// Copyright 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 "extensions/browser/extension_protocols.h"
#include <algorithm>
#include <string>
#include <vector>
#include "base/base64.h"
#include "base/compiler_specific.h"
#include "base/file_util.h"
#include "base/files/file_path.h"
#include "base/format_macros.h"
#include "base/logging.h"
#include "base/memory/weak_ptr.h"
#include "base/message_loop/message_loop.h"
#include "base/metrics/field_trial.h"
#include "base/metrics/histogram.h"
#include "base/metrics/sparse_histogram.h"
#include "base/path_service.h"
#include "base/sha1.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "base/strings/utf_string_conversions.h"
#include "base/threading/sequenced_worker_pool.h"
#include "base/threading/thread_restrictions.h"
#include "base/timer/elapsed_timer.h"
#include "build/build_config.h"
#include "content/public/browser/browser_thread.h"
#include "content/public/browser/resource_request_info.h"
#include "crypto/secure_hash.h"
#include "crypto/sha2.h"
#include "extensions/browser/content_verifier.h"
#include "extensions/browser/content_verify_job.h"
#include "extensions/browser/extensions_browser_client.h"
#include "extensions/browser/info_map.h"
#include "extensions/common/constants.h"
#include "extensions/common/extension.h"
#include "extensions/common/extension_resource.h"
#include "extensions/common/file_util.h"
#include "extensions/common/manifest_handlers/background_info.h"
#include "extensions/common/manifest_handlers/csp_info.h"
#include "extensions/common/manifest_handlers/icons_handler.h"
#include "extensions/common/manifest_handlers/incognito_info.h"
#include "extensions/common/manifest_handlers/shared_module_info.h"
#include "extensions/common/manifest_handlers/web_accessible_resources_info.h"
#include "net/base/io_buffer.h"
#include "net/base/net_errors.h"
#include "net/http/http_request_headers.h"
#include "net/http/http_response_headers.h"
#include "net/http/http_response_info.h"
#include "net/url_request/url_request_error_job.h"
#include "net/url_request/url_request_file_job.h"
#include "net/url_request/url_request_simple_job.h"
#include "url/url_util.h"
using content::BrowserThread;
using content::ResourceRequestInfo;
using extensions::Extension;
using extensions::SharedModuleInfo;
namespace extensions {
namespace {
class GeneratedBackgroundPageJob : public net::URLRequestSimpleJob {
public:
GeneratedBackgroundPageJob(net::URLRequest* request,
net::NetworkDelegate* network_delegate,
const scoped_refptr<const Extension> extension,
const std::string& content_security_policy)
: net::URLRequestSimpleJob(request, network_delegate),
extension_(extension) {
const bool send_cors_headers = false;
// Leave cache headers out of generated background page jobs.
response_info_.headers = BuildHttpHeaders(content_security_policy,
send_cors_headers,
base::Time());
}
// Overridden from URLRequestSimpleJob:
virtual int GetData(std::string* mime_type,
std::string* charset,
std::string* data,
const net::CompletionCallback& callback) const OVERRIDE {
*mime_type = "text/html";
*charset = "utf-8";
*data = "<!DOCTYPE html>\n<body>\n";
const std::vector<std::string>& background_scripts =
extensions::BackgroundInfo::GetBackgroundScripts(extension_.get());
for (size_t i = 0; i < background_scripts.size(); ++i) {
*data += "<script src=\"";
*data += background_scripts[i];
*data += "\"></script>\n";
}
return net::OK;
}
virtual void GetResponseInfo(net::HttpResponseInfo* info) OVERRIDE {
*info = response_info_;
}
private:
virtual ~GeneratedBackgroundPageJob() {}
scoped_refptr<const Extension> extension_;
net::HttpResponseInfo response_info_;
};
base::Time GetFileLastModifiedTime(const base::FilePath& filename) {
if (base::PathExists(filename)) {
base::File::Info info;
if (base::GetFileInfo(filename, &info))
return info.last_modified;
}
return base::Time();
}
base::Time GetFileCreationTime(const base::FilePath& filename) {
if (base::PathExists(filename)) {
base::File::Info info;
if (base::GetFileInfo(filename, &info))
return info.creation_time;
}
return base::Time();
}
void ReadResourceFilePathAndLastModifiedTime(
const extensions::ExtensionResource& resource,
const base::FilePath& directory,
base::FilePath* file_path,
base::Time* last_modified_time) {
*file_path = resource.GetFilePath();
*last_modified_time = GetFileLastModifiedTime(*file_path);
// While we're here, log the delta between extension directory
// creation time and the resource's last modification time.
