зеркало из https://github.com/mozilla/gecko-dev.git
463 строки
14 KiB
C++
463 строки
14 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this file,
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* You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "mozilla/dom/WebAuthnUtil.h"
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#include "mozilla/dom/WebAuthnCBORUtil.h"
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#include "nsComponentManagerUtils.h"
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#include "nsICryptoHash.h"
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#include "nsIEffectiveTLDService.h"
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#include "nsNetUtil.h"
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#include "mozpkix/pkixutil.h"
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#include "nsHTMLDocument.h"
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#include "hasht.h"
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namespace mozilla {
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namespace dom {
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// Bug #1436078 - Permit Google Accounts. Remove in Bug #1436085 in Jan 2023.
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constexpr auto kGoogleAccountsAppId1 =
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u"https://www.gstatic.com/securitykey/origins.json"_ns;
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constexpr auto kGoogleAccountsAppId2 =
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u"https://www.gstatic.com/securitykey/a/google.com/origins.json"_ns;
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const uint8_t FLAG_TUP = 0x01; // Test of User Presence required
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const uint8_t FLAG_AT = 0x40; // Authenticator Data is provided
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bool EvaluateAppID(nsPIDOMWindowInner* aParent, const nsString& aOrigin,
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/* in/out */ nsString& aAppId) {
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// Facet is the specification's way of referring to the web origin.
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nsAutoCString facetString = NS_ConvertUTF16toUTF8(aOrigin);
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nsCOMPtr<nsIURI> facetUri;
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if (NS_FAILED(NS_NewURI(getter_AddRefs(facetUri), facetString))) {
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return false;
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}
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// If the facetId (origin) is not HTTPS, reject
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if (!facetUri->SchemeIs("https")) {
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return false;
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}
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// If the appId is empty or null, overwrite it with the facetId and accept
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if (aAppId.IsEmpty() || aAppId.EqualsLiteral("null")) {
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aAppId.Assign(aOrigin);
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return true;
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}
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// AppID is user-supplied. It's quite possible for this parse to fail.
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nsAutoCString appIdString = NS_ConvertUTF16toUTF8(aAppId);
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nsCOMPtr<nsIURI> appIdUri;
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if (NS_FAILED(NS_NewURI(getter_AddRefs(appIdUri), appIdString))) {
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return false;
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}
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// if the appId URL is not HTTPS, reject.
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if (!appIdUri->SchemeIs("https")) {
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return false;
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}
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nsAutoCString appIdHost;
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if (NS_FAILED(appIdUri->GetAsciiHost(appIdHost))) {
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return false;
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}
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// Allow localhost.
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if (appIdHost.EqualsLiteral("localhost")) {
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nsAutoCString facetHost;
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if (NS_FAILED(facetUri->GetAsciiHost(facetHost))) {
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return false;
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}
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if (facetHost.EqualsLiteral("localhost")) {
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return true;
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}
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}
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// Run the HTML5 algorithm to relax the same-origin policy, copied from W3C
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// Web Authentication. See Bug 1244959 comment #8 for context on why we are
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// doing this instead of implementing the external-fetch FacetID logic.
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nsCOMPtr<Document> document = aParent->GetDoc();
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if (!document || !document->IsHTMLDocument()) {
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return false;
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}
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nsHTMLDocument* html = document->AsHTMLDocument();
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// Use the base domain as the facet for evaluation. This lets this algorithm
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// relax the whole eTLD+1.
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nsCOMPtr<nsIEffectiveTLDService> tldService =
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do_GetService(NS_EFFECTIVETLDSERVICE_CONTRACTID);
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if (!tldService) {
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return false;
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}
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nsAutoCString lowestFacetHost;
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if (NS_FAILED(tldService->GetBaseDomain(facetUri, 0, lowestFacetHost))) {
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return false;
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}
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if (html->IsRegistrableDomainSuffixOfOrEqualTo(
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NS_ConvertUTF8toUTF16(lowestFacetHost), appIdHost)) {
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return true;
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}
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// Bug #1436078 - Permit Google Accounts. Remove in Bug #1436085 in Jan 2023.
