90 lines
2.8 KiB
Go
90 lines
2.8 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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"fmt"
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"go/ast"
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"github.com/securego/gosec/v2"
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)
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type integerOverflowCheck struct {
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gosec.MetaData
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calls gosec.CallList
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}
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func (i *integerOverflowCheck) ID() string {
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return i.MetaData.ID
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}
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func (i *integerOverflowCheck) Match(node ast.Node, ctx *gosec.Context) (*gosec.Issue, error) {
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var atoiVarObj map[*ast.Object]ast.Node
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// To check multiple lines, ctx.PassedValues is used to store temporary data.
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if _, ok := ctx.PassedValues[i.ID()]; !ok {
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atoiVarObj = make(map[*ast.Object]ast.Node)
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ctx.PassedValues[i.ID()] = atoiVarObj
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} else if pv, ok := ctx.PassedValues[i.ID()].(map[*ast.Object]ast.Node); ok {
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atoiVarObj = pv
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} else {
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return nil, fmt.Errorf("PassedValues[%s] of Context is not map[*ast.Object]ast.Node, but %T", i.ID(), ctx.PassedValues[i.ID()])
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}
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// strconv.Atoi is a common function.
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// To reduce false positives, This rule detects code which is converted to int32/int16 only.
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switch n := node.(type) {
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case *ast.AssignStmt:
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for _, expr := range n.Rhs {
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if callExpr, ok := expr.(*ast.CallExpr); ok && i.calls.ContainsPkgCallExpr(callExpr, ctx, false) != nil {
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if idt, ok := n.Lhs[0].(*ast.Ident); ok && idt.Name != "_" {
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// Example:
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// v, _ := strconv.Atoi("1111")
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// Add v's Obj to atoiVarObj map
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atoiVarObj[idt.Obj] = n
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}
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}
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}
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case *ast.CallExpr:
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if fun, ok := n.Fun.(*ast.Ident); ok {
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if fun.Name == "int32" || fun.Name == "int16" {
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if idt, ok := n.Args[0].(*ast.Ident); ok {
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if n, ok := atoiVarObj[idt.Obj]; ok {
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// Detect int32(v) and int16(v)
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return gosec.NewIssue(ctx, n, i.ID(), i.What, i.Severity, i.Confidence), nil
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}
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}
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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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// NewIntegerOverflowCheck detects if there is potential Integer OverFlow
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func NewIntegerOverflowCheck(id string, conf gosec.Config) (gosec.Rule, []ast.Node) {
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calls := gosec.NewCallList()
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calls.Add("strconv", "Atoi")
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return &integerOverflowCheck{
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MetaData: gosec.MetaData{
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ID: id,
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Severity: gosec.High,
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Confidence: gosec.Medium,
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What: "Potential Integer overflow made by strconv.Atoi result conversion to int16/32",
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},
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calls: calls,
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}, []ast.Node{(*ast.FuncDecl)(nil), (*ast.AssignStmt)(nil), (*ast.CallExpr)(nil)}
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}
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