	EnableKCSAN      bool `json:"kcsan,omitempty"`
 
 	UseTmpDir  bool `json:"tmpdir,omitempty"`
 	HandleSegv bool `json:"segv,omitempty"`
@@ -121,7 +122,10 @@ func (opts Options) checkLinuxOnly(OS string) error {
 		return fmt.Errorf("option EnableBinfmtMisc is not supported on %v", OS)
 	}
 	if opts.EnableCloseFds {
-		return fmt.Errorf("EnableCloseFds is not supported on %v", OS)
+		return fmt.Errorf("option EnableCloseFds is not supported on %v", OS)
+	}
+	if opts.EnableKCSAN {
+		return fmt.Errorf("option EnableKCSAN is not supported on %v", OS)
 	}
 	if opts.Sandbox == sandboxNamespace ||
 		(opts.Sandbox == sandboxSetuid && !(OS == openbsd || OS == freebsd || OS == netbsd)) ||
-- 
cgit mrf-deployment