gecko-dev/dom/security/SRICheck.cpp
2015-11-30 08:54:52 -06:00

389 lines
13 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "SRICheck.h"
#include "mozilla/Base64.h"
#include "mozilla/Logging.h"
#include "mozilla/Preferences.h"
#include "nsContentUtils.h"
#include "nsIChannel.h"
#include "nsIDocument.h"
#include "nsIProtocolHandler.h"
#include "nsIScriptError.h"
#include "nsIScriptSecurityManager.h"
#include "nsIIncrementalStreamLoader.h"
#include "nsIUnicharStreamLoader.h"
#include "nsIURI.h"
#include "nsNetUtil.h"
#include "nsWhitespaceTokenizer.h"
static mozilla::LogModule*
GetSriLog()
{
static mozilla::LazyLogModule gSriPRLog("SRI");
return gSriPRLog;
}
#define SRILOG(args) MOZ_LOG(GetSriLog(), mozilla::LogLevel::Debug, args)
#define SRIERROR(args) MOZ_LOG(GetSriLog(), mozilla::LogLevel::Error, args)
namespace mozilla {
namespace dom {
/**
* Returns whether or not the sub-resource about to be loaded is eligible
* for integrity checks. If it's not, the checks will be skipped and the
* sub-resource will be loaded.
*/
static nsresult
IsEligible(nsIChannel* aChannel, const CORSMode aCORSMode,
const nsIDocument* aDocument)
{
NS_ENSURE_ARG_POINTER(aDocument);
if (!aChannel) {
SRILOG(("SRICheck::IsEligible, null channel"));
return NS_ERROR_SRI_NOT_ELIGIBLE;
}
// Was the sub-resource loaded via CORS?
if (aCORSMode != CORS_NONE) {
SRILOG(("SRICheck::IsEligible, CORS mode"));
return NS_OK;
}
nsCOMPtr<nsIURI> finalURI;
nsresult rv = NS_GetFinalChannelURI(aChannel, getter_AddRefs(finalURI));
NS_ENSURE_SUCCESS(rv, rv);
nsCOMPtr<nsIURI> originalURI;
rv = aChannel->GetOriginalURI(getter_AddRefs(originalURI));
NS_ENSURE_SUCCESS(rv, rv);
nsAutoCString requestSpec;
rv = originalURI->GetSpec(requestSpec);
NS_ENSURE_SUCCESS(rv, rv);
if (MOZ_LOG_TEST(GetSriLog(), mozilla::LogLevel::Debug)) {
nsAutoCString documentSpec, finalSpec;
aDocument->GetDocumentURI()->GetAsciiSpec(documentSpec);
if (finalURI) {
finalURI->GetSpec(finalSpec);
}
SRILOG(("SRICheck::IsEligible, documentURI=%s; requestURI=%s; finalURI=%s",
documentSpec.get(), requestSpec.get(), finalSpec.get()));
}
// Is the sub-resource same-origin?
nsIScriptSecurityManager* ssm = nsContentUtils::GetSecurityManager();
if (NS_SUCCEEDED(ssm->CheckSameOriginURI(aDocument->GetDocumentURI(),
finalURI, false))) {
SRILOG(("SRICheck::IsEligible, same-origin"));
return NS_OK;
}
SRILOG(("SRICheck::IsEligible, NOT same origin"));
NS_ConvertUTF8toUTF16 requestSpecUTF16(requestSpec);
const char16_t* params[] = { requestSpecUTF16.get() };
nsContentUtils::ReportToConsole(nsIScriptError::errorFlag,
NS_LITERAL_CSTRING("Sub-resource Integrity"),
aDocument,
nsContentUtils::eSECURITY_PROPERTIES,
"IneligibleResource",
params, ArrayLength(params));
return NS_ERROR_SRI_NOT_ELIGIBLE;
}
/* static */ nsresult
SRICheck::IntegrityMetadata(const nsAString& aMetadataList,
const nsIDocument* aDocument,
SRIMetadata* outMetadata)
{
NS_ENSURE_ARG_POINTER(outMetadata);
NS_ENSURE_ARG_POINTER(aDocument);
MOZ_ASSERT(outMetadata->IsEmpty()); // caller must pass empty metadata
if (!Preferences::GetBool("security.sri.enable", false)) {
SRILOG(("SRICheck::IntegrityMetadata, sri is disabled (pref)"));
return NS_ERROR_SRI_DISABLED;
}
// put a reasonable bound on the length of the metadata
NS_ConvertUTF16toUTF8 metadataList(aMetadataList);
if (metadataList.Length() > SRICheck::MAX_METADATA_LENGTH) {
metadataList.Truncate(SRICheck::MAX_METADATA_LENGTH);
}
MOZ_ASSERT(metadataList.Length() <= aMetadataList.Length());
// the integrity attribute is a list of whitespace-separated hashes
// and options so we need to look at them one by one and pick the
// strongest (valid) one
