Proxy private UMA pepper interface for out-of-process and NaCl plugins.

chrome/renderer/pepper/pepper_uma_host.cc

+// Copyright (c) 2014 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 "chrome/renderer/pepper/pepper_uma_host.h"
+
+#include "base/metrics/histogram.h"
+#include "base/sha1.h"
+#include "base/strings/string_number_conversions.h"
+#include "chrome/common/chrome_switches.h"
+#include "chrome/renderer/chrome_content_renderer_client.h"
+#include "content/public/renderer/renderer_ppapi_host.h"
+#include "extensions/common/constants.h"
+#include "extensions/common/extension.h"
+#include "ppapi/c/pp_errors.h"
+#include "ppapi/host/dispatch_host_message.h"
+#include "ppapi/host/host_message_context.h"
+#include "ppapi/host/ppapi_host.h"
+#include "ppapi/proxy/ppapi_messages.h"
+
+namespace {
+
+const char* kPredefinedAllowedUMAOrigins[] = {
+  "6EAED1924DB611B6EEF2A664BD077BE7EAD33B8F",  // see crbug.com/317833
+  "4EB74897CB187C7633357C2FE832E0AD6A44883A"   // see crbug.com/317833
+};
+
+const char* kWhitelistedHistogramHashes[] = {
+  "F131550DAB7A7C6E6633EF81FB5998CC0482AC63",  // see crbug.com/317833
+  "BFA80E7D71DE24D08B7363B108CD6DABFF24B9A0",  // see crbug.com/317833
+  "13955AB4DAD798384DFB4304734FCF2A95F353CC",  // see crbug.com/317833
+  "404E800582901F1B937B8E287235FC603A5DEDFB",  // see crbug.com/317833
+  "D95DDB0F180CF797AD30E221D659A9E2B6404BC8"   // see crbug.com/317833

[Alexei Svitkine (slow), 2014/01/16 22:12:47]

The bug doesn't seem to provide more context here. (What are these hashes and
why does this use hashes?)

I've cc'd myself on the bug, so if you prefer we can discuss there.

[elijahtaylor1, 2014/01/16 22:55:26]

Thanks for catching this.  I forgot to update the bug and there are indeed two
extra ones I was using early on but later abandoned.  Now removed.

