1package crypto
2
3import (
4	"fmt"
5
6	"github.com/zclconf/go-cty/cty"
7	"github.com/zclconf/go-cty/cty/function"
8	"github.com/zclconf/go-cty/cty/gocty"
9	"golang.org/x/crypto/bcrypt"
10)
11
12// BcryptFunc is a function that computes a hash of the given string using the
13// Blowfish cipher.
14var BcryptFunc = function.New(&function.Spec{
15	Params: []function.Parameter{
16		{
17			Name: "str",
18			Type: cty.String,
19		},
20	},
21	VarParam: &function.Parameter{
22		Name: "cost",
23		Type: cty.Number,
24	},
25	Type: function.StaticReturnType(cty.String),
26	Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
27		defaultCost := 10
28
29		if len(args) > 1 {
30			var val int
31			if err := gocty.FromCtyValue(args[1], &val); err != nil {
32				return cty.UnknownVal(cty.String), err
33			}
34			defaultCost = val
35		}
36
37		if len(args) > 2 {
38			return cty.UnknownVal(cty.String), fmt.Errorf("bcrypt() takes no more than two arguments")
39		}
40
41		input := args[0].AsString()
42		out, err := bcrypt.GenerateFromPassword([]byte(input), defaultCost)
43		if err != nil {
44			return cty.UnknownVal(cty.String), fmt.Errorf("error occured generating password %s", err.Error())
45		}
46
47		return cty.StringVal(string(out)), nil
48	},
49})
50
51// Bcrypt computes a hash of the given string using the Blowfish cipher,
52// returning a string in the Modular Crypt Format usually expected in the
53// shadow password file on many Unix systems.
54func Bcrypt(str cty.Value, cost ...cty.Value) (cty.Value, error) {
55	args := make([]cty.Value, len(cost)+1)
56	args[0] = str
57	copy(args[1:], cost)
58	return BcryptFunc.Call(args)
59}
60