Return a soft error when we detect the 3rd party problem causing bug 27870.

net/socket/tcp_client_socket_win.cc

 // Copyright (c) 2006-2008 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/socket/tcp_client_socket_win.h"
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory_debug.h"
 #include "base/stats_counters.h"
@@ skipping 129 matching lines @@
   // |read_overlapped_| is used for both Connect() and Read().
   // |write_overlapped_| is only used for Write();
   OVERLAPPED read_overlapped_;
   OVERLAPPED write_overlapped_;
 
   // The buffers used in Read() and Write().
   WSABUF read_buffer_;
   WSABUF write_buffer_;
   scoped_refptr<IOBuffer> read_iobuffer_;
   scoped_refptr<IOBuffer> write_iobuffer_;
-  // TODO(vandebo) remove when bug 27870 is resolved.
-  size_t write_buffer_length_;
+  int write_buffer_length_;
 
   // Throttle the read size based on our current slow start state.
   // Returns the throttled read size.
   int ThrottleReadSize(int size) {
     if (slow_start_throttle_ < kMaxSlowStartThrottle) {
       size = std::min(size, slow_start_throttle_);
       slow_start_throttle_ *= 2;
     }
     return size;
   }
@@ skipping 336 matching lines @@
   DCHECK(!write_callback_);
   //TODO(vandebo) change back to a DCHECK when 27870 is resolved
   CHECK(buf_len > 0);
   DCHECK(!core_->write_iobuffer_);
 
   static StatsCounter reads("tcp.writes");
   reads.Increment();
 
   core_->write_buffer_.len = buf_len;
   core_->write_buffer_.buf = buf->data();
-  core_->write_buffer_length_ = static_cast<size_t>(buf_len);
+  core_->write_buffer_length_ = buf_len;
 
   TRACE_EVENT_BEGIN("socket.write", this, "");
   // TODO(wtc): Remove the CHECK after enough testing.
   CHECK(
       WaitForSingleObject(core_->write_overlapped_.hEvent, 0) == WAIT_TIMEOUT);
   DWORD num;
   int rv = WSASend(socket_, &core_->write_buffer_, 1, &num, 0,
                    &core_->write_overlapped_, NULL);
   if (rv == 0) {
     if (ResetEventIfSignaled(core_->write_overlapped_.hEvent)) {
-      TRACE_EVENT_END("socket.write", this, StringPrintf("%d bytes", num));
+      rv = static_cast<int>(num);
+      if (rv > buf_len || rv < 0) {
+        // It seems that some winsock interceptors report that more was written
+        // than was available. Treat this as an error.  http://crbug.com/27870
+        LOG(ERROR) << "Detected broken LSP: Asked to write " << buf_len
+                   << " bytes, but " << rv << " bytes reported.";
+        return ERR_WINSOCK_UNEXPECTED_WRITTEN_BYTES;
+      }
+      TRACE_EVENT_END("socket.write", this, StringPrintf("%d bytes", rv));
       static StatsCounter write_bytes("tcp.write_bytes");
-      write_bytes.Add(num);
-      return static_cast<int>(num);
+      write_bytes.Add(rv);
+      return rv;
     }
   } else {
     int os_error = WSAGetLastError();
     if (os_error != WSA_IO_PENDING)
       return MapWinsockError(os_error);
   }
   core_->WatchForWrite();
   waiting_write_ = true;
   write_callback_ = callback;
   core_->write_iobuffer_ = buf;
@@ skipping 156 matching lines @@
 
 void TCPClientSocketWin::DidCompleteWrite() {
   DCHECK(waiting_write_);
 
   DWORD num_bytes, flags;
   BOOL ok = WSAGetOverlappedResult(socket_, &core_->write_overlapped_,
                                    &num_bytes, FALSE, &flags);
   WSAResetEvent(core_->write_overlapped_.hEvent);
   TRACE_EVENT_END("socket.write", this, StringPrintf("%d bytes", num_bytes));
   waiting_write_ = false;
-  if (ok) {
-    CHECK(num_bytes <= core_->write_buffer_length_) <<
-        core_->write_buffer_length_;
+  int rv;
+  if (!ok) {
+    rv = MapWinsockError(WSAGetLastError());
+  } else {
+    rv = static_cast<int>(num_bytes);
+    if (rv > core_->write_buffer_length_ || rv < 0) {
+      // It seems that some winsock interceptors report that more was written
+      // than was available. Treat this as an error.  http://crbug.com/27870
+      LOG(ERROR) << "Detected broken LSP: Asked to write "
+                 << core_->write_buffer_length_ << " bytes, but " << rv
+                 << " bytes reported.";
+      rv = ERR_WINSOCK_UNEXPECTED_WRITTEN_BYTES;
+    }
   }
   core_->write_iobuffer_ = NULL;
-  DoWriteCallback(ok ? num_bytes : MapWinsockError(WSAGetLastError()));
+  DoWriteCallback(rv);
 }
 
 }  // namespace net