nsCWhitespaceTokenizer tokenizer(metadataList);
nsAutoCString token;
for (uint32_t i=0; tokenizer.hasMoreTokens() &&
i < SRICheck::MAX_METADATA_TOKENS; ++i) {
token = tokenizer.nextToken();
SRIMetadata metadata(token);
if (metadata.IsMalformed()) {
NS_ConvertUTF8toUTF16 tokenUTF16(token);
const char16_t* params[] = { tokenUTF16.get() };
nsContentUtils::ReportToConsole(nsIScriptError::warningFlag,
NS_LITERAL_CSTRING("Sub-resource Integrity"),
aDocument,
nsContentUtils::eSECURITY_PROPERTIES,
"MalformedIntegrityHash",
params, ArrayLength(params));
} else if (!metadata.IsAlgorithmSupported()) {
nsAutoCString alg;
metadata.GetAlgorithm(&alg);
NS_ConvertUTF8toUTF16 algUTF16(alg);
const char16_t* params[] = { algUTF16.get() };
nsContentUtils::ReportToConsole(nsIScriptError::warningFlag,
NS_LITERAL_CSTRING("Sub-resource Integrity"),
aDocument,
nsContentUtils::eSECURITY_PROPERTIES,
"UnsupportedHashAlg",
params, ArrayLength(params));
}
nsAutoCString alg1, alg2;
if (MOZ_LOG_TEST(GetSriLog(), mozilla::LogLevel::Debug)) {
outMetadata->GetAlgorithm(&alg1);
metadata.GetAlgorithm(&alg2);
}
if (*outMetadata == metadata) {
SRILOG(("SRICheck::IntegrityMetadata, alg '%s' is the same as '%s'",
alg1.get(), alg2.get()));
*outMetadata += metadata; // add new hash to strongest metadata
} else if (*outMetadata < metadata) {
SRILOG(("SRICheck::IntegrityMetadata, alg '%s' is weaker than '%s'",
alg1.get(), alg2.get()));
*outMetadata = metadata; // replace strongest metadata with current
}
}
if (MOZ_LOG_TEST(GetSriLog(), mozilla::LogLevel::Debug)) {
if (outMetadata->IsValid()) {
nsAutoCString alg;
outMetadata->GetAlgorithm(&alg);
SRILOG(("SRICheck::IntegrityMetadata, using a '%s' hash", alg.get()));
} else if (outMetadata->IsEmpty()) {
SRILOG(("SRICheck::IntegrityMetadata, no metadata"));
} else {
SRILOG(("SRICheck::IntegrityMetadata, no valid metadata found"));
}
}
return NS_OK;
}
/* static */ nsresult
SRICheck::VerifyIntegrity(const SRIMetadata& aMetadata,
nsIUnicharStreamLoader* aLoader,
const CORSMode aCORSMode,
const nsAString& aString,
const nsIDocument* aDocument)
{
NS_ENSURE_ARG_POINTER(aLoader);
NS_ConvertUTF16toUTF8 utf8Hash(aString);
nsCOMPtr<nsIChannel> channel;
aLoader->GetChannel(getter_AddRefs(channel));
if (MOZ_LOG_TEST(GetSriLog(), mozilla::LogLevel::Debug)) {
nsAutoCString requestURL;
nsCOMPtr<nsIURI> originalURI;
if (channel &&
NS_SUCCEEDED(channel->GetOriginalURI(getter_AddRefs(originalURI))) &&
originalURI) {
originalURI->GetAsciiSpec(requestURL);
}
SRILOG(("SRICheck::VerifyIntegrity (unichar stream)"));
}
SRICheckDataVerifier verifier(aMetadata, aDocument);
nsresult rv;
rv = verifier.Update(utf8Hash.Length(), (uint8_t*)utf8Hash.get());
NS_ENSURE_SUCCESS(rv, rv);
return verifier.Verify(aMetadata, channel, aCORSMode, aDocument);
}
//////////////////////////////////////////////////////////////
//
//////////////////////////////////////////////////////////////
SRICheckDataVerifier::SRICheckDataVerifier(const SRIMetadata& aMetadata,
const nsIDocument* aDocument)
: mCryptoHash(nullptr),
mBytesHashed(0),
mInvalidMetadata(false),
mComplete(false)
{
MOZ_ASSERT(!aMetadata.IsEmpty()); // should be checked by caller
// IntegrityMetadata() checks this and returns "no metadata" if
// it's disabled so we should never make it this far
MOZ_ASSERT(Preferences::GetBool("security.sri.enable", false));
if (!aMetadata.IsValid()) {
nsContentUtils::ReportToConsole(nsIScriptError::warningFlag,
NS_LITERAL_CSTRING("Sub-resource Integrity"),
aDocument,
nsContentUtils::eSECURITY_PROPERTIES,
"NoValidMetadata");
mInvalidMetadata = true;
return; // ignore invalid metadata for forward-compatibility
}
