From 85c277284219155c42ef32a1c77c12357cb02f5d Mon Sep 17 00:00:00 2001 From: Radek Zikmund <32671551+rzikm@users.noreply.github.com> Date: Wed, 17 Jan 2024 00:08:05 +0100 Subject: [PATCH] [release/8.0] Fix server-side OCSP stapling on Linux (#96838) * Add entire issuer chain to trusted X509_STORE when stapling OCSP_Response (#96792) * Add entire issuer chain to trusted X509_STORE when validating OCSP_Response * Code review feedback * More code review feedback * Update src/libraries/System.Net.Security/src/System/Net/Security/SslStreamCertificateContext.Linux.cs Co-authored-by: Jeremy Barton * Fix compilation * Always include root certificate --------- Co-authored-by: Jeremy Barton * Recover from failed OCSP download. (#96448) * Recover from failed OCSP check. * Add 5s back-off after failed OCSP querry * Don't shorten OCSP expriation on failed server OCSP fetch (#96972) * Don't shorten OCSP expriation on failed server OCSP fetch * Code review feedback --------- Co-authored-by: Jeremy Barton --- .../Interop.OCSP.cs | 9 ++- .../SslStreamCertificateContext.Linux.cs | 59 ++++++++++++++----- .../pal_x509.c | 17 ++++-- .../pal_x509.h | 2 +- 4 files changed, 65 insertions(+), 22 deletions(-) diff --git a/src/libraries/Common/src/Interop/Unix/System.Security.Cryptography.Native/Interop.OCSP.cs b/src/libraries/Common/src/Interop/Unix/System.Security.Cryptography.Native/Interop.OCSP.cs index 59736b39f47e82..8b07660a3fb657 100644 --- a/src/libraries/Common/src/Interop/Unix/System.Security.Cryptography.Native/Interop.OCSP.cs +++ b/src/libraries/Common/src/Interop/Unix/System.Security.Cryptography.Native/Interop.OCSP.cs @@ -29,27 +29,30 @@ private static unsafe partial int CryptoNative_X509DecodeOcspToExpiration( int len, SafeOcspRequestHandle req, IntPtr subject, - IntPtr issuer, + IntPtr* issuers, + int issuersLen, ref long expiration); internal static unsafe bool X509DecodeOcspToExpiration( ReadOnlySpan buf, SafeOcspRequestHandle request, IntPtr x509Subject, - IntPtr x509Issuer, + ReadOnlySpan x509Issuers, out DateTimeOffset expiration) { long timeT = 0; int ret; fixed (byte* pBuf = buf) + fixed (IntPtr* pIssuers = x509Issuers) { ret = CryptoNative_X509DecodeOcspToExpiration( pBuf, buf.Length, request, x509Subject, - x509Issuer, + pIssuers, + x509Issuers.Length, ref timeT); } diff --git a/src/libraries/System.Net.Security/src/System/Net/Security/SslStreamCertificateContext.Linux.cs b/src/libraries/System.Net.Security/src/System/Net/Security/SslStreamCertificateContext.Linux.cs index cc80cc6e27badf..9c7902d7948b03 100644 --- a/src/libraries/System.Net.Security/src/System/Net/Security/SslStreamCertificateContext.Linux.cs +++ b/src/libraries/System.Net.Security/src/System/Net/Security/SslStreamCertificateContext.Linux.cs @@ -26,13 +26,30 @@ public partial class SslStreamCertificateContext private byte[]? _ocspResponse; private DateTimeOffset _ocspExpiration; private DateTimeOffset _nextDownload; + // Private copy of the intermediate certificates, in case the user decides to dispose the + // instances reachable through IntermediateCertificates property. + private X509Certificate2[] _privateIntermediateCertificates; + private X509Certificate2? _rootCertificate; private Task? _pendingDownload; private List? _ocspUrls; - private