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gecko-dev/security/apps/AppSignatureVerification.cpp

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=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 "nsNSSCertificateDB.h"
#include "AppTrustDomain.h"
#include "CryptoTask.h"
#include "NSSCertDBTrustDomain.h"
#include "ScopedNSSTypes.h"
#include "SharedCertVerifier.h"
#include "certdb.h"
#include "cms.h"
#include "mozilla/Base64.h"
#include "mozilla/Casting.h"
#include "mozilla/Logging.h"
#include "mozilla/RefPtr.h"
#include "mozilla/UniquePtr.h"
#include "mozilla/Unused.h"
#include "nsCOMPtr.h"
#include "nsComponentManagerUtils.h"
#include "nsDependentString.h"
#include "nsHashKeys.h"
#include "nsIDirectoryEnumerator.h"
#include "nsIFile.h"
#include "nsIFileStreams.h"
#include "nsIInputStream.h"
#include "nsIStringEnumerator.h"
#include "nsIZipReader.h"
#include "nsNSSCertificate.h"
#include "nsNetUtil.h"
#include "nsProxyRelease.h"
#include "nsString.h"
#include "nsTHashtable.h"
#include "pkix/pkix.h"
#include "pkix/pkixnss.h"
#include "plstr.h"
#include "secmime.h"
using namespace mozilla::pkix;
using namespace mozilla;
using namespace mozilla::psm;
extern mozilla::LazyLogModule gPIPNSSLog;
namespace {
// A convenient way to pair the bytes of a digest with the algorithm that
// purportedly produced those bytes. Only SHA-1 and SHA-256 are supported.
struct DigestWithAlgorithm
{
nsresult ValidateLength() const
{
size_t hashLen;
switch (mAlgorithm) {
case SEC_OID_SHA256:
hashLen = SHA256_LENGTH;
break;
case SEC_OID_SHA1:
hashLen = SHA1_LENGTH;
break;
default:
MOZ_ASSERT_UNREACHABLE(
"unsupported hash type in DigestWithAlgorithm::ValidateLength");
return NS_ERROR_FAILURE;
}
if (mDigest.Length() != hashLen) {
return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
}
return NS_OK;
}
nsAutoCString mDigest;
SECOidTag mAlgorithm;
};
// The digest must have a lifetime greater than or equal to the returned string.
inline nsDependentCSubstring
DigestToDependentString(const Digest& digest)
{
return nsDependentCSubstring(
BitwiseCast<char*, unsigned char*>(digest.get().data),
digest.get().len);
}
// Reads a maximum of 1MB from a stream into the supplied buffer.
// The reason for the 1MB limit is because this function is used to read
// signature-related files and we want to avoid OOM. The uncompressed length of
// an entry can be hundreds of times larger than the compressed version,
// especially if someone has specifically crafted the entry to cause OOM or to
// consume massive amounts of disk space.
//
// @param stream The input stream to read from.
// @param buf The buffer that we read the stream into, which must have
// already been allocated.
nsresult
ReadStream(const nsCOMPtr<nsIInputStream>& stream, /*out*/ SECItem& buf)
{
// The size returned by Available() might be inaccurate so we need
// to check that Available() matches up with the actual length of
// the file.
uint64_t length;
nsresult rv = stream->Available(&length);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
// Cap the maximum accepted size of signature-related files at 1MB (which is
// still crazily huge) to avoid OOM. The uncompressed length of an entry can be
// hundreds of times larger than the compressed version, especially if
// someone has speifically crafted the entry to cause OOM or to consume
// massive amounts of disk space.
static const uint32_t MAX_LENGTH = 1024 * 1024;
if (length > MAX_LENGTH) {
return NS_ERROR_FILE_TOO_BIG;
}
// With bug 164695 in mind we +1 to leave room for null-terminating
// the buffer.
SECITEM_AllocItem(buf, static_cast<uint32_t>(length + 1));
// buf.len == length + 1. We attempt to read length + 1 bytes
// instead of length, so that we can check whether the metadata for
// the entry is incorrect.
uint32_t bytesRead;
rv = stream->Read(BitwiseCast<char*, unsigned char*>(buf.data), buf.len,
&bytesRead);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
if (bytesRead != length) {
return NS_ERROR_FILE_CORRUPTED;
}
buf.data[buf.len - 1] = 0; // null-terminate
return NS_OK;
}
// Finds exactly one (signature metadata) JAR entry that matches the given
// search pattern, and then loads it. Fails if there are no matches or if
// there is more than one match. If bufDigest is not null then on success
// bufDigest will contain the digeset of the entry using the given digest
// algorithm.
