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OpenSslX509ChainProcessor: ignore NotSignatureValid on last element. #69668

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Merged
bartonjs merged 5 commits into from
May 25, 2022
Merged

OpenSslX509ChainProcessor: ignore NotSignatureValid on last element. #69668

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dce3f86
OpenSslX509ChainProcessor: ignore NotSignatureValid on last element.
tmds May 23, 2022
056ca8d
Add test
tmds May 24, 2022
c491aaa
Test: verify NotSignatureValid is not filtered from end cert.
tmds May 24, 2022
97156d2
PR feedback.
tmds May 24, 2022
1433760
PR feedback
tmds May 25, 2022
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66 changes: 66 additions & 0 deletions src/libraries/System.Security.Cryptography.X509Certificates/tests/ChainTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -66,6 +66,72 @@ public static void BuildChain()
}
}

public enum BuildChainWithNotSignatureValidTest : int
{
TrustedRoot,
UntrustedRoot,
PartialChain
}

public static IEnumerable<object[]> BuildChainWithNotSignatureValidData()
{
yield return new object[] { true, X509ChainStatusFlags.NoError, BuildChainWithNotSignatureValidTest.TrustedRoot };
yield return new object[] { false, X509ChainStatusFlags.UntrustedRoot | X509ChainStatusFlags.NotSignatureValid, BuildChainWithNotSignatureValidTest.UntrustedRoot };
yield return new object[] { false, X509ChainStatusFlags.PartialChain, BuildChainWithNotSignatureValidTest.PartialChain };
}

[Theory]
[MemberData(nameof(BuildChainWithNotSignatureValidData))]
[PlatformSpecific(TestPlatforms.Linux)] // NotSignatureValid gets ignored on the root certificate.
public static void BuildChainWithNotSignatureValid(
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bool chainBuildsSuccessfully,
X509ChainStatusFlags chainFlags,
BuildChainWithNotSignatureValidTest test)
{
TestDataGenerator.MakeTestChain3(
out X509Certificate2 endCert,
out X509Certificate2 intermediateCert,
out X509Certificate2 rootCert,
testName: test.ToString());

// Make root cert signature invalid.
X509Certificate2 tampered = TestDataGenerator.TamperSignature(rootCert);
rootCert.Dispose();
rootCert = tampered;

using (endCert)
using (intermediateCert)
using (rootCert)
using (ChainHolder chainHolder = new ChainHolder())
{
X509Chain chainTest = chainHolder.Chain;
chainTest.ChainPolicy.RevocationMode = X509RevocationMode.NoCheck;
chainTest.ChainPolicy.VerificationTime = endCert.NotBefore.AddSeconds(1);
chainTest.ChainPolicy.TrustMode = X509ChainTrustMode.CustomRootTrust;
chainTest.ChainPolicy.ExtraStore.Add(endCert);
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switch (test)
{
case BuildChainWithNotSignatureValidTest.TrustedRoot:
chainTest.ChainPolicy.ExtraStore.Add(intermediateCert);
chainTest.ChainPolicy.CustomTrustStore.Add(rootCert);
break;
case BuildChainWithNotSignatureValidTest.PartialChain:
chainTest.ChainPolicy.CustomTrustStore.Add(rootCert);
break;
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case BuildChainWithNotSignatureValidTest.UntrustedRoot:
chainTest.ChainPolicy.ExtraStore.Add(intermediateCert);
chainTest.ChainPolicy.ExtraStore.Add(rootCert);
break;
default:
throw new InvalidDataException();
}

Assert.Equal(chainBuildsSuccessfully, chainTest.Build(endCert));
Assert.Equal(chainFlags, chainTest.AllStatusFlags());
}
}

[PlatformSpecific(TestPlatforms.Windows)]
[Fact]
public static void VerifyChainFromHandle()
Expand Down
9 changes: 1 addition & 8 deletions src/libraries/System.Security.Cryptography.X509Certificates/tests/DynamicChainTests.cs
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Expand Up @@ -84,7 +84,7 @@ X509Certificate2 TamperIfNeeded(X509Certificate2 input, X509ChainStatusFlags fla
{
if ((flags & X509ChainStatusFlags.NotSignatureValid) != 0)
{
X509Certificate2 tampered = TamperSignature(input);
X509Certificate2 tampered = TestDataGenerator.TamperSignature(input);
input.Dispose();
return tampered;
}
Expand Down Expand Up @@ -948,13 +948,6 @@ private static void TestNameConstrainedChain(
}
}

private static X509Certificate2 TamperSignature(X509Certificate2 input)
{
byte[] cert = input.RawData;
cert[cert.Length - 1] ^= 0xFF;
return new X509Certificate2(cert);
}