base::ElapsedTimer query_timer;
base::Time dir_creation_time = GetFileCreationTime(directory);
UMA_HISTOGRAM_TIMES("Extensions.ResourceDirectoryTimestampQueryLatency",
query_timer.Elapsed());
int64 delta_seconds = (*last_modified_time - dir_creation_time).InSeconds();
if (delta_seconds >= 0) {
UMA_HISTOGRAM_CUSTOM_COUNTS("Extensions.ResourceLastModifiedDelta",
delta_seconds,
0,
base::TimeDelta::FromDays(30).InSeconds(),
50);
} else {
UMA_HISTOGRAM_CUSTOM_COUNTS("Extensions.ResourceLastModifiedNegativeDelta",
-delta_seconds,
1,
base::TimeDelta::FromDays(30).InSeconds(),
50);
}
}
class URLRequestExtensionJob : public net::URLRequestFileJob {
public:
URLRequestExtensionJob(net::URLRequest* request,
net::NetworkDelegate* network_delegate,
const std::string& extension_id,
const base::FilePath& directory_path,
const base::FilePath& relative_path,
const std::string& content_security_policy,
bool send_cors_header,
bool follow_symlinks_anywhere,
ContentVerifyJob* verify_job)
: net::URLRequestFileJob(
request,
network_delegate,
base::FilePath(),
BrowserThread::GetBlockingPool()->GetTaskRunnerWithShutdownBehavior(
base::SequencedWorkerPool::SKIP_ON_SHUTDOWN)),
verify_job_(verify_job),
seek_position_(0),
bytes_read_(0),
directory_path_(directory_path),
// TODO(tc): Move all of these files into resources.pak so we don't
// break when updating on Linux.
resource_(extension_id, directory_path, relative_path),
content_security_policy_(content_security_policy),
send_cors_header_(send_cors_header),
weak_factory_(this) {
if (follow_symlinks_anywhere) {
resource_.set_follow_symlinks_anywhere();
}
}
virtual void GetResponseInfo(net::HttpResponseInfo* info) OVERRIDE {
*info = response_info_;
}
virtual void Start() OVERRIDE {
base::FilePath* read_file_path = new base::FilePath;
base::Time* last_modified_time = new base::Time();
bool posted = BrowserThread::PostBlockingPoolTaskAndReply(
FROM_HERE,
base::Bind(&ReadResourceFilePathAndLastModifiedTime,
resource_,
directory_path_,
base::Unretained(read_file_path),
base::Unretained(last_modified_time)),
base::Bind(&URLRequestExtensionJob::OnFilePathAndLastModifiedTimeRead,
weak_factory_.GetWeakPtr(),
base::Owned(read_file_path),
base::Owned(last_modified_time)));
DCHECK(posted);
}
virtual void SetExtraRequestHeaders(
const net::HttpRequestHeaders& headers) OVERRIDE {
// TODO(asargent) - we'll need to add proper support for range headers.
// crbug.com/369895.
std::string range_header;
if (headers.GetHeader(net::HttpRequestHeaders::kRange, &range_header)) {
if (verify_job_)
verify_job_ = NULL;
}
URLRequestFileJob::SetExtraRequestHeaders(headers);
}
virtual void OnSeekComplete(int64 result) OVERRIDE {
DCHECK_EQ(seek_position_, 0);
seek_position_ = result;
// TODO(asargent) - we'll need to add proper support for range headers.