nsresult
FindAndLoadOneEntry(nsIZipReader* zip,
const nsACString& searchPattern,
/*out*/ nsACString& filename,
/*out*/ SECItem& buf,
/*optional, in*/ SECOidTag digestAlgorithm = SEC_OID_SHA1,
/*optional, out*/ Digest* bufDigest = nullptr)
{
nsCOMPtr<nsIUTF8StringEnumerator> files;
nsresult rv = zip->FindEntries(searchPattern, getter_AddRefs(files));
if (NS_FAILED(rv) || !files) {
return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
}
bool more;
rv = files->HasMore(&more);
NS_ENSURE_SUCCESS(rv, rv);
if (!more) {
return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
}
rv = files->GetNext(filename);
NS_ENSURE_SUCCESS(rv, rv);
// Check if there is more than one match, if so then error!
rv = files->HasMore(&more);
NS_ENSURE_SUCCESS(rv, rv);
if (more) {
return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
}
nsCOMPtr<nsIInputStream> stream;
rv = zip->GetInputStream(filename, getter_AddRefs(stream));
NS_ENSURE_SUCCESS(rv, rv);
rv = ReadStream(stream, buf);
if (NS_WARN_IF(NS_FAILED(rv))) {
return NS_ERROR_SIGNED_JAR_ENTRY_INVALID;
}
if (bufDigest) {
rv = bufDigest->DigestBuf(digestAlgorithm, buf.data, buf.len - 1);
NS_ENSURE_SUCCESS(rv, rv);
}
return NS_OK;
}
// Verify the digest of an entry. We avoid loading the entire entry into memory
// at once, which would require memory in proportion to the size of the largest
// entry. Instead, we require only a small, fixed amount of memory.
//
// @param stream an input stream from a JAR entry or file depending on whether
// it is from a signed archive or unpacked into a directory
// @param digestFromManifest The digest that we're supposed to check the file's
// contents against, from the manifest
// @param buf A scratch buffer that we use for doing the I/O, which must have
// already been allocated. The size of this buffer is the unit
// size of our I/O.
nsresult
VerifyStreamContentDigest(nsIInputStream* stream,
const DigestWithAlgorithm& digestFromManifest,
SECItem& buf)
{
MOZ_ASSERT(buf.len > 0);
nsresult rv = digestFromManifest.ValidateLength();
if (NS_FAILED(rv)) {
return rv;
}
uint64_t len64;
rv = stream->Available(&len64);
NS_ENSURE_SUCCESS(rv, rv);
if (len64 > UINT32_MAX) {
return NS_ERROR_SIGNED_JAR_ENTRY_TOO_LARGE;
}
UniquePK11Context digestContext(
PK11_CreateDigestContext(digestFromManifest.mAlgorithm));
if (!digestContext) {
return mozilla::psm::GetXPCOMFromNSSError(PR_GetError());
}
rv = MapSECStatus(PK11_DigestBegin(digestContext.get()));
NS_ENSURE_SUCCESS(rv, rv);
uint64_t totalBytesRead = 0;
for (;;) {
uint32_t bytesRead;
rv = stream->Read(BitwiseCast<char*, unsigned char*>(buf.data), buf.len,
&bytesRead);
NS_ENSURE_SUCCESS(rv, rv);
if (bytesRead == 0) {
break; // EOF
}
totalBytesRead += bytesRead;
if (totalBytesRead >= UINT32_MAX) {
return NS_ERROR_SIGNED_JAR_ENTRY_TOO_LARGE;
}
rv = MapSECStatus(PK11_DigestOp(digestContext.get(), buf.data, bytesRead));
NS_ENSURE_SUCCESS(rv, rv);
}
if (totalBytesRead != len64) {
// The metadata we used for Available() doesn't match the actual size of
// the entry.
return NS_ERROR_SIGNED_JAR_ENTRY_INVALID;
}
// Verify that the digests match.
Digest digest;
rv = digest.End(digestFromManifest.mAlgorithm, digestContext);
NS_ENSURE_SUCCESS(rv, rv);
nsDependentCSubstring digestStr(DigestToDependentString(digest));
if (!digestStr.Equals(digestFromManifest.mDigest)) {
return NS_ERROR_SIGNED_JAR_MODIFIED_ENTRY;
}
return NS_OK;
}
nsresult
VerifyEntryContentDigest(nsIZipReader* zip, const nsACString& aFilename,
const DigestWithAlgorithm& digestFromManifest,
SECItem& buf)
{
nsCOMPtr<nsIInputStream> stream;
nsresult rv = zip->GetInputStream(aFilename, getter_AddRefs(stream));
if (NS_FAILED(rv)) {
return NS_ERROR_SIGNED_JAR_ENTRY_MISSING;
}
return VerifyStreamContentDigest(stream, digestFromManifest, buf);
}
// On input, nextLineStart is the start of the current line. On output,
// nextLineStart is the start of the next line.
