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Diffstat (limited to '')
| -rw-r--r-- | dom/security/SRICheck.cpp | 516 |
1 files changed, 516 insertions, 0 deletions
diff --git a/dom/security/SRICheck.cpp b/dom/security/SRICheck.cpp new file mode 100644 index 0000000000..61d34bfb5a --- /dev/null +++ b/dom/security/SRICheck.cpp @@ -0,0 +1,516 @@ +/* -*- 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/LoadTainting.h" +#include "mozilla/Logging.h" +#include "mozilla/Preferences.h" +#include "mozilla/dom/SRILogHelper.h" +#include "mozilla/dom/SRIMetadata.h" +#include "nsComponentManagerUtils.h" +#include "nsContentUtils.h" +#include "nsIChannel.h" +#include "nsIConsoleReportCollector.h" +#include "nsIScriptError.h" +#include "nsIURI.h" +#include "nsNetUtil.h" +#include "nsWhitespaceTokenizer.h" + +#define SRIVERBOSE(args) \ + MOZ_LOG(SRILogHelper::GetSriLog(), mozilla::LogLevel::Verbose, args) +#define SRILOG(args) \ + MOZ_LOG(SRILogHelper::GetSriLog(), mozilla::LogLevel::Debug, args) +#define SRIERROR(args) \ + MOZ_LOG(SRILogHelper::GetSriLog(), mozilla::LogLevel::Error, args) + +namespace mozilla::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, + mozilla::LoadTainting aTainting, + const nsACString& aSourceFileURI, + nsIConsoleReportCollector* aReporter) { + NS_ENSURE_ARG_POINTER(aReporter); + + if (!aChannel) { + SRILOG(("SRICheck::IsEligible, null channel")); + return NS_ERROR_SRI_NOT_ELIGIBLE; + } + + // Was the sub-resource loaded via CORS? + if (aTainting == LoadTainting::CORS) { + 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(SRILogHelper::GetSriLog(), mozilla::LogLevel::Debug)) { + SRILOG(("SRICheck::IsEligible, requestURI=%s; finalURI=%s", + requestSpec.get(), + finalURI ? finalURI->GetSpecOrDefault().get() : "")); + } + + // Is the sub-resource same-origin? + if (aTainting == LoadTainting::Basic) { + SRILOG(("SRICheck::IsEligible, same-origin")); + return NS_OK; + } + SRILOG(("SRICheck::IsEligible, NOT same-origin")); + + NS_ConvertUTF8toUTF16 requestSpecUTF16(requestSpec); + nsTArray<nsString> params; + params.AppendElement(requestSpecUTF16); + aReporter->AddConsoleReport( + nsIScriptError::errorFlag, "Sub-resource Integrity"_ns, + nsContentUtils::eSECURITY_PROPERTIES, aSourceFileURI, 0, 0, + "IneligibleResource"_ns, const_cast<const nsTArray<nsString>&>(params)); + return NS_ERROR_SRI_NOT_ELIGIBLE; +} + +/* static */ +nsresult SRICheck::IntegrityMetadata(const nsAString& aMetadataList, + const nsACString& aSourceFileURI, + nsIConsoleReportCollector* aReporter, + SRIMetadata* outMetadata) { + NS_ENSURE_ARG_POINTER(outMetadata); + NS_ENSURE_ARG_POINTER(aReporter); + MOZ_ASSERT(outMetadata->IsEmpty()); // caller must pass empty metadata + + // 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); + } + SRILOG(("SRICheck::IntegrityMetadata, metadataList=%s", metadataList.get())); + + // 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); + nsTArray<nsString> params; + params.AppendElement(tokenUTF16); + aReporter->AddConsoleReport( + nsIScriptError::warningFlag, "Sub-resource Integrity"_ns, + nsContentUtils::eSECURITY_PROPERTIES, aSourceFileURI, 0, 0, + "MalformedIntegrityHash"_ns, + const_cast<const nsTArray<nsString>&>(params)); + } else if (!metadata.IsAlgorithmSupported()) { + nsAutoCString alg; + metadata.GetAlgorithm(&alg); + NS_ConvertUTF8toUTF16 