// crbug.com/369895.
if (result > 0 && verify_job_)
verify_job_ = NULL;
}
virtual void OnReadComplete(net::IOBuffer* buffer, int result) OVERRIDE {
if (result >= 0)
UMA_HISTOGRAM_COUNTS("ExtensionUrlRequest.OnReadCompleteResult", result);
else
UMA_HISTOGRAM_SPARSE_SLOWLY("ExtensionUrlRequest.OnReadCompleteError",
-result);
if (result > 0) {
bytes_read_ += result;
if (verify_job_) {
verify_job_->BytesRead(result, buffer->data());
if (!remaining_bytes())
verify_job_->DoneReading();
}
}
}
private:
virtual ~URLRequestExtensionJob() {
UMA_HISTOGRAM_COUNTS("ExtensionUrlRequest.TotalKbRead", bytes_read_ / 1024);
UMA_HISTOGRAM_COUNTS("ExtensionUrlRequest.SeekPosition", seek_position_);
}
void OnFilePathAndLastModifiedTimeRead(base::FilePath* read_file_path,
base::Time* last_modified_time) {
file_path_ = *read_file_path;
response_info_.headers = BuildHttpHeaders(
content_security_policy_,
send_cors_header_,
*last_modified_time);
URLRequestFileJob::Start();
}
scoped_refptr<ContentVerifyJob> verify_job_;
// The position we seeked to in the file.
int64 seek_position_;
// The number of bytes of content we read from the file.
int bytes_read_;
net::HttpResponseInfo response_info_;
base::FilePath directory_path_;
extensions::ExtensionResource resource_;
std::string content_security_policy_;
bool send_cors_header_;
base::WeakPtrFactory<URLRequestExtensionJob> weak_factory_;
};
bool ExtensionCanLoadInIncognito(const ResourceRequestInfo* info,
const std::string& extension_id,
extensions::InfoMap* extension_info_map) {
if (!extension_info_map->IsIncognitoEnabled(extension_id))
return false;
// Only allow incognito toplevel navigations to extension resources in
// split mode. In spanning mode, the extension must run in a single process,
// and an incognito tab prevents that.
if (info->GetResourceType() == ResourceType::MAIN_FRAME) {
const Extension* extension =
extension_info_map->extensions().GetByID(extension_id);
return extension && extensions::IncognitoInfo::IsSplitMode(extension);
}
return true;
}
// Returns true if an chrome-extension:// resource should be allowed to load.
// Pass true for |is_incognito| only for incognito profiles and not Chrome OS
// guest mode profiles.
// TODO(aa): This should be moved into ExtensionResourceRequestPolicy, but we
// first need to find a way to get CanLoadInIncognito state into the renderers.
bool AllowExtensionResourceLoad(net::URLRequest* request,
bool is_incognito,
const Extension* extension,
extensions::InfoMap* extension_info_map) {
const ResourceRequestInfo* info = ResourceRequestInfo::ForRequest(request);
// We have seen crashes where info is NULL: crbug.com/52374.
if (!info) {
LOG(ERROR) << "Allowing load of " << request->url().spec()
<< "from unknown origin. Could not find user data for "
<< "request.";
return true;
}
if (is_incognito && !ExtensionCanLoadInIncognito(
info, request->url().host(), extension_info_map)) {
return false;
}
// The following checks are meant to replicate similar set of checks in the
// renderer process, performed by ResourceRequestPolicy::CanRequestResource.
// These are not exactly equivalent, because we don't have the same bits of
// information. The two checks need to be kept in sync as much as possible, as
// an exploited renderer can bypass the checks in ResourceRequestPolicy.
// Check if the extension for which this request is made is indeed loaded in
// the process sending the request. If not, we need to explicitly check if
// the resource is explicitly accessible or fits in a set of exception cases.