nsresult
ReadLine(/*in/out*/ const char* & nextLineStart, /*out*/ nsCString & line,
bool allowContinuations = true)
{
line.Truncate();
size_t previousLength = 0;
size_t currentLength = 0;
for (;;) {
const char* eol = PL_strpbrk(nextLineStart, "\r\n");
if (!eol) { // Reached end of file before newline
eol = nextLineStart + strlen(nextLineStart);
}
previousLength = currentLength;
line.Append(nextLineStart, eol - nextLineStart);
currentLength = line.Length();
// The spec says "No line may be longer than 72 bytes (not characters)"
// in its UTF8-encoded form.
static const size_t lineLimit = 72;
if (currentLength - previousLength > lineLimit) {
return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
}
// The spec says: "Implementations should support 65535-byte
// (not character) header values..."
if (currentLength > 65535) {
return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
}
if (*eol == '\r') {
++eol;
}
if (*eol == '\n') {
++eol;
}
nextLineStart = eol;
if (*eol != ' ') {
// not a continuation
return NS_OK;
}
// continuation
if (!allowContinuations) {
return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
}
++nextLineStart; // skip space and keep appending
}
}
// The header strings are defined in the JAR specification.
#define JAR_MF_SEARCH_STRING "(M|/M)ETA-INF/(M|m)(ANIFEST|anifest).(MF|mf)$"
#define JAR_SF_SEARCH_STRING "(M|/M)ETA-INF/*.(SF|sf)$"
#define JAR_RSA_SEARCH_STRING "(M|/M)ETA-INF/*.(RSA|rsa)$"
#define JAR_META_DIR "META-INF"
#define JAR_MF_HEADER "Manifest-Version: 1.0"
#define JAR_SF_HEADER "Signature-Version: 1.0"
nsresult
ParseAttribute(const nsAutoCString & curLine,
/*out*/ nsAutoCString & attrName,
/*out*/ nsAutoCString & attrValue)
{
// Find the colon that separates the name from the value.
int32_t colonPos = curLine.FindChar(':');
if (colonPos == kNotFound) {
return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
}
// set attrName to the name, skipping spaces between the name and colon
int32_t nameEnd = colonPos;
for (;;) {
if (nameEnd == 0) {
return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID; // colon with no name
}
if (curLine[nameEnd - 1] != ' ')
break;
--nameEnd;
}
curLine.Left(attrName, nameEnd);
// Set attrValue to the value, skipping spaces between the colon and the
// value. The value may be empty.
int32_t valueStart = colonPos + 1;
int32_t curLineLength = curLine.Length();
while (valueStart != curLineLength && curLine[valueStart] == ' ') {
++valueStart;
}
curLine.Right(attrValue, curLineLength - valueStart);
return NS_OK;
}
// Parses the version line of the MF or SF header.
nsresult
CheckManifestVersion(const char* & nextLineStart,
const nsACString & expectedHeader)
{
// The JAR spec says: "Manifest-Version and Signature-Version must be first,
// and in exactly that case (so that they can be recognized easily as magic
// strings)."
nsAutoCString curLine;
nsresult rv = ReadLine(nextLineStart, curLine, false);
if (NS_FAILED(rv)) {
return rv;
}
if (!curLine.Equals(expectedHeader)) {
return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
}
return NS_OK;
}
// Parses a signature file (SF) based on the JDK 8 JAR Specification.
//
// The SF file must contain a SHA*-Digest-Manifest attribute in the main
// section (where the * is either 1 or 256, depending on the given digest
// algorithm). All other sections are ignored. This means that this will NOT
// parse old-style signature files that have separate digests per entry.
// The JDK8 x-Digest-Manifest variant is better because:
//
// (1) It allows us to follow the principle that we should minimize the
// processing of data that we do before we verify its signature. In
// particular, with the x-Digest-Manifest style, we can verify the digest
// of MANIFEST.MF before we parse it, which prevents malicious JARs
// exploiting our MANIFEST.MF parser.
// (2) It is more time-efficient and space-efficient to have one
// x-Digest-Manifest instead of multiple x-Digest values.
