private SignatureVerificationStatus VerifyRepositorySignature(
Signature signature,
X509Certificate2Collection certificates)
{
var settings = new SignatureVerifySettings(
treatIssuesAsErrors: !_settings.AllowIllegal,
allowUntrustedRoot: _settings.AllowUntrusted,
allowUnknownRevocation: _settings.AllowUnknownRevocation,
logOnSignatureExpired: false);
var issues = new List <SignatureLog>();
Timestamp timestamp = null;
if (!_settings.AllowIgnoreTimestamp &&
!signature.TryGetValidTimestamp(
_settings,
_fingerprintAlgorithm,
issues,
out var verificationFlags,
out timestamp))
{
return(VerificationUtility.GetSignatureVerificationStatus(verificationFlags));
}
var summary = signature.Verify(
timestamp,
settings,
_fingerprintAlgorithm,
certificates,
issues);
return(summary.Status);
}
private SignatureVerificationSummary GetTimestamp(
Signature signature,
SignedPackageVerifierSettings verifierSettings,
out Timestamp timestamp)
{
var issues = new List <SignatureLog>();
SignatureVerificationStatus status;
SignatureVerificationStatusFlags statusFlags;
var succeeded = signature.TryGetValidTimestamp(verifierSettings, _fingerprintAlgorithm, issues, out statusFlags, out timestamp);
status = VerificationUtility.GetSignatureVerificationStatus(statusFlags);
if (!succeeded)
{
if (statusFlags == SignatureVerificationStatusFlags.NoValidTimestamp ||
statusFlags == SignatureVerificationStatusFlags.MultipleTimestamps)
{
status = SignatureVerificationStatus.Disallowed;
}
}
return(new SignatureVerificationSummary(signature.Type, status, statusFlags, issues));
}
/// <summary>
/// Verify if the signature object meets the specification trust and validity requirements.
/// </summary>
/// <param name="timestamp">Timestamp for this signature, if signature is not timestamped it can be null.</param>
/// <param name="allowUntrusted">Setting that tells if a signature that does not meet any soft failure requirements can still be allowed. Used to know if warnings or errors should be logged for an issue.</param>
/// <param name="allowUnknownRevocation">Setting that tells if unkown revocation is valid when building the chain.</param>
/// <param name="allowUntrustedSelfSignedCertificate">Setting that tells if an untrusted self-signed certificate should be allowed as the signing certificate.</param>
/// <param name="fingerprintAlgorithm">Algorithm used to calculate and display the certificate's fingerprint.</param>
/// <param name="certificateExtraStore">Collection of certificates to help the chain building engine as an extra store.</param>
/// <param name="issues">List of log messages.</param>
/// <remarks>This is only public for ease of testing</remarks>
/// <returns>Status of trust for signature.</returns>
public virtual SignatureVerificationSummary Verify(
Timestamp timestamp,
SignatureVerifySettings settings,
HashAlgorithmName fingerprintAlgorithm,
X509Certificate2Collection certificateExtraStore)
{
settings = settings ?? SignatureVerifySettings.Default;
var flags = SignatureVerificationStatusFlags.NoErrors;
var issues = new List <SignatureLog>();
SignatureVerificationStatus status;
var certificate = SignerInfo.Certificate;
if (certificate == null)
{
issues.Add(SignatureLog.Issue(!settings.AllowIllegal, NuGetLogCode.NU3010, string.Format(CultureInfo.CurrentCulture, Strings.Verify_ErrorNoCertificate, FriendlyName)));
flags |= SignatureVerificationStatusFlags.NoCertificate;
status = settings.AllowIllegal? SignatureVerificationStatus.Valid: SignatureVerificationStatus.Disallowed;
return(new SignatureVerificationSummary(Type, status, flags, issues));
}
issues.Add(SignatureLog.InformationLog(string.Format(CultureInfo.CurrentCulture,
Strings.VerificationCertDisplay,
FriendlyName,
$"{Environment.NewLine}{CertificateUtility.X509Certificate2ToString(certificate, fingerprintAlgorithm)}")));
try
{
SignerInfo.CheckSignature(verifySignatureOnly: true);
}
catch (Exception e)
{
issues.Add(SignatureLog.Issue(!settings.AllowIllegal, NuGetLogCode.NU3012, string.Format(CultureInfo.CurrentCulture, Strings.VerifyError_SignatureVerificationFailed, FriendlyName)));
issues.Add(SignatureLog.DebugLog(e.ToString()));
flags |= SignatureVerificationStatusFlags.SignatureCheckFailed;
status = settings.AllowIllegal ? SignatureVerificationStatus.Valid : SignatureVerificationStatus.Disallowed;
return(new SignatureVerificationSummary(Type, status, flags, issues));
}
DateTimeOffset?expirationTime = null;
var certificateFlags = VerificationUtility.ValidateSigningCertificate(certificate, !settings.AllowIllegal, FriendlyName, issues);
if (certificateFlags != SignatureVerificationStatusFlags.NoErrors)
{
flags |= certificateFlags;
}
else
{
timestamp = timestamp ?? new Timestamp();
using (var chainHolder = new X509ChainHolder())
{
var chain = chainHolder.Chain;
// This flag should only be set for verification scenarios, not signing.
