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	"go/ast"
19
20	"github.com/securego/gosec/v2"
21)
22
23type usesWeakCryptography struct {
24	gosec.MetaData
25	blocklist map[string][]string
26}
27
28func (r *usesWeakCryptography) ID() string {
29	return r.MetaData.ID
30}
31
32func (r *usesWeakCryptography) Match(n ast.Node, c *gosec.Context) (*gosec.Issue, error) {
33	for pkg, funcs := range r.blocklist {
34		if _, matched := gosec.MatchCallByPackage(n, c, pkg, funcs...); matched {
35			return gosec.NewIssue(c, n, r.ID(), r.What, r.Severity, r.Confidence), nil
36		}
37	}
38	return nil, nil
39}
40
41// NewUsesWeakCryptography detects uses of des.* md5.* or rc4.*
42func NewUsesWeakCryptography(id string, conf gosec.Config) (gosec.Rule, []ast.Node) {
43	calls := make(map[string][]string)
44	calls["crypto/des"] = []string{"NewCipher", "NewTripleDESCipher"}
45	calls["crypto/md5"] = []string{"New", "Sum"}
46	calls["crypto/sha1"] = []string{"New", "Sum"}
47	calls["crypto/rc4"] = []string{"NewCipher"}
48	rule := &usesWeakCryptography{
49		blocklist: calls,
50		MetaData: gosec.MetaData{
51			ID:         id,
52			Severity:   gosec.Medium,
53			Confidence: gosec.High,
54			What:       "Use of weak cryptographic primitive",
55		},
56	}
57	return rule, []ast.Node{(*ast.CallExpr)(nil)}
58}
59