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// (c) Copyright 2016 Hewlett Packard Enterprise Development LP
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package gosec
import (
"errors"
"fmt"
"go/ast"
"go/token"
"go/types"
"os"
"os/user"
"path/filepath"
"regexp"
"runtime"
"strconv"
"strings"
)
// MatchCallByPackage ensures that the specified package is imported,
// adjusts the name for any aliases and ignores cases that are
// initialization only imports.
//
// Usage:
// node, matched := MatchCallByPackage(n, ctx, "math/rand", "Read")
//
func MatchCallByPackage(n ast.Node, c *Context, pkg string, names ...string) (*ast.CallExpr, bool) {
importedName, found := GetImportedName(pkg, c)
if !found {
return nil, false
}
if callExpr, ok := n.(*ast.CallExpr); ok {
packageName, callName, err := GetCallInfo(callExpr, c)
if err != nil {
return nil, false
}
if packageName == importedName {
for _, name := range names {
if callName == name {
return callExpr, true
}
}
}
}
return nil, false
}
// MatchCallByType ensures that the node is a call expression to a
// specific object type.
//
// Usage:
// node, matched := MatchCallByType(n, ctx, "bytes.Buffer", "WriteTo", "Write")
//
func MatchCallByType(n ast.Node, ctx *Context, requiredType string, calls ...string) (*ast.CallExpr, bool) {
if callExpr, ok := n.(*ast.CallExpr); ok {
typeName, callName, err := GetCallInfo(callExpr, ctx)
if err != nil {
return nil, false
}
if typeName == requiredType {
for _, call := range calls {
if call == callName {
return callExpr, true
}
}
}
}
return nil, false
}
// MatchCompLit will match an ast.CompositeLit based on the supplied type
func MatchCompLit(n ast.Node, ctx *Context, required string) *ast.CompositeLit {
if complit, ok := n.(*ast.CompositeLit); ok {
typeOf := ctx.Info.TypeOf(complit)
if typeOf.String() == required {
return complit
}
}
return nil
}
// GetInt will read and return an integer value from an ast.BasicLit
func GetInt(n ast.Node) (int64, error) {
if node, ok := n.(*ast.BasicLit); ok && node.Kind == token.INT {
return strconv.ParseInt(node.Value, 0, 64)
}
return 0, fmt.Errorf("Unexpected AST node type: %T", n)
}
// GetFloat will read and return a float value from an ast.BasicLit
func GetFloat(n ast.Node) (float64, error) {
if node, ok := n.(*ast.BasicLit); ok && node.Kind == token.FLOAT {
return strconv.ParseFloat(node.Value, 64)
}
return 0.0, fmt.Errorf("Unexpected AST node type: %T", n)
}
// GetChar will read and return a char value from an ast.BasicLit
func GetChar(n ast.Node) (byte, error) {
if node, ok := n.(*ast.BasicLit); ok && node.Kind == token.CHAR {
return node.Value[0], nil
}
return 0, fmt.Errorf("Unexpected AST node type: %T", n)
}
// GetString will read and return a string value from an ast.BasicLit
func GetString(n ast.Node) (string, error) {
if node, ok := n.(*ast.BasicLit); ok && node.Kind == token.STRING {
return strconv.Unquote(node.Value)
}
return "", fmt.Errorf("Unexpected AST node type: %T", n)
}
// GetCallObject returns the object and call expression and associated
// object for a given AST node. nil, nil will be returned if the
// object cannot be resolved.
func GetCallObject(n ast.Node, ctx *Context) (*ast.CallExpr, types.Object) {
switch node := n.(type) {
case *ast.CallExpr:
switch fn := node.Fun.(type) {
case *ast.Ident:
return node, ctx.Info.Uses[fn]
case *ast.SelectorExpr:
return node, ctx.Info.Uses[fn.Sel]
}
}
return nil, nil
}
// GetCallInfo returns the package or type and name associated with a
// call expression.
func GetCallInfo(n ast.Node, ctx *Context) (string, string, error) {
switch node := n.(type) {
case *ast.CallExpr:
switch fn := node.Fun.(type) {
case *ast.SelectorExpr:
switch expr := fn.X.(type) {
case *ast.Ident:
if expr.Obj != nil && expr.Obj.Kind == ast.Var {
t := ctx.Info.TypeOf(expr)
if t != nil {
return t.String(), fn.Sel.Name, nil
}
return "undefined", fn.Sel.Name, fmt.Errorf("missing type info")
}
return expr.Name, fn.Sel.Name, nil
}
case *ast.Ident:
return ctx.Pkg.Name(), fn.Name, nil
}
}
return "", "", fmt.Errorf("unable to determine call info")
}
// GetCallStringArgsValues returns the values of strings arguments if they can be resolved
func GetCallStringArgsValues(n ast.Node, ctx *Context) []string {
values := []string{}
switch node := n.(type) {
case *ast.CallExpr:
for _, arg := range node.Args {
switch param := arg.(type) {
case *ast.BasicLit:
value, err := GetString(param)
if err == nil {
values = append(values, value)
}
case *ast.Ident:
values = append(values, GetIdentStringValues(param)...)