chain.ChainPolicy.VerificationFlags = X509VerificationFlags.IgnoreNotTimeValid;
CertificateChainUtility.SetCertBuildChainPolicy(chain.ChainPolicy, certificateExtraStore, timestamp.UpperLimit.LocalDateTime, CertificateType.Signature);
if (settings.RevocationMode == RevocationMode.Offline)
{
chain.ChainPolicy.RevocationMode = X509RevocationMode.Offline;
}
else
{
chain.ChainPolicy.RevocationMode = X509RevocationMode.Online;
}
var chainBuildingSucceeded = CertificateChainUtility.BuildCertificateChain(chain, certificate, out var chainStatuses);
var x509ChainString = CertificateUtility.X509ChainToString(chain, fingerprintAlgorithm);
if (!string.IsNullOrWhiteSpace(x509ChainString))
{
issues.Add(SignatureLog.DetailedLog(x509ChainString));
}
var chainBuildingHasIssues = false;
if (!chainBuildingSucceeded)
{
var statusFlags = CertificateChainUtility.DefaultObservedStatusFlags;
IEnumerable <string> messages;
if (CertificateChainUtility.TryGetStatusMessage(chainStatuses, statusFlags, out messages))
{
foreach (var message in messages)
{
issues.Add(SignatureLog.Issue(!settings.AllowIllegal, NuGetLogCode.NU3012, string.Format(CultureInfo.CurrentCulture, Strings.VerifyChainBuildingIssue, FriendlyName, message)));
}
chainBuildingHasIssues = true;
flags |= SignatureVerificationStatusFlags.ChainBuildingFailure;
}
// For all the special cases, chain status list only has unique elements for each chain status flag present
// therefore if we are checking for one specific chain status we can use the first of the returned list
// if we are combining checks for more than one, then we have to use the whole list.
if (CertificateChainUtility.TryGetStatusMessage(chainStatuses, X509ChainStatusFlags.Revoked, out messages))
{
issues.Add(SignatureLog.Error(NuGetLogCode.NU3012, string.Format(CultureInfo.CurrentCulture, Strings.VerifyChainBuildingIssue, FriendlyName, messages.First())));
flags |= SignatureVerificationStatusFlags.CertificateRevoked;
return(new SignatureVerificationSummary(Type, SignatureVerificationStatus.Suspect, flags, timestamp, issues));
}
if (CertificateChainUtility.TryGetStatusMessage(chainStatuses, X509ChainStatusFlags.UntrustedRoot, out messages))
{
if (settings.ReportUntrustedRoot)
{
issues.Add(SignatureLog.Issue(!settings.AllowUntrusted, NuGetLogCode.NU3018, string.Format(CultureInfo.CurrentCulture, Strings.VerifyChainBuildingIssue, FriendlyName, messages.First())));
}
if (!settings.AllowUntrusted)
{
chainBuildingHasIssues = true;
flags |= SignatureVerificationStatusFlags.UntrustedRoot;
}
}
var offlineRevocationErrors = CertificateChainUtility.TryGetStatusMessage(chainStatuses, X509ChainStatusFlags.OfflineRevocation, out var _);
var unknownRevocationErrors = CertificateChainUtility.TryGetStatusMessage(chainStatuses, X509ChainStatusFlags.RevocationStatusUnknown, out var unknownRevocationStatusMessages);
if (offlineRevocationErrors || unknownRevocationErrors)
{
if (settings.ReportUnknownRevocation)
{
string unknownRevocationMessage = null;
if (unknownRevocationErrors)
{
unknownRevocationMessage = string.Format(CultureInfo.CurrentCulture, Strings.VerifyChainBuildingIssue, FriendlyName, unknownRevocationStatusMessages.First());
}
if (settings.RevocationMode == RevocationMode.Offline)
{
if (offlineRevocationErrors)
{
issues.Add(SignatureLog.InformationLog(string.Format(CultureInfo.CurrentCulture, Strings.VerifyChainBuildingIssue, FriendlyName, Strings.VerifyCertTrustOfflineWhileRevocationModeOffline)));
}
if (unknownRevocationMessage != null)
{
issues.Add(SignatureLog.InformationLog(unknownRevocationMessage));
}
}
else
{
if (offlineRevocationErrors)
{
issues.Add(SignatureLog.Issue(!settings.AllowUnknownRevocation, NuGetLogCode.NU3018, string.Format(CultureInfo.CurrentCulture, Strings.VerifyChainBuildingIssue, FriendlyName, Strings.VerifyCertTrustOfflineWhileRevocationModeOnline)));
