pkg/csource: minimize netdevices and net reset

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

Fixes #581

9 files changed, 113 insertions, 57 deletions

diff --git a/executor/common_linux.h b/executor/common_linux.h
index 45a74e36f..ae83e5d46 100644
--- a/executor/common_linux.h
+++ b/executor/common_linux.h
@@ -58,7 +58,7 @@
 #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>
@@ -261,7 +261,7 @@ 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;
@@ -273,15 +273,6 @@ 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)
@@ -306,7 +297,9 @@ 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;
 
@@ -393,12 +386,24 @@ 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)
 
 // Addresses are chosen to be in the same subnet as tun addresses.
 #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);
+}
+
 // We test in a separate namespace, which does not have any network devices initially (even lo).
 // Create/up as many as we can.
 static void initialize_netdevices(void)
@@ -415,10 +420,6 @@ 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]);
 	// This adds connected veth0 and veth1 devices.
@@ -1202,10 +1203,10 @@ static int do_sandbox_none(void)
 	}
 #if defined(SYZ_EXECUTOR) || defined(SYZ_TUN_ENABLE)
 	initialize_tun();
-	// TODO(dvyukov): this should be separated from tun and minimized by csource separately.
+#endif
+#if defined(SYZ_EXECUTOR) || defined(SYZ_ENABLE_NETDEV)
 	initialize_netdevices();
 #endif
-
 	loop();
 	doexit(1);
 }
@@ -1231,7 +1232,8 @@ static int do_sandbox_setuid(void)
 		fail("unshare(CLONE_NEWNET)");
 #if defined(SYZ_EXECUTOR) || defined(SYZ_TUN_ENABLE)
 	initialize_tun();
-	// TODO(dvyukov): this should be separated from tun and minimized by csource separately.
+#endif
+#if defined(SYZ_EXECUTOR) || defined(SYZ_ENABLE_NETDEV)
 	initialize_netdevices();
 #endif
 
@@ -1279,7 +1281,8 @@ static int namespace_sandbox_proc(void* arg)
 	// However, IFF_NAPI_FRAGS will fail as we are not root already.
 	// There does not seem to be a call sequence that would satisfy all of that.
 	initialize_tun();
-	// TODO(dvyukov): this should be separated from tun and minimized by csource separately.
+#endif
+#if defined(SYZ_EXECUTOR) || defined(SYZ_ENABLE_NETDEV)
 	initialize_netdevices();
 #endif
 
