package dkim
import (
"crypto"
"encoding/base64"
"errors"
"fmt"
"strconv"
"testing"
"time"
"github.com/google/go-cmp/cmp"
"github.com/google/go-cmp/cmp/cmpopts"
)
func TestSignatureFromHeader(t *testing.T) {
cases := []struct {
in string
want *dkimSignature
err error
}{
{
in: "v=1; a=rsa-sha256",
want: nil,
err: errMissingRequiredTag,
},
{
in: "v=1; a=rsa-sha256 ; c = simple/relaxed ;" +
" d=example.com; h= from : to: subject ; " +
"i=agent@example.com; l=77; q=dns/txt; " +
"s=selector; t=1600700888; x=1600700999; " +
"z=From:lala@lele | to:lili@lolo;" +
"b=aG9sY\r\n SBxdWUgdGFs;" +
"bh = Y29\ttby Bhbm Rhcw==",
want: &dkimSignature{
v: "1",
a: "rsa-sha256",
cH: simpleCanonicalization,
cB: relaxedCanonicalization,
d: "example.com",
h: []string{"from", "to", "subject"},
i: "agent@example.com",
l: 77,
q: []string{"dns/txt"},
s: "selector",
t: time.Unix(1600700888, 0),
x: time.Unix(1600700999, 0),
z: "From:lala@lele|to:lili@lolo",
b: []byte("hola que tal"),
bh: []byte("como andas"),
KeyType: keyTypeRSA,
Hash: crypto.SHA256,
},
},
{
// Example from RFC.
// https://datatracker.ietf.org/doc/html/rfc6376#section-3.5
in: "v=1; a=rsa-sha256; d=example.net; s=brisbane;\r\n" +
" c=simple; q=dns/txt; i=@eng.example.net;\r\n" +
" t=1117574938; x=1118006938;\r\n" +
" h=from:to:subject:date;\r\n" +
" z=From:foo@eng.example.net|To:joe@example.com|\r\n" +
" Subject:demo=20run|Date:July=205,=202005=203:44:08=20PM=20-0700;\r\n" +
"bh=MTIzNDU2Nzg5MDEyMzQ1Njc4OTAxMjM0NTY3ODkwMTI=;\r\n" +
"b=dzdVyOfAKCdLXdJOc9G2q8LoXSlEniS" +
"bav+yuU4zGeeruD00lszZVoG4ZHRNiYzR",
want: &dkimSignature{
v: "1",
a: "rsa-sha256",
d: "example.net",
s: "brisbane",
cH: simpleCanonicalization,
cB: simpleCanonicalization,
q: []string{"dns/txt"},
i: "@eng.example.net",
t: time.Unix(1117574938, 0),
x: time.Unix(1118006938, 0),
h: []string{"from", "to", "subject", "date"},
z: "From:foo@eng.example.net|To:joe@example.com|" +
"Subject:demo=20run|" +
"Date:July=205,=202005=203:44:08=20PM=20-0700",
bh: []byte("12345678901234567890123456789012"),
b: []byte("w7U\xc8\xe7\xc0('K]\xd2Ns\xd1\xb6" +
"\xab\xc2\xe8])D\x9e$\x9bj\xff\xb2\xb9N3" +
"\x19\xe7\xab\xb8=4\x96\xcc\xd9V\x81\xb8" +
"dtM\x89\x8c\xd1"),
KeyType: keyTypeRSA,
Hash: crypto.SHA256,
},
},
{
in: "",
want: nil,
err: errInvalidTag,
},
{
in: "v=666",
want: nil,
err: errInvalidVersion,
},
{
in: "v=1; a=something;",
want: nil,
err: errBadATag,
},
{
// Invalid b= tag.
in: "v=1; a=rsa-sha256; b=invalid",
want: nil,
err: base64.CorruptInputError(4),
},
{
// Invalid bh= tag.