}
if (unknownRevocationMessage != null)
{
issues.Add(SignatureLog.Issue(!settings.AllowUnknownRevocation, NuGetLogCode.NU3018, unknownRevocationMessage));
}
}
}
if (!settings.AllowUnknownRevocation)
{
chainBuildingHasIssues = true;
flags |= SignatureVerificationStatusFlags.UnknownRevocation;
}
}
// Debug log any errors
issues.Add(SignatureLog.DebugLog(
string.Format(
CultureInfo.CurrentCulture,
Strings.VerifyError_InvalidCertificateChain,
FriendlyName,
string.Join(", ", chainStatuses.Select(x => x.Status.ToString())))));
}
var isSignatureTimeValid = Rfc3161TimestampVerificationUtility.ValidateSignerCertificateAgainstTimestamp(certificate, timestamp);
if (isSignatureTimeValid && !chainBuildingHasIssues)
{
return(new SignatureVerificationSummary(Type, SignatureVerificationStatus.Valid, flags, timestamp, issues));
}
else if (!isSignatureTimeValid)
{
issues.Add(
SignatureLog.Issue(
!settings.AllowUntrusted,
NuGetLogCode.NU3037,
string.Format(CultureInfo.CurrentCulture, Strings.VerifyError_SignatureNotTimeValid, FriendlyName)));
if (!settings.AllowUntrusted)
{
flags |= SignatureVerificationStatusFlags.CertificateExpired;
}
expirationTime = DateTime.SpecifyKind(certificate.NotAfter, DateTimeKind.Local);
}
}
}
status = VerificationUtility.GetSignatureVerificationStatus(flags);
return(new SignatureVerificationSummary(Type, status, flags, timestamp, expirationTime, issues));
}
private PackageVerificationResult Verify(
PrimarySignature signature,
SignedPackageVerifierSettings settings)
{
var certificateExtraStore = signature.SignedCms.Certificates;
var repositoryCountersignatureExists = SignatureUtility.HasRepositoryCountersignature(signature);
var isRepositoryCountersignatureVerificationRequested = settings.VerificationTarget.HasFlag(VerificationTarget.Repository) &&
settings.SignaturePlacement.HasFlag(SignaturePlacement.Countersignature);
var allowDeferralToRepositoryCountersignature = isRepositoryCountersignatureVerificationRequested &&
repositoryCountersignatureExists;
var status = SignatureVerificationStatus.Unknown;
var issues = Enumerable.Empty <SignatureLog>();
var isUntrustedRootAllowed = IsUntrustedRootAllowed(signature);
var verifySettings = new SignatureVerifySettings(
allowIllegal: settings.AllowIllegal,
allowUntrusted: settings.AllowUntrusted || isUntrustedRootAllowed,
allowUnknownRevocation: settings.AllowUnknownRevocation,
reportUnknownRevocation: settings.ReportUnknownRevocation,
reportUntrustedRoot: !isUntrustedRootAllowed,
revocationMode: settings.RevocationMode);
SignatureVerificationSummary primarySummary = null;
if (settings.SignaturePlacement.HasFlag(SignaturePlacement.PrimarySignature) &&
VerificationUtility.IsVerificationTarget(signature.Type, settings.VerificationTarget))
{
primarySummary = VerifyValidityAndTrust(signature, settings, verifySettings, certificateExtraStore);
issues = issues.Concat(primarySummary.Issues);
status = primarySummary.Status;
}
Debug.Assert(isRepositoryCountersignatureVerificationRequested != (settings.RepositoryCountersignatureVerificationBehavior == SignatureVerificationBehavior.Never));
bool shouldVerifyRepositoryCountersignature;
switch (settings.RepositoryCountersignatureVerificationBehavior)
{
case SignatureVerificationBehavior.IfExists:
shouldVerifyRepositoryCountersignature = isRepositoryCountersignatureVerificationRequested &&
repositoryCountersignatureExists;
break;
case SignatureVerificationBehavior.IfExistsAndIsNecessary:
// The repository countersignature should be evaluated if settings allow it, if a repository countersignature exists
// and if either settings only allow a repository countersignature to be evaluated or the primary signature has some
// validation/trust issues that may benefit from a repository countersignature fallback.
