Add a buffer reader/writer for NTLM.

net/ntlm/ntlm_buffer_reader.cc

Index: net/ntlm/ntlm_buffer_reader.cc
diff --git a/net/ntlm/ntlm_buffer_reader.cc b/net/ntlm/ntlm_buffer_reader.cc
new file mode 100644
index 0000000000000000000000000000000000000000..95ae2e6ee43b216e4537fb091480239a20e76d8a
--- /dev/null
+++ b/net/ntlm/ntlm_buffer_reader.cc
@@ -0,0 +1,179 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "net/ntlm/ntlm_buffer_reader.h"
+
+#include <string.h>
+
+#include "base/logging.h"
+
+namespace net {
+namespace ntlm {
+
+NtlmBufferReader::NtlmBufferReader(base::StringPiece buffer)
+    : buffer_(buffer), cursor_(0) {
+  DCHECK(buffer.data());
+}
+
+NtlmBufferReader::NtlmBufferReader(const uint8_t* ptr, size_t len)
+    : NtlmBufferReader(
+          base::StringPiece(reinterpret_cast<const char*>(ptr), len)) {}
+
+NtlmBufferReader::~NtlmBufferReader() {}
+
+bool NtlmBufferReader::CanRead(size_t len) const {
+  return CanReadFrom(GetCursor(), len);
+}
+
+bool NtlmBufferReader::CanReadFrom(size_t offset, size_t len) const {
+  if (len == 0)
+    return true;
+
+  return (len <= GetLength() && offset <= GetLength() - len);
+}
+
+bool NtlmBufferReader::ReadUInt16(uint16_t* value) {
+  return ReadUInt<uint16_t>(value);
+}
+
+bool NtlmBufferReader::ReadUInt32(uint32_t* value) {
+  return ReadUInt<uint32_t>(value);
+}
+
+bool NtlmBufferReader::ReadUInt64(uint64_t* value) {
+  return ReadUInt<uint64_t>(value);
+}
+
+bool NtlmBufferReader::ReadFlags(NegotiateFlags* flags) {
+  uint32_t raw;
+  if (!ReadUInt32(&raw))
+    return false;
+
+  *flags = static_cast<NegotiateFlags>(raw);
+  return true;
+}
+
+bool NtlmBufferReader::ReadBytes(uint8_t* buffer, size_t len) {
+  if (!CanRead(len))
+    return false;
+
+  memcpy(reinterpret_cast<void*>(buffer),
+         reinterpret_cast<const void*>(GetBufferAtCursor()), len);
+
+  AdvanceCursor(len);
+  return true;
+}
+
+bool NtlmBufferReader::ReadBytesFrom(const SecurityBuffer& sec_buf,
+                                     uint8_t* buffer) {
+  if (!CanReadFrom(sec_buf))
+    return false;
+
+  memcpy(reinterpret_cast<void*>(buffer),
+         reinterpret_cast<const void*>(GetBufferPtr() + sec_buf.offset),
+         sec_buf.length);
+
+  return true;
+}
+
+bool NtlmBufferReader::ReadSecurityBuffer(SecurityBuffer* sec_buf) {
+  return ReadUInt16(&sec_buf->length) && SkipBytes(sizeof(uint16_t)) &&
+         ReadUInt32(&sec_buf->offset);
+}
+
+bool NtlmBufferReader::ReadMessageType(MessageType* message_type) {
+  uint32_t raw_message_type;
+  if (!ReadUInt32(&raw_message_type))
+    return false;
+
+  *message_type = static_cast<MessageType>(raw_message_type);
+
+  if (*message_type != MessageType::kNegotiate &&
+      *message_type != MessageType::kChallenge &&
+      *message_type != MessageType::kAuthenticate)
+    return false;
+
+  return true;
+}
+
+bool NtlmBufferReader::SkipSecurityBuffer() {
+  return SkipBytes(kSecurityBufferLen);
+}
+
+bool NtlmBufferReader::SkipSecurityBufferWithValidation() {
+  SecurityBuffer sec_buf;
+  return ReadSecurityBuffer(&sec_buf) && CanReadFrom(sec_buf);
+}
+
+bool NtlmBufferReader::SkipBytes(size_t count) {
+  if (!CanRead(count))
+    return false;
+
+  AdvanceCursor(count);
+  return true;
+}
+
+bool NtlmBufferReader::MatchSignature() {
+  if (!CanRead(kSignatureLen))
+    return false;
+
+  if (memcmp(kSignature, GetBufferAtCursor(), kSignatureLen) != 0)
+    return false;
+
+  AdvanceCursor(kSignatureLen);
+  return true;
+}
+
+bool NtlmBufferReader::MatchMessageType(MessageType message_type) {
+  MessageType actual_message_type;
+  return ReadMessageType(&actual_message_type) &&
+         (actual_message_type == message_type);
+}
+
+bool NtlmBufferReader::MatchMessageHeader(MessageType message_type) {
+  return MatchSignature() && MatchMessageType(message_type);
+}
+
+bool NtlmBufferReader::MatchZeros(size_t count) {
+  if (!CanRead(count))
+    return false;
+
+  for (size_t i = 0; i < count; i++) {
+    if (GetBufferAtCursor()[i] != 0)
+      return false;
+  }
+
+  AdvanceCursor(count);
+  return true;
+}
+
+bool NtlmBufferReader::MatchEmptySecurityBuffer() {
+  SecurityBuffer sec_buf;
+  return ReadSecurityBuffer(&sec_buf) && (sec_buf.offset <= GetLength()) &&
+         (sec_buf.length == 0);
+}
+
+template <typename T>
+bool NtlmBufferReader::ReadUInt(T* value) {
+  size_t int_size = sizeof(T);
+  if (!CanRead(int_size))
+    return false;
+
+  *value = 0;
+  for (size_t i = 0; i < int_size; i++) {
+    *value += static_cast<T>(GetByteAtCursor()) << (i * 8);
+    AdvanceCursor(1);
+  }
+
+  return true;
+}
+
+void NtlmBufferReader::SetCursor(size_t cursor) {
+  DCHECK_LE(cursor, GetLength());
+
+  cursor_ = cursor;
+}
+
+}  // namespace ntlm
+}  // namespace net