//
// filebuf must be null-terminated. On output, mfDigest will contain the
// decoded value of the appropriate SHA*-DigestManifest, if found.
nsresult
ParseSF(const char* filebuf, SECOidTag digestAlgorithm,
/*out*/ nsAutoCString& mfDigest)
{
const char* digestNameToFind = nullptr;
switch (digestAlgorithm) {
case SEC_OID_SHA256:
digestNameToFind = "sha256-digest-manifest";
break;
case SEC_OID_SHA1:
digestNameToFind = "sha1-digest-manifest";
break;
default:
MOZ_ASSERT_UNREACHABLE("bad argument to ParseSF");
return NS_ERROR_FAILURE;
}
const char* nextLineStart = filebuf;
nsresult rv = CheckManifestVersion(nextLineStart,
NS_LITERAL_CSTRING(JAR_SF_HEADER));
if (NS_FAILED(rv)) {
return rv;
}
for (;;) {
nsAutoCString curLine;
rv = ReadLine(nextLineStart, curLine);
if (NS_FAILED(rv)) {
return rv;
}
if (curLine.Length() == 0) {
// End of main section (blank line or end-of-file). We didn't find the
// SHA*-Digest-Manifest we were looking for.
return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
}
nsAutoCString attrName;
nsAutoCString attrValue;
rv = ParseAttribute(curLine, attrName, attrValue);
if (NS_FAILED(rv)) {
return rv;
}
if (attrName.EqualsIgnoreCase(digestNameToFind)) {
rv = Base64Decode(attrValue, mfDigest);
if (NS_FAILED(rv)) {
return rv;
}
// There could be multiple SHA*-Digest-Manifest attributes, which
// would be an error, but it's better to just skip any erroneous
// duplicate entries rather than trying to detect them, because:
//
// (1) It's simpler, and simpler generally means more secure
// (2) An attacker can't make us accept a JAR we would otherwise
// reject just by adding additional SHA*-Digest-Manifest
// attributes.
return NS_OK;
}
// ignore unrecognized attributes
}
MOZ_ASSERT_UNREACHABLE("somehow exited loop in ParseSF without returning");
return NS_ERROR_FAILURE;
}
// Parses MANIFEST.MF. The filenames of all entries will be returned in
// mfItems. buf must be a pre-allocated scratch buffer that is used for doing
// I/O. Each file's contents are verified against the entry in the manifest with
// the digest algorithm that matches the given one. This algorithm comes from
// the signature file. If the signature file has a SHA-256 digest, then SHA-256
// entries must be present in the manifest file. If the signature file only has
// a SHA-1 digest, then only SHA-1 digests will be used in the manifest file.
nsresult
ParseMF(const char* filebuf, nsIZipReader* zip, SECOidTag digestAlgorithm,
/*out*/ nsTHashtable<nsCStringHashKey>& mfItems, ScopedAutoSECItem& buf)
{
const char* digestNameToFind = nullptr;
switch (digestAlgorithm) {
case SEC_OID_SHA256:
digestNameToFind = "sha256-digest";
break;
case SEC_OID_SHA1:
digestNameToFind = "sha1-digest";
break;
default:
MOZ_ASSERT_UNREACHABLE("bad argument to ParseMF");
return NS_ERROR_FAILURE;
}
const char* nextLineStart = filebuf;
nsresult rv = CheckManifestVersion(nextLineStart,
NS_LITERAL_CSTRING(JAR_MF_HEADER));
if (NS_FAILED(rv)) {
return rv;
}
// Skip the rest of the header section, which ends with a blank line.
{
nsAutoCString line;
do {
rv = ReadLine(nextLineStart, line);
if (NS_FAILED(rv)) {
return rv;
}
} while (line.Length() > 0);
// Manifest containing no file entries is OK, though useless.
if (*nextLineStart == '\0') {
return NS_OK;
}
}
nsAutoCString curItemName;
nsAutoCString digest;
for (;;) {
nsAutoCString curLine;
rv = ReadLine(nextLineStart, curLine);
if (NS_FAILED(rv)) {
return rv;
}
if (curLine.Length() == 0) {
// end of section (blank line or end-of-file)
if (curItemName.Length() == 0) {
// '...Each section must start with an attribute with the name as
// "Name",...', so every section must have a Name attribute.
return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
}
if (digest.IsEmpty()) {
// We require every entry to have a digest, since we require every
// entry to be signed and we don't allow duplicate entries.
return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
}
if (mfItems.Contains(curItemName)) {
// Duplicate entry
return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
}
// Verify that the entry's content digest matches the digest from this
// MF section.