shouldVerifyRepositoryCountersignature = isRepositoryCountersignatureVerificationRequested &&
repositoryCountersignatureExists &&
(primarySummary == null ||
(primarySummary != null &&
(HasUntrustedRoot(primarySummary) || IsSignatureExpired(primarySummary))));
break;
case SignatureVerificationBehavior.Always:
shouldVerifyRepositoryCountersignature = isRepositoryCountersignatureVerificationRequested;
break;
case SignatureVerificationBehavior.Never:
shouldVerifyRepositoryCountersignature = false;
break;
default:
throw new NotImplementedException();
}
if (shouldVerifyRepositoryCountersignature)
{
var countersignature = RepositoryCountersignature.GetRepositoryCountersignature(signature);
if (countersignature == null)
{
if (settings.RepositoryCountersignatureVerificationBehavior == SignatureVerificationBehavior.Always)
{
issues = issues.Concat(new[] { SignatureLog.Error(NuGetLogCode.NU3038, Strings.NoRepositoryCountersignature) });
status = SignatureVerificationStatus.Disallowed;
}
}
else
{
isUntrustedRootAllowed = IsUntrustedRootAllowed(countersignature);
verifySettings = new SignatureVerifySettings(
allowIllegal: settings.AllowIllegal,
allowUntrusted: settings.AllowUntrusted || isUntrustedRootAllowed,
allowUnknownRevocation: settings.AllowUnknownRevocation,
reportUnknownRevocation: settings.ReportUnknownRevocation,
reportUntrustedRoot: !isUntrustedRootAllowed,
revocationMode: settings.RevocationMode);
var countersignatureSummary = VerifyValidityAndTrust(countersignature, settings, verifySettings, certificateExtraStore);
if (primarySummary == null)
{
status = countersignatureSummary.Status;
}
else
{
if (countersignatureSummary.Status == SignatureVerificationStatus.Valid)
{
if (IsSignatureExpired(primarySummary) && HasUntrustedRoot(primarySummary))
{
// Exclude the issue of the primary signature being untrusted since the repository countersignature fulfills the role of a trust anchor.
issues = issues.Where(log => log.Code != NuGetLogCode.NU3018);
if (countersignatureSummary.Timestamp != null &&
Rfc3161TimestampVerificationUtility.ValidateSignerCertificateAgainstTimestamp(signature.SignerInfo.Certificate, countersignatureSummary.Timestamp))
{
// Exclude the issue of the primary signature being expired since the repository countersignature fulfills the role of a trusted timestamp.
issues = issues.Where(log => log.Code != NuGetLogCode.NU3037);
status = SignatureVerificationStatus.Valid;
}
}
else if (IsSignatureExpired(primarySummary) &&
countersignatureSummary.Timestamp != null &&
Rfc3161TimestampVerificationUtility.ValidateSignerCertificateAgainstTimestamp(signature.SignerInfo.Certificate, countersignatureSummary.Timestamp))
{
// Exclude the issue of the primary signature being expired since the repository countersignature fulfills the role of a trusted timestamp.
issues = issues.Where(log => log.Code != NuGetLogCode.NU3037);
status = SignatureVerificationStatus.Valid;
}
else if (HasUntrustedRoot(primarySummary))
{
// Exclude the issue of the primary signature being untrusted since the repository countersignature fulfills the role of a trust anchor.
issues = issues.Where(log => log.Code != NuGetLogCode.NU3018);
status = SignatureVerificationStatus.Valid;
}
}
// Both the primary signature and the repository countersignature were evaluated.
// The overall status should be the more severe status of the two.
status = (SignatureVerificationStatus)Math.Min((int)status, (int)countersignatureSummary.Status);
}
issues = issues.Concat(countersignatureSummary.Issues);
}
}
return(new SignedPackageVerificationResult(status, signature, issues));
}
/// <summary>
/// Verify if the timestamp object meets the specification requirements.