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if (lowestFacetHost.EqualsLiteral("google.com") &&
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(aAppId.Equals(kGoogleAccountsAppId1) ||
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aAppId.Equals(kGoogleAccountsAppId2))) {
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return true;
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}
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return false;
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}
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nsresult ReadToCryptoBuffer(pkix::Reader& aSrc, /* out */ CryptoBuffer& aDest,
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uint32_t aLen) {
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if (aSrc.EnsureLength(aLen) != pkix::Success) {
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return NS_ERROR_DOM_UNKNOWN_ERR;
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}
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if (!aDest.SetCapacity(aLen, mozilla::fallible)) {
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return NS_ERROR_OUT_OF_MEMORY;
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}
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for (uint32_t offset = 0; offset < aLen; ++offset) {
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uint8_t b;
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if (aSrc.Read(b) != pkix::Success) {
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return NS_ERROR_DOM_UNKNOWN_ERR;
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}
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if (!aDest.AppendElement(b, mozilla::fallible)) {
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return NS_ERROR_OUT_OF_MEMORY;
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}
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}
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return NS_OK;
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}
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// Format:
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// 32 bytes: SHA256 of the RP ID
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// 1 byte: flags (TUP & AT)
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// 4 bytes: sign counter
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// variable: attestation data struct
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// variable: CBOR-format extension auth data (optional, not flagged)
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nsresult AssembleAuthenticatorData(const CryptoBuffer& rpIdHashBuf,
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const uint8_t flags,
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const CryptoBuffer& counterBuf,
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const CryptoBuffer& attestationDataBuf,
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/* out */ CryptoBuffer& authDataBuf) {
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if (NS_WARN_IF(!authDataBuf.SetCapacity(
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32 + 1 + 4 + attestationDataBuf.Length(), mozilla::fallible))) {
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return NS_ERROR_OUT_OF_MEMORY;
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}
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if (rpIdHashBuf.Length() != 32 || counterBuf.Length() != 4) {
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return NS_ERROR_INVALID_ARG;
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}
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(void)authDataBuf.AppendElements(rpIdHashBuf, mozilla::fallible);
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(void)authDataBuf.AppendElement(flags, mozilla::fallible);
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(void)authDataBuf.AppendElements(counterBuf, mozilla::fallible);
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(void)authDataBuf.AppendElements(attestationDataBuf, mozilla::fallible);
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return NS_OK;
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}
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// attestation data struct format:
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// - 16 bytes: AAGUID
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// - 2 bytes: Length of Credential ID
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// - L bytes: Credential ID
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// - variable: CBOR-format public key
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nsresult AssembleAttestationData(const CryptoBuffer& aaguidBuf,
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const CryptoBuffer& keyHandleBuf,
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const CryptoBuffer& pubKeyObj,
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/* out */ CryptoBuffer& attestationDataBuf) {
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if (NS_WARN_IF(!attestationDataBuf.SetCapacity(
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aaguidBuf.Length() + 2 + keyHandleBuf.Length() + pubKeyObj.Length(),
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mozilla::fallible))) {
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return NS_ERROR_OUT_OF_MEMORY;
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}
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if (keyHandleBuf.Length() > 0xFFFF) {
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return NS_ERROR_INVALID_ARG;
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}
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(void)attestationDataBuf.AppendElements(aaguidBuf, mozilla::fallible);
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(void)attestationDataBuf.AppendElement((keyHandleBuf.Length() >> 8) & 0xFF,
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mozilla::fallible);
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(void)attestationDataBuf.AppendElement((keyHandleBuf.Length() >> 0) & 0xFF,
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mozilla::fallible);
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(void)attestationDataBuf.AppendElements(keyHandleBuf, mozilla::fallible);
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(void)attestationDataBuf.AppendElements(pubKeyObj, mozilla::fallible);
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return NS_OK;
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}
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nsresult AssembleAttestationObject(const CryptoBuffer& aRpIdHash,
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const CryptoBuffer& aPubKeyBuf,
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const CryptoBuffer& aKeyHandleBuf,
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const CryptoBuffer& aAttestationCertBuf,
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const CryptoBuffer& aSignatureBuf,
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bool aForceNoneAttestation,
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/* out */ CryptoBuffer& aAttestationObjBuf) {
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// Construct the public key object
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CryptoBuffer pubKeyObj;
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nsresult rv = CBOREncodePublicKeyObj(aPubKeyBuf, pubKeyObj);
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if (NS_FAILED(rv)) {
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return rv;
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}
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mozilla::dom::CryptoBuffer aaguidBuf;
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if (NS_WARN_IF(!aaguidBuf.SetCapacity(16, mozilla::fallible))) {
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return NS_ERROR_OUT_OF_MEMORY;
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}
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// FIDO U2F devices have no AAGUIDs, so they'll be all zeros until we add
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// support for CTAP2 devices.
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for (int i = 0; i < 16; i++) {
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// SetCapacity was just called, these cannot fail.