DigestWithAlgorithm digestWithAlgorithm = { digest, digestAlgorithm };
rv = VerifyEntryContentDigest(zip, curItemName, digestWithAlgorithm, buf);
if (NS_FAILED(rv)) {
return rv;
}
mfItems.PutEntry(curItemName);
if (*nextLineStart == '\0') {
// end-of-file
break;
}
// reset so we know we haven't encountered either of these for the next
// item yet.
curItemName.Truncate();
digest.Truncate();
continue; // skip the rest of the loop below
}
nsAutoCString attrName;
nsAutoCString attrValue;
rv = ParseAttribute(curLine, attrName, attrValue);
if (NS_FAILED(rv)) {
return rv;
}
// Lines to look for:
// (1) Digest:
if (attrName.EqualsIgnoreCase(digestNameToFind)) {
if (!digest.IsEmpty()) { // multiple SHA* digests in section
return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
}
rv = Base64Decode(attrValue, digest);
if (NS_FAILED(rv)) {
return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
}
continue;
}
// (2) Name: associates this manifest section with a file in the jar.
if (attrName.LowerCaseEqualsLiteral("name")) {
if (MOZ_UNLIKELY(curItemName.Length() > 0)) // multiple names in section
return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
if (MOZ_UNLIKELY(attrValue.Length() == 0))
return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
curItemName = attrValue;
continue;
}
// (3) Magic: the only other must-understand attribute
if (attrName.LowerCaseEqualsLiteral("magic")) {
// We don't understand any magic, so we can't verify an entry that
// requires magic. Since we require every entry to have a valid
// signature, we have no choice but to reject the entry.
return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
}
// unrecognized attributes must be ignored
}
return NS_OK;
}
nsresult
VerifyCertificate(CERTCertificate* signerCert, AppTrustedRoot trustedRoot,
/*out*/ UniqueCERTCertList& builtChain)
{
if (NS_WARN_IF(!signerCert)) {
return NS_ERROR_INVALID_ARG;
}
// TODO: pinArg is null.
AppTrustDomain trustDomain(builtChain, nullptr);
nsresult rv = trustDomain.SetTrustedRoot(trustedRoot);
if (NS_FAILED(rv)) {
return rv;
}
Input certDER;
mozilla::pkix::Result result = certDER.Init(signerCert->derCert.data,
signerCert->derCert.len);
if (result != Success) {
return mozilla::psm::GetXPCOMFromNSSError(MapResultToPRErrorCode(result));
}
result = BuildCertChain(trustDomain, certDER, Now(),
EndEntityOrCA::MustBeEndEntity,
KeyUsage::digitalSignature,
KeyPurposeId::id_kp_codeSigning,
CertPolicyId::anyPolicy,
nullptr /*stapledOCSPResponse*/);
if (result == mozilla::pkix::Result::ERROR_EXPIRED_CERTIFICATE) {
// For code-signing you normally need trusted 3rd-party timestamps to
// handle expiration properly. The signer could always mess with their
// system clock so you can't trust the certificate was un-expired when
// the signing took place. The choice is either to ignore expiration
// or to enforce expiration at time of use. The latter leads to the
// user-hostile result that perfectly good code stops working.
//
// Our package format doesn't support timestamps (nor do we have a
// trusted 3rd party timestamper), but since we sign all of our apps and
// add-ons ourselves we can trust ourselves not to mess with the clock
// on the signing systems. We also have a revocation mechanism if we
// need it. It's OK to ignore cert expiration under these conditions.
//
// This is an invalid approach if
// * we issue certs to let others sign their own packages
// * mozilla::pkix returns "expired" when there are "worse" problems
// with the certificate or chain.
// (see bug 1267318)
result = Success;
}
if (result != Success) {
return mozilla::psm::GetXPCOMFromNSSError(MapResultToPRErrorCode(result));
}
return NS_OK;
}
// Given a SECOidTag representing a digest algorithm (either SEC_OID_SHA1 or
// SEC_OID_SHA256), returns the first signerInfo in the given signedData that
// purports to have been created using that digest algorithm, or nullptr if
// there is none.
// The returned signerInfo is owned by signedData, so the caller must ensure
// that the lifetime of the signerInfo is contained by the lifetime of the
// signedData.
NSSCMSSignerInfo*
GetSignerInfoForDigestAlgorithm(NSSCMSSignedData* signedData,
SECOidTag digestAlgorithm)
{
MOZ_ASSERT(digestAlgorithm == SEC_OID_SHA1 ||
digestAlgorithm == SEC_OID_SHA256);
if (digestAlgorithm != SEC_OID_SHA1 && digestAlgorithm != SEC_OID_SHA256) {
return nullptr;
}
int numSigners = NSS_CMSSignedData_SignerInfoCount(signedData);
if (numSigners < 1) {
return nullptr;
}
for (int i = 0; i < numSigners; i++) {
NSSCMSSignerInfo* signerInfo =
NSS_CMSSignedData_GetSignerInfo(signedData, i);
// NSS_CMSSignerInfo_GetDigestAlgTag isn't exported from NSS.