/// </summary>
/// <param name="signature">Signature which this timestamp is for.</param>
/// <param name="allowIgnoreTimestamp">Setting that tells if a timestamp can be ignored if it doesn't meet the requirements. Used to know if warnings or errors should be logged for an issue.</param>
/// <param name="allowUnknownRevocation">Setting that tells if unkown revocation is valid when building the chain.</param>
/// <param name="issues">List of log messages.</param>
/// <returns>true if the timestamp meets the requierements, false otherwise.</returns>
internal SignatureVerificationStatusFlags Verify(
Signature signature,
SignedPackageVerifierSettings settings,
HashAlgorithmName fingerprintAlgorithm,
List <SignatureLog> issues)
{
settings = settings ?? SignedPackageVerifierSettings.GetDefault();
var flags = SignatureVerificationStatusFlags.NoErrors;
if (signature == null)
{
throw new ArgumentNullException(nameof(signature));
}
if (issues == null)
{
throw new ArgumentNullException(nameof(issues));
}
var treatIssueAsError = !settings.AllowIgnoreTimestamp;
var timestamperCertificate = SignerInfo.Certificate;
if (timestamperCertificate == null)
{
flags |= SignatureVerificationStatusFlags.NoCertificate;
issues.Add(SignatureLog.Issue(treatIssueAsError, NuGetLogCode.NU3020, string.Format(CultureInfo.CurrentCulture, Strings.VerifyError_TimestampNoCertificate, signature.FriendlyName)));
return(flags);
}
flags |= VerificationUtility.ValidateTimestamp(this, signature, treatIssueAsError, issues, SigningSpecifications.V1);
if (flags == SignatureVerificationStatusFlags.NoErrors)
{
issues.Add(SignatureLog.InformationLog(string.Format(CultureInfo.CurrentCulture, Strings.TimestampValue, GeneralizedTime.LocalDateTime.ToString()) + Environment.NewLine));
issues.Add(SignatureLog.InformationLog(string.Format(CultureInfo.CurrentCulture,
Strings.VerificationTimestamperCertDisplay,
signature.FriendlyName,
$"{Environment.NewLine}{CertificateUtility.X509Certificate2ToString(timestamperCertificate, fingerprintAlgorithm)}")));
var certificateExtraStore = SignedCms.Certificates;
using (var chainHolder = new X509ChainHolder())
{
var chain = chainHolder.Chain;
// This flag should only be set for verification scenarios, not signing.
chain.ChainPolicy.VerificationFlags = X509VerificationFlags.IgnoreNotTimeValid;
CertificateChainUtility.SetCertBuildChainPolicy(chain.ChainPolicy, certificateExtraStore, DateTime.Now, CertificateType.Timestamp);
if (settings.RevocationMode == RevocationMode.Offline)
{
chain.ChainPolicy.RevocationMode = X509RevocationMode.Offline;
}
else
{
chain.ChainPolicy.RevocationMode = X509RevocationMode.Online;
}
var chainBuildSucceed = CertificateChainUtility.BuildCertificateChain(chain, timestamperCertificate, out var chainStatusList);
var x509ChainString = CertificateUtility.X509ChainToString(chain, fingerprintAlgorithm);
if (!string.IsNullOrWhiteSpace(x509ChainString))
{
issues.Add(SignatureLog.DetailedLog(x509ChainString));
}
if (chainBuildSucceed)
{
return(flags);
}
var chainBuildingHasIssues = false;
IEnumerable <string> messages;
var timestampInvalidCertificateFlags = CertificateChainUtility.DefaultObservedStatusFlags;
if (CertificateChainUtility.TryGetStatusMessage(chainStatusList, timestampInvalidCertificateFlags, out messages))
{
foreach (var message in messages)
{
issues.Add(SignatureLog.Issue(treatIssueAsError, NuGetLogCode.NU3028, string.Format(CultureInfo.CurrentCulture, Strings.VerifyError_TimestampVerifyChainBuildingIssue, signature.FriendlyName, message)));
}
flags |= SignatureVerificationStatusFlags.ChainBuildingFailure;
chainBuildingHasIssues = true;
}
// For all the special cases, chain status list only has unique elements for each chain status flag present
// therefore if we are checking for one specific chain status we can use the first of the returned list
// if we are combining checks for more than one, then we have to use the whole list.
