blob: ac133263e3a4cc42428d4f0695d69ef7586e5413 [file] [log] [blame]
// Copyright 2013 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/common/manifest_handlers/csp_info.h"
#include <memory>
#include <utility>
#include "base/feature_list.h"
#include "base/no_destructor.h"
#include "base/strings/string_piece.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "base/values.h"
#include "extensions/common/csp_validator.h"
#include "extensions/common/error_utils.h"
#include "extensions/common/extension_features.h"
#include "extensions/common/install_warning.h"
#include "extensions/common/manifest_constants.h"
#include "extensions/common/manifest_handlers/sandboxed_page_info.h"
namespace extensions {
namespace keys = manifest_keys;
namespace errors = manifest_errors;
using csp_validator::ContentSecurityPolicyIsLegal;
using csp_validator::SanitizeContentSecurityPolicy;
namespace {
const char kDefaultContentSecurityPolicy[] =
"script-src 'self' blob: filesystem:; "
"object-src 'self' blob: filesystem:;";
const char kDefaultSandboxedPageContentSecurityPolicy[] =
"sandbox allow-scripts allow-forms allow-popups allow-modals; "
"script-src 'self' 'unsafe-inline' 'unsafe-eval'; child-src 'self';";
#define PLATFORM_APP_LOCAL_CSP_SOURCES "'self' blob: filesystem: data:"
// clang-format off
const char kDefaultPlatformAppContentSecurityPolicy[] =
// Platform apps can only use local resources by default.
"default-src 'self' blob: filesystem:;"
// For remote resources, they can fetch them via XMLHttpRequest.
" connect-src * data: blob: filesystem:;"
// And serve them via data: or same-origin (blob:, filesystem:) URLs
" style-src " PLATFORM_APP_LOCAL_CSP_SOURCES " 'unsafe-inline';"
" img-src " PLATFORM_APP_LOCAL_CSP_SOURCES ";"
" frame-src " PLATFORM_APP_LOCAL_CSP_SOURCES ";"
" font-src " PLATFORM_APP_LOCAL_CSP_SOURCES ";"
// Media can be loaded from remote resources since:
// 1. <video> and <audio> have good fallback behavior when offline or under
// spotty connectivity.
// 2. Fetching via XHR and serving via blob: URLs currently does not allow
// streaming or partial buffering.
" media-src * data: blob: filesystem:;"
// Scripts are allowed to use WebAssembly
" script-src 'self' blob: filesystem: 'wasm-eval';";
// clang-format on
const char* GetDefaultMV3CSP(absl::optional<bool> allow_wasm = absl::nullopt) {
// The default CSP to be used in order to prevent remote scripts.
static const char kDefaultMV3CSP[] = "script-src 'self'; object-src 'self';";
// Same as `kDefaultMV3CSP` but allows web assembly usage.
static const char kDefaultMV3CSPWithWasmAllowed[] =
"script-src 'self' 'wasm-eval'; object-src 'self';";
return allow_wasm.value_or(
base::FeatureList::IsEnabled(extensions_features::kAllowWasmInMV3))
? kDefaultMV3CSPWithWasmAllowed
: kDefaultMV3CSP;
}
int GetValidatorOptions(Extension* extension) {
int options = csp_validator::OPTIONS_NONE;
// crbug.com/146487
if (extension->GetType() == Manifest::TYPE_EXTENSION ||
extension->GetType() == Manifest::TYPE_LEGACY_PACKAGED_APP) {
options |= csp_validator::OPTIONS_ALLOW_UNSAFE_EVAL;
}
// Component extensions can specify an insecure object-src directive. This
// should be safe because non-NPAPI plugins should load in a sandboxed process
// and only allow communication via postMessage.
if (extensions::Manifest::IsComponentLocation(extension->location()))
options |= csp_validator::OPTIONS_ALLOW_INSECURE_OBJECT_SRC;
return options;
}
std::u16string GetInvalidManifestKeyError(base::StringPiece key) {
return ErrorUtils::FormatErrorMessageUTF16(errors::kInvalidManifestKey, key);
}
// Returns null if the manifest type can't access the path. Else returns the
// corresponding Value.
