public static MachineFamily GetMachineFamily(this ExtendedMachine extendedMachine)
{
if (extendedMachine.IsArmFamily())
{
return(MachineFamily.Arm);
}
if (extendedMachine.IsX86Family())
{
return(MachineFamily.X86);
}
return(MachineFamily.Unknown);
}
public static bool IsX86Family(this ExtendedMachine machine)
{
bool isFamily = false;
switch (machine)
{
case ExtendedMachine.Amd64:
case ExtendedMachine.I386:
isFamily = true;
break;
default:
break;
}
return(isFamily);
}
public static bool IsArmFamily(this ExtendedMachine machine)
{
bool isFamily = false;
switch (machine)
{
case ExtendedMachine.Arm:
case ExtendedMachine.Arm64:
case ExtendedMachine.ArmThumb2:
isFamily = true;
break;
default:
break;
}
return(isFamily);
}
public void GetCompilerData_VersionPresent_WorksAsExpected(string versionStr, ExtendedMachine machine, CompilerMitigations expectedMitgations)
{
var context = new BinaryAnalyzerContext
{
Policy = new PropertiesDictionary()
};
this.AddFakeConfigTestData(context.Policy);
CompilerMitigations actualMitigations = EnableSpectreMitigations.GetAvailableMitigations(context, machine, new Version(versionStr));
Assert.Equal(expectedMitgations, actualMitigations);
}
public void GetNextCompilerVersionUp_WithSpectreMitigations_WorksAsExpected(string firstVersionStr, ExtendedMachine machine, string expectedVersionStr)
{
var actualVersion = new Version(firstVersionStr);
var context = new BinaryAnalyzerContext
{
Policy = new PropertiesDictionary()
};
this.AddFakeConfigTestData(context.Policy);
Version nextUp = EnableSpectreMitigations.GetClosestCompilerVersionWithSpectreMitigations(context, machine, actualVersion);
nextUp.ShouldBeEquivalentTo(new Version(expectedVersionStr));
}
public override void AnalyzePortableExecutableAndPdb(BinaryAnalyzerContext context)
{
PEBinary target = context.PEBinary();
Pdb pdb = target.Pdb;
Version minCompilerVersion;
minCompilerVersion = (target.PE.IsXBox)
? context.Policy.GetProperty(MinimumToolVersions)[MIN_XBOX_COMPILER_VER]
: context.Policy.GetProperty(MinimumToolVersions)[MIN_COMPILER_VER];
TruncatedCompilandRecordList badModuleList = new TruncatedCompilandRecordList();
StringToVersionMap allowedLibraries = context.Policy.GetProperty(AllowedLibraries);
foreach (DisposableEnumerableView <Symbol> omView in pdb.CreateObjectModuleIterator())
{
Symbol om = omView.Value;
ObjectModuleDetails omDetails = om.GetObjectModuleDetails();
if (omDetails.WellKnownCompiler != WellKnownCompilers.MicrosoftNativeCompiler)
{
continue;
}
// See if the item is in our skip list
if (!string.IsNullOrEmpty(om.Lib))
{
string libFileName = string.Concat(System.IO.Path.GetFileName(om.Lib), ",", omDetails.Language.ToString()).ToLowerInvariant();
Version minAllowedVersion;
if (allowedLibraries.TryGetValue(libFileName, out minAllowedVersion) &&
omDetails.CompilerVersion >= minAllowedVersion)
{
continue;
}
}
Version actualVersion;
Version minimumVersion;
Language omLanguage = omDetails.Language;
switch (omLanguage)
{
case Language.C:
case Language.Cxx:
actualVersion = Minimum(omDetails.CompilerVersion, omDetails.CompilerFrontEndVersion);
minimumVersion = minCompilerVersion;
break;
default:
continue;
}
bool foundIssue = actualVersion < minimumVersion;
AdvancedMitigations advancedMitigations = context.Policy.GetProperty(AdvancedMitigationsEnforced);
if (!foundIssue &&
(advancedMitigations & AdvancedMitigations.Spectre) == AdvancedMitigations.Spectre)
{
ExtendedMachine machineType = (ExtendedMachine)target.PE.Machine;
// Current toolchain is within the version range to validate.
// Now we'll retrieve relevant compiler mitigation details to
// ensure this object module's build and revision meet
// expectations.
CompilerMitigations newMitigationData =
EnableSpectreMitigations.GetAvailableMitigations(context, machineType, actualVersion);
// Current compiler version does not support Spectre mitigations.
foundIssue = !newMitigationData.HasFlag(CompilerMitigations.D2GuardSpecLoadAvailable) &&
!newMitigationData.HasFlag(CompilerMitigations.QSpectreAvailable);
if (foundIssue)
{
// Get the closest compiler version that has mitigations--i.e. if the user is using a 19.0 (VS2015) compiler, we should be recommending an upgrade to the
// 19.0 version that has the mitigations, not an upgrade to a 19.10+ (VS2017) compiler.