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(void)aaguidBuf.AppendElement(0x00, mozilla::fallible);
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}
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// During create credential, counter is always 0 for U2F
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// See https://github.com/w3c/webauthn/issues/507
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mozilla::dom::CryptoBuffer counterBuf;
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if (NS_WARN_IF(!counterBuf.SetCapacity(4, mozilla::fallible))) {
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return NS_ERROR_OUT_OF_MEMORY;
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}
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// SetCapacity was just called, these cannot fail.
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(void)counterBuf.AppendElement(0x00, mozilla::fallible);
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(void)counterBuf.AppendElement(0x00, mozilla::fallible);
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(void)counterBuf.AppendElement(0x00, mozilla::fallible);
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(void)counterBuf.AppendElement(0x00, mozilla::fallible);
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// Construct the Attestation Data, which slots into the end of the
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// Authentication Data buffer.
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CryptoBuffer attDataBuf;
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rv = AssembleAttestationData(aaguidBuf, aKeyHandleBuf, pubKeyObj, attDataBuf);
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if (NS_FAILED(rv)) {
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return rv;
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}
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CryptoBuffer authDataBuf;
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// attDataBuf always contains data, so per [1] we have to set the AT flag.
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// [1] https://w3c.github.io/webauthn/#sec-authenticator-data
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const uint8_t flags = FLAG_TUP | FLAG_AT;
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rv = AssembleAuthenticatorData(aRpIdHash, flags, counterBuf, attDataBuf,
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authDataBuf);
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if (NS_FAILED(rv)) {
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return rv;
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}
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// Direct attestation might have been requested by the RP.
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// The user might override this and request anonymization anyway.
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if (aForceNoneAttestation) {
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rv = CBOREncodeNoneAttestationObj(authDataBuf, aAttestationObjBuf);
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} else {
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rv = CBOREncodeFidoU2FAttestationObj(authDataBuf, aAttestationCertBuf,
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aSignatureBuf, aAttestationObjBuf);
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}
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return rv;
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}
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nsresult U2FDecomposeSignResponse(const CryptoBuffer& aResponse,
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/* out */ uint8_t& aFlags,
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/* out */ CryptoBuffer& aCounterBuf,
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/* out */ CryptoBuffer& aSignatureBuf) {
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if (aResponse.Length() < 5) {
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return NS_ERROR_INVALID_ARG;
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}
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Span<const uint8_t> rspView = Span(aResponse);
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aFlags = rspView[0];
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if (NS_WARN_IF(!aCounterBuf.AppendElements(rspView.FromTo(1, 5),
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mozilla::fallible))) {
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return NS_ERROR_OUT_OF_MEMORY;
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}
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if (NS_WARN_IF(
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!aSignatureBuf.AppendElements(rspView.From(5), mozilla::fallible))) {
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return NS_ERROR_OUT_OF_MEMORY;
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}
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return NS_OK;
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}
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nsresult U2FDecomposeRegistrationResponse(
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const CryptoBuffer& aResponse,
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/* out */ CryptoBuffer& aPubKeyBuf,
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/* out */ CryptoBuffer& aKeyHandleBuf,
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/* out */ CryptoBuffer& aAttestationCertBuf,
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/* out */ CryptoBuffer& aSignatureBuf) {
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// U2F v1.1 Format via
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// http://fidoalliance.org/specs/fido-u2f-v1.1-id-20160915/fido-u2f-raw-message-formats-v1.1-id-20160915.html
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//
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// Bytes Value
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// 1 0x05
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// 65 public key
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// 1 key handle length
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// * key handle
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// ASN.1 attestation certificate
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// * attestation signature
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pkix::Input u2fResponse;
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u2fResponse.Init(aResponse.Elements(), aResponse.Length());
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pkix::Reader input(u2fResponse);
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uint8_t b;
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if (input.Read(b) != pkix::Success) {
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return NS_ERROR_DOM_UNKNOWN_ERR;
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}
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if (b != 0x05) {
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return NS_ERROR_DOM_UNKNOWN_ERR;
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}
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nsresult rv = ReadToCryptoBuffer(input, aPubKeyBuf, 65);
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if (NS_FAILED(rv)) {
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return rv;
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}
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uint8_t handleLen;
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if (input.Read(handleLen) != pkix::Success) {
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return NS_ERROR_DOM_UNKNOWN_ERR;
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}
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rv = ReadToCryptoBuffer(input, aKeyHandleBuf, handleLen);
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if (NS_FAILED(rv)) {
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return rv;
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}
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// We have to parse the ASN.1 SEQUENCE on the outside to determine the cert's
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// length.
