From fe6e54fb1f5cda652b9489f740763f8d735621dd Mon Sep 17 00:00:00 2001 From: Timur Pocheptsov Date: Fri, 14 Jun 2019 11:34:08 +0200 Subject: TLS socket: make verification callback lock-free (OpenSSL) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When our QSslSocketBackendPrivate (OpenSSL backend) was developed, the ancient versions of OpenSSL did not have an API needed to pass an application-specific data into verification callback. Thus the developers resorted to the use of global variables (a list with errors) and locks. Some of our auto-tests use QNAM and in-process server. Whenever the client (essentially qhttpthreadeddelegate) and the server live in different threads, any use of 'https' is dead-lock prone, which recent events demonstrated and which were previously observed but not understood properly (rare occasions, not always easy to reproduce). Now we fix this for good by removing locking. There are two places (in 5.12) where these locks are needed: 1. Before calling SSL_connect/SSL_accept (handshake) - here we reuse the same trick we do in PSK callback ('SSL' has an external data set, and it's 'this', meaning an object of type QSslSocketBackendPrivate). 2. The static member function 'verify', here we do not have 'SSL', but we have our temporary 'X509_STORE', to which we can directly attach an external data - a pointer to a vector to collect verification errors. Note, this change assumes that OpenSSL Qt is build/linked against is at least of version 1.0.1 - we set external data on SSL unconditionally (no version checks). Fixes: QTBUG-76157 Change-Id: I05c98e77dfd5fb0c2c260fb6c463732facf53ffc Reviewed-by: Mårten Nordheim --- src/network/ssl/qsslsocket_openssl.cpp | 106 +++++++++++---------- src/network/ssl/qsslsocket_openssl11_symbols_p.h | 2 + src/network/ssl/qsslsocket_openssl_symbols.cpp | 10 ++ src/network/ssl/qsslsocket_openssl_symbols_p.h | 1 + .../ssl/qsslsocket_opensslpre11_symbols_p.h | 2 + 5 files changed, 70 insertions(+), 51 deletions(-) (limited to 'src/network/ssl') diff --git a/src/network/ssl/qsslsocket_openssl.cpp b/src/network/ssl/qsslsocket_openssl.cpp index c8bc6e069a..ec772ddb45 100644 --- a/src/network/ssl/qsslsocket_openssl.cpp +++ b/src/network/ssl/qsslsocket_openssl.cpp @@ -70,6 +70,10 @@ #include "qwindowscarootfetcher_p.h" #endif +#if !QT_CONFIG(opensslv11) +#include +#endif + #include #include #include @@ -253,44 +257,41 @@ QSslErrorEntry QSslErrorEntry::fromStoreContext(X509_STORE_CTX *ctx) }; } -// ### This list is shared between all threads, and protected by a -// mutex. Investigate using thread local storage instead. -struct QSslErrorList -{ - QMutex mutex; - QVector errors; -}; - -Q_GLOBAL_STATIC(QSslErrorList, _q_sslErrorList) - int q_X509Callback(int ok, X509_STORE_CTX *ctx) { if (!ok) { // Store the error and at which depth the error was detected. - _q_sslErrorList()->errors << QSslErrorEntry::fromStoreContext(ctx); -#if !QT_CONFIG(opensslv11) -#ifdef QSSLSOCKET_DEBUG - qCDebug(lcSsl) << "verification error: dumping bad certificate"; - qCDebug(lcSsl) << QSslCertificatePrivate::QSslCertificate_from_X509(q_X509_STORE_CTX_get_current_cert(ctx)).toPem(); - qCDebug(lcSsl) << "dumping chain"; - const auto certs = QSslSocketBackendPrivate::STACKOFX509_to_QSslCertificates(q_X509_STORE_CTX_get_chain(ctx)); - for (const QSslCertificate &cert : certs) { - qCDebug(lcSsl) << "Issuer:" << "O=" << cert.issuerInfo(QSslCertificate::Organization) - << "CN=" << cert.issuerInfo(QSslCertificate::CommonName) - << "L=" << cert.issuerInfo(QSslCertificate::LocalityName) - << "OU=" << cert.issuerInfo(QSslCertificate::OrganizationalUnitName) - << "C=" << cert.issuerInfo(QSslCertificate::CountryName) - << "ST=" << cert.issuerInfo(QSslCertificate::StateOrProvinceName); - qCDebug(lcSsl) << "Subject:" << "O=" << cert.subjectInfo(QSslCertificate::Organization) - << "CN=" << cert.subjectInfo(QSslCertificate::CommonName) - << "L=" << cert.subjectInfo(QSslCertificate::LocalityName) - << "OU=" << cert.subjectInfo(QSslCertificate::OrganizationalUnitName) - << "C=" << cert.subjectInfo(QSslCertificate::CountryName) - << "ST=" << cert.subjectInfo(QSslCertificate::StateOrProvinceName); - qCDebug(lcSsl) << "Valid:" << cert.effectiveDate() << '-' << cert.expiryDate(); + + using ErrorListPtr = QVector*; + ErrorListPtr errors = nullptr; + + // Error list is attached to either 'SSL' or 'X509_STORE'. + if (X509_STORE *store = q_X509_STORE_CTX_get0_store(ctx)) { // We try store first: +#if QT_CONFIG(opensslv11) + errors = ErrorListPtr(q_X509_STORE_get_ex_data(store, 0)); +#else + errors = ErrorListPtr(q_CRYPTO_get_ex_data(&store->ex_data, 0)); +#endif // opensslv11 + } + + if (!errors) { + // Not found on store? Try SSL and its external data then. According to the OpenSSL's + // documentation: + // + // "Whenever a X509_STORE_CTX object is created for the verification of the peers certificate + // during a handshake, a pointer to the SSL object is stored into the X509_STORE_CTX object + // to identify the connection affected. To retrieve this pointer the X509_STORE_CTX_get_ex_data() + // function can be used with the correct index." + if (SSL *ssl = static_cast(q_X509_STORE_CTX_get_ex_data(ctx, q_SSL_get_ex_data_X509_STORE_CTX_idx()))) + errors = ErrorListPtr(q_SSL_get_ex_data(ssl, QSslSocketBackendPrivate::s_indexForSSLExtraData + 1)); + } + + if (!errors) { + qCWarning(lcSsl, "Neither X509_STORE, nor SSL contains error list, handshake failure"); + return 0; } -#endif // QSSLSOCKET_DEBUG -#endif // !QT_CONFIG(opensslv11) + + errors->append(QSslErrorEntry::fromStoreContext(ctx)); } // Always return OK to allow verification to continue. We handle the // errors gracefully after collecting all errors, after verification has @@ -445,11 +446,7 @@ bool QSslSocketBackendPrivate::initSslContext() else q_SSL_set_accept_state(ssl); -#if OPENSSL_VERSION_NUMBER >= 0x10001000L - // Save a pointer to this object into the SSL structure. - if (QSslSocket::sslLibraryVersionNumber() >= 0x10001000L) - q_SSL_set_ex_data(ssl, s_indexForSSLExtraData, this); -#endif + q_SSL_set_ex_data(ssl, s_indexForSSLExtraData, this); #if OPENSSL_VERSION_NUMBER >= 0x10001000L && !defined(OPENSSL_NO_PSK) // Set the client callback for PSK @@ -1002,14 +999,14 @@ bool QSslSocketBackendPrivate::startHandshake() if (inSetAndEmitError) return false; - QMutexLocker locker(&_q_sslErrorList()->mutex); - _q_sslErrorList()->errors.clear(); + QVector lastErrors; + q_SSL_set_ex_data(ssl, s_indexForSSLExtraData + 1, &lastErrors); int result = (mode == QSslSocket::SslClientMode) ? q_SSL_connect(ssl) : q_SSL_accept(ssl); + q_SSL_set_ex_data(ssl, s_indexForSSLExtraData + 1, nullptr); - const auto &lastErrors = _q_sslErrorList()->errors; if (!lastErrors.isEmpty()) storePeerCertificates(); - for (const auto ¤tError : lastErrors) { + for (const auto ¤tError : qAsConst(lastErrors)) { emit q->peerVerifyError(_q_OpenSSL_to_QSslError(currentError.code, configuration.peerCertificateChain.value(currentError.depth))); if (q->state() != QAbstractSocket::ConnectedState) @@ -1017,7 +1014,6 @@ bool QSslSocketBackendPrivate::startHandshake() } errorList << lastErrors; - locker.unlock(); // Connection aborted during handshake phase. if (q->state() != QAbstractSocket::ConnectedState) @@ -1420,7 +1416,20 @@ QList QSslSocketBackendPrivate::verify(const QList & } } - QMutexLocker sslErrorListMutexLocker(&_q_sslErrorList()->mutex); + QVector lastErrors; +#if QT_CONFIG(opensslv11) + if (!q_X509_STORE_set_ex_data(certStore, 0, &lastErrors)) { + qCWarning(lcSsl) << "Unable to attach external data (error list) to a store"; + errors << QSslError(QSslError::UnspecifiedError); + return errors; + } +#else + if (!q_CRYPTO_set_ex_data(&certStore->ex_data, 0, &lastErrors)) { + qCWarning(lcSsl) << "Unable to attach external data (error list) to a store"; + errors << QSslError(QSslError::UnspecifiedError); + return errors; + } +#endif // opensslv11 // Register a custom callback to get all verification errors. q_X509_STORE_set_verify_cb(certStore, q_X509Callback); @@ -1470,12 +1479,7 @@ QList QSslSocketBackendPrivate::verify(const QList & q_OPENSSL_sk_free((OPENSSL_STACK *)intermediates); // Now process the errors - const auto errorList = std::move(_q_sslErrorList()->errors); - _q_sslErrorList()->errors.clear(); - sslErrorListMutexLocker.unlock(); - - // Translate the errors if (QSslCertificatePrivate::isBlacklisted(certificateChain[0])) { QSslError error(QSslError::CertificateBlacklisted, certificateChain[0]); errors << error; @@ -1489,8 +1493,8 @@ QList QSslSocketBackendPrivate::verify(const QList & } // Translate errors from the error list into QSslErrors. - errors.reserve(errors.size() + errorList.size()); - for (const auto &error : qAsConst(errorList)) + errors.reserve(errors.size() + lastErrors.size()); + for (const auto &error : qAsConst(lastErrors)) errors << _q_OpenSSL_to_QSslError(error.code, certificateChain.value(error.depth)); q_X509_STORE_free(certStore); diff --git a/src/network/ssl/qsslsocket_openssl11_symbols_p.h b/src/network/ssl/qsslsocket_openssl11_symbols_p.h index ec7e7ea1b8..0c32b0a934 100644 --- a/src/network/ssl/qsslsocket_openssl11_symbols_p.h +++ b/src/network/ssl/qsslsocket_openssl11_symbols_p.h @@ -105,6 +105,8 @@ ASN1_TIME *q_X509_getm_notAfter(X509 *a); long q_X509_get_version(X509 *a); EVP_PKEY *q_X509_get_pubkey(X509 *a); void q_X509_STORE_set_verify_cb(X509_STORE *ctx, X509_STORE_CTX_verify_cb verify_cb); +int q_X509_STORE_set_ex_data(X509_STORE *ctx, int idx, void *data); +void *q_X509_STORE_get_ex_data(X509_STORE *r, int idx); STACK_OF(X509) *q_X509_STORE_CTX_get0_chain(X509_STORE_CTX *ctx); void q_DH_get0_pqg(const DH *dh, const BIGNUM **p, const BIGNUM **q, const BIGNUM **g); int q_DH_bits(DH *dh); diff --git a/src/network/ssl/qsslsocket_openssl_symbols.cpp b/src/network/ssl/qsslsocket_openssl_symbols.cpp index 6a5ab91669..483a2cbad0 100644 --- a/src/network/ssl/qsslsocket_openssl_symbols.cpp +++ b/src/network/ssl/qsslsocket_openssl_symbols.cpp @@ -178,6 +178,8 @@ DEFINEFUNC(ASN1_TIME *, X509_getm_notAfter, X509 *a, a, return nullptr, return) DEFINEFUNC(long, X509_get_version, X509 *a, a, return -1, return) DEFINEFUNC(EVP_PKEY *, X509_get_pubkey, X509 *a, a, return nullptr, return) DEFINEFUNC2(void, X509_STORE_set_verify_cb, X509_STORE *a, a, X509_STORE_CTX_verify_cb verify_cb, verify_cb, return, DUMMYARG) +DEFINEFUNC3(int, X509_STORE_set_ex_data, X509_STORE *a, a, int idx, idx, void *data, data, return 0, return) +DEFINEFUNC2(void *, X509_STORE_get_ex_data, X509_STORE *r, r, int idx, idx, return nullptr, return) DEFINEFUNC(STACK_OF(X509) *, X509_STORE_CTX_get0_chain, X509_STORE_CTX *a, a, return nullptr, return) DEFINEFUNC3(void, CRYPTO_free, void *str, str, const char *file, file, int line, line, return, DUMMYARG) DEFINEFUNC(long, OpenSSL_version_num, void, DUMMYARG, return 0, return) @@ -223,6 +225,8 @@ DEFINEFUNC(int, CRYPTO_num_locks, DUMMYARG, DUMMYARG, return 0, return) DEFINEFUNC(void, CRYPTO_set_locking_callback, void (*a)(int, int, const char *, int), a, return, DUMMYARG) DEFINEFUNC(void, CRYPTO_set_id_callback, unsigned long (*a)(), a, return, DUMMYARG) DEFINEFUNC(void, CRYPTO_free, void *a, a, return, DUMMYARG) +DEFINEFUNC3(int, CRYPTO_set_ex_data, CRYPTO_EX_DATA *ad, ad, int idx, idx, void *val, val, return 0, return) +DEFINEFUNC2(void *, CRYPTO_get_ex_data, const CRYPTO_EX_DATA *ad, ad, int idx, idx, return nullptr, return) DEFINEFUNC(unsigned long, ERR_peek_last_error, DUMMYARG, DUMMYARG, return 0, return) DEFINEFUNC(void, ERR_free_strings, void, DUMMYARG, return, DUMMYARG) DEFINEFUNC(void, EVP_CIPHER_CTX_cleanup, EVP_CIPHER_CTX *a, a, return, DUMMYARG) @@ -533,6 +537,7 @@ DEFINEFUNC2(int, X509_STORE_CTX_set_purpose, X509_STORE_CTX *a, a, int b, b, ret