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cryptobyte: add support for UTCTime

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Mostly cribbed from encoding/asn1.parseUTCTime.

Fixes golang/go#45411

Change-Id: I6c6ab2a2ad7c05a7f8bd81ecce4fcbb4e608e8db
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/273286
Trust: Roland Shoemaker <roland@golang.org>
Trust: Katie Hockman <katie@golang.org>
Run-TryBot: Roland Shoemaker <roland@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Katie Hockman <katie@golang.org>
This commit is contained in:
Roland Shoemaker
2021-04-15 15:40:28 +00:00
committed by Roland Shoemaker
parent 0c34fe9e7d
commit 4f45737414
2 changed files with 83 additions and 0 deletions
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cryptobyte/asn1.go
+52
View File
@@ -117,6 +117,19 @@ func (b *Builder) AddASN1GeneralizedTime(t time.Time) {
})
}
// AddASN1UTCTime appends a DER-encoded ASN.1 UTCTime.
func (b *Builder) AddASN1UTCTime(t time.Time) {
b.AddASN1(asn1.UTCTime, func(c *Builder) {
// As utilized by the X.509 profile, UTCTime can only
// represent the years 1950 through 2049.
if t.Year() < 1950 || t.Year() >= 2050 {
b.err = fmt.Errorf("cryptobyte: cannot represent %v as a UTCTime", t)
return
}
c.AddBytes([]byte(t.Format(defaultUTCTimeFormatStr)))
})
}
// AddASN1BitString appends a DER-encoded ASN.1 BIT STRING. This does not
// support BIT STRINGs that are not a whole number of bytes.
func (b *Builder) AddASN1BitString(data []byte) {
@@ -466,6 +479,45 @@ func (s *String) ReadASN1GeneralizedTime(out *time.Time) bool {
return true
}
const defaultUTCTimeFormatStr = "060102150405Z0700"
// ReadASN1UTCTime decodes an ASN.1 UTCTime into out and advances.
// It reports whether the read was successful.
func (s *String) ReadASN1UTCTime(out *time.Time) bool {
var bytes String
if !s.ReadASN1(&bytes, asn1.UTCTime) {
return false
}
t := string(bytes)
formatStr := defaultUTCTimeFormatStr
var err error
res, err := time.Parse(formatStr, t)
if err != nil {
// Fallback to minute precision if we can't parse second
// precision. If we are following X.509 or X.690 we shouldn't
// support this, but we do.
formatStr = "0601021504Z0700"
res, err = time.Parse(formatStr, t)
}
if err != nil {
return false
}
if serialized := res.Format(formatStr); serialized != t {
return false
}
if res.Year() >= 2050 {
// UTCTime interprets the low order digits 50-99 as 1950-99.
// This only applies to its use in the X.509 profile.
// See https://tools.ietf.org/html/rfc5280#section-4.1.2.5.1
res = res.AddDate(-100, 0, 0)
}
*out = res
return true
}
// ReadASN1BitString decodes an ASN.1 BIT STRING into out and advances.
// It reports whether the read was successful.
func (s *String) ReadASN1BitString(out *encoding_asn1.BitString) bool {
cryptobyte/asn1_test.go
+31
View File
@@ -311,6 +311,37 @@ func TestReadASN1GeneralizedTime(t *testing.T) {
}
}
func TestReadASN1UTCTime(t *testing.T) {
testData := []struct {
in string
ok bool
out time.Time
}{
{"000102030405Z", true, time.Date(2000, 01, 02, 03, 04, 05, 0, time.UTC)},
{"500102030405Z", true, time.Date(1950, 01, 02, 03, 04, 05, 0, time.UTC)},
{"490102030405Z", true, time.Date(2049, 01, 02, 03, 04, 05, 0, time.UTC)},
{"990102030405Z", true, time.Date(1999, 01, 02, 03, 04, 05, 0, time.UTC)},
{"250102030405Z", true, time.Date(2025, 01, 02, 03, 04, 05, 0, time.UTC)},
{"750102030405Z", true, time.Date(1975, 01, 02, 03, 04, 05, 0, time.UTC)},
{"000102030405+0905", true, time.Date(2000, 01, 02, 03, 04, 05, 0, time.FixedZone("", 9*60*60+5*60))},
{"000102030405-0905", true, time.Date(2000, 01, 02, 03, 04, 05, 0, time.FixedZone("", -9*60*60-5*60))},
{"0001020304Z", true, time.Date(2000, 01, 02, 03, 04, 0, 0, time.UTC)},
{"5001020304Z", true, time.Date(1950, 01, 02, 03, 04, 00, 0, time.UTC)},
{"0001020304+0905", true, time.Date(2000, 01, 02, 03, 04, 0, 0, time.FixedZone("", 9*60*60+5*60))},
{"0001020304-0905", true, time.Date(2000, 01, 02, 03, 04, 0, 0, time.FixedZone("", -9*60*60-5*60))},
{"000102030405Z0700", false, time.Time{}},
{"000102030405", false, time.Time{}},
}
for i, test := range testData {
in := String(append([]byte{byte(asn1.UTCTime), byte(len(test.in))}, test.in...))
var out time.Time
ok := in.ReadASN1UTCTime(&out)
if ok != test.ok || ok && !reflect.DeepEqual(out, test.out) {
t.Errorf("#%d: in.ReadASN1UTCTime() = %v, want %v; out = %q, want %q", i, ok, test.ok, out, test.out)
}
}
}
func TestReadASN1BitString(t *testing.T) {
testData := []struct {
in []byte