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,
diff --git a/pkg/repro/repro.go b/pkg/repro/repro.go
index 07214a630..3b6b190e1 100644
--- a/pkg/repro/repro.go
+++ b/pkg/repro/repro.go
@@ -298,6 +298,8 @@ func (ctx *context) createDefaultOps() csource.Options {
 		Sandbox:       ctx.cfg.Sandbox,
 		EnableTun:     true,
 		EnableCgroups: true,
+		EnableNetdev:  true,
+		ResetNet:      true,
 		UseTmpDir:     true,
 		HandleSegv:    true,
 		WaitRepeat:    true,
@@ -795,6 +797,8 @@ var progSimplifies = []Simplify{
 		}
 		opts.Repeat = false
 		opts.WaitRepeat = false
+		opts.EnableCgroups = false
+		opts.ResetNet = false
 		opts.Procs = 1
 		return true
 	},
@@ -822,6 +826,8 @@ var cSimplifies = append(progSimplifies, []Simplify{
 		opts.Sandbox = ""
 		opts.EnableTun = false
 		opts.EnableCgroups = false
+		opts.EnableNetdev = false
+		opts.ResetNet = false
 		return true
 	},
 	func(opts *csource.Options) bool {
@@ -839,6 +845,20 @@ var cSimplifies = append(progSimplifies, []Simplify{
 		return true
 	},
 	func(opts *csource.Options) bool {
+		if !opts.EnableNetdev {
+			return false
+		}
+		opts.EnableNetdev = false
+		return true
+	},
+	func(opts *csource.Options) bool {
+		if !opts.ResetNet {
+			return false
+		}
+		opts.ResetNet = false
+		return true
+	},
+	func(opts *csource.Options) bool {
 		if !opts.UseTmpDir || opts.Sandbox == "namespace" || opts.EnableCgroups {
 			return false
 		}
@@ -857,6 +877,8 @@ var cSimplifies = append(progSimplifies, []Simplify{
 			return false
 		}
 		opts.WaitRepeat = false
+		opts.EnableCgroups = false
+		opts.ResetNet = false
 		return true
 	},
 }...)
diff --git a/pkg/repro/repro_test.go b/pkg/repro/repro_test.go
index 8f0440784..0a437e713 100644
--- a/pkg/repro/repro_test.go
+++ b/pkg/repro/repro_test.go
@@ -74,6 +74,8 @@ func TestSimplifies(t *testing.T) {
 		Sandbox:       "namespace",
 		EnableTun:     true,
 		EnableCgroups: true,
+		EnableNetdev:  true,
+		ResetNet:      true,
 		UseTmpDir:     true,
 		HandleSegv:    true,
 		WaitRepeat:    true,
diff --git a/tools/syz-execprog/execprog.go b/tools/syz-execprog/execprog.go
index 40aa521ce..ff7e6d838 100644
--- a/tools/syz-execprog/execprog.go
+++ b/tools/syz-execprog/execprog.go
@@ -226,8 +226,5 @@ func createConfig(entries []*prog.LogEntry) (*ipc.Config, *ipc.ExecOpts) {
 			handled[call.Meta.CallName] = true
 		}
 	}
-	if handled["syz_emit_ethernet"] || handled["syz_extract_tcp_res"] {
-		config.Flags |= ipc.FlagEnableTun
-	}
 	return config, execOpts
 }
diff --git a/tools/syz-prog2c/prog2c.go b/tools/syz-prog2c/prog2c.go
index 9eaf5fefe..b7f13f971 100644
--- a/tools/syz-prog2c/prog2c.go
+++ b/tools/syz-prog2c/prog2c.go
@@ -28,9 +28,11 @@ var (
 	flagFaultNth   = flag.Int("fault_nth", 0, "inject fault on n-th operation (0-based)")
 	flagEnableTun  = flag.Bool("tun", false, "set up TUN/TAP interface")
 	flagUseTmpDir  = flag.Bool("tmpdir", false, "create a temporary dir and execute inside it")
+	flagCgroups    = flag.Bool("cgroups", false, "enable cgroups support")
+	flagNetdev     = flag.Bool("netdev", false, "setup various net devices")
+	flagResetNet   = flag.Bool("resetnet", false, "reset net namespace after each test")
 	flagHandleSegv = flag.Bool("segv", false, "catch and ignore SIGSEGV")
 	flagWaitRepeat = flag.Bool("waitrepeat", false, "wait for each repeat attempt")
-	flagCgroups = flag.Bool("cgroups", false, "enable cgroups support")
 	flagDebug      = flag.Bool("debug", false, "generate debug printfs")
 )
 
@@ -56,21 +58,23 @@ func main() {
 		os.Exit(1)
 	}
 	opts := csource.Options{
-		Threaded:   *flagThreaded,
-		Collide:    *flagCollide,
-		Repeat:     *flagRepeat,
-		Procs:      *flagProcs,
-		Sandbox:    *flagSandbox,
-		Fault:      *flagFaultCall >= 0,
-		FaultCall:  *flagFaultCall,
-		FaultNth:   *flagFaultNth,
-		EnableTun:  *flagEnableTun,
-		UseTmpDir:  *flagUseTmpDir,
+		Threaded:      *flagThreaded,
+		Collide:       *flagCollide,
+		Repeat:        *flagRepeat,
+		Procs:         *flagProcs,
+		Sandbox:       *flagSandbox,
+		Fault:         *flagFaultCall >= 0,
+		FaultCall:     *flagFaultCall,
+		FaultNth:      *flagFaultNth,
+		EnableTun:     *flagEnableTun,
+		UseTmpDir:     *flagUseTmpDir,
 		EnableCgroups: *flagCgroups,
-		HandleSegv: *flagHandleSegv,
-		WaitRepeat: *flagWaitRepeat,
-		Debug:      *flagDebug,
-		Repro:      false,
+		EnableNetdev:  *flagNetdev,
+		ResetNet:      *flagResetNet,
+		HandleSegv:    *flagHandleSegv,
+		WaitRepeat:    *flagWaitRepeat,
+		Debug:         *flagDebug,
+		Repro:         false,
 	}
 	src, err := csource.Write(p, opts)
 	if err != nil {