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// Copyright 2025 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chrome/browser/safe_browsing/download_protection/download_protection_delegate_desktop.h"
#include "base/strings/escape.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/browser/safe_browsing/download_protection/check_client_download_request.h"
#include "chrome/browser/safe_browsing/download_protection/check_file_system_access_write_request.h"
#include "chrome/browser/safe_browsing/download_protection/download_protection_util.h"
#include "chrome/common/safe_browsing/download_type_util.h"
#include "components/download/public/common/download_item.h"
#include "components/safe_browsing/content/common/file_type_policies.h"
#include "components/safe_browsing/core/common/safe_browsing_prefs.h"
#include "content/public/browser/browser_context.h"
#include "content/public/browser/download_item_utils.h"
#include "content/public/browser/file_system_access_write_item.h"
#include "google_apis/google_api_keys.h"
#include "net/http/http_request_headers.h"
#include "services/network/public/cpp/resource_request.h"
namespace safe_browsing {
namespace {
const char kDownloadRequestUrl[] =
"https://sb-ssl.google.com/safebrowsing/clientreport/download";
// Content-Type HTTP header field for the request.
const char kCheckClientDownloadRequestContentType[] =
"application/octet-stream";
// We sample 1% of allowlisted downloads to still send out download pings.
const double kAllowlistDownloadSampleRate = 0.01;
// The API key should not change so we can construct this GURL once and cache
// it.
GURL ConstructDownloadRequestUrl() {
GURL url(kDownloadRequestUrl);
std::string api_key = google_apis::GetAPIKey();
if (!api_key.empty()) {
url = url.Resolve("?key=" +
base::EscapeQueryParamValue(api_key, /*use_plus=*/true));
}
return url;
}
bool IsSafeBrowsingEnabledForDownloadProfile(download::DownloadItem* item) {
Profile* profile = Profile::FromBrowserContext(
content::DownloadItemUtils::GetBrowserContext(item));
return profile && IsSafeBrowsingEnabled(*profile->GetPrefs());
}
} // namespace
DownloadProtectionDelegateDesktop::DownloadProtectionDelegateDesktop()
: download_request_url_(ConstructDownloadRequestUrl()) {
CHECK(download_request_url_.is_valid());
}
DownloadProtectionDelegateDesktop::~DownloadProtectionDelegateDesktop() =
default;
bool DownloadProtectionDelegateDesktop::ShouldCheckDownloadUrl(
download::DownloadItem* item) const {
return IsSafeBrowsingEnabledForDownloadProfile(item);
}
bool DownloadProtectionDelegateDesktop::MayCheckClientDownload(
download::DownloadItem* item) const {
if (!IsSafeBrowsingEnabledForDownloadProfile(item)) {
return false;
}
return IsSupportedDownload(*item, item->GetTargetFilePath()) !=
MayCheckDownloadResult::kMayNotCheckDownload;
}
bool DownloadProtectionDelegateDesktop::MayCheckFileSystemAccessWrite(
content::FileSystemAccessWriteItem* item) const {
Profile* profile = Profile::FromBrowserContext(item->browser_context);
if (!profile || !IsSafeBrowsingEnabled(*profile->GetPrefs())) {
return false;
}
DownloadCheckResultReason ignored_reason = REASON_MAX;
return CheckFileSystemAccessWriteRequest::IsSupportedDownload(
item->target_file_path, &ignored_reason) !=
MayCheckDownloadResult::kMayNotCheckDownload;
}
MayCheckDownloadResult DownloadProtectionDelegateDesktop::IsSupportedDownload(
download::DownloadItem& item,
const base::FilePath& target_path) const {
// TODO(nparker): Remove the CRX check here once can support
// UNKNOWN types properly. http://crbug.com/581044
if (download_type_util::GetDownloadType(target_path) ==
ClientDownloadRequest::CHROME_EXTENSION) {
return MayCheckDownloadResult::kMayNotCheckDownload;
}
DownloadCheckResultReason ignored_reason = REASON_MAX;
return CheckClientDownloadRequest::IsSupportedDownload(item, target_path,
&ignored_reason);
}
void DownloadProtectionDelegateDesktop::FinalizeResourceRequest(
network::ResourceRequest& resource_request) {
resource_request.headers.SetHeader(net::HttpRequestHeaders::kContentType,
kCheckClientDownloadRequestContentType);
}
const GURL& DownloadProtectionDelegateDesktop::GetDownloadRequestUrl() const {
return download_request_url_;
}
net::NetworkTrafficAnnotationTag DownloadProtectionDelegateDesktop::
CompleteClientDownloadRequestTrafficAnnotation(
const net::PartialNetworkTrafficAnnotationTag&
partial_traffic_annotation) const {
return net::BranchedCompleteNetworkTrafficAnnotation(
"client_download_request_desktop", "client_download_request_for_platform",
partial_traffic_annotation, R"(
semantics {
description:
"Chromium checks whether a given download is likely to be "
"dangerous by sending this client download request to Google's "
"Safe Browsing servers. Safe Browsing server will respond to "
"this request by sending back a verdict, indicating if this "
"download is safe or the danger type of this download (e.g. "
"dangerous content, uncommon content, potentially harmful, etc)."
trigger:
"This request is triggered when a download is about to complete, "
"the download is not allowlisted, and its file extension is "
"supported by download protection service (e.g. executables, "
"archives). Please refer to https://cs.chromium.org/chromium/src/"
"chrome/browser/resources/safe_browsing/"
"download_file_types.asciipb for the complete list of supported "
"files."
data:
"URL of the file to be downloaded, its referrer chain, digest "
"and other features extracted from the downloaded file. Refer to "
"ClientDownloadRequest message in https://cs.chromium.org/"
"chromium/src/components/safe_browsing/csd.proto for all "
"submitted features."
user_data {
type: SENSITIVE_URL
type: WEB_CONTENT
}
last_reviewed: "2025-02-25"
})");
}
float DownloadProtectionDelegateDesktop::GetAllowlistedDownloadSampleRate()
const {
return kAllowlistDownloadSampleRate;
}
float DownloadProtectionDelegateDesktop::GetUnsupportedFileSampleRate(
const base::FilePath& filename) const {
// If this extension is specifically marked as SAMPLED_PING (as are
// all "unknown" extensions), we may want to sample it. Sampling it means
// we'll send a "light ping" with private info removed, and we won't
// use the verdict.
const FileTypePolicies* policies = FileTypePolicies::GetInstance();
return policies->PingSettingForFile(filename) ==
DownloadFileType::SAMPLED_PING
? policies->SampledPingProbability()
: 0.0;
}
} // namespace safe_browsing
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