DEFINEFUNC(int, X509_STORE_CTX_get_error, X509_STORE_CTX *a, a, return -1, return) DEFINEFUNC(int, X509_STORE_CTX_get_error_depth, X509_STORE_CTX *a, a, return -1, return) DEFINEFUNC(X509 *, X509_STORE_CTX_get_current_cert, X509_STORE_CTX *a, a, return nullptr, return) +DEFINEFUNC(X509_STORE *, X509_STORE_CTX_get0_store, X509_STORE_CTX *ctx, ctx, return nullptr, return) DEFINEFUNC(X509_STORE_CTX *, X509_STORE_CTX_new, DUMMYARG, DUMMYARG, return nullptr, return) DEFINEFUNC2(void *, X509_STORE_CTX_get_ex_data, X509_STORE_CTX *ctx, ctx, int idx, idx, return nullptr, return) DEFINEFUNC(int, SSL_get_ex_data_X509_STORE_CTX_idx, DUMMYARG, DUMMYARG, return -1, return) @@ -998,6 +1003,8 @@ bool q_resolveOpenSslSymbols() RESOLVEFUNC(X509_get_version) RESOLVEFUNC(X509_get_pubkey) RESOLVEFUNC(X509_STORE_set_verify_cb) + RESOLVEFUNC(X509_STORE_set_ex_data) + RESOLVEFUNC(X509_STORE_get_ex_data) RESOLVEFUNC(CRYPTO_free) RESOLVEFUNC(OpenSSL_version_num) RESOLVEFUNC(OpenSSL_version) @@ -1046,6 +1053,8 @@ bool q_resolveOpenSslSymbols() RESOLVEFUNC(CRYPTO_num_locks) RESOLVEFUNC(CRYPTO_set_id_callback) RESOLVEFUNC(CRYPTO_set_locking_callback) + RESOLVEFUNC(CRYPTO_set_ex_data) + RESOLVEFUNC(CRYPTO_get_ex_data) RESOLVEFUNC(ERR_peek_last_error) RESOLVEFUNC(ERR_free_strings) RESOLVEFUNC(EVP_CIPHER_CTX_cleanup) @@ -1305,6 +1314,7 @@ bool q_resolveOpenSslSymbols() RESOLVEFUNC(X509_STORE_CTX_get_error) RESOLVEFUNC(X509_STORE_CTX_get_error_depth) RESOLVEFUNC(X509_STORE_CTX_get_current_cert) + RESOLVEFUNC(X509_STORE_CTX_get0_store) RESOLVEFUNC(X509_cmp) RESOLVEFUNC(X509_STORE_CTX_get_ex_data) diff --git a/src/network/ssl/qsslsocket_openssl_symbols_p.h b/src/network/ssl/qsslsocket_openssl_symbols_p.h index bfdfbf0efc..3143117621 100644 --- a/src/network/ssl/qsslsocket_openssl_symbols_p.h +++ b/src/network/ssl/qsslsocket_openssl_symbols_p.h @@ -450,6 +450,7 @@ int q_X509_STORE_CTX_set_purpose(X509_STORE_CTX *ctx, int purpose); int q_X509_STORE_CTX_get_error(X509_STORE_CTX *ctx); int q_X509_STORE_CTX_get_error_depth(X509_STORE_CTX *ctx); X509 *q_X509_STORE_CTX_get_current_cert(X509_STORE_CTX *ctx); +X509_STORE *q_X509_STORE_CTX_get0_store(X509_STORE_CTX *ctx); // Diffie-Hellman support DH *q_DH_new(); diff --git a/src/network/ssl/qsslsocket_opensslpre11_symbols_p.h b/src/network/ssl/qsslsocket_opensslpre11_symbols_p.h index b7bac5d2a2..48364ceb1d 100644 --- a/src/network/ssl/qsslsocket_opensslpre11_symbols_p.h +++ b/src/network/ssl/qsslsocket_opensslpre11_symbols_p.h @@ -84,6 +84,8 @@ int q_CRYPTO_num_locks(); void q_CRYPTO_set_locking_callback(void (*a)(int, int, const char *, int)); void q_CRYPTO_set_id_callback(unsigned long (*a)()); void q_CRYPTO_free(void *a); +int q_CRYPTO_set_ex_data(CRYPTO_EX_DATA *ad, int idx, void *val); +void *q_CRYPTO_get_ex_data(const CRYPTO_EX_DATA *ad, int idx); unsigned long q_ERR_peek_last_error(); void q_ERR_free_strings(); void q_EVP_CIPHER_CTX_cleanup(EVP_CIPHER_CTX *a); -- cgit v1.2.3