in: "v=1; a=rsa-sha256; bh=invalid",
want: nil,
err: base64.CorruptInputError(4),
},
{
// Invalid c= tag.
in: "v=1; a=rsa-sha256; c=caca",
want: nil,
err: errUnknownCanonicalization,
},
{
// Invalid l= tag.
in: "v=1; a=rsa-sha256; l=a1234b",
want: nil,
err: strconv.ErrSyntax,
},
{
// q= tag without dns/txt.
in: "v=1; a=rsa-sha256; q=other/method",
want: nil,
err: errInvalidSignature,
},
{
// Invalid t= tag.
in: "v=1; a=rsa-sha256; t=a1234b",
want: nil,
err: strconv.ErrSyntax,
},
{
// Invalid x= tag.
in: "v=1; a=rsa-sha256; x=a1234b",
want: nil,
err: strconv.ErrSyntax,
},
{
// Invalid t= tag.
in: "v=1; a=rsa-sha256; t=-12345",
want: nil,
err: errNegativeTimestamp,
},
{
// Invalid x= tag.
in: "v=1; a=rsa-sha256; x=-1234",
want: nil,
err: errNegativeTimestamp,
},
{
// Unknown hash algorithm.
in: "v=1; a=rsa-sxa666",
want: nil,
err: errUnsupportedHash,
},
{
// Unknown key type.
in: "v=1; a=rxa-sha256",
want: nil,
err: errUnsupportedKeyType,
},
}
for _, c := range cases {
sig, err := dkimSignatureFromHeader(c.in)
diff := cmp.Diff(c.want, sig,
cmp.AllowUnexported(dkimSignature{}),
cmpopts.EquateEmpty(),
)
if diff != "" {
t.Errorf("dkimSignatureFromHeader(%q) mismatch (-want +got):\n%s",
c.in, diff)
}
if !errors.Is(err, c.err) {
t.Errorf("dkimSignatureFromHeader(%q) error: got %v, want %v",
c.in, err, c.err)
}
}
}
func TestCanonicalizationFromString(t *testing.T) {
cases := []struct {
in string
cH, cB canonicalization
err error
}{
{
in: "",
cH: simpleCanonicalization,
cB: simpleCanonicalization,
},
{
in: "simple",
cH: simpleCanonicalization,
cB: simpleCanonicalization,
},
{
in: "relaxed",
cH: relaxedCanonicalization,
cB: simpleCanonicalization,
},
{
in: "simple/simple",
cH: simpleCanonicalization,
cB: simpleCanonicalization,
},
{
in: "relaxed/relaxed",
cH: relaxedCanonicalization,
cB: relaxedCanonicalization,
},
{
in: "simple/relaxed",
cH: simpleCanonicalization,
cB: relaxedCanonicalization,
},
{
in: "relaxed/bad",
cH: relaxedCanonicalization,
err: errUnknownCanonicalization,
},
{
in: "bad/relaxed",
err: errUnknownCanonicalization,
},
{
in: "bad",
err: errUnknownCanonicalization,
},
}
for _, c := range cases {
sig := &dkimSignature{}
err := sig.canonicalizationFromString(c.in)
if sig.cH != c.cH || sig.cB != c.cB || !errors.Is(err, c.err) {
t.Errorf("canonicalizationFromString(%q) "+
"got (%v, %v, %v), want (%v, %v, %v)",
c.in, sig.cH, sig.cB, err, c.cH, c.cB, c.err)
}
}
}
func TestCheckRequiredTags(t *testing.T) {
cases := []struct {
sig *dkimSignature
err string
}{
{
sig: &dkimSignature{},
err: "missing required tag: a=",
},
{
sig: &dkimSignature{a: "rsa-sha256"},
err: "missing required tag: b=",
},
{
sig: &dkimSignature{a: "rsa-sha256", b: []byte("hola que tal")},
err: "missing required tag: bh=",
},
{
sig: &dkimSignature{
a: "rsa-sha256",
b: []byte("hola que tal"),
bh: []byte("como andas"),