// Limitation--if there are multiple 'upgrade to' versions to recommend, this just going to give users the last one we see in the error.
minCompilerVersion = EnableSpectreMitigations.GetClosestCompilerVersionWithSpectreMitigations(context, machineType, actualVersion);
// Indicates Spectre mitigations are not supported on this platform. We won't flag this case.
if (minCompilerVersion == null)
{
foundIssue = false;
}
}
}
if (foundIssue)
{
// built with {0} compiler version {1} (Front end version: {2})
badModuleList.Add(
om.CreateCompilandRecordWithSuffix(
String.Format(CultureInfo.InvariantCulture,
RuleResources.BA2006_Error_BadModule,
omLanguage, omDetails.CompilerVersion, omDetails.CompilerFrontEndVersion)));
}
}
if (!badModuleList.Empty)
{
// '{0}' was compiled with one or more modules which were not built using
// minimum required tool versions (compiler version {1}). More recent toolchains
// contain mitigations that make it more difficult for an attacker to exploit
// vulnerabilities in programs they produce. To resolve this issue, compile
// and /or link your binary with more recent tools. If you are servicing a
// product where the tool chain cannot be modified (e.g. producing a hotfix
// for an already shipped version) ignore this warning. Modules built outside
// of policy: {2}
context.Logger.Log(this,
RuleUtilities.BuildResult(ResultLevel.Error, context, null,
nameof(RuleResources.BA2006_Error),
context.TargetUri.GetFileName(),
minCompilerVersion.ToString(),
badModuleList.CreateSortedObjectList()));
return;
}
// All linked modules of '{0}' generated by the Microsoft front-end
// satisfy configured policy (compiler minimum version {1}).
context.Logger.Log(this,
RuleUtilities.BuildResult(ResultLevel.Pass, context, null,
nameof(RuleResources.BA2006_Pass),
context.TargetUri.GetFileName(),
minCompilerVersion.ToString()));
}
public static bool CanBeMitigated(this ExtendedMachine machine)
{
return(IsArmFamily(machine) || IsX86Family(machine));
}
/// <summary>
/// Get the Spectre compiler compiler mitigations available for a particular compiler version and machine type.
/// </summary>
internal static CompilerMitigations GetAvailableMitigations(BinaryAnalyzerContext context, ExtendedMachine machine, Version omVersion)
{
var compilerMitigationData = LoadCompilerDataFromConfig(context.Policy);
var machineFamily = machine.GetMachineFamily();
if (!compilerMitigationData.ContainsKey(machineFamily))
{
return(CompilerMitigations.None);
}
else
{
var listOfMitigatedCompilers = compilerMitigationData[machineFamily];
for (int i = 0; i < listOfMitigatedCompilers.Length; i++)
{
if (omVersion >= listOfMitigatedCompilers[i].MinimalSupportedVersion && omVersion < listOfMitigatedCompilers[i].MaximumSupportedVersion)
{
return(listOfMitigatedCompilers[i].SupportedMitigations);
}
}
}
return(CompilerMitigations.None);
}
internal static Version GetClosestCompilerVersionWithSpectreMitigations(BinaryAnalyzerContext context, ExtendedMachine machine, Version omVersion)
{
var compilerMitigationData = LoadCompilerDataFromConfig(context.Policy);
var machineFamily = machine.GetMachineFamily();
if (!compilerMitigationData.ContainsKey(machineFamily))
{
// Mitigations are not supported on this platform at all. No appropriate 'closest compiler version'.
return(null);
}
else
{
var listOfMitigatedCompilers = compilerMitigationData[machineFamily];
// If the compiler version is not supported, then either:
// 1) it is earlier than any supported compiler version
// 2) it is in-between two supported compiler versions (e.x. VS2017.1-4)--it is larger than some supported version numbers and smaller than others.
// 3) it's greater than any of them.
// We want to give users the 'next greatest' compiler version that supports the spectre mitigations--this should be the "smallest available upgrade."
Version previousMaximum = new Version(0, 0, 0, 0);
for (int i = 0; i < listOfMitigatedCompilers.Length; i++)
{
if (omVersion > previousMaximum &&
omVersion <= listOfMitigatedCompilers[i].MinimalSupportedVersion &&
(listOfMitigatedCompilers[i].SupportedMitigations
& (CompilerMitigations.QSpectreAvailable
| CompilerMitigations.D2GuardSpecLoadAvailable)) != 0)
{
return(listOfMitigatedCompilers[i].MinimalSupportedVersion);
}
else
{
previousMaximum = listOfMitigatedCompilers[i].MaximumSupportedVersion;
}
}
// If we're here, we're in situation (3)--the compiler is greater than any we recognize. We'll return the largest compiler we know supports Spectre mitigations.
