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// Copyright (c) 2011 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/browser/external_protocol_handler.h"
#include <set>
#include "base/logging.h"
#include "base/message_loop.h"
#include "base/string_util.h"
#include "base/threading/thread.h"
#include "build/build_config.h"
#include "chrome/browser/browser_process_impl.h"
#include "chrome/browser/platform_util.h"
#include "chrome/browser/prefs/pref_service.h"
#include "chrome/browser/prefs/scoped_user_pref_update.h"
#include "chrome/common/pref_names.h"
#include "googleurl/src/gurl.h"
#include "net/base/escape.h"
// Whether we accept requests for launching external protocols. This is set to
// false every time an external protocol is requested, and set back to true on
// each user gesture. This variable should only be accessed from the UI thread.
static bool g_accept_requests = true;
// static
void ExternalProtocolHandler::PrepopulateDictionary(DictionaryValue* win_pref) {
static bool is_warm = false;
if (is_warm)
return;
is_warm = true;
static const char* const denied_schemes[] = {
"afp",
"data",
"disk",
"disks",
// ShellExecuting file:///C:/WINDOWS/system32/notepad.exe will simply
// execute the file specified! Hopefully we won't see any "file" schemes
// because we think of file:// URLs as handled URLs, but better to be safe
// than to let an attacker format the user's hard drive.
"file",
"hcp",
"javascript",
"ms-help",
"nntp",
"shell",
"vbscript",
// view-source is a special case in chrome. When it comes through an
// iframe or a redirect, it looks like an external protocol, but we don't
// want to shellexecute it.
"view-source",
"vnd.ms.radio",
};
static const char* const allowed_schemes[] = {
"mailto",
"news",
"snews",
};
bool should_block;
for (size_t i = 0; i < arraysize(denied_schemes); ++i) {
if (!win_pref->GetBoolean(denied_schemes[i], &should_block)) {
win_pref->SetBoolean(denied_schemes[i], true);
}
}
for (size_t i = 0; i < arraysize(allowed_schemes); ++i) {
if (!win_pref->GetBoolean(allowed_schemes[i], &should_block)) {
win_pref->SetBoolean(allowed_schemes[i], false);
}
}
}
// static
ExternalProtocolHandler::BlockState ExternalProtocolHandler::GetBlockState(
const std::string& scheme) {
// If we are being carpet bombed, block the request.
if (!g_accept_requests)
return BLOCK;
if (scheme.length() == 1) {
// We have a URL that looks something like:
// C:/WINDOWS/system32/notepad.exe
// ShellExecuting this URL will cause the specified program to be executed.
return BLOCK;
}
// Check the stored prefs.
// TODO(pkasting): http://b/1119651 This kind of thing should go in the
// preferences on the profile, not in the local state.
PrefService* pref = g_browser_process->local_state();
if (pref) { // May be NULL during testing.
DictionaryPrefUpdate update_excluded_schemas(pref, prefs::kExcludedSchemes);
// Warm up the dictionary if needed.
PrepopulateDictionary(update_excluded_schemas.Get());
bool should_block;
if (update_excluded_schemas->GetBoolean(scheme, &should_block))
return should_block ? BLOCK : DONT_BLOCK;
}
return UNKNOWN;
}
// static
void ExternalProtocolHandler::SetBlockState(const std::string& scheme,
BlockState state) {
// Set in the stored prefs.
// TODO(pkasting): http://b/1119651 This kind of thing should go in the
// preferences on the profile, not in the local state.
PrefService* pref = g_browser_process->local_state();
if (pref) { // May be NULL during testing.
DictionaryPrefUpdate update_excluded_schemas(pref, prefs::kExcludedSchemes);
if (state == UNKNOWN) {
update_excluded_schemas->Remove(scheme, NULL);
} else {
update_excluded_schemas->SetBoolean(scheme,
state == BLOCK ? true : false);
}
}
}
// static
void ExternalProtocolHandler::LaunchUrl(const GURL& url,
int render_process_host_id,
int tab_contents_id) {
DCHECK_EQ(MessageLoop::TYPE_UI, MessageLoop::current()->type());
// Escape the input scheme to be sure that the command does not
// have parameters unexpected by the external program.
std::string escaped_url_string = EscapeExternalHandlerValue(url.spec());
GURL escaped_url(escaped_url_string);
BlockState block_state = GetBlockState(escaped_url.scheme());
if (block_state == BLOCK)
return;
g_accept_requests = false;
if (block_state == UNKNOWN) {
// Ask the user if they want to allow the protocol. This will call
// LaunchUrlWithoutSecurityCheck if the user decides to accept the protocol.
RunExternalProtocolDialog(escaped_url,
render_process_host_id,
tab_contents_id);
return;
}
LaunchUrlWithoutSecurityCheck(escaped_url);
}
// static
void ExternalProtocolHandler::LaunchUrlWithoutSecurityCheck(const GURL& url) {
#if defined(OS_MACOSX)
// This must run on the UI thread on OS X.
platform_util::OpenExternal(url);
#else
// Otherwise put this work on the file thread. On Windows ShellExecute may
// block for a significant amount of time, and it shouldn't hurt on Linux.
MessageLoop* loop = g_browser_process->file_thread()->message_loop();
if (loop == NULL) {
return;
}
loop->PostTask(FROM_HERE,
NewRunnableFunction(&platform_util::OpenExternal, url));
#endif
}
// static
void ExternalProtocolHandler::RegisterPrefs(PrefService* prefs) {
prefs->RegisterDictionaryPref(prefs::kExcludedSchemes);
}
// static
void ExternalProtocolHandler::PermitLaunchUrl() {
DCHECK_EQ(MessageLoop::TYPE_UI, MessageLoop::current()->type());
g_accept_requests = true;
}
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