Update vendored x/crypto/cryptobyte

- Adds "cryptobyte: fix panic due to malformed ASN.1 inputs on 32-bit archs"

vendor/golang.org/x/crypto/cryptobyte/asn1.go

@@ -470,7 +470,8 @@ func (s *String) ReadASN1GeneralizedTime(out *time.Time) bool {
 // It reports whether the read was successful.
 func (s *String) ReadASN1BitString(out *encoding_asn1.BitString) bool {
 	var bytes String
-	if !s.ReadASN1(&bytes, asn1.BIT_STRING) || len(bytes) == 0 {
+	if !s.ReadASN1(&bytes, asn1.BIT_STRING) || len(bytes) == 0 ||
+		len(bytes)*8/8 != len(bytes) {
 		return false
 	}
 
@@ -740,7 +741,7 @@ func (s *String) readASN1(out *String, outTag *asn1.Tag, skipHeader bool) bool {
 		length = headerLen + len32
 	}
 
-	if uint32(int(length)) != length || !s.ReadBytes((*[]byte)(out), int(length)) {
+	if int(length) < 0 || !s.ReadBytes((*[]byte)(out), int(length)) {
 		return false
 	}
 	if skipHeader && !out.Skip(int(headerLen)) {

vendor/golang.org/x/crypto/cryptobyte/string.go

@@ -24,7 +24,7 @@ type String []byte
 // read advances a String by n bytes and returns them. If less than n bytes
 // remain, it returns nil.
 func (s *String) read(n int) []byte {
-	if len(*s) < n {
+	if len(*s) < n || n < 0 {
 		return nil
 	}
 	v := (*s)[:n]
@@ -105,11 +105,6 @@ func (s *String) readLengthPrefixed(lenLen int, outChild *String) bool {
 		length = length << 8
 		length = length | uint32(b)
 	}
-	if int(length) < 0 {
-		// This currently cannot overflow because we read uint24 at most, but check
-		// anyway in case that changes in the future.
-		return false
-	}
 	v := s.read(int(length))
 	if v == nil {
 		return false

vendor/vendor.json

@@ -604,10 +604,10 @@
 			"revisionTime": "2019-02-05T21:23:42Z"
 		},
 		{
-			"checksumSHA1": "1ezNasqd516o9HG59beqc5s+2Ro=",
+			"checksumSHA1": "doZpjkzTAPKKLXeKMJZfIL0T5Nw=",
 			"path": "golang.org/x/crypto/cryptobyte",
-			"revision": "a1f597ede03a7bef967a422b5b3a5bd08805a01e",
-			"revisionTime": "2019-02-05T21:23:42Z"
+			"revision": "1d94cc7ab1c630336ab82ccb9c9cda72a875c382",
+			"revisionTime": "2020-02-12T18:29:22Z"
 		},
 		{
 			"checksumSHA1": "YEoV2AiZZPDuF7pMVzDt7buS9gc=",