const base::Value* GetManifestPath(const Extension* extension,
const char* path) {
const base::Value* value = nullptr;
return extension->manifest()->Get(path, &value) ? value : nullptr;
}
const char* GetDefaultExtensionPagesCSP(Extension* extension) {
if (extension->manifest_version() >= 3)
return GetDefaultMV3CSP();
if (extension->GetType() == Manifest::TYPE_PLATFORM_APP)
return kDefaultPlatformAppContentSecurityPolicy;
return kDefaultContentSecurityPolicy;
}
} // namespace
CSPInfo::CSPInfo(std::string extension_pages_csp)
: extension_pages_csp(std::move(extension_pages_csp)) {}
CSPInfo::~CSPInfo() {
}
// static
const std::string& CSPInfo::GetExtensionPagesCSP(const Extension* extension) {
CSPInfo* csp_info = static_cast<CSPInfo*>(
extension->GetManifestData(keys::kContentSecurityPolicy));
return csp_info ? csp_info->extension_pages_csp : base::EmptyString();
}
// static
const std::string* CSPInfo::GetDefaultCSPToAppend(
const Extension& extension,
const std::string& relative_path) {
if (!extension.is_extension())
return nullptr;
// For sandboxed pages and manifest V2 extensions, append the parsed CSP. This
// helps ensure that extension's can't get around our parsing rules by CSP
// modifications through, say service workers.
if (SandboxedPageInfo::IsSandboxedPage(&extension, relative_path))
return &GetSandboxContentSecurityPolicy(&extension);
if (extension.manifest_version() <= 2)
return &GetExtensionPagesCSP(&extension);
// For manifest V3 extensions, append the default secure CSP. This
// additionally helps protect against bugs in our CSP parsing code which may
// cause the parsed CSP to not be as strong as the default one. For example,
// see crbug.com/1042963.
static const base::NoDestructor<std::string> default_csp(GetDefaultMV3CSP());
return default_csp.get();
}
// static
const std::string* CSPInfo::GetIsolatedWorldCSP(const Extension& extension) {
if (extension.manifest_version() >= 3) {
// The isolated world will use its own CSP which blocks remotely hosted
// code.
static const base::NoDestructor<std::string> default_isolated_world_csp(
GetDefaultMV3CSP(false /* allow_wasm */));
return default_isolated_world_csp.get();
}
Manifest::Type type = extension.GetType();
bool bypass_main_world_csp = type == Manifest::TYPE_PLATFORM_APP ||
type == Manifest::TYPE_EXTENSION ||
type == Manifest::TYPE_LEGACY_PACKAGED_APP;
if (!bypass_main_world_csp) {
// The isolated world will use the main world CSP.
return nullptr;
}
// The isolated world will bypass the main world CSP.
return &base::EmptyString();
}
// static
const std::string& CSPInfo::GetSandboxContentSecurityPolicy(
const Extension* extension) {
CSPInfo* csp_info = static_cast<CSPInfo*>(
extension->GetManifestData(keys::kContentSecurityPolicy));
return csp_info ? csp_info->sandbox_csp : base::EmptyString();
}
// static
const std::string& CSPInfo::GetResourceContentSecurityPolicy(
const Extension* extension,
const std::string& relative_path) {
return SandboxedPageInfo::IsSandboxedPage(extension, relative_path)
? GetSandboxContentSecurityPolicy(extension)
: GetExtensionPagesCSP(extension);
}
CSPHandler::CSPHandler() = default;
CSPHandler::~CSPHandler() = default;
bool CSPHandler::Parse(Extension* extension, std::u16string* error) {
const char* key = extension->GetType() == Manifest::TYPE_PLATFORM_APP
? keys::kPlatformAppContentSecurityPolicy
: keys::kContentSecurityPolicy;
// The "content_security_policy" manifest key can either be a string or a
// dictionary of the format.
// "content_security_policy" : {
// "extension_pages": "",
// "sandbox": "",
// }
// The dictionary is supported (and mandated) for manifest v3 (and above)
// extensions.
const base::Value* csp = GetManifestPath(extension, key);
bool parse_as_dictionary = extension->manifest_version() >= 3;
if (parse_as_dictionary) {
if (csp && !csp->is_dict()) {
*error = GetInvalidManifestKeyError(key);
return false;
}
return ParseCSPDictionary(extension, error);
}
if (!ParseExtensionPagesCSP(extension, error, key, csp)) {
return false;
}
if (!ParseSandboxCSP(extension, error, keys::kSandboxedPagesCSP,
GetManifestPath(extension, keys::kSandboxedPagesCSP))) {
return false;
}
return true;
}
bool CSPHandler::ParseCSPDictionary(Extension* extension,
std::u16string* error) {
// keys::kSandboxedPagesCSP shouldn't be used when using
// keys::kContentSecurityPolicy as a dictionary.