// With appropriate configuration (i.e. a catch-all entry with a maximum of *.*.*.* is present), we should never really hit this case.
return(listOfMitigatedCompilers[listOfMitigatedCompilers.Length - 1].MinimalSupportedVersion);
}
}
public override void AnalyzePortableExecutableAndPdb(BinaryAnalyzerContext context)
{
PEBinary target = context.PEBinary();
Machine reflectionMachineType = target.PE.Machine;
// The current Machine enum does not have support for Arm64, so translate to our Machine enum
ExtendedMachine machineType = (ExtendedMachine)reflectionMachineType;
if (!machineType.CanBeMitigated())
{
// QUESTION:
// Machine HW is unsupported for mitigations...
// should this be in the CanAnalyze() method or here and issue a warning?
return;
}
Pdb pdb = target.Pdb;
TruncatedCompilandRecordList masmModules = new TruncatedCompilandRecordList();
TruncatedCompilandRecordList mitigationNotEnabledModules = new TruncatedCompilandRecordList();
TruncatedCompilandRecordList mitigationDisabledInDebugBuild = new TruncatedCompilandRecordList();
TruncatedCompilandRecordList mitigationExplicitlyDisabledModules = new TruncatedCompilandRecordList();
StringToVersionMap allowedLibraries = context.Policy.GetProperty(AllowedLibraries);
foreach (DisposableEnumerableView <Symbol> omView in pdb.CreateObjectModuleIterator())
{
Symbol om = omView.Value;
ObjectModuleDetails omDetails = om.GetObjectModuleDetails();
// See if the item is in our skip list.
if (!string.IsNullOrEmpty(om.Lib))
{
string libFileName = string.Concat(System.IO.Path.GetFileName(om.Lib), ",", omDetails.Language.ToString()).ToLowerInvariant();
Version minAllowedVersion;
if (allowedLibraries.TryGetValue(libFileName, out minAllowedVersion) &&
omDetails.CompilerVersion >= minAllowedVersion)
{
continue;
}
}
Version actualVersion;
Language omLanguage = omDetails.Language;
// We already opted-out of IL Only binaries, so only check for native languages
// or those that can appear in mixed binaries.
switch (omLanguage)
{
case Language.C:
case Language.Cxx:
{
if (omDetails.WellKnownCompiler != WellKnownCompilers.MicrosoftNativeCompiler)
{
// TODO: https://github.com/Microsoft/binskim/issues/114
continue;
}
else
{
actualVersion = omDetails.CompilerVersion;
}
break;
}
case Language.MASM:
{
masmModules.Add(om.CreateCompilandRecord());
continue;
}
case Language.LINK:
{
// Linker is not involved in the mitigations, so no need to check version or switches at this time.
continue;
}
case Language.CVTRES:
{
// Resource compiler is not involved in the mitigations, so no need to check version or switches at this time.
continue;
}
case Language.HLSL:
{
// HLSL compiler is not involved in the mitigations, so no need to check version or switches at this time.
continue;
}
// Mixed binaries (/clr) can contain non C++ compilands if they are linked in via netmodules
// .NET IL should be mitigated by the runtime if any mitigations are necessary
// At this point simply accept them as safe until this is disproven.
case Language.CSharp:
case Language.MSIL:
case Language.ILASM:
{
continue;
}
case Language.Unknown:
{
// The linker may emit debug information for modules from static libraries that do not contribute to actual code.
// do not contribute to actual code. Currently these come back as Language.Unknown :(
// TODO: https://github.com/Microsoft/binskim/issues/116
continue;
}
default:
{
// TODO: https://github.com/Microsoft/binskim/issues/117
// Review unknown languages for this and all checks
}
continue;
}
// Get the appropriate compiler version against which to check this compiland.
// check that we are greater than or equal to the first fully supported release: 15.6 first
Version omVersion = omDetails.CompilerVersion;
CompilerMitigations availableMitigations = GetAvailableMitigations(context, machineType, omVersion);
if (availableMitigations == CompilerMitigations.None)
{
// Built with a compiler version {0} that does not support any Spectre
// mitigations. We do not report here. BA2006 will fire instead.
