pkg/csource: minimize netdevices and net reset

Add separate options to minimize netdevices setup and net namespace reset.

Fixes #581

4 files changed, 48 insertions, 20 deletions

diff --git a/pkg/csource/common.go b/pkg/csource/common.go
index 27caac40d..e8fce42a6 100644
--- a/pkg/csource/common.go
+++ b/pkg/csource/common.go
@@ -92,6 +92,12 @@ func defineList(p *prog.Prog, opts Options) ([]string, error) {
 	if opts.EnableCgroups {
 		defines = append(defines, "SYZ_ENABLE_CGROUPS")
 	}
+	if opts.EnableNetdev {
+		defines = append(defines, "SYZ_ENABLE_NETDEV")
+	}
+	if opts.ResetNet {
+		defines = append(defines, "SYZ_RESET_NET_NAMESPACE")
+	}
 	if opts.UseTmpDir {
 		defines = append(defines, "SYZ_USE_TMP_DIR")
 	}
@@ -100,9 +106,6 @@ func defineList(p *prog.Prog, opts Options) ([]string, error) {
 	}
 	if opts.WaitRepeat {
 		defines = append(defines, "SYZ_WAIT_REPEAT")
-		// TODO(dvyukov): this should have a separate option,
-		// but for now it's bundled with WaitRepeat.
-		defines = append(defines, "SYZ_RESET_NET_NAMESPACE")
 	}
 	if opts.Debug {
 		defines = append(defines, "SYZ_DEBUG")
diff --git a/pkg/csource/linux_common.go b/pkg/csource/linux_common.go
index 77ba9b36f..4d168e661 100644
--- a/pkg/csource/linux_common.go
+++ b/pkg/csource/linux_common.go
@@ -60,7 +60,7 @@ var commonHeaderLinux = `
 #include <sys/mman.h>
 #include <sys/mount.h>
 #endif
-#if defined(SYZ_EXECUTOR) || defined(SYZ_TUN_ENABLE)
+#if defined(SYZ_EXECUTOR) || defined(SYZ_TUN_ENABLE) || defined(SYZ_ENABLE_NETDEV)
 #include <arpa/inet.h>
 #include <errno.h>
 #include <fcntl.h>
@@ -422,7 +422,7 @@ static void use_temporary_dir()
 }
 #endif
 
-#if defined(SYZ_EXECUTOR) || defined(SYZ_TUN_ENABLE)
+#if defined(SYZ_EXECUTOR) || defined(SYZ_TUN_ENABLE) || defined(SYZ_ENABLE_NETDEV)
 static void vsnprintf_check(char* str, size_t size, const char* format, va_list args)
 {
 	int rv;
@@ -434,15 +434,6 @@ static void vsnprintf_check(char* str, size_t size, const char* format, va_list
 		fail("tun: string '%s...' doesn't fit into buffer", str);
 }
 
-static void snprintf_check(char* str, size_t size, const char* format, ...)
-{
-	va_list args;
-
-	va_start(args, format);
-	vsnprintf_check(str, size, format, args);
-	va_end(args);
-}
-
 #define COMMAND_MAX_LEN 128
 #define PATH_PREFIX "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin "
 #define PATH_PREFIX_LEN (sizeof(PATH_PREFIX) - 1)
@@ -464,7 +455,9 @@ static void execute_command(bool panic, const char* format, ...)
 		debug("command '%s': %d\n", &command[0], rv);
 	}
 }
+#endif
 
+#if defined(SYZ_EXECUTOR) || defined(SYZ_TUN_ENABLE)
 static int tunfd = -1;
 static int tun_frags_enabled;
 
@@ -541,11 +534,23 @@ static void initialize_tun(void)
 			REMOTE_IPV6, REMOTE_MAC, TUN_IFACE);
 	execute_command(1, "ip link set dev %s up", TUN_IFACE);
 }
+#endif
+
+#if defined(SYZ_EXECUTOR) || defined(SYZ_ENABLE_NETDEV)
 
 #define DEV_IPV4 "172.20.20.%d"
 #define DEV_IPV6 "fe80::%02hx"
 #define DEV_MAC "aa:aa:aa:aa:aa:%02hx"
 
+static void snprintf_check(char* str, size_t size, const char* format, ...)
+{
+	va_list args;
+
+	va_start(args, format);
+	vsnprintf_check(str, size, format, args);
+	va_end(args);
+}
+
 static void initialize_netdevices(void)
 {
 	unsigned i;
@@ -559,10 +564,6 @@ static void initialize_netdevices(void)
 				  "veth0_to_team", "veth1_to_team"};
 	const char* devmasters[] = {"bridge", "bond", "team"};
 