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pkix::Input cert;
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if (pkix::der::ExpectTagAndGetTLV(input, pkix::der::SEQUENCE, cert) !=
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pkix::Success) {
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return NS_ERROR_DOM_UNKNOWN_ERR;
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}
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pkix::Reader certInput(cert);
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rv = ReadToCryptoBuffer(certInput, aAttestationCertBuf, cert.GetLength());
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if (NS_FAILED(rv)) {
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return rv;
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}
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// The remainder of u2fResponse is the signature
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pkix::Input u2fSig;
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input.SkipToEnd(u2fSig);
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pkix::Reader sigInput(u2fSig);
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rv = ReadToCryptoBuffer(sigInput, aSignatureBuf, u2fSig.GetLength());
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if (NS_FAILED(rv)) {
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return rv;
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}
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MOZ_ASSERT(input.AtEnd());
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return NS_OK;
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}
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nsresult U2FDecomposeECKey(const CryptoBuffer& aPubKeyBuf,
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/* out */ CryptoBuffer& aXcoord,
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/* out */ CryptoBuffer& aYcoord) {
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pkix::Input pubKey;
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pubKey.Init(aPubKeyBuf.Elements(), aPubKeyBuf.Length());
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pkix::Reader input(pubKey);
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uint8_t b;
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if (input.Read(b) != pkix::Success) {
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return NS_ERROR_DOM_UNKNOWN_ERR;
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}
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if (b != 0x04) {
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return NS_ERROR_DOM_UNKNOWN_ERR;
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}
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nsresult rv = ReadToCryptoBuffer(input, aXcoord, 32);
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if (NS_FAILED(rv)) {
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return rv;
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}
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rv = ReadToCryptoBuffer(input, aYcoord, 32);
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if (NS_FAILED(rv)) {
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return rv;
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}
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MOZ_ASSERT(input.AtEnd());
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return NS_OK;
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}
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static nsresult HashCString(nsICryptoHash* aHashService, const nsACString& aIn,
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/* out */ CryptoBuffer& aOut) {
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MOZ_ASSERT(aHashService);
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nsresult rv = aHashService->Init(nsICryptoHash::SHA256);
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if (NS_WARN_IF(NS_FAILED(rv))) {
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return rv;
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}
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rv = aHashService->Update(
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reinterpret_cast<const uint8_t*>(aIn.BeginReading()), aIn.Length());
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if (NS_WARN_IF(NS_FAILED(rv))) {
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return rv;
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}
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nsAutoCString fullHash;
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// Passing false below means we will get a binary result rather than a
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// base64-encoded string.
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rv = aHashService->Finish(false, fullHash);
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if (NS_WARN_IF(NS_FAILED(rv))) {
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return rv;
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}
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if (NS_WARN_IF(!aOut.Assign(fullHash))) {
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return NS_ERROR_OUT_OF_MEMORY;
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}
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return NS_OK;
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}
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nsresult HashCString(const nsACString& aIn, /* out */ CryptoBuffer& aOut) {
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nsresult srv;
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nsCOMPtr<nsICryptoHash> hashService =
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do_CreateInstance(NS_CRYPTO_HASH_CONTRACTID, &srv);
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if (NS_FAILED(srv)) {
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return srv;
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}
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srv = HashCString(hashService, aIn, aOut);
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if (NS_WARN_IF(NS_FAILED(srv))) {
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return NS_ERROR_FAILURE;
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}
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return NS_OK;
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}
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nsresult BuildTransactionHashes(const nsCString& aRpId,
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const nsCString& aClientDataJSON,
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/* out */ CryptoBuffer& aRpIdHash,
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/* out */ CryptoBuffer& aClientDataHash) {
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nsresult srv;
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nsCOMPtr<nsICryptoHash> hashService =
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do_CreateInstance(NS_CRYPTO_HASH_CONTRACTID, &srv);
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if (NS_FAILED(srv)) {
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return srv;
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}
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if (!aRpIdHash.SetLength(SHA256_LENGTH, fallible)) {
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return NS_ERROR_OUT_OF_MEMORY;
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}
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srv = HashCString(hashService, aRpId, aRpIdHash);
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if (NS_WARN_IF(NS_FAILED(srv))) {
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return NS_ERROR_FAILURE;
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}
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if (!aClientDataHash.SetLength(SHA256_LENGTH, fallible)) {
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return NS_ERROR_OUT_OF_MEMORY;
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}
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srv = HashCString(hashService, aClientDataJSON, aClientDataHash);
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if (NS_WARN_IF(NS_FAILED(srv))) {
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return NS_ERROR_FAILURE;
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}
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return NS_OK;
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}
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} // namespace dom
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} // namespace mozilla
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