SECOidData* digestAlgOID = SECOID_FindOID(&signerInfo->digestAlg.algorithm);
if (!digestAlgOID) {
continue;
}
if (digestAlgorithm == digestAlgOID->offset) {
return signerInfo;
}
}
return nullptr;
}
nsresult
VerifySignature(AppTrustedRoot trustedRoot, const SECItem& buffer,
const SECItem& detachedSHA1Digest,
const SECItem& detachedSHA256Digest,
/*out*/ SECOidTag& digestAlgorithm,
/*out*/ UniqueCERTCertList& builtChain)
{
// Currently, this function is only called within the CalculateResult() method
// of CryptoTasks. As such, NSS should not be shut down at this point and the
// CryptoTask implementation should already hold a nsNSSShutDownPreventionLock.
if (NS_WARN_IF(!buffer.data || buffer.len == 0 || !detachedSHA1Digest.data ||
detachedSHA1Digest.len == 0 || !detachedSHA256Digest.data ||
detachedSHA256Digest.len == 0)) {
return NS_ERROR_INVALID_ARG;
}
UniqueNSSCMSMessage
cmsMsg(NSS_CMSMessage_CreateFromDER(const_cast<SECItem*>(&buffer), nullptr,
nullptr, nullptr, nullptr, nullptr,
nullptr));
if (!cmsMsg) {
return NS_ERROR_CMS_VERIFY_NOT_SIGNED;
}
if (!NSS_CMSMessage_IsSigned(cmsMsg.get())) {
return NS_ERROR_CMS_VERIFY_NOT_SIGNED;
}
NSSCMSContentInfo* cinfo = NSS_CMSMessage_ContentLevel(cmsMsg.get(), 0);
if (!cinfo) {
return NS_ERROR_CMS_VERIFY_NO_CONTENT_INFO;
}
// We're expecting this to be a PKCS#7 signedData content info.
if (NSS_CMSContentInfo_GetContentTypeTag(cinfo)
!= SEC_OID_PKCS7_SIGNED_DATA) {
return NS_ERROR_CMS_VERIFY_NO_CONTENT_INFO;
}
// signedData is non-owning
NSSCMSSignedData* signedData =
static_cast<NSSCMSSignedData*>(NSS_CMSContentInfo_GetContent(cinfo));
if (!signedData) {
return NS_ERROR_CMS_VERIFY_NO_CONTENT_INFO;
}
// Parse the certificates into CERTCertificate objects held in memory so
// verifyCertificate will be able to find them during path building.
UniqueCERTCertList certs(CERT_NewCertList());
if (!certs) {
return NS_ERROR_OUT_OF_MEMORY;
}
if (signedData->rawCerts) {
for (size_t i = 0; signedData->rawCerts[i]; ++i) {
UniqueCERTCertificate
cert(CERT_NewTempCertificate(CERT_GetDefaultCertDB(),
signedData->rawCerts[i], nullptr, false,
true));
// Skip certificates that fail to parse
if (!cert) {
continue;
}
if (CERT_AddCertToListTail(certs.get(), cert.get()) != SECSuccess) {
return NS_ERROR_OUT_OF_MEMORY;
}
Unused << cert.release(); // Ownership transferred to the cert list.
}
}
NSSCMSSignerInfo* signerInfo =
GetSignerInfoForDigestAlgorithm(signedData, SEC_OID_SHA256);
const SECItem* detachedDigest = &detachedSHA256Digest;
digestAlgorithm = SEC_OID_SHA256;
if (!signerInfo) {
signerInfo = GetSignerInfoForDigestAlgorithm(signedData, SEC_OID_SHA1);
if (!signerInfo) {
return NS_ERROR_CMS_VERIFY_NOT_SIGNED;
}
detachedDigest = &detachedSHA1Digest;
digestAlgorithm = SEC_OID_SHA1;
}
// Get the end-entity certificate.
CERTCertificate* signerCert =
NSS_CMSSignerInfo_GetSigningCertificate(signerInfo,
CERT_GetDefaultCertDB());
if (!signerCert) {
return NS_ERROR_CMS_VERIFY_ERROR_PROCESSING;
}
nsresult rv = VerifyCertificate(signerCert, trustedRoot, builtChain);
if (NS_FAILED(rv)) {
return rv;
}
// Ensure that the PKCS#7 data OID is present as the PKCS#9 contentType.