uint32_t hashLength;
aMetadata.GetHashType(&mHashType, &hashLength);
}
nsresult
SRICheckDataVerifier::EnsureCryptoHash()
{
MOZ_ASSERT(!mInvalidMetadata);
if (mCryptoHash) {
return NS_OK;
}
nsresult rv;
nsCOMPtr<nsICryptoHash> cryptoHash =
do_CreateInstance("@mozilla.org/security/hash;1", &rv);
NS_ENSURE_SUCCESS(rv, rv);
rv = cryptoHash->Init(mHashType);
NS_ENSURE_SUCCESS(rv, rv);
mCryptoHash = cryptoHash;
return NS_OK;
}
nsresult
SRICheckDataVerifier::Update(uint32_t aStringLen, const uint8_t* aString)
{
NS_ENSURE_ARG_POINTER(aString);
if (mInvalidMetadata) {
return NS_OK; // ignoring any data updates, see mInvalidMetadata usage
}
nsresult rv;
rv = EnsureCryptoHash();
NS_ENSURE_SUCCESS(rv, rv);
mBytesHashed += aStringLen;
return mCryptoHash->Update(aString, aStringLen);
}
nsresult
SRICheckDataVerifier::Finish()
{
if (mInvalidMetadata || mComplete) {
return NS_OK; // already finished or invalid metadata
}
nsresult rv;
rv = EnsureCryptoHash(); // we need computed hash even for 0-length data
NS_ENSURE_SUCCESS(rv, rv);
rv = mCryptoHash->Finish(false, mComputedHash);
mCryptoHash = nullptr;
mComplete = true;
return rv;
}
nsresult
SRICheckDataVerifier::VerifyHash(const SRIMetadata& aMetadata,
uint32_t aHashIndex,
const nsIDocument* aDocument)
{
NS_ENSURE_ARG_POINTER(aDocument);
nsAutoCString base64Hash;
aMetadata.GetHash(aHashIndex, &base64Hash);
SRILOG(("SRICheckDataVerifier::VerifyHash, hash[%u]=%s", aHashIndex, base64Hash.get()));
nsAutoCString binaryHash;
if (NS_WARN_IF(NS_FAILED(Base64Decode(base64Hash, binaryHash)))) {
nsContentUtils::ReportToConsole(nsIScriptError::errorFlag,
NS_LITERAL_CSTRING("Sub-resource Integrity"),
aDocument,
nsContentUtils::eSECURITY_PROPERTIES,
"InvalidIntegrityBase64");
return NS_ERROR_SRI_CORRUPT;
}
uint32_t hashLength;
int8_t hashType;
aMetadata.GetHashType(&hashType, &hashLength);
if (binaryHash.Length() != hashLength) {
nsContentUtils::ReportToConsole(nsIScriptError::errorFlag,
NS_LITERAL_CSTRING("Sub-resource Integrity"),
aDocument,
nsContentUtils::eSECURITY_PROPERTIES,
"InvalidIntegrityLength");
return NS_ERROR_SRI_CORRUPT;
}
if (!binaryHash.Equals(mComputedHash)) {
SRILOG(("SRICheckDataVerifier::VerifyHash, hash[%u] did not match", aHashIndex));
return NS_ERROR_SRI_CORRUPT;
}
SRILOG(("SRICheckDataVerifier::VerifyHash, hash[%u] verified successfully", aHashIndex));
return NS_OK;
}
nsresult
SRICheckDataVerifier::Verify(const SRIMetadata& aMetadata,
nsIChannel* aChannel,
const CORSMode aCORSMode,
const nsIDocument* aDocument)
{
NS_ENSURE_ARG_POINTER(aDocument);
if (MOZ_LOG_TEST(GetSriLog(), mozilla::LogLevel::Debug)) {
nsAutoCString requestURL;
nsCOMPtr<nsIRequest> request;
request = do_QueryInterface(aChannel);
request->GetName(requestURL);
SRILOG(("SRICheckDataVerifier::Verify, url=%s (length=%lu)",
requestURL.get(), mBytesHashed));
}
nsresult rv = Finish();
NS_ENSURE_SUCCESS(rv, rv);
if (NS_FAILED(IsEligible(aChannel, aCORSMode, aDocument))) {
return NS_ERROR_SRI_NOT_ELIGIBLE;
}
if (mInvalidMetadata) {
return NS_OK; // ignore invalid metadata for forward-compatibility
}
for (uint32_t i = 0; i < aMetadata.HashCount(); i++) {
if (NS_SUCCEEDED(VerifyHash(aMetadata, i, aDocument))) {
return NS_OK; // stop at the first valid hash
}
}
nsAutoCString alg;
aMetadata.GetAlgorithm(&alg);
NS_ConvertUTF8toUTF16 algUTF16(alg);
const char16_t* params[] = { algUTF16.get() };
nsContentUtils::ReportToConsole(nsIScriptError::errorFlag,
NS_LITERAL_CSTRING("Sub-resource Integrity"),
aDocument,
nsContentUtils::eSECURITY_PROPERTIES,
"IntegrityMismatch",
params, ArrayLength(params));
return NS_ERROR_SRI_CORRUPT;
}
} // namespace dom
} // namespace mozilla