// Note: This allows a case where two extensions execute in the same renderer
// process to request each other's resources. We can't do a more precise
// check, since the renderer can lie about which extension has made the
// request.
if (extension_info_map->process_map().Contains(
request->url().host(), info->GetChildID())) {
return true;
}
// Allow the extension module embedder to grant permission for loads.
if (ExtensionsBrowserClient::Get()->AllowCrossRendererResourceLoad(
request, is_incognito, extension, extension_info_map)) {
return true;
}
// No special exceptions for cross-process loading. Block the load.
return false;
}
// Returns true if the given URL references an icon in the given extension.
bool URLIsForExtensionIcon(const GURL& url, const Extension* extension) {
DCHECK(url.SchemeIs(extensions::kExtensionScheme));
if (!extension)
return false;
std::string path = url.path();
DCHECK_EQ(url.host(), extension->id());
DCHECK(path.length() > 0 && path[0] == '/');
path = path.substr(1);
return extensions::IconsInfo::GetIcons(extension).ContainsPath(path);
}
class ExtensionProtocolHandler
: public net::URLRequestJobFactory::ProtocolHandler {
public:
ExtensionProtocolHandler(bool is_incognito,
extensions::InfoMap* extension_info_map)
: is_incognito_(is_incognito), extension_info_map_(extension_info_map) {}
virtual ~ExtensionProtocolHandler() {}
virtual net::URLRequestJob* MaybeCreateJob(
net::URLRequest* request,
net::NetworkDelegate* network_delegate) const OVERRIDE;
private:
const bool is_incognito_;
extensions::InfoMap* const extension_info_map_;
DISALLOW_COPY_AND_ASSIGN(ExtensionProtocolHandler);
};
// Creates URLRequestJobs for extension:// URLs.
net::URLRequestJob*
ExtensionProtocolHandler::MaybeCreateJob(
net::URLRequest* request, net::NetworkDelegate* network_delegate) const {
// chrome-extension://extension-id/resource/path.js
std::string extension_id = request->url().host();
const Extension* extension =
extension_info_map_->extensions().GetByID(extension_id);
// TODO(mpcomplete): better error code.
if (!AllowExtensionResourceLoad(
request, is_incognito_, extension, extension_info_map_)) {
return new net::URLRequestErrorJob(
request, network_delegate, net::ERR_ADDRESS_UNREACHABLE);
}
// If this is a disabled extension only allow the icon to load.
base::FilePath directory_path;
if (extension)
directory_path = extension->path();
if (directory_path.value().empty()) {
const Extension* disabled_extension =
extension_info_map_->disabled_extensions().GetByID(extension_id);
if (URLIsForExtensionIcon(request->url(), disabled_extension))
directory_path = disabled_extension->path();
if (directory_path.value().empty()) {
LOG(WARNING) << "Failed to GetPathForExtension: " << extension_id;
return NULL;
}
}
// Set up content security policy.
std::string content_security_policy;
bool send_cors_header = false;
bool follow_symlinks_anywhere = false;
if (extension) {
std::string resource_path = request->url().path();
// Use default CSP for <webview>.
if (!ExtensionsBrowserClient::Get()->IsWebViewRequest(request)) {
content_security_policy =
extensions::CSPInfo::GetResourceContentSecurityPolicy(extension,
resource_path);
}
if ((extension->manifest_version() >= 2 ||
extensions::WebAccessibleResourcesInfo::HasWebAccessibleResources(
extension)) &&
extensions::WebAccessibleResourcesInfo::IsResourceWebAccessible(
extension, resource_path)) {
send_cors_header = true;
}
follow_symlinks_anywhere =
(extension->creation_flags() & Extension::FOLLOW_SYMLINKS_ANYWHERE)
!= 0;
}
// Create a job for a generated background page.