+};
+
+std::string HashHistogram(const std::string& histogram) {
+  const std::string id_hash = base::SHA1HashString(histogram);
+  DCHECK_EQ(id_hash.length(), base::kSHA1Length);
+  return base::HexEncode(id_hash.c_str(), id_hash.length());
+}
+
+}  // namespace
+
+PepperUMAHost::PepperUMAHost(
+    content::RendererPpapiHost* host,
+    PP_Instance instance,
+    PP_Resource resource)
+    : ResourceHost(host->GetPpapiHost(), instance, resource),
+      document_url_(host->GetDocumentURL(instance)),
+      is_plugin_in_process_(host->IsRunningInProcess()) {
+  for (size_t i = 0; i < arraysize(kPredefinedAllowedUMAOrigins); ++i)
+    allowed_origins_.insert(kPredefinedAllowedUMAOrigins[i]);
+  for (size_t i = 0; i < arraysize(kWhitelistedHistogramHashes); ++i)
+    allowed_histograms_.insert(kWhitelistedHistogramHashes[i]);
+}
+
+PepperUMAHost::~PepperUMAHost() {
+}
+
+int32_t PepperUMAHost::OnResourceMessageReceived(
+    const IPC::Message& msg,
+    ppapi::host::HostMessageContext* context) {
+  IPC_BEGIN_MESSAGE_MAP(PepperUMAHost, msg)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL(PpapiHostMsg_UMA_HistogramCustomTimes,
+        OnHistogramCustomTimes);
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL(PpapiHostMsg_UMA_HistogramCustomCounts,
+        OnHistogramCustomCounts);
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL(PpapiHostMsg_UMA_HistogramEnumeration,
+        OnHistogramEnumeration);
+  IPC_END_MESSAGE_MAP()
+  return PP_ERROR_FAILED;
+}
+
+bool PepperUMAHost::IsHistogramAllowed(const std::string& histogram) {
+  if (is_plugin_in_process_ && histogram.find("NaCl.") == 0) {
+    return true;
+  }
+
+  bool is_whitelisted =
+      ChromeContentRendererClient::IsExtensionOrSharedModuleWhitelisted(
+          document_url_, allowed_origins_);
+  if (is_whitelisted &&
+      allowed_histograms_.find(HashHistogram(histogram)) !=
+          allowed_histograms_.end()) {
+    return true;
+  }
+
+  LOG(ERROR) << "Host or histogram name is not allowed to use the UMA API.";
+  return false;
+}
+
+#define RETURN_IF_BAD_ARGS(_sample, _min, _max, _buckets) \
+  do { \
+    if (_min >= _max || _sample < _min || _sample > _max || _buckets <= 1) \
+      return PP_ERROR_BADARGUMENT; \
+  } while (0)
+
+int32_t PepperUMAHost::OnHistogramCustomTimes(
+    ppapi::host::HostMessageContext* context,
+    const std::string& name,
+    int64_t sample,
+    int64_t min,
+    int64_t max,
+    uint32_t bucket_count) {
+  if (!IsHistogramAllowed(name)) {
+    return PP_ERROR_NOACCESS;
+  }
+  RETURN_IF_BAD_ARGS(sample, min, max, bucket_count);
+
+  base::HistogramBase* counter =
+      base::Histogram::FactoryTimeGet(
+          name,
+          base::TimeDelta::FromMilliseconds(min),
+          base::TimeDelta::FromMilliseconds(max),
+          bucket_count,
+          base::HistogramBase::kUmaTargetedHistogramFlag);
+  counter->AddTime(base::TimeDelta::FromMilliseconds(sample));
+  return PP_OK;
+}
+
+int32_t PepperUMAHost::OnHistogramCustomCounts(
+    ppapi::host::HostMessageContext* context,
+    const std::string& name,
+    int32_t sample,
+    int32_t min,
+    int32_t max,
+    uint32_t bucket_count) {
+  if (!IsHistogramAllowed(name)) {
+    return PP_ERROR_NOACCESS;
+  }
+  RETURN_IF_BAD_ARGS(sample, min, max, bucket_count);
+
+  base::HistogramBase* counter =
+      base::Histogram::FactoryGet(
+          name,
+          min,
+          max,
+          bucket_count,

[Alexei Svitkine (slow), 2014/01/16 22:12:47]

We also have a metricsPrivate API that works similarly to this, for some
extensions.

There was a recent bug filed that incorrect use of the API can result in crashes
- see: https://code.google.com/p/chromium/issues/detail?id=334135

It was hit by two different versions of extensions (with different bucket
counts) running in the same browser. I suspect the same problem exists with
this. Since presumably different PPAPI plugins could be loaded and they may have
different versions, it can trigger the same problem .

I would prefer we not add any more entry points into the API until that's fixed.
Would you mind taking a look at what it would take to fix that? I suspect some
extra validation in FactoryGet()...

[elijahtaylor1, 2014/01/16 22:55:26]

Right now, the only users of this API by policy are the NaCl/PNaCl in-process
plugins (who were already using it) and now one additional extension (there are
two listed above in the whitelist, but they are mutually exclusive), which is
not shipping to users.

We discussed this offline and you said it was ok to submit as-is and I'll take a
look at fixing the crash you mentioned.

+          base::HistogramBase::kUmaTargetedHistogramFlag);
+  counter->Add(sample);
+  return PP_OK;
+}
+
+int32_t PepperUMAHost::OnHistogramEnumeration(
+    ppapi::host::HostMessageContext* context,
+    const std::string& name,
+    int32_t sample,
+    int32_t boundary_value) {
+  if (!IsHistogramAllowed(name)) {
+    return PP_ERROR_NOACCESS;
+  }
+  RETURN_IF_BAD_ARGS(sample, 0, boundary_value, boundary_value + 1);
+
+  base::HistogramBase* counter =
+      base::LinearHistogram::FactoryGet(
+          name,
+          1,
+          boundary_value,
+          boundary_value + 1,
+          base::HistogramBase::kUmaTargetedHistogramFlag);
+  counter->Add(sample);
+  return PP_OK;
+}
+