const char* pkcs7DataOidString = "1.2.840.113549.1.7.1";
ScopedAutoSECItem pkcs7DataOid;
if (SEC_StringToOID(nullptr, &pkcs7DataOid, pkcs7DataOidString, 0)
!= SECSuccess) {
return NS_ERROR_CMS_VERIFY_ERROR_PROCESSING;
}
return MapSECStatus(
NSS_CMSSignerInfo_Verify(signerInfo, const_cast<SECItem*>(detachedDigest),
&pkcs7DataOid));
}
nsresult
OpenSignedAppFile(AppTrustedRoot aTrustedRoot, nsIFile* aJarFile,
/*out, optional */ nsIZipReader** aZipReader,
/*out, optional */ nsIX509Cert** aSignerCert)
{
NS_ENSURE_ARG_POINTER(aJarFile);
if (aZipReader) {
*aZipReader = nullptr;
}
if (aSignerCert) {
*aSignerCert = nullptr;
}
nsresult rv;
static NS_DEFINE_CID(kZipReaderCID, NS_ZIPREADER_CID);
nsCOMPtr<nsIZipReader> zip = do_CreateInstance(kZipReaderCID, &rv);
NS_ENSURE_SUCCESS(rv, rv);
rv = zip->Open(aJarFile);
NS_ENSURE_SUCCESS(rv, rv);
// Signature (RSA) file
nsAutoCString sigFilename;
ScopedAutoSECItem sigBuffer;
rv = FindAndLoadOneEntry(zip, nsLiteralCString(JAR_RSA_SEARCH_STRING),
sigFilename, sigBuffer);
if (NS_FAILED(rv)) {
return NS_ERROR_SIGNED_JAR_NOT_SIGNED;
}
// Signature (SF) file
nsAutoCString sfFilename;
ScopedAutoSECItem sfBuffer;
rv = FindAndLoadOneEntry(zip, NS_LITERAL_CSTRING(JAR_SF_SEARCH_STRING),
sfFilename, sfBuffer);
if (NS_FAILED(rv)) {
return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
}
// Calculate both the SHA-1 and SHA-256 hashes of the signature file - we
// don't know what algorithm the PKCS#7 signature used.
Digest sfCalculatedSHA1Digest;
rv = sfCalculatedSHA1Digest.DigestBuf(SEC_OID_SHA1, sfBuffer.data,
sfBuffer.len - 1);
if (NS_FAILED(rv)) {
return rv;
}
Digest sfCalculatedSHA256Digest;
rv = sfCalculatedSHA256Digest.DigestBuf(SEC_OID_SHA256, sfBuffer.data,
sfBuffer.len - 1);
if (NS_FAILED(rv)) {
return rv;
}
sigBuffer.type = siBuffer;
UniqueCERTCertList builtChain;
SECOidTag digestToUse;
rv = VerifySignature(aTrustedRoot, sigBuffer, sfCalculatedSHA1Digest.get(),
sfCalculatedSHA256Digest.get(), digestToUse, builtChain);
if (NS_FAILED(rv)) {
return rv;
}
nsAutoCString mfDigest;
rv = ParseSF(BitwiseCast<char*, unsigned char*>(sfBuffer.data), digestToUse,
mfDigest);
if (NS_FAILED(rv)) {
return rv;
}
// Manifest (MF) file
nsAutoCString mfFilename;
ScopedAutoSECItem manifestBuffer;
Digest mfCalculatedDigest;
rv = FindAndLoadOneEntry(zip, NS_LITERAL_CSTRING(JAR_MF_SEARCH_STRING),
mfFilename, manifestBuffer, digestToUse,
&mfCalculatedDigest);
if (NS_FAILED(rv)) {
return rv;
}
nsDependentCSubstring calculatedDigest(
DigestToDependentString(mfCalculatedDigest));
if (!mfDigest.Equals(calculatedDigest)) {
return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
}
// Allocate the I/O buffer only once per JAR, instead of once per entry, in
// order to minimize malloc/free calls and in order to avoid fragmenting
// memory.
ScopedAutoSECItem buf(128 * 1024);
nsTHashtable<nsCStringHashKey> items;
rv = ParseMF(BitwiseCast<char*, unsigned char*>(manifestBuffer.data), zip,
digestToUse, items, buf);
if (NS_FAILED(rv)) {
return rv;
}
// Verify every entry in the file.
nsCOMPtr<nsIUTF8StringEnumerator> entries;
rv = zip->FindEntries(EmptyCString(), getter_AddRefs(entries));
if (NS_SUCCEEDED(rv) && !entries) {
rv = NS_ERROR_UNEXPECTED;
}
if (NS_FAILED(rv)) {
return rv;
}
for (;;) {
bool hasMore;
rv = entries->HasMore(&hasMore);
NS_ENSURE_SUCCESS(rv, rv);
if (!hasMore) {
break;
}
nsAutoCString entryFilename;
rv = entries->GetNext(entryFilename);
NS_ENSURE_SUCCESS(rv, rv);
MOZ_LOG(gPIPNSSLog, LogLevel::Debug, ("Verifying digests for %s",
entryFilename.get()));
// The files that comprise the signature mechanism are not covered by the
// signature.