if (extension->manifest()->HasPath(keys::kSandboxedPagesCSP)) {
*error = base::ASCIIToUTF16(errors::kSandboxPagesCSPKeyNotAllowed);
return false;
}
return ParseExtensionPagesCSP(
extension, error, keys::kContentSecurityPolicy_ExtensionPagesPath,
GetManifestPath(
extension, keys::kContentSecurityPolicy_ExtensionPagesPath)) &&
ParseSandboxCSP(
extension, error, keys::kContentSecurityPolicy_SandboxedPagesPath,
GetManifestPath(extension,
keys::kContentSecurityPolicy_SandboxedPagesPath));
}
bool CSPHandler::ParseExtensionPagesCSP(
Extension* extension,
std::u16string* error,
base::StringPiece manifest_key,
const base::Value* content_security_policy) {
if (!content_security_policy) {
return SetExtensionPagesCSP(extension, manifest_key,
GetDefaultExtensionPagesCSP(extension));
}
if (!content_security_policy->is_string()) {
*error = GetInvalidManifestKeyError(manifest_key);
return false;
}
const std::string& content_security_policy_str =
content_security_policy->GetString();
if (!ContentSecurityPolicyIsLegal(content_security_policy_str)) {
*error = GetInvalidManifestKeyError(manifest_key);
return false;
}
if (extension->manifest_version() >= 3) {
if (!csp_validator::DoesCSPDisallowRemoteCode(content_security_policy_str,
manifest_key, error)) {
return false;
}
SetExtensionPagesCSP(extension, manifest_key, content_security_policy_str);
return true;
}
std::vector<InstallWarning> warnings;
std::string sanitized_content_security_policy = SanitizeContentSecurityPolicy(
content_security_policy_str, std::string(manifest_key),
GetValidatorOptions(extension), &warnings);
extension->AddInstallWarnings(std::move(warnings));
SetExtensionPagesCSP(extension, manifest_key,
std::move(sanitized_content_security_policy));
return true;
}
bool CSPHandler::ParseSandboxCSP(Extension* extension,
std::u16string* error,
base::StringPiece manifest_key,
const base::Value* sandbox_csp) {
if (!sandbox_csp) {
SetSandboxCSP(extension, kDefaultSandboxedPageContentSecurityPolicy);
return true;
}
if (!sandbox_csp->is_string()) {
*error = GetInvalidManifestKeyError(manifest_key);
return false;
}
const std::string& sandbox_csp_str = sandbox_csp->GetString();
if (!ContentSecurityPolicyIsLegal(sandbox_csp_str) ||
!csp_validator::ContentSecurityPolicyIsSandboxed(sandbox_csp_str,
extension->GetType())) {
*error = GetInvalidManifestKeyError(manifest_key);
return false;
}
std::vector<InstallWarning> warnings;
std::string effective_sandbox_csp =
csp_validator::GetEffectiveSandoxedPageCSP(
sandbox_csp_str, std::string(manifest_key), &warnings);
SetSandboxCSP(extension, std::move(effective_sandbox_csp));
extension->AddInstallWarnings(std::move(warnings));
return true;
}
bool CSPHandler::SetExtensionPagesCSP(Extension* extension,
base::StringPiece manifest_key,
std::string content_security_policy) {
if (extension->manifest_version() >= 3) {
std::u16string error;
DCHECK(csp_validator::DoesCSPDisallowRemoteCode(content_security_policy,
manifest_key, &error));
} else {
DCHECK_EQ(content_security_policy,
SanitizeContentSecurityPolicy(
content_security_policy, std::string(manifest_key),
GetValidatorOptions(extension), nullptr));
}
extension->SetManifestData(
keys::kContentSecurityPolicy,
std::make_unique<CSPInfo>(std::move(content_security_policy)));
return true;
}
void CSPHandler::SetSandboxCSP(Extension* extension, std::string sandbox_csp) {
CHECK(csp_validator::ContentSecurityPolicyIsSandboxed(sandbox_csp,
extension->GetType()));
// By now we must have parsed the extension page CSP.
CSPInfo* csp_info = static_cast<CSPInfo*>(
extension->GetManifestData(keys::kContentSecurityPolicy));
DCHECK(csp_info);
csp_info->sandbox_csp = std::move(sandbox_csp);
}
bool CSPHandler::AlwaysParseForType(Manifest::Type type) const {
// TODO(crbug.com/1005978): Check if TYPE_USER_SCRIPT needs to be included
// here.
return type == Manifest::TYPE_PLATFORM_APP ||
type == Manifest::TYPE_EXTENSION ||
type == Manifest::TYPE_LEGACY_PACKAGED_APP;
}
base::span<const char* const> CSPHandler::Keys() const {
static constexpr const char* kKeys[] = {
keys::kContentSecurityPolicy, keys::kPlatformAppContentSecurityPolicy,
keys::kSandboxedPagesCSP};
return kKeys;
}
} // namespace extensions