mirror of
https://github.com/securego/gosec.git
synced 2026-01-15 01:33:41 +08:00
126 lines
3.9 KiB
Go
126 lines
3.9 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/token"
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"go/types"
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"github.com/securego/gosec/v2"
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"github.com/securego/gosec/v2/issue"
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)
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type subprocess struct {
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issue.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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// getEnclosingBodyStart returns the position of the '{' for the innermost function body enclosing the given position.
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// Returns token.NoPos if no enclosing body found.
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func getEnclosingBodyStart(pos token.Pos, ctx *gosec.Context) token.Pos {
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if ctx.Root == nil {
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return token.NoPos
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}
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var bodyStart token.Pos
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ast.Inspect(ctx.Root, func(n ast.Node) bool {
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var body *ast.BlockStmt
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switch f := n.(type) {
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case *ast.FuncDecl:
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body = f.Body
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case *ast.FuncLit:
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body = f.Body
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}
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if body != nil && body.Pos() <= pos && pos < body.End() && body.Lbrace.IsValid() {
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bodyStart = body.Lbrace
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}
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return true
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})
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return bodyStart
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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) (*issue.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 i, 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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if v, ok := obj.(*types.Var); ok {
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// Special case: struct fields OR function parameters/receivers used as executable name (i==0) -> skip
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if i == 0 {
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if v.IsField() {
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continue
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}
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bodyStart := getEnclosingBodyStart(ident.Pos(), c)
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if bodyStart != token.NoPos && obj.Pos() < bodyStart {
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continue // Parameter or receiver (declared before body brace)
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}
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}
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// For all variables: flag if not resolvable to a constant
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if !gosec.TryResolve(ident, c) {
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return c.NewIssue(n, r.ID(), "Subprocess launched with variable", issue.Medium, issue.High), nil
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}
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}
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} else if !gosec.TryResolve(arg, c) {
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// Non-identifier arguments that cannot be resolved
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return c.NewIssue(n, r.ID(), "Subprocess launched with a potential tainted input or cmd arguments", issue.Medium, issue.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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// This 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, _ gosec.Config) (gosec.Rule, []ast.Node) {
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rule := &subprocess{issue.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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