algUTF16(alg); + nsTArray<nsString> params; + params.AppendElement(algUTF16); + aReporter->AddConsoleReport( + nsIScriptError::warningFlag, "Sub-resource Integrity"_ns, + nsContentUtils::eSECURITY_PROPERTIES, aSourceFileURI, 0, 0, + "UnsupportedHashAlg"_ns, + const_cast<const nsTArray<nsString>&>(params)); + } + + nsAutoCString alg1, alg2; + if (MOZ_LOG_TEST(SRILogHelper::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 + } + } + + outMetadata->mIntegrityString = aMetadataList; + + if (MOZ_LOG_TEST(SRILogHelper::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; +} + +////////////////////////////////////////////////////////////// +// +////////////////////////////////////////////////////////////// +SRICheckDataVerifier::SRICheckDataVerifier(const SRIMetadata& aMetadata, + const nsACString& aSourceFileURI, + nsIConsoleReportCollector* aReporter) + : mCryptoHash(nullptr), + mBytesHashed(0), + mHashLength(0), + mHashType('\0'), + mInvalidMetadata(false), + mComplete(false) { + MOZ_ASSERT(!aMetadata.IsEmpty()); // should be checked by caller + MOZ_ASSERT(aReporter); + + if (!aMetadata.IsValid()) { + nsTArray<nsString> params; + aReporter->AddConsoleReport( + nsIScriptError::warningFlag, "Sub-resource Integrity"_ns, + nsContentUtils::eSECURITY_PROPERTIES, aSourceFileURI, 0, 0, + "NoValidMetadata"_ns, const_cast<const nsTArray<nsString>&>(params)); + mInvalidMetadata = true; + return; // ignore invalid metadata for forward-compatibility + } + + aMetadata.GetHashType(&mHashType, &mHashLength); +} + +nsresult SRICheckDataVerifier::EnsureCryptoHash() { + MOZ_ASSERT(!mInvalidMetadata); + + if (mCryptoHash) { + return NS_OK; + } + + nsCOMPtr<nsICryptoHash> cryptoHash; + nsresult rv = NS_NewCryptoHash(mHashType, getter_AddRefs(cryptoHash)); + 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 nsACString& aSourceFileURI, nsIConsoleReportCollector* aReporter) { + NS_ENSURE_ARG_POINTER(aReporter); + + nsAutoCString base64Hash; + aMetadata.GetHash(aHashIndex, &base64Hash); + SRILOG(("SRICheckDataVerifier::VerifyHash, hash[%u]=%s", aHashIndex, + base64Hash.get())); + + nsAutoCString binaryHash; + + // We're decoding the supplied hash twice. Trying base64 first. + nsresult rv = Base64Decode(base64Hash, binaryHash); + + if (NS_FAILED(rv)) { + SRILOG( + ("SRICheckDataVerifier::VerifyHash, base64 decoding failed. Trying " + "base64url next.")); + FallibleTArray<uint8_t> decoded; + rv = Base64URLDecode(base64Hash, Base64URLDecodePaddingPolicy::Ignore, + decoded); + if (NS_FAILED(rv)) { + SRILOG( + ("SRICheckDataVerifier::VerifyHash, base64url decoding failed too. " + "Bailing out.")); + // if neither succeeded, we can bail out and warn + nsTArray<nsString> params; + aReporter->AddConsoleReport( + nsIScriptError::errorFlag, "Sub-resource Integrity"_ns, + nsContentUtils::eSECURITY_PROPERTIES, aSourceFileURI, 0, 0, + "InvalidIntegrityBase64"_ns, + const_cast<const nsTArray<nsString>&>(params)); + return NS_ERROR_SRI_CORRUPT; + } + binaryHash.Assign(reinterpret_cast<const char*>(decoded.Elements()), + decoded.Length()); + SRILOG( + ("SRICheckDataVerifier::VerifyHash, decoded supplied base64url hash " + "successfully.")); + } else { + SRILOG( + ("SRICheckDataVerifier::VerifyHash, decoded supplied base64 hash " + "successfully.")); + } + + uint32_t hashLength; + int8_t hashType; + aMetadata.GetHashType(&hashType, &hashLength); + if (binaryHash.Length() != hashLength) { + SRILOG( + ("SRICheckDataVerifier::VerifyHash, supplied base64(url) hash was " + "incorrect length after decoding.")); + nsTArray<nsString> params; + aReporter->AddConsoleReport( + nsIScriptError::errorFlag, "Sub-resource Integrity"_ns, + nsContentUtils::eSECURITY_PROPERTIES, aSourceFileURI, 0, 0, + "InvalidIntegrityLength"_ns, + const_cast<const nsTArray<nsString>&>(params)); + return NS_ERROR_SRI_CORRUPT; + } + + // the decoded supplied hash should match our computed binary hash. + 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 nsACString& aSourceFileURI, + nsIConsoleReportCollector* aReporter) { + NS_ENSURE_ARG_POINTER(aReporter); + + if (MOZ_LOG_TEST(SRILogHelper::GetSriLog(), mozilla::LogLevel::Debug)) { + nsAutoCString requestURL; + nsCOMPtr<nsIRequest> request = aChannel; + request->GetName(requestURL); + SRILOG(("SRICheckDataVerifier::Verify, url=%s (length=%zu)", + requestURL.get(), mBytesHashed)); + } + + nsresult rv = Finish(); + NS_ENSURE_SUCCESS(rv, rv); + + nsCOMPtr<nsILoadInfo> loadInfo = aChannel->LoadInfo(); + LoadTainting tainting = loadInfo->GetTainting(); + + if (NS_FAILED(IsEligible(aChannel, tainting, aSourceFileURI, aReporter))) { + 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, aSourceFileURI, aReporter))) { + return NS_OK; // stop at the first valid hash + } + } + + nsAutoCString alg; + aMetadata.GetAlgorithm(&alg); + NS_ConvertUTF8toUTF16 algUTF16(alg); + nsAutoCString encodedHash; + rv = Base64Encode(mComputedHash, encodedHash); + NS_ENSURE_SUCCESS(rv, rv); + NS_ConvertUTF8toUTF16 encodedHashUTF16(encodedHash); + + nsTArray<nsString> params; + params.AppendElement(algUTF16); + params.AppendElement(encodedHashUTF16); + aReporter->AddConsoleReport( + nsIScriptError::errorFlag, "Sub-resource Integrity"_ns, + nsContentUtils::eSECURITY_PROPERTIES, aSourceFileURI, 0, 0, + "IntegrityMismatch2"_ns, const_cast<const nsTArray<nsString>&>(params)); + + return NS_ERROR_SRI_CORRUPT; +} + +uint32_t SRICheckDataVerifier::DataSummaryLength() { + MOZ_ASSERT(!mInvalidMetadata); + return sizeof(mHashType) + sizeof(mHashLength) + mHashLength; +} + +uint32_t SRICheckDataVerifier::EmptyDataSummaryLength() { + return sizeof(int8_t) + sizeof(uint32_t); +} + +nsresult SRICheckDataVerifier::DataSummaryLength(uint32_t aDataLen, + const uint8_t* aData, + uint32_t* length) { + *length = 0; + NS_ENSURE_ARG_POINTER(aData); + + // we expect to always encode an SRI, even if it is empty or incomplete + if (aDataLen < EmptyDataSummaryLength()) { + SRILOG( + ("SRICheckDataVerifier::DataSummaryLength, encoded length[%u] is too " + "small", + aDataLen)); + return NS_ERROR_SRI_IMPORT; + } + + // decode the content of the buffer + size_t offset = sizeof(mHashType); + decltype(mHashLength) len = 0; + memcpy(&len, &aData[offset], sizeof(mHashLength)); + offset += sizeof(mHashLength); + + SRIVERBOSE( + ("SRICheckDataVerifier::DataSummaryLength, header {%x, %x, %x, %x, %x, " + "...