if (CertificateChainUtility.TryGetStatusMessage(chainStatusList, X509ChainStatusFlags.UntrustedRoot, out messages))
{
issues.Add(SignatureLog.Error(NuGetLogCode.NU3028, string.Format(CultureInfo.CurrentCulture, Strings.VerifyError_TimestampVerifyChainBuildingIssue, signature.FriendlyName, messages.First())));
flags |= SignatureVerificationStatusFlags.UntrustedRoot;
chainBuildingHasIssues = true;
}
if (CertificateChainUtility.TryGetStatusMessage(chainStatusList, X509ChainStatusFlags.Revoked, out messages))
{
issues.Add(SignatureLog.Error(NuGetLogCode.NU3028, string.Format(CultureInfo.CurrentCulture, Strings.VerifyError_TimestampVerifyChainBuildingIssue, signature.FriendlyName, messages.First())));
flags |= SignatureVerificationStatusFlags.CertificateRevoked;
return(flags);
}
var offlineRevocationErrors = CertificateChainUtility.TryGetStatusMessage(chainStatusList, X509ChainStatusFlags.OfflineRevocation, out var _);
var unknownRevocationErrors = CertificateChainUtility.TryGetStatusMessage(chainStatusList, X509ChainStatusFlags.RevocationStatusUnknown, out var unknownRevocationStatusMessages);
if (offlineRevocationErrors || unknownRevocationErrors)
{
if (treatIssueAsError)
{
string unknownRevocationMessage = null;
if (unknownRevocationErrors)
{
unknownRevocationMessage = string.Format(CultureInfo.CurrentCulture, Strings.VerifyError_TimestampVerifyChainBuildingIssue, signature.FriendlyName, unknownRevocationStatusMessages.First());
}
if (settings.RevocationMode == RevocationMode.Offline)
{
if (offlineRevocationErrors)
{
issues.Add(SignatureLog.InformationLog(string.Format(CultureInfo.CurrentCulture, Strings.VerifyError_TimestampVerifyChainBuildingIssue, signature.FriendlyName, Strings.VerifyCertTrustOfflineWhileRevocationModeOffline)));
}
if (unknownRevocationMessage != null)
{
issues.Add(SignatureLog.InformationLog(unknownRevocationMessage));
}
}
else
{
if (offlineRevocationErrors)
{
issues.Add(SignatureLog.Issue(!settings.AllowUnknownRevocation, NuGetLogCode.NU3018, string.Format(CultureInfo.CurrentCulture, Strings.VerifyError_TimestampVerifyChainBuildingIssue, signature.FriendlyName, Strings.VerifyCertTrustOfflineWhileRevocationModeOnline)));
}
if (unknownRevocationMessage != null)
{
issues.Add(SignatureLog.Issue(!settings.AllowUnknownRevocation, NuGetLogCode.NU3018, unknownRevocationMessage));
}
}
}
if (!chainBuildingHasIssues && (settings.AllowIgnoreTimestamp || settings.AllowUnknownRevocation))
{
return(flags);
}
flags |= SignatureVerificationStatusFlags.UnknownRevocation;
chainBuildingHasIssues = true;
}
// Debug log any errors
issues.Add(
SignatureLog.DebugLog(
string.Format(
CultureInfo.CurrentCulture,
$"{signature.FriendlyName}'s timestamp",
Strings.VerifyError_InvalidCertificateChain,
string.Join(", ", chainStatusList.Select(x => x.Status.ToString())))));
}
}
return(flags);
}
/// <summary>
/// Verify if the signature object meets the specification trust and validity requirements.
/// </summary>
/// <param name="timestamp">Timestamp for this signature, if signature is not timestamped it can be null.</param>
/// <param name="allowUntrusted">Setting that tells if a signature that does not meet any soft failure requirements can still be allowed. Used to know if warnings or errors should be logged for an issue.</param>
/// <param name="allowUnknownRevocation">Setting that tells if unkown revocation is valid when building the chain.</param>
/// <param name="allowUntrustedSelfSignedCertificate">Setting that tells if an untrusted self-signed certificate should be allowed as the signing certificate.</param>
/// <param name="fingerprintAlgorithm">Algorithm used to calculate and display the certificate's fingerprint.</param>
/// <param name="certificateExtraStore">Collection of certificates to help the chain building engine as an extra store.</param>
/// <param name="issues">List of log messages.</param>
/// <returns>Status of trust for signature.</returns>
internal virtual SignatureVerificationStatus Verify(
Timestamp timestamp,
SignedPackageVerifierSettings settings,
HashAlgorithmName fingerprintAlgorithm,
X509Certificate2Collection certificateExtraStore,
List <SignatureLog> issues)
{
if (issues == null)
{
throw new ArgumentNullException(nameof(issues));
}
settings = settings ?? SignedPackageVerifierSettings.Default;
