summaries

Documentation

Overview

Package summaries defines how data flow information can be summarized for a given function. These summaries are only for pre-determined functions (e.g. standard library functions) and are not computed during the analysis.

Index

• Variables
• func IsStdFunction(function *ssa.Function) bool
• func IsStdPackageName(name string) bool
• func IsSummaryRequired(function *ssa.Function) bool
• func IsUserDefinedFunction(function *ssa.Function) bool
• func PkgHasSummaries(pkg *ssa.Package) bool
• type Summary
  • func SummaryOfFunc(function *ssa.Function) (Summary, bool)

Variables

var FormatterPropagation = Summary{Args: [][]int{{0}, {1}}, Rets: [][]int{{0}, {0}}}

FormatterPropagation is a summary for functions like Printf where the first and second arguments might be tainted, and this will taint the returned value (for example: an error, a string with Sprintf).

var NoDataFlowPropagation = Summary{Rets: [][]int{}, Args: [][]int{}}

NoDataFlowPropagation is a summary for functions that do not have a data flow. The return value, if used, is a sanitized value.

var SingleVarArgPropagation = Summary{Args: [][]int{{0}}, Rets: [][]int{{0}}}

SingleVarArgPropagation is a summary for functions that have a single variadic argument (func f(arg ..any) {...}) This will propagate the data flow to the return value.

var TwoArgPropagation = Summary{Args: [][]int{{0}, {1}}, Rets: [][]int{{0}, {0}}}

TwoArgPropagation is a summary for functions that have two arguments and both propagate their data to the return value, but there is no dataflow between arguments.

Functions

func IsStdFunction

func IsStdFunction(function *ssa.Function) bool

IsStdFunction returns true if the input function is a function from the standard library or the runtime.

Returns false if the input is nil.

func IsStdPackageName

func IsStdPackageName(name string) bool

IsStdPackageName returns true if the package name is a package of the standard library

func IsSummaryRequired

func IsSummaryRequired(function *ssa.Function) bool

IsSummaryRequired returns true if the summary of function is needed to build a sound analysis. For example, sync.Once.Do needs to be summarized because its argument will be called only inside the function, and therefore, it cannot be stubbed out.

func IsUserDefinedFunction

func IsUserDefinedFunction(function *ssa.Function) bool

IsUserDefinedFunction returns true when function is a user-defined function. A function is considered to be user-defined if it is not in the standard library (in summaries.stdPackages) or in the runtime. For example, the functions in the non-standard library packages are considered user-defined.

func PkgHasSummaries

func PkgHasSummaries(pkg *ssa.Package) bool

PkgHasSummaries returns true if the input package has summaries. A package has summaries if it is present in the stdPackages.

Returns false if the input package is nil.

Types

type Summary

type Summary struct {
	// Args is an array A that maps input argument positions to the arguments that are tainted
	// if the input argument is tainted. For example,  A[0] = [0,1] means that if the first argument
	// of the function is tainted, then when the function returns, the first and the last argument
	// are tainted. TODO word this better for data flows (and not taints)
	// A[1] = [] means that the second argument is sanitized.
	// A[1] = [1] means that the taint on the second argument is conserved, but no other argument is tainted.
	Args [][]int
	// Rets is an array A that links information between input arguments and outputs.
	// A[0] = [0] marks a data flow from argument 0 to the first returned value.
	Rets [][]int
}

Summary summarizes data flow information for a function. This makes an analysis faster because it does not have to compute this information for the pre-summarized functions.

func SummaryOfFunc

func SummaryOfFunc(function *ssa.Function) (Summary, bool)

SummaryOfFunc returns the summary of function and true if function has a summary, otherwise it returns an empty summary and false.

Returns (Summary{}, false) if function is nil.