mirror of
https://github.com/securego/gosec.git
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111 lines
3.5 KiB
Go
111 lines
3.5 KiB
Go
// (c) Copyright 2016 Hewlett Packard Enterprise Development LP
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package rules
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import (
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"go/ast"
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"go/types"
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"github.com/securego/gosec/v2"
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)
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type subprocess struct {
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gosec.MetaData
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gosec.CallList
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}
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func (r *subprocess) ID() string {
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return r.MetaData.ID
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}
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// TODO(gm) The only real potential for command injection with a Go project
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// is something like this:
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//
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// syscall.Exec("/bin/sh", []string{"-c", tainted})
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//
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// E.g. Input is correctly escaped but the execution context being used
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// is unsafe. For example:
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//
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// syscall.Exec("echo", "foobar" + tainted)
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func (r *subprocess) Match(n ast.Node, c *gosec.Context) (*gosec.Issue, error) {
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if node := r.ContainsPkgCallExpr(n, c, false); node != nil {
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args := node.Args
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if r.isContext(n, c) {
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args = args[1:]
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}
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for _, arg := range args {
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if ident, ok := arg.(*ast.Ident); ok {
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obj := c.Info.ObjectOf(ident)
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// need to cast and check whether it is for a variable ?
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_, variable := obj.(*types.Var)
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// .. indeed it is a variable then processing is different than a normal
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// field assignment
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if variable {
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switch ident.Obj.Decl.(type) {
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case *ast.AssignStmt:
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_, assignment := ident.Obj.Decl.(*ast.AssignStmt)
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if variable && assignment {
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if !gosec.TryResolve(ident, c) {
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return gosec.NewIssue(c, n, r.ID(), "Subprocess launched with variable", gosec.Medium, gosec.High), nil
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}
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}
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case *ast.Field:
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_, field := ident.Obj.Decl.(*ast.Field)
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if variable && field {
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// check if the variable exist in the scope
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vv, vvok := obj.(*types.Var)
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if vvok && vv.Parent().Lookup(ident.Name) == nil {
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return gosec.NewIssue(c, n, r.ID(), "Subprocess launched with variable", gosec.Medium, gosec.High), nil
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}
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}
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}
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}
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} else if !gosec.TryResolve(arg, c) {
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// the arg is not a constant or a variable but instead a function call or os.Args[i]
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return gosec.NewIssue(c, n, r.ID(), "Subprocess launched with function call as argument or cmd arguments", gosec.Medium, gosec.High), nil
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}
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}
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}
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return nil, nil
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}
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// isContext checks whether or not the node is a CommandContext call or not
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// Thi is required in order to skip the first argument from the check.
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func (r *subprocess) isContext(n ast.Node, ctx *gosec.Context) bool {
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selector, indent, err := gosec.GetCallInfo(n, ctx)
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if err != nil {
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return false
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}
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if selector == "exec" && indent == "CommandContext" {
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return true
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}
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return false
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}
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// NewSubproc detects cases where we are forking out to an external process
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func NewSubproc(id string, conf gosec.Config) (gosec.Rule, []ast.Node) {
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rule := &subprocess{gosec.MetaData{ID: id}, gosec.NewCallList()}
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rule.Add("os/exec", "Command")
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rule.Add("os/exec", "CommandContext")
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rule.Add("syscall", "Exec")
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rule.Add("syscall", "ForkExec")
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rule.Add("syscall", "StartProcess")
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rule.Add("golang.org/x/sys/execabs", "Command")
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rule.Add("golang.org/x/sys/execabs", "CommandContext")
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return rule, []ast.Node{(*ast.CallExpr)(nil)}
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}
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