var treatIssueAsError = !settings.AllowUntrusted;
var certificate = SignerInfo.Certificate;
if (certificate == null)
{
issues.Add(SignatureLog.Issue(treatIssueAsError, NuGetLogCode.NU3010, Strings.ErrorNoCertificate));
return(SignatureVerificationStatus.Invalid);
}
issues.Add(SignatureLog.InformationLog(string.Format(CultureInfo.CurrentCulture,
Strings.VerificationAuthorCertDisplay,
$"{Environment.NewLine}{CertificateUtility.X509Certificate2ToString(certificate, fingerprintAlgorithm)}")));
try
{
SignerInfo.CheckSignature(verifySignatureOnly: true);
}
catch (Exception e)
{
issues.Add(SignatureLog.Issue(treatIssueAsError, NuGetLogCode.NU3012, Strings.ErrorSignatureVerificationFailed));
issues.Add(SignatureLog.DebugLog(e.ToString()));
return(SignatureVerificationStatus.Invalid);
}
if (VerificationUtility.IsSigningCertificateValid(certificate, treatIssueAsError, issues))
{
timestamp = timestamp ?? new Timestamp();
if (Rfc3161TimestampVerificationUtility.ValidateSignerCertificateAgainstTimestamp(certificate, timestamp))
{
using (var chainHolder = new X509ChainHolder())
{
var chain = chainHolder.Chain;
// These flags should only be set for verification scenarios not signing
chain.ChainPolicy.VerificationFlags = X509VerificationFlags.IgnoreNotTimeValid | X509VerificationFlags.IgnoreCtlNotTimeValid;
CertificateChainUtility.SetCertBuildChainPolicy(chain.ChainPolicy, certificateExtraStore, timestamp.UpperLimit.LocalDateTime, CertificateType.Signature);
var chainBuildingSucceed = CertificateChainUtility.BuildCertificateChain(chain, certificate, out var chainStatuses);
issues.Add(SignatureLog.DetailedLog(CertificateUtility.X509ChainToString(chain, fingerprintAlgorithm)));
if (chainBuildingSucceed)
{
return(SignatureVerificationStatus.Trusted);
}
var chainBuildingHasIssues = false;
var statusFlags = CertificateChainUtility.DefaultObservedStatusFlags;
var isSelfSignedCertificate = CertificateUtility.IsSelfIssued(certificate);
if (isSelfSignedCertificate)
{
statusFlags &= ~X509ChainStatusFlags.UntrustedRoot;
}
IEnumerable <string> messages;
if (CertificateChainUtility.TryGetStatusMessage(chainStatuses, statusFlags, out messages))
{
foreach (var message in messages)
{
issues.Add(SignatureLog.Issue(treatIssueAsError, NuGetLogCode.NU3012, message));
}
chainBuildingHasIssues = true;
}
// For all the special cases, chain status list only has unique elements for each chain status flag present
// therefore if we are checking for one specific chain status we can use the first of the returned list
// if we are combining checks for more than one, then we have to use the whole list.
IEnumerable <X509ChainStatus> chainStatus = null;
if (CertificateChainUtility.ChainStatusListIncludesStatus(chainStatuses, X509ChainStatusFlags.Revoked, out chainStatus))
{
var status = chainStatus.First();
issues.Add(SignatureLog.Error(NuGetLogCode.NU3012, status.StatusInformation));
return(SignatureVerificationStatus.Invalid);
}
if (isSelfSignedCertificate &&
CertificateChainUtility.TryGetStatusMessage(chainStatuses, X509ChainStatusFlags.UntrustedRoot, out messages))
{
issues.Add(SignatureLog.Issue(!settings.AllowUntrustedSelfIssuedCertificate, NuGetLogCode.NU3018, messages.First()));
if (!chainBuildingHasIssues && settings.AllowUntrustedSelfIssuedCertificate)
{
return(SignatureVerificationStatus.Trusted);
}
}
const X509ChainStatusFlags RevocationStatusFlags = X509ChainStatusFlags.RevocationStatusUnknown | X509ChainStatusFlags.OfflineRevocation;
if (CertificateChainUtility.TryGetStatusMessage(chainStatuses, RevocationStatusFlags, out messages))
{
if (treatIssueAsError)
{
foreach (var message in messages)
{
issues.Add(SignatureLog.Issue(!settings.AllowUnknownRevocation, NuGetLogCode.NU3018, message));
}
}
if (!chainBuildingHasIssues && settings.AllowUnknownRevocation)
{
return(SignatureVerificationStatus.Trusted);
}
chainBuildingHasIssues = true;
}
// Debug log any errors
issues.Add(SignatureLog.DebugLog(
string.Format(
CultureInfo.CurrentCulture,
Strings.ErrorInvalidCertificateChain,
string.Join(", ", chainStatuses.Select(x => x.Status.ToString())))));
}
}
else
{
issues.Add(SignatureLog.Issue(treatIssueAsError, NuGetLogCode.NU3011, Strings.SignatureNotTimeValid));
}
}
return(SignatureVerificationStatus.Untrusted);
}
/// <summary>
/// Verify if the timestamp object meets the specification requirements.
