csource

package
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 Go to latest Published: Apr 16, 2024 License: Apache-2.0 Imports: 16 Imported by: 143

Documentation

Overview

Package csource generates [almost] equivalent C programs from syzkaller programs.

Outline of the process:

  • inputs to the generation are the program and options
  • options control multiple aspects of the resulting C program, like if we want a multi-threaded program or a single-threaded, what type of sandbox we want to use, if we want to setup net devices or not, etc
  • we use actual executor sources as the base
  • gen.go takes all executor/common*.h headers and bundles them into generated.go
  • during generation we tear executor headers apart and take only the bits we need for the current program/options, this is done by running C preprocessor with particular set of defines so that the preprocessor removes unneeded #ifdef SYZ_FOO sections
  • then we generate actual syscall calls with the given arguments based on the binary "encodingexec" representation of the program (the same representation executor uses for interpretation)
  • then we glue it all together
  • as the last step we run some text post-processing on the resulting source code: remove debug calls, replace exitf/fail with exit, hoist/sort/dedup includes, remove duplicate empty lines, etc

Index

Constants

This section is empty.

Variables

View Source 
var ExecutorOpts = Options{
	Threaded:  true,
	Repeat:    true,
	Procs:     2,
	Slowdown:  1,
	Sandbox:   "none",
	Repro:     true,
	UseTmpDir: true,
}

This is the main configuration used by executor, only for testing.

Functions

func Build 

func Build(target *prog.Target, src []byte) (string, error)

Build builds a C program from source src and returns name of the resulting binary.

func BuildFile 

func BuildFile(target *prog.Target, src string, cflags ...string) (string, error)

BuildFile builds a C/C++ program from file src and returns name of the resulting binary.

func BuildNoWarn 

func BuildNoWarn(target *prog.Target, src []byte) (string, error)

BuildNoWarn is the same as Build, but ignores all compilation warnings. Should not be used in tests, but may be used e.g. when we are bisecting and potentially using an old repro with newer compiler, or a compiler that we never seen before. In these cases it's more important to build successfully.

func Format 

func Format(src []byte) ([]byte, error)

Format reformats C source using clang-format.

func PrintAvailableFeaturesFlags 

func PrintAvailableFeaturesFlags()

func Write 

func Write(p *prog.Prog, opts Options) ([]byte, error)

Write generates C source for program p based on the provided options opt.

Types

type Feature 

type Feature struct {
	Description string
	Enabled     bool
}

type Features 

type Features map[string]Feature

func ParseFeaturesFlags 

func ParseFeaturesFlags(enable, disable string, defaultValue bool) (Features, error)

type LegacyOptions 

type LegacyOptions struct {
	Collide   bool `json:"collide,omitempty"`
	Fault     bool `json:"fault,omitempty"`
	FaultCall int  `json:"fault_call,omitempty"`
	FaultNth  int  `json:"fault_nth,omitempty"`
}

These are legacy options, they remain only for the sake of backward compatibility.

type Options 

type Options struct {
	Threaded    bool   `json:"threaded,omitempty"`
	Repeat      bool   `json:"repeat,omitempty"`
	RepeatTimes int    `json:"repeat_times,omitempty"` // if non-0, repeat that many times
	Procs       int    `json:"procs"`
	Slowdown    int    `json:"slowdown"`
	Sandbox     string `json:"sandbox"`
	SandboxArg  int    `json:"sandbox_arg"`

	Leak bool `json:"leak,omitempty"` // do leak checking

	// These options allow for a more fine-tuned control over the generated C code.
	NetInjection  bool `json:"tun,omitempty"`
	NetDevices    bool `json:"netdev,omitempty"`
	NetReset      bool `json:"resetnet,omitempty"`
	Cgroups       bool `json:"cgroups,omitempty"`
	BinfmtMisc    bool `json:"binfmt_misc,omitempty"`
	CloseFDs      bool `json:"close_fds"`
	KCSAN         bool `json:"kcsan,omitempty"`
	DevlinkPCI    bool `json:"devlinkpci,omitempty"`
	NicVF         bool `json:"nicvf,omitempty"`
	USB           bool `json:"usb,omitempty"`
	VhciInjection bool `json:"vhci,omitempty"`
	Wifi          bool `json:"wifi,omitempty"`
	IEEE802154    bool `json:"ieee802154,omitempty"`
	Sysctl        bool `json:"sysctl,omitempty"`
	Swap          bool `json:"swap,omitempty"`

	UseTmpDir  bool `json:"tmpdir,omitempty"`
	HandleSegv bool `json:"segv,omitempty"`

	// Generate code for use with repro package to prints log messages,
	// which allows to detect hangs.
	Repro bool `json:"repro,omitempty"`
	Trace bool `json:"trace,omitempty"`
	LegacyOptions
}

Options control various aspects of source generation. Dashboard also provides serialized Options along with syzkaller reproducers.

func DefaultOpts 

func DefaultOpts(cfg *mgrconfig.Config) Options

func DeserializeOptions 

func DeserializeOptions(data []byte) (Options, error)

func (Options) Check 

func (opts Options) Check(OS string) error

Check checks if the opts combination is valid or not. For example, Collide without Threaded is not valid. Invalid combinations must not be passed to Write.

func (Options) Serialize 

func (opts Options) Serialize() []byte

Source Files

View all Source files

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