std::string path = request->url().path();
if (path.size() > 1 &&
path.substr(1) == extensions::kGeneratedBackgroundPageFilename) {
return new GeneratedBackgroundPageJob(
request, network_delegate, extension, content_security_policy);
}
// Component extension resources may be part of the embedder's resource files,
// for example component_extension_resources.pak in Chrome.
net::URLRequestJob* resource_bundle_job =
extensions::ExtensionsBrowserClient::Get()
->MaybeCreateResourceBundleRequestJob(request,
network_delegate,
directory_path,
content_security_policy,
send_cors_header);
if (resource_bundle_job)
return resource_bundle_job;
base::FilePath relative_path =
extensions::file_util::ExtensionURLToRelativeFilePath(request->url());
// Handle shared resources (extension A loading resources out of extension B).
if (SharedModuleInfo::IsImportedPath(path)) {
std::string new_extension_id;
std::string new_relative_path;
SharedModuleInfo::ParseImportedPath(path, &new_extension_id,
&new_relative_path);
const Extension* new_extension =
extension_info_map_->extensions().GetByID(new_extension_id);
bool first_party_in_import = false;
// NB: This first_party_for_cookies call is not for security, it is only
// used so an exported extension can limit the visible surface to the
// extension that imports it, more or less constituting its API.
const std::string& first_party_path =
request->first_party_for_cookies().path();
if (SharedModuleInfo::IsImportedPath(first_party_path)) {
std::string first_party_id;
std::string dummy;
SharedModuleInfo::ParseImportedPath(first_party_path, &first_party_id,
&dummy);
if (first_party_id == new_extension_id) {
first_party_in_import = true;
}
}
if (SharedModuleInfo::ImportsExtensionById(extension, new_extension_id) &&
new_extension &&
(first_party_in_import ||
SharedModuleInfo::IsExportAllowed(new_extension, new_relative_path))) {
directory_path = new_extension->path();
extension_id = new_extension_id;
relative_path = base::FilePath::FromUTF8Unsafe(new_relative_path);
} else {
return NULL;
}
}
ContentVerifyJob* verify_job = NULL;
ContentVerifier* verifier = extension_info_map_->content_verifier();
if (verifier) {
verify_job =
verifier->CreateJobFor(extension_id, directory_path, relative_path);
if (verify_job)
verify_job->Start();
}
return new URLRequestExtensionJob(request,
network_delegate,
extension_id,
directory_path,
relative_path,
content_security_policy,
send_cors_header,
follow_symlinks_anywhere,
verify_job);
}
} // namespace
net::HttpResponseHeaders* BuildHttpHeaders(
const std::string& content_security_policy,
bool send_cors_header,
const base::Time& last_modified_time) {
std::string raw_headers;
raw_headers.append("HTTP/1.1 200 OK");
if (!content_security_policy.empty()) {
raw_headers.append(1, '\0');
raw_headers.append("Content-Security-Policy: ");
raw_headers.append(content_security_policy);
}
if (send_cors_header) {
raw_headers.append(1, '\0');
raw_headers.append("Access-Control-Allow-Origin: *");
}
if (!last_modified_time.is_null()) {
// Hash the time and make an etag to avoid exposing the exact
// user installation time of the extension.
std::string hash =
base::StringPrintf("%" PRId64, last_modified_time.ToInternalValue());
hash = base::SHA1HashString(hash);
std::string etag;
base::Base64Encode(hash, &etag);
raw_headers.append(1, '\0');
raw_headers.append("ETag: \"");
raw_headers.append(etag);
raw_headers.append("\"");
// Also force revalidation.
raw_headers.append(1, '\0');
raw_headers.append("cache-control: no-cache");
}
raw_headers.append(2, '\0');
return new net::HttpResponseHeaders(raw_headers);
}
net::URLRequestJobFactory::ProtocolHandler* CreateExtensionProtocolHandler(
bool is_incognito,
extensions::InfoMap* extension_info_map) {
return new ExtensionProtocolHandler(is_incognito, extension_info_map);
}
} // namespace extensions