},
err: "missing required tag: d=",
},
{
sig: &dkimSignature{
a: "rsa-sha256",
b: []byte("hola que tal"),
bh: []byte("como andas"),
d: "example.com",
},
err: "missing required tag: h=",
},
{
sig: &dkimSignature{
a: "rsa-sha256",
b: []byte("hola que tal"),
bh: []byte("como andas"),
d: "example.com",
h: []string{"from"},
},
err: "missing required tag: s=",
},
{
sig: &dkimSignature{
a: "rsa-sha256",
b: []byte("hola que tal"),
bh: []byte("como andas"),
d: "example.com",
h: []string{"subject"},
s: "selector",
},
err: "invalid tag: h= does not contain 'from'",
},
{
sig: &dkimSignature{
a: "rsa-sha256",
b: []byte("hola que tal"),
bh: []byte("como andas"),
d: "example.com",
h: []string{"from"},
s: "selector",
i: "@example.net",
},
err: "invalid tag: i= is not a subdomain of d=",
},
{
sig: &dkimSignature{
a: "rsa-sha256",
b: []byte("hola que tal"),
bh: []byte("como andas"),
d: "example.com",
h: []string{"from"},
s: "selector",
i: "@anexample.com", // i= is a substring but not subdomain.
},
err: "invalid tag: i= is not a subdomain of d=",
},
{
sig: &dkimSignature{
a: "rsa-sha256",
b: []byte("hola que tal"),
bh: []byte("como andas"),
d: "example.com",
h: []string{"From"}, // Capitalize to check case fold.
s: "selector",
i: "@example.com", // i= is the same as d=
},
err: "<nil>",
},
{
sig: &dkimSignature{
a: "rsa-sha256",
b: []byte("hola que tal"),
bh: []byte("como andas"),
d: "example.com",
h: []string{"From"},
s: "selector",
i: "@sub.example.com", // i= is a subdomain of d=
},
err: "<nil>",
},
{
sig: &dkimSignature{
a: "rsa-sha256",
b: []byte("hola que tal"),
bh: []byte("como andas"),
d: "example.com",
h: []string{"from"},
s: "selector",
},
err: "<nil>",
},
}
for i, c := range cases {
err := c.sig.checkRequiredTags()
got := fmt.Sprintf("%v", err)
if c.err != got {
t.Errorf("%d: checkRequiredTags() got %v, want %v",
i, err, c.err)
}
}
}
func TestParseTags(t *testing.T) {
cases := []struct {
in string
want tags
err error
}{
{
in: "v=1; a=lalala; b = 123 ; c= 456;\t d \t= \t789\t ",
want: tags{
"v": "1",
"a": "lalala",
"b": "123",
"c": "456",
"d": "789",
},
err: nil,
},
{
// Trailing semicolon.
in: "v=1; a=lalala ; ",
want: tags{
"v": "1",
"a": "lalala",
},
err: nil,
},
{
// Missing tag value; this is okay.
in: "v=1; b = ; c = d;",
want: tags{
"v": "1",
"b": "",
"c": "d",
},
err: nil,
},
{
// Missing '='.
in: "v=1; ; c = d;",
want: nil,
err: errInvalidTag,
},
{
// Missing tag name.
in: "v=1; = b ; c = d;",
want: nil,
err: errInvalidTag,
},
{
// Duplicate tag.
in: "v=1; a=b; a=c;",
want: nil,
err: errInvalidTag,
},
}
for _, c := range cases {
got, err := parseTags(c.in)
if diff := cmp.Diff(c.want, got); diff != "" {
t.Errorf("parseTags(%q) mismatch (-want +got):\n%s", c.in, diff)
}
if !errors.Is(err, c.err) {
t.Errorf("parseTags(%q) error: got %v, want %v", c.in, err, c.err)
}
}
}