1// (c) Copyright 2016 Hewlett Packard Enterprise Development LP
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15package rules
16
17import (
18	"fmt"
19	"go/ast"
20
21	"github.com/securego/gosec/v2"
22)
23
24type weakKeyStrength struct {
25	gosec.MetaData
26	calls gosec.CallList
27	bits  int
28}
29
30func (w *weakKeyStrength) ID() string {
31	return w.MetaData.ID
32}
33
34func (w *weakKeyStrength) Match(n ast.Node, c *gosec.Context) (*gosec.Issue, error) {
35	if callExpr := w.calls.ContainsPkgCallExpr(n, c, false); callExpr != nil {
36		if bits, err := gosec.GetInt(callExpr.Args[1]); err == nil && bits < (int64)(w.bits) {
37			return gosec.NewIssue(c, n, w.ID(), w.What, w.Severity, w.Confidence), nil
38		}
39	}
40	return nil, nil
41}
42
43// NewWeakKeyStrength builds a rule that detects RSA keys < 2048 bits
44func NewWeakKeyStrength(id string, conf gosec.Config) (gosec.Rule, []ast.Node) {
45	calls := gosec.NewCallList()
46	calls.Add("crypto/rsa", "GenerateKey")
47	bits := 2048
48	return &weakKeyStrength{
49		calls: calls,
50		bits:  bits,
51		MetaData: gosec.MetaData{
52			ID:         id,
53			Severity:   gosec.Medium,
54			Confidence: gosec.High,
55			What:       fmt.Sprintf("RSA keys should be at least %d bits", bits),
56		},
57	}, []ast.Node{(*ast.CallExpr)(nil)}
58}
59