}", + aData[0], aData[1], aData[2], aData[3], aData[4])); + + if (offset + len > aDataLen) { + SRILOG( + ("SRICheckDataVerifier::DataSummaryLength, encoded length[%u] overflow " + "the buffer size", + aDataLen)); + SRIVERBOSE(("SRICheckDataVerifier::DataSummaryLength, offset[%u], len[%u]", + uint32_t(offset), uint32_t(len))); + return NS_ERROR_SRI_IMPORT; + } + *length = uint32_t(offset + len); + return NS_OK; +} + +nsresult SRICheckDataVerifier::ImportDataSummary(uint32_t aDataLen, + const uint8_t* aData) { + MOZ_ASSERT(!mInvalidMetadata); // mHashType and mHashLength should be valid + MOZ_ASSERT(!mCryptoHash); // EnsureCryptoHash should not have been called + NS_ENSURE_ARG_POINTER(aData); + if (mInvalidMetadata) { + return NS_OK; // ignoring any data updates, see mInvalidMetadata usage + } + + // we expect to always encode an SRI, even if it is empty or incomplete + if (aDataLen < DataSummaryLength()) { + SRILOG( + ("SRICheckDataVerifier::ImportDataSummary, encoded length[%u] is too " + "small", + aDataLen)); + return NS_ERROR_SRI_IMPORT; + } + + SRIVERBOSE( + ("SRICheckDataVerifier::ImportDataSummary, header {%x, %x, %x, %x, %x, " + "...}", + aData[0], aData[1], aData[2], aData[3], aData[4])); + + // decode the content of the buffer + size_t offset = 0; + decltype(mHashType) hashType; + memcpy(&hashType, &aData[offset], sizeof(mHashType)); + if (hashType != mHashType) { + SRILOG( + ("SRICheckDataVerifier::ImportDataSummary, hash type[%d] does not " + "match[%d]", + hashType, mHashType)); + return NS_ERROR_SRI_UNEXPECTED_HASH_TYPE; + } + offset += sizeof(mHashType); + + decltype(mHashLength) hashLength; + memcpy(&hashLength, &aData[offset], sizeof(mHashLength)); + if (hashLength != mHashLength) { + SRILOG( + ("SRICheckDataVerifier::ImportDataSummary, hash length[%d] does not " + "match[%d]", + hashLength, mHashLength)); + return NS_ERROR_SRI_UNEXPECTED_HASH_TYPE; + } + offset += sizeof(mHashLength); + + // copy the hash to mComputedHash, as-if we had finished streaming the bytes + mComputedHash.Assign(reinterpret_cast<const char*>(&aData[offset]), + mHashLength); + mCryptoHash = nullptr; + mComplete = true; + return NS_OK; +} + +nsresult SRICheckDataVerifier::ExportDataSummary(uint32_t aDataLen, + uint8_t* aData) { + MOZ_ASSERT(!mInvalidMetadata); // mHashType and mHashLength should be valid + MOZ_ASSERT(mComplete); // finished streaming + NS_ENSURE_ARG_POINTER(aData); + NS_ENSURE_TRUE(aDataLen >= DataSummaryLength(), NS_ERROR_INVALID_ARG); + + // serialize the hash in the buffer + size_t offset = 0; + memcpy(&aData[offset], &mHashType, sizeof(mHashType)); + offset += sizeof(mHashType); + memcpy(&aData[offset], &mHashLength, sizeof(mHashLength)); + offset += sizeof(mHashLength); + + SRIVERBOSE( + ("SRICheckDataVerifier::ExportDataSummary, header {%x, %x, %x, %x, %x, " + "...}", + aData[0], aData[1], aData[2], aData[3], aData[4])); + + // copy the hash to mComputedHash, as-if we had finished streaming the bytes + nsCharTraits<char>::copy(reinterpret_cast<char*>(&aData[offset]), + mComputedHash.get(), mHashLength); + return NS_OK; +} + +nsresult SRICheckDataVerifier::ExportEmptyDataSummary(uint32_t aDataLen, + uint8_t* aData) { + NS_ENSURE_ARG_POINTER(aData); + NS_ENSURE_TRUE(aDataLen >= EmptyDataSummaryLength(), NS_ERROR_INVALID_ARG); + + // serialize an unknown hash in the buffer, to be able to skip it later + size_t offset = 0; + memset(&aData[offset], 0, sizeof(mHashType)); + offset += sizeof(mHashType); + memset(&aData[offset], 0, sizeof(mHashLength)); + + SRIVERBOSE( + ("SRICheckDataVerifier::ExportEmptyDataSummary, header {%x, %x, %x, %x, " + "%x, ...}", + aData[0], aData[1], aData[2], aData[3], aData[4])); + + return NS_OK; +} + +} // namespace mozilla::dom |