continue;
}
string[] mitigationSwitches = new string[] { "/Qspectre", "/guardspecload" };
SwitchState effectiveState;
// Go process the command line to check for switches
effectiveState = omDetails.GetSwitchState(mitigationSwitches, null, SwitchState.SwitchDisabled, OrderOfPrecedence.LastWins);
if (effectiveState == SwitchState.SwitchDisabled)
{
SwitchState QSpectreState = SwitchState.SwitchNotFound;
SwitchState d2guardspecloadState = SwitchState.SwitchNotFound;
if (availableMitigations.HasFlag(CompilerMitigations.QSpectreAvailable))
{
QSpectreState = omDetails.GetSwitchState(mitigationSwitches[0] /*"/Qspectre"*/, OrderOfPrecedence.LastWins);
}
if (availableMitigations.HasFlag(CompilerMitigations.D2GuardSpecLoadAvailable))
{
// /d2xxxx options show up in the PDB without the d2 string
// So search for just /guardspecload
d2guardspecloadState = omDetails.GetSwitchState(mitigationSwitches[1] /*"/guardspecload"*/, OrderOfPrecedence.LastWins);
}
// TODO: https://github.com/Microsoft/binskim/issues/119
// We should flag cases where /d2guardspecload is enabled but the
// toolset supports /qSpectre (which should be preferred).
if (QSpectreState == SwitchState.SwitchNotFound && d2guardspecloadState == SwitchState.SwitchNotFound)
{
// Built with tools that support the Spectre mitigations but these have not been enabled.
mitigationNotEnabledModules.Add(om.CreateCompilandRecord());
}
else
{
// Built with the Spectre mitigations explicitly disabled.
mitigationExplicitlyDisabledModules.Add(om.CreateCompilandRecord());
}
continue;
}
if (!availableMitigations.HasFlag(CompilerMitigations.NonoptimizedCodeMitigated))
{
string[] OdSwitches = { "/Od" };
// These switches override /Od - there is no one place to find this information on msdn at this time.
string[] OptimizeSwitches = { "/O1", "/O2", "/Ox", "/Og" };
bool debugEnabled = false;
if (omDetails.GetSwitchState(OdSwitches, OptimizeSwitches, SwitchState.SwitchEnabled, OrderOfPrecedence.LastWins) == SwitchState.SwitchEnabled)
{
debugEnabled = true;
}
if (debugEnabled)
{
// Built with /Od which disables Spectre mitigations.
mitigationDisabledInDebugBuild.Add(om.CreateCompilandRecord());
continue;
}
}
}
string line;
var sb = new StringBuilder();
if (!mitigationExplicitlyDisabledModules.Empty)
{
// The following modules were compiled with Spectre
// mitigations explicitly disabled: {0}
line = string.Format(
RuleResources.BA2024_Error_SpectreMitigationExplicitlyDisabled,
mitigationExplicitlyDisabledModules.CreateSortedObjectList());
sb.AppendLine(line);
}
if (!mitigationNotEnabledModules.Empty)
{
// The following modules were compiled with a toolset that supports
// /Qspectre but the switch was not enabled on the command-line: {0}
line = string.Format(
RuleResources.BA2024_Error_SpectreMitigationNotEnabled,
mitigationNotEnabledModules.CreateSortedObjectList());
sb.AppendLine(line);
}
if (!mitigationDisabledInDebugBuild.Empty)
{
// The following modules were compiled with optimizations disabled(/ Od),
// a condition that disables Spectre mitigations: {0}
line = string.Format(
RuleResources.BA2024_Error_OptimizationsDisabled,
mitigationDisabledInDebugBuild.CreateSortedObjectList());
sb.AppendLine(line);
}
if ((context.Policy.GetProperty(Reporting) & ReportingOptions.WarnIfMasmModulesPresent) == ReportingOptions.WarnIfMasmModulesPresent &&
!masmModules.Empty)
{
line = string.Format(
RuleResources.BA2024_Error_MasmModulesDetected,
masmModules.CreateSortedObjectList());
sb.AppendLine(line);
}
if (sb.Length > 0)
{
// '{0}' was compiled with one or more modules that do not properly enable code
// generation mitigations for speculative execution side-channel attack (Spectre)
// vulnerabilities. Spectre attacks can compromise hardware-based isolation,
// allowing non-privileged users to retrieve potentially sensitive data from the
// CPU cache. To resolve the issue, provide the /Qspectre switch on the compiler
// command-line (or /d2guardspecload in cases where your compiler supports this
// switch and it is not possible to update to a toolset that supports /Qspectre).
// The following modules are out of policy: {1}
context.Logger.Log(this,
RuleUtilities.BuildResult(ResultLevel.Error, context, null,
nameof(RuleResources.BA2024_Error),
context.TargetUri.GetFileName(),
sb.ToString()));
return;
}
// All linked modules ‘{0}’ were compiled with mitigations enabled that help prevent Spectre (speculative execution side-channel attack) vulnerabilities.
context.Logger.Log(this,
RuleUtilities.BuildResult(ResultLevel.Pass, context, null,
nameof(RuleResources.BA2024_Pass),
context.TargetUri.GetFileName()));
}
public static MachineFamily GetMachineFamily(this ExtendedMachine extendedMachine)
{
return(extendedMachine.IsArmFamily() ? MachineFamily.Arm :
extendedMachine.IsX86Family() ? MachineFamily.X86 :
MachineFamily.Unknown);
}