/// </summary>
/// <param name="signature">Signature which this timestamp is for.</param>
/// <param name="allowIgnoreTimestamp">Setting that tells if a timestamp can be ignored if it doesn't meet the requirements. Used to know if warnings or errors should be logged for an issue.</param>
/// <param name="allowUnknownRevocation">Setting that tells if unkown revocation is valid when building the chain.</param>
/// <param name="issues">List of log messages.</param>
/// <returns>true if the timestamp meets the requierements, false otherwise.</returns>
internal bool Verify(
Signature signature,
SignedPackageVerifierSettings settings,
HashAlgorithmName fingerprintAlgorithm,
List <SignatureLog> issues)
{
settings = settings ?? SignedPackageVerifierSettings.GetDefault();
if (signature == null)
{
throw new ArgumentNullException(nameof(signature));
}
if (issues == null)
{
throw new ArgumentNullException(nameof(issues));
}
var treatIssueAsError = !settings.AllowIgnoreTimestamp;
var timestamperCertificate = SignerInfo.Certificate;
if (timestamperCertificate == null)
{
issues.Add(SignatureLog.Issue(treatIssueAsError, NuGetLogCode.NU3020, Strings.TimestampNoCertificate));
return(false);
}
if (VerificationUtility.IsTimestampValid(this, signature, treatIssueAsError, issues, SigningSpecifications.V1))
{
issues.Add(SignatureLog.InformationLog(string.Format(CultureInfo.CurrentCulture, Strings.TimestampValue, GeneralizedTime.LocalDateTime.ToString()) + Environment.NewLine));
issues.Add(SignatureLog.InformationLog(string.Format(CultureInfo.CurrentCulture,
Strings.VerificationTimestamperCertDisplay,
$"{Environment.NewLine}{CertificateUtility.X509Certificate2ToString(timestamperCertificate, fingerprintAlgorithm)}")));
var certificateExtraStore = SignedCms.Certificates;
using (var chainHolder = new X509ChainHolder())
{
var chain = chainHolder.Chain;
// This flags should only be set for verification scenarios, not signing
chain.ChainPolicy.VerificationFlags = X509VerificationFlags.IgnoreNotTimeValid | X509VerificationFlags.IgnoreCtlNotTimeValid;
CertificateChainUtility.SetCertBuildChainPolicy(chain.ChainPolicy, certificateExtraStore, DateTime.Now, CertificateType.Timestamp);
var chainBuildSucceed = CertificateChainUtility.BuildCertificateChain(chain, timestamperCertificate, out var chainStatusList);
issues.Add(SignatureLog.DetailedLog(CertificateUtility.X509ChainToString(chain, fingerprintAlgorithm)));
if (chainBuildSucceed)
{
return(true);
}
var chainBuildingHasIssues = false;
IEnumerable <string> messages;
var timestampInvalidCertificateFlags = CertificateChainUtility.DefaultObservedStatusFlags |
(X509ChainStatusFlags.Revoked) |
(X509ChainStatusFlags.NotTimeValid) |
(X509ChainStatusFlags.CtlNotTimeValid);
if (CertificateChainUtility.TryGetStatusMessage(chainStatusList, timestampInvalidCertificateFlags, out messages))
{
foreach (var message in messages)
{
issues.Add(SignatureLog.Issue(treatIssueAsError, NuGetLogCode.NU3028, message));
}
chainBuildingHasIssues = true;
}
// For all the special cases, chain status list only has unique elements for each chain status flag present
// therefore if we are checking for one specific chain status we can use the first of the returned list
// if we are combining checks for more than one, then we have to use the whole list.
const X509ChainStatusFlags RevocationStatusFlags = X509ChainStatusFlags.RevocationStatusUnknown | X509ChainStatusFlags.OfflineRevocation;
if (CertificateChainUtility.TryGetStatusMessage(chainStatusList, RevocationStatusFlags, out messages))
{
if (treatIssueAsError)
{
foreach (var message in messages)
{
issues.Add(SignatureLog.Issue(!settings.AllowUnknownRevocation, NuGetLogCode.NU3028, message));
}
}
if (!chainBuildingHasIssues && (settings.AllowIgnoreTimestamp || settings.AllowUnknownRevocation))
{
return(true);
}
chainBuildingHasIssues = true;
}
// Debug log any errors
issues.Add(
SignatureLog.DebugLog(
string.Format(
CultureInfo.CurrentCulture,
Strings.ErrorInvalidCertificateChain,
string.Join(", ", chainStatusList.Select(x => x.Status.ToString())))));
}
}
return(false);
}