}
}
}
return values
}
// GetIdentStringValues return the string values of an Ident if they can be resolved
func GetIdentStringValues(ident *ast.Ident) []string {
values := []string{}
obj := ident.Obj
if obj != nil {
switch decl := obj.Decl.(type) {
case *ast.ValueSpec:
for _, v := range decl.Values {
value, err := GetString(v)
if err == nil {
values = append(values, value)
}
}
case *ast.AssignStmt:
for _, v := range decl.Rhs {
value, err := GetString(v)
if err == nil {
values = append(values, value)
}
}
}
}
return values
}
// GetImportedName returns the name used for the package within the
// code. It will resolve aliases and ignores initialization only imports.
func GetImportedName(path string, ctx *Context) (string, bool) {
importName, imported := ctx.Imports.Imported[path]
if !imported {
return "", false
}
if _, initonly := ctx.Imports.InitOnly[path]; initonly {
return "", false
}
if alias, ok := ctx.Imports.Aliased[path]; ok {
importName = alias
}
return importName, true
}
// GetImportPath resolves the full import path of an identifier based on
// the imports in the current context.
func GetImportPath(name string, ctx *Context) (string, bool) {
for path := range ctx.Imports.Imported {
if imported, ok := GetImportedName(path, ctx); ok && imported == name {
return path, true
}
}
return "", false
}
// GetLocation returns the filename and line number of an ast.Node
func GetLocation(n ast.Node, ctx *Context) (string, int) {
fobj := ctx.FileSet.File(n.Pos())
return fobj.Name(), fobj.Line(n.Pos())
}
// Gopath returns all GOPATHs
func Gopath() []string {
defaultGoPath := runtime.GOROOT()
if u, err := user.Current(); err == nil {
defaultGoPath = filepath.Join(u.HomeDir, "go")
}
path := Getenv("GOPATH", defaultGoPath)
paths := strings.Split(path, string(os.PathListSeparator))
for idx, path := range paths {
if abs, err := filepath.Abs(path); err == nil {
paths[idx] = abs
}
}
return paths
}
// Getenv returns the values of the environment variable, otherwise
//returns the default if variable is not set
func Getenv(key, userDefault string) string {
if val := os.Getenv(key); val != "" {
return val
}
return userDefault
}
// GetPkgRelativePath returns the Go relative relative path derived
// form the given path
func GetPkgRelativePath(path string) (string, error) {
abspath, err := filepath.Abs(path)
if err != nil {
abspath = path
}
if strings.HasSuffix(abspath, ".go") {
abspath = filepath.Dir(abspath)
}
for _, base := range Gopath() {
projectRoot := filepath.FromSlash(fmt.Sprintf("%s/src/", base))
if strings.HasPrefix(abspath, projectRoot) {
return strings.TrimPrefix(abspath, projectRoot), nil
}
}
return "", errors.New("no project relative path found")
}
// GetPkgAbsPath returns the Go package absolute path derived from
// the given path
func GetPkgAbsPath(pkgPath string) (string, error) {
absPath, err := filepath.Abs(pkgPath)
if err != nil {
return "", err
}
if _, err := os.Stat(absPath); os.IsNotExist(err) {
return "", errors.New("no project absolute path found")
}
return absPath, nil
}
// ConcatString recursively concatenates strings from a binary expression
func ConcatString(n *ast.BinaryExpr) (string, bool) {
var s string
// sub expressions are found in X object, Y object is always last BasicLit
if rightOperand, ok := n.Y.(*ast.BasicLit); ok {
if str, err := GetString(rightOperand); err == nil {
s = str + s
}
} else {
return "", false
}
if leftOperand, ok := n.X.(*ast.BinaryExpr); ok {
if recursion, ok := ConcatString(leftOperand); ok {
s = recursion + s
}
} else if leftOperand, ok := n.X.(*ast.BasicLit); ok {
if str, err := GetString(leftOperand); err == nil {
s = str + s
}
} else {
return "", false
}
return s, true
}
// FindVarIdentities returns array of all variable identities in a given binary expression
func FindVarIdentities(n *ast.BinaryExpr, c *Context) ([]*ast.Ident, bool) {
identities := []*ast.Ident{}
// sub expressions are found in X object, Y object is always the last term
if rightOperand, ok := n.Y.(*ast.Ident); ok {
obj := c.Info.ObjectOf(rightOperand)
if _, ok := obj.(*types.Var); ok && !TryResolve(rightOperand, c) {
identities = append(identities, rightOperand)
}
}
if leftOperand, ok := n.X.(*ast.BinaryExpr); ok {
if leftIdentities, ok := FindVarIdentities(leftOperand, c); ok {
identities = append(identities, leftIdentities...)
}
} else {
if leftOperand, ok := n.X.(*ast.Ident); ok {
obj := c.Info.ObjectOf(leftOperand)
if _, ok := obj.(*types.Var); ok && !TryResolve(leftOperand, c) {
identities = append(identities, leftOperand)
}
}
}
if len(identities) > 0 {
return identities, true
}
// if nil or error, return false
return nil, false
}
// PackagePaths returns a slice with all packages path at given root directory
func PackagePaths(root string, exclude *regexp.Regexp) ([]string, error) {
if strings.HasSuffix(root, "...") {
root = root[0 : len(root)-3]
} else {
return []string{root}, nil
}
paths := map[string]bool{}
err := filepath.Walk(root, func(path string, f os.FileInfo, err error) error {
if filepath.Ext(path) == ".go" {
path = filepath.Dir(path)
if exclude != nil && exclude.MatchString(path) {
return nil
}
paths[path] = true
}
return nil
})
if err != nil {
return []string{}, err
}
result := []string{}
for path := range paths {
result = append(result, path)
}
return result, nil
}
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