X509Certificate2? _ca; private SslStreamCertificateContext(X509Certificate2 target, ReadOnlyCollection intermediates, SslCertificateTrust? trust) { IntermediateCertificates = intermediates; + if (intermediates.Count > 0) + { + _privateIntermediateCertificates = new X509Certificate2[intermediates.Count]; + + for (int i = 0; i < intermediates.Count; i++) + { + _privateIntermediateCertificates[i] = new X509Certificate2(intermediates[i]); + } + } + else + { + _privateIntermediateCertificates = Array.Empty(); + } + TargetCertificate = target; Trust = trust; SslContexts = new ConcurrentDictionary(); @@ -76,15 +93,8 @@ partial void SetNoOcspFetch(bool noOcspFetch) partial void AddRootCertificate(X509Certificate2? rootCertificate, ref bool transferredOwnership) { - if (IntermediateCertificates.Count == 0) - { - _ca = rootCertificate; - transferredOwnership = true; - } - else - { - _ca = IntermediateCertificates[0]; - } + _rootCertificate = rootCertificate; + transferredOwnership = rootCertificate != null; if (!_staplingForbidden) { @@ -149,7 +159,7 @@ partial void AddRootCertificate(X509Certificate2? rootCertificate, ref bool tran return new ValueTask(pending); } - if (_ocspUrls is null && _ca is not null) + if (_ocspUrls is null && _rootCertificate is not null) { foreach (X509Extension ext in TargetCertificate.Extensions) { @@ -192,7 +202,9 @@ partial void AddRootCertificate(X509Certificate2? rootCertificate, ref bool tran private async Task FetchOcspAsync() { - X509Certificate2? caCert = _ca; + Debug.Assert(_rootCertificate != null); + X509Certificate2? caCert = _privateIntermediateCertificates.Length > 0 ? _privateIntermediateCertificates[0] : _rootCertificate; + Debug.Assert(_ocspUrls is not null); Debug.Assert(_ocspUrls.Count > 0); Debug.Assert(caCert is not null); @@ -211,6 +223,13 @@ partial void AddRootCertificate(X509Certificate2? rootCertificate, ref bool tran return null; } + IntPtr[] issuerHandles = ArrayPool.Shared.Rent(_privateIntermediateCertificates.Length + 1); + for (int i = 0; i < _privateIntermediateCertificates.Length; i++) + { + issuerHandles[i] = _privateIntermediateCertificates[i].Handle; + } + issuerHandles[_privateIntermediateCertificates.Length] = _rootCertificate.Handle; + using (SafeOcspRequestHandle ocspRequest = Interop.Crypto.X509BuildOcspRequest(subject, issuer)) { byte[] rentedBytes = ArrayPool.Shared.Rent(Interop.Crypto.GetOcspRequestDerSize(ocspRequest)); @@ -227,7 +246,7 @@ partial void AddRootCertificate(X509Certificate2? rootCertificate, ref bool tran if (ret is not null) { - if (!Interop.Crypto.X509DecodeOcspToExpiration(ret, ocspRequest, subject, issuer, out DateTimeOffset expiration)) + if (!Interop.Crypto.X509DecodeOcspToExpiration(ret, ocspRequest, subject, issuerHandles.AsSpan(0, _privateIntermediateCertificates.Length + 1), out DateTimeOffset expiration)) { ret = null; continue; @@ -247,15 +266,27 @@ partial void AddRootCertificate(X509Certificate2? rootCertificate, ref bool tran _ocspResponse = ret; _ocspExpiration = expiration; _nextDownload = nextCheckA < nextCheckB ? nextCheckA : nextCheckB; - _pendingDownload = null; break; } } + issuerHandles.AsSpan().Clear(); + ArrayPool.Shared.Return(issuerHandles); ArrayPool.Shared.Return(rentedBytes); ArrayPool.Shared.Return(rentedChars.Array!); GC.KeepAlive(TargetCertificate); + GC.KeepAlive(_privateIntermediateCertificates); + GC.KeepAlive(_rootCertificate); GC.KeepAlive(caCert); + + _pendingDownload = null; + if (ret == null) + { + // All download attempts failed, don't try again for 5 seconds. + // This backoff will be applied only if the OCSP staple is not expired. + // If it is expired, we will force-refresh it during next GetOcspResponseAsync call. + _nextDownload = DateTimeOffset.UtcNow.AddSeconds(5); + } return ret; } } diff --git a/src/native/libs/System.Security.Cryptography.Native/pal_x509.c b/src/native/libs/System.Security.Cryptography.Native/pal_x509.c index 40f7c604e8f39d..04c6ba06cd5dce 100644 --- a/src/native/libs/System.Security.Cryptography.Native/pal_x509.c +++ b/src/native/libs/System.Security.Cryptography.Native/pal_x509.c @@ -1302,11 +1302,11 @@ CryptoNative_X509ChainVerifyOcsp(X509_STORE_CTX* storeCtx, OCSP_REQUEST* req, OC return X509ChainVerifyOcsp(storeCtx, subject, issuer, req, resp, cachePath); } -int32_t CryptoNative_X509DecodeOcspToExpiration(const uint8_t* buf, int32_t len, OCSP_REQUEST* req, X509* subject, X509* issuer, int64_t* expiration) +int32_t CryptoNative_X509DecodeOcspToExpiration(const uint8_t* buf, int32_t len, OCSP_REQUEST* req, X509* subject, X509** issuers, int issuersLen, int64_t* expiration) { ERR_clear_error(); - if (buf == NULL || len == 0) + if (buf == NULL || len == 0 || issuersLen == 0) { return 0; } @@ -1329,7 +1329,16 @@ int32_t CryptoNative_X509DecodeOcspToExpiration(const uint8_t* buf, int32_t len, if (bag != NULL) { - if (X509_STORE_add_cert(store, issuer) && sk_X509_push(bag, issuer)) + int i; + for (i = 0; i < issuersLen; i++) + { + if (!X509_STORE_add_cert(store, issuers[i]) || !sk_X509_push(bag, issuers[i])) + { + break; + } + } + + if (i == issuersLen) { ctx = X509_STORE_CTX_new(); } @@ -1343,7 +1352,7 @@ int32_t CryptoNative_X509DecodeOcspToExpiration(const uint8_t* buf, int32_t len, { int canCache = 0; time_t expiration_t = 0; - X509VerifyStatusCode code = CheckOcspGetExpiry(req, resp, subject, issuer, ctx, &canCache, &expiration_t); + X509VerifyStatusCode code = CheckOcspGetExpiry(req, resp, subject, issuers[0], ctx, &canCache, &expiration_t); if (sizeof(time_t) == sizeof(int64_t)) { diff --git a/src/native/libs/System.Security.Cryptography.Native/pal_x509.h b/src/native/libs/System.Security.Cryptography.Native/pal_x509.h index be376882d127f6..bf76a1c2345ffd 100644 --- a/src/native/libs/System.Security.Cryptography.Native/pal_x509.h +++ b/src/native/libs/System.Security.Cryptography.Native/pal_x509.h @@ -412,4 +412,4 @@ PALEXPORT int32_t CryptoNative_X509ChainVerifyOcsp(X509_STORE_CTX* storeCtx, Decode len bytes of buf into an OCSP response, process it against the OCSP request, and return if the bytes were valid. If the bytes were valid, and the OCSP response had a nextUpdate value, assign it to expiration. */ -PALEXPORT int32_t CryptoNative_X509DecodeOcspToExpiration(const uint8_t* buf, int32_t len, OCSP_REQUEST* req, X509* subject, X509* issuer, int64_t* expiration); +PALEXPORT int32_t CryptoNative_X509DecodeOcspToExpiration(const uint8_t* buf, int32_t len, OCSP_REQUEST* req, X509* subject, X509** issuers, int issuersLen, int64_t* expiration);