Update NSS to 3.38

- Added HACL*Poly1305 32-bit (INRIA/Microsoft)
- Updated to final TLS 1.3 draft version (28)
- Removed TLS 1.3 prerelease draft limit check
- Removed NPN code
- Enabled dev/urandom-only RNG on Linux with NSS_SEED_ONLY_DEV_URANDOM for non-standard environments
- Fixed several bugs with TLS 1.3 negotiation
- Updated internal certificate store
- Added support for the TLS Record Size Limit Extension.
- Fixed CVE-2018-0495
- Various security fixes in the ASN.1 code.

security/nss/cpputil/tls_parser.cc

@@ -46,6 +46,21 @@ bool TlsParser::Read(DataBuffer* val, size_t len) {
   return true;
 }
 
+bool TlsParser::ReadFromMark(DataBuffer* val, size_t len, size_t mark) {
+  auto saved = offset_;
+  offset_ = mark;
+
+  if (remaining() < len) {
+    offset_ = saved;
+    return false;
+  }
+
+  val->Assign(ptr(), len);
+
+  offset_ = saved;
+  return true;
+}
+
 bool TlsParser::ReadVariable(DataBuffer* val, size_t len_size) {
   uint32_t len;
   if (!Read(&len, len_size)) {