-#ifdef SYZ_EXECUTOR
-	if (!flag_enable_tun)
-		return;
-#endif
 	for (i = 0; i < sizeof(devtypes) / (sizeof(devtypes[0])); i++)
 		execute_command(0, "ip link add dev %s0 type %s", devtypes[i], devtypes[i]);
 	execute_command(0, "ip link add type veth");
@@ -2243,9 +2244,10 @@ static int do_sandbox_none(void)
 	}
 #if defined(SYZ_EXECUTOR) || defined(SYZ_TUN_ENABLE)
 	initialize_tun();
+#endif
+#if defined(SYZ_EXECUTOR) || defined(SYZ_ENABLE_NETDEV)
 	initialize_netdevices();
 #endif
-
 	loop();
 	doexit(1);
 }
@@ -2271,6 +2273,8 @@ static int do_sandbox_setuid(void)
 		fail("unshare(CLONE_NEWNET)");
 #if defined(SYZ_EXECUTOR) || defined(SYZ_TUN_ENABLE)
 	initialize_tun();
+#endif
+#if defined(SYZ_EXECUTOR) || defined(SYZ_ENABLE_NETDEV)
 	initialize_netdevices();
 #endif
 
@@ -2308,6 +2312,8 @@ static int namespace_sandbox_proc(void* arg)
 		fail("unshare(CLONE_NEWNET)");
 #if defined(SYZ_EXECUTOR) || defined(SYZ_TUN_ENABLE)
 	initialize_tun();
+#endif
+#if defined(SYZ_EXECUTOR) || defined(SYZ_ENABLE_NETDEV)
 	initialize_netdevices();
 #endif
 
diff --git a/pkg/csource/options.go b/pkg/csource/options.go
index 7b9ed7050..fd89abcb6 100644
--- a/pkg/csource/options.go
+++ b/pkg/csource/options.go
@@ -27,6 +27,8 @@ type Options struct {
 	EnableTun     bool `json:"tun,omitempty"`
 	UseTmpDir     bool `json:"tmpdir,omitempty"`
 	EnableCgroups bool `json:"cgroups,omitempty"`
+	EnableNetdev  bool `json:"netdev,omitempty"`
+	ResetNet      bool `json:"resetnet,omitempty"`
 	HandleSegv    bool `json:"segv,omitempty"`
 	WaitRepeat    bool `json:"waitrepeat,omitempty"`
 	Debug         bool `json:"debug,omitempty"`
@@ -66,6 +68,18 @@ func (opts Options) Check() error {
 	if opts.EnableCgroups && !opts.UseTmpDir {
 		return errors.New("EnableCgroups without UseTmpDir")
 	}
+	if opts.EnableCgroups && !opts.WaitRepeat {
+		return errors.New("EnableCgroups without WaitRepeat")
+	}
+	if opts.EnableNetdev && opts.Sandbox == "" {
+		return errors.New("EnableNetdev without sandbox")
+	}
+	if opts.ResetNet && opts.Sandbox == "" {
+		return errors.New("ResetNet without sandbox")
+	}
+	if opts.ResetNet && !opts.WaitRepeat {
+		return errors.New("ResetNet without WaitRepeat")
+	}
 	return nil
 }
 
diff --git a/pkg/csource/options_test.go b/pkg/csource/options_test.go
index 9aee780a3..4cccf1c6e 100644
--- a/pkg/csource/options_test.go
+++ b/pkg/csource/options_test.go
@@ -27,7 +27,10 @@ func TestParseOptionsCanned(t *testing.T) {
 	// so we need to be able to parse old formats.
 	// nolint: lll
 	canned := map[string]Options{
-		`{"threaded":true,"collide":true,"repeat":true,"procs":10,"sandbox":"namespace","fault":true,"fault_call":1,"fault_nth":2,"tun":true,"tmpdir":true,"cgroups":true,"segv":true,"waitrepeat":true,"debug":true,"repro":true}`: Options{
+		`{"threaded":true,"collide":true,"repeat":true,"procs":10,"sandbox":"namespace",
+		"fault":true,"fault_call":1,"fault_nth":2,"tun":true,"tmpdir":true,"cgroups":true,
+		"netdev":true,"resetnet":true,
+		"segv":true,"waitrepeat":true,"debug":true,"repro":true}`: Options{
 			Threaded:      true,
 			Collide:       true,
 			Repeat:        true,
@@ -39,6 +42,8 @@ func TestParseOptionsCanned(t *testing.T) {
 			EnableTun:     true,
 			UseTmpDir:     true,
 			EnableCgroups: true,
+			EnableNetdev:  true,
+			ResetNet:      true,
 			HandleSegv:    true,
 			WaitRepeat:    true,
 			Debug:         true,