//
// XXX: This is OK for a single signature, but doesn't work for
// multiple signatures, because the metadata for the other signatures
// is not signed either.
if (entryFilename == mfFilename ||
entryFilename == sfFilename ||
entryFilename == sigFilename) {
continue;
}
if (entryFilename.Length() == 0) {
return NS_ERROR_SIGNED_JAR_ENTRY_INVALID;
}
// Entries with names that end in "/" are directory entries, which are not
// signed.
//
// XXX: As long as we don't unpack the JAR into the filesystem, the "/"
// entries are harmless. But, it is not clear what the security
// implications of directory entries are if/when we were to unpackage the
// JAR into the filesystem.
if (entryFilename[entryFilename.Length() - 1] == '/') {
continue;
}
nsCStringHashKey * item = items.GetEntry(entryFilename);
if (!item) {
return NS_ERROR_SIGNED_JAR_UNSIGNED_ENTRY;
}
// Remove the item so we can check for leftover items later
items.RemoveEntry(item);
}
// We verified that every entry that we require to be signed is signed. But,
// were there any missing entries--that is, entries that are mentioned in the
// manifest but missing from the archive?
if (items.Count() != 0) {
return NS_ERROR_SIGNED_JAR_ENTRY_MISSING;
}
// Return the reader to the caller if they want it
if (aZipReader) {
zip.forget(aZipReader);
}
// Return the signer's certificate to the reader if they want it.
// XXX: We should return an nsIX509CertList with the whole validated chain.
if (aSignerCert) {
CERTCertListNode* signerCertNode = CERT_LIST_HEAD(builtChain);
if (!signerCertNode || CERT_LIST_END(signerCertNode, builtChain) ||
!signerCertNode->cert) {
return NS_ERROR_FAILURE;
}
nsCOMPtr<nsIX509Cert> signerCert =
nsNSSCertificate::Create(signerCertNode->cert);
NS_ENSURE_TRUE(signerCert, NS_ERROR_OUT_OF_MEMORY);
signerCert.forget(aSignerCert);
}
return NS_OK;
}
class OpenSignedAppFileTask final : public CryptoTask
{
public:
OpenSignedAppFileTask(AppTrustedRoot aTrustedRoot, nsIFile* aJarFile,
nsIOpenSignedAppFileCallback* aCallback)
: mTrustedRoot(aTrustedRoot)
, mJarFile(aJarFile)
, mCallback(new nsMainThreadPtrHolder<nsIOpenSignedAppFileCallback>(
"OpenSignedAppFileTask::mCallback", aCallback))
{
}
private:
virtual nsresult CalculateResult() override
{
return OpenSignedAppFile(mTrustedRoot, mJarFile,
getter_AddRefs(mZipReader),
getter_AddRefs(mSignerCert));
}
// nsNSSCertificate implements nsNSSShutdownObject, so there's nothing that
// needs to be released
virtual void ReleaseNSSResources() override { }
virtual void CallCallback(nsresult rv) override
{
(void) mCallback->OpenSignedAppFileFinished(rv, mZipReader, mSignerCert);
}
const AppTrustedRoot mTrustedRoot;
const nsCOMPtr<nsIFile> mJarFile;
nsMainThreadPtrHandle<nsIOpenSignedAppFileCallback> mCallback;
nsCOMPtr<nsIZipReader> mZipReader; // out
nsCOMPtr<nsIX509Cert> mSignerCert; // out
};
} // unnamed namespace
NS_IMETHODIMP
nsNSSCertificateDB::OpenSignedAppFileAsync(
AppTrustedRoot aTrustedRoot, nsIFile* aJarFile,
nsIOpenSignedAppFileCallback* aCallback)
{
NS_ENSURE_ARG_POINTER(aJarFile);
NS_ENSURE_ARG_POINTER(aCallback);
RefPtr<OpenSignedAppFileTask> task(new OpenSignedAppFileTask(aTrustedRoot,
aJarFile,
aCallback));
return task->Dispatch("SignedJAR");
}
NS_IMETHODIMP
nsNSSCertificateDB::VerifySignedDirectoryAsync(AppTrustedRoot, nsIFile*,
nsIVerifySignedDirectoryCallback* aCallback)
{
NS_ENSURE_ARG_POINTER(aCallback);
return aCallback->VerifySignedDirectoryFinished(
NS_ERROR_SIGNED_JAR_NOT_SIGNED, nullptr);
}
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