Quelle SRICheck.cpp Sprache: 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/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

  NS_ConvertUTF16toUTF8 metadataList(aMetadataList);
  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;
  while (tokenizer.hasMoreTokens()) {
    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);

  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);

  nsAutoCString encodedHash;
  rv = Base64Encode(mComputedHash, encodedHash);
  NS_ENSURE_SUCCESS(rv, rv);

  nsTArray<nsString> params;
  params.AppendElement(NS_ConvertUTF8toUTF16(alg));
  params.AppendElement(NS_ConvertUTF8toUTF16(requestSpec));
  params.AppendElement(NS_ConvertUTF8toUTF16(encodedHash));
  aReporter->AddConsoleReport(
      nsIScriptError::errorFlag, "Sub-resource Integrity"_ns,
      nsContentUtils::eSECURITY_PROPERTIES, aSourceFileURI, 0, 0,
      "IntegrityMismatch3"_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

quality97%

¤ Dauer der Verarbeitung: 0.23 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.