private static X509Extension BuildPolicyConstraints(
int? requireExplicitPolicySkipCerts = null,
int? inhibitPolicyMappingSkipCerts = null)
Expand Down
7 changes: 7 additions & 0 deletions src/libraries/System.Security.Cryptography.X509Certificates/tests/TestDataGenerator.cs
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Expand Up @@ -202,5 +202,12 @@ private static byte[] CreateSerial()
RandomNumberGenerator.Fill(bytes);
return bytes;
}

internal static X509Certificate2 TamperSignature(X509Certificate2 input)
{
byte[] cert = input.RawData;
cert[cert.Length - 1] ^= 0xFF;
return new X509Certificate2(cert);
}
}
}
54 changes: 49 additions & 5 deletions ...yptography/src/System/Security/Cryptography/X509Certificates/OpenSslX509ChainProcessor.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -904,7 +904,7 @@ private X509ChainElement[] BuildChainElements(
overallStatus = null;

List<X509ChainStatus>? statusBuilder = null;

bool overallHasNotSignatureValid = false;
using (SafeX509StackHandle chainStack = Interop.Crypto.X509StoreCtxGetChain(_storeCtx))
{
int chainSize = Interop.Crypto.GetX509StackFieldCount(chainStack);
Expand All @@ -921,7 +921,20 @@ private X509ChainElement[] BuildChainElements(
statusBuilder ??= new List<X509ChainStatus>();
overallStatus ??= new List<X509ChainStatus>();

AddElementStatus(elementErrors.Value, statusBuilder, overallStatus);
bool hadSignatureNotValid = overallHasNotSignatureValid;
AddElementStatus(elementErrors.Value, statusBuilder, overallStatus, ref overallHasNotSignatureValid);

// Clear NotSignatureValid for the last element when overall chain is not PartialChain or UntrustedRoot.
bool isLastElement = i == chainSize - 1;
if (isLastElement && !hadSignatureNotValid && overallHasNotSignatureValid)
{
if (!ContainsStatus(overallStatus, X509ChainStatusFlags.PartialChain) &&
!ContainsStatus(overallStatus, X509ChainStatusFlags.UntrustedRoot))
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{
RemoveStatus(statusBuilder, X509ChainStatusFlags.NotSignatureValid);
RemoveStatus(overallStatus, X509ChainStatusFlags.NotSignatureValid);
}
}
status = statusBuilder.ToArray();
statusBuilder.Clear();
}
Expand Down Expand Up @@ -1013,11 +1026,12 @@ private static void ProcessPolicy(
private static void AddElementStatus(
ErrorCollection errorCodes,
List<X509ChainStatus> elementStatus,
List<X509ChainStatus> overallStatus)
List<X509ChainStatus> overallStatus,
ref bool overallHasNotSignatureValid)
{
foreach (var errorCode in errorCodes)
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{
AddElementStatus(errorCode, elementStatus, overallStatus);
AddElementStatus(errorCode, elementStatus, overallStatus, ref overallHasNotSignatureValid);
}

foreach (X509ChainStatus element in elementStatus)
Expand All @@ -1042,7 +1056,8 @@ private static void AddElementStatus(
private static void AddElementStatus(
Interop.Crypto.X509VerifyStatusCode errorCode,
List<X509ChainStatus> elementStatus,
List<X509ChainStatus> overallStatus)
List<X509ChainStatus> overallStatus,
ref bool overallHasNotSignatureValid)
{
X509ChainStatusFlags statusFlag = MapVerifyErrorToChainStatus(errorCode);

Expand All @@ -1069,6 +1084,10 @@ private static void AddElementStatus(

elementStatus.Add(chainStatus);
AddUniqueStatus(overallStatus, ref chainStatus);
if (statusFlag == X509ChainStatusFlags.NotSignatureValid)
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{
overallHasNotSignatureValid = true;
}
}

private static void AddUniqueStatus(List<X509ChainStatus> list, ref X509ChainStatus status)
Expand All @@ -1086,6 +1105,31 @@ private static void AddUniqueStatus(List<X509ChainStatus> list, ref X509ChainSta
list.Add(status);
}

private static bool ContainsStatus(List<X509ChainStatus> list, X509ChainStatusFlags statusCode)
{
for (int i = 0; i < list.Count; i++)
{
if (list[i].Status == statusCode)
{
return true;
}
}

return false;
}

private static void RemoveStatus(List<X509ChainStatus> list, X509ChainStatusFlags statusCode)
{
for (int i = 0; i < list.Count; i++)
{
if (list[i].Status == statusCode)
{
list.RemoveAt(i);
return;
}
}
}

private static X509ChainStatusFlags MapVerifyErrorToChainStatus(Interop.Crypto.X509VerifyStatusCode code)
{
switch (code.UniversalCode)
Expand Down