Re: [PATCH] qt4: security advisory - blacklist fraudulent comodo certificates

[Denys Dmytriyenko <denis@denix.org>]

On Wed, Mar 30, 2011 at 05:24:49PM -0400, Denys Dmytriyenko wrote:
> From: Denys Dmytriyenko <denys@ti.com>
> 
> Security advisory: Blacklist fraudulent certificates. More info is in the
> patch and at the following links:
> http://www.comodo.com/Comodo-Fraud-Incident-2011-03-23.html
> http://qt.nokia.com/files/qt-patches/blacklist-fraudulent-comodo-certificates-patch.diff/view
> 
> Signed-off-by: Denys Dmytriyenko <denys@ti.com>

Ping. Test-built both versions on Angstrom...


> ---
>  ...klist-fraudulent-comodo-certificates-patch.diff |  134 ++++++++++++++++++++
>  recipes/qt4/qt-4.6.3.inc                           |    8 +-
>  recipes/qt4/qt-4.7.2.inc                           |    3 +-
>  recipes/qt4/qt4-embedded_4.6.3.bb                  |    2 +-
>  recipes/qt4/qt4-embedded_4.7.2.bb                  |    2 +-
>  5 files changed, 141 insertions(+), 8 deletions(-)
>  create mode 100644 recipes/qt4/files/blacklist-fraudulent-comodo-certificates-patch.diff
> 
> diff --git a/recipes/qt4/files/blacklist-fraudulent-comodo-certificates-patch.diff b/recipes/qt4/files/blacklist-fraudulent-comodo-certificates-patch.diff
> new file mode 100644
> index 0000000..00faf75
> --- /dev/null
> +++ b/recipes/qt4/files/blacklist-fraudulent-comodo-certificates-patch.diff
> @@ -0,0 +1,134 @@
> +Security advisory: Fraudulent certificates
> +
> +Background:
> +
> +Recently a group of people managed to get fraudulent SSL certificates signed
> +by a Certificate Authority (CA).
> +
> +These certificates potentially enable their owners to pretend to be other
> +entities on the Web; the attackers can present valid certificates for e.g.
> +mail.google.com, login.yahoo.com and login.live.com, among others.
> +
> +The patch below solves this problem by blacklisting those fake certificates
> +and aborting an SSL handshake with entities that present these certificates.
> +The patch applies to all 4.6 and 4.7 versions, and should be applied to all Qt
> +4.6.x and 4.7.x versions; upcoming Qt releases will contain a fix for this
> +problem.
> +
> +More technical background:
> +
> +In order to trick a user into establishing an SSL connection to a site using
> +one of those fake certificates, in addition to controlling the certificate, an
> +attacker would need to either control the DNS server used by the victim, or
> +have control over a proxy that the victim uses. That way, the attacker could
> +trick the victim to connect to the attacker?s site and then present the user
> +with a valid certificate.
> +
> +One obvious question now is: Should those certificates not just be revoked,
> +which would solve the problem?
> +
> +First, they have been revoked by the affected Certificate Authority (see above
> +link).
> +
> +However, the problem in this case, and probably part of the reason why most
> +browser vendors release new versions blacklisting those certificates, is that
> +by default browsers do not treat invalid responses from an OCSP server (a
> +server used for checking the revocation status of a certificate) as fatal, and
> +will allow the SSL connection to proceed anyway. Qt itself does not support
> +OCSP yet, which makes blacklisting the certificates the only valid option (now
> +would be a good moment to vote on the task for implementing OCSP in Qt); since
> +Qt is relying on the system root certificates since version 4.7, it cannot
> +control the root certificates that Qt trusts automatically anymore.
> +
> +http://www.comodo.com/Comodo-Fraud-Incident-2011-03-23.html
> +http://qt.nokia.com/files/qt-patches/blacklist-fraudulent-comodo-certificates-patch.diff/view
> +
> +diff --git a/src/network/ssl/qsslcertificate.cpp b/src/network/ssl/qsslcertificate.cpp
> +index 618ac79..a5cdf01 100644
> +--- a/src/network/ssl/qsslcertificate.cpp
> ++++ b/src/network/ssl/qsslcertificate.cpp
> +@@ -219,17 +219,19 @@ bool QSslCertificate::isNull() const
> +     Returns true if this certificate is valid; otherwise returns
> +     false.
> + 
> +-    Note: Currently, this function only checks that the current
> ++    Note: Currently, this function checks that the current
> +     data-time is within the date-time range during which the
> +-    certificate is considered valid. No other checks are
> +-    currently performed.
> ++    certificate is considered valid, and checks that the
> ++    certificate is not in a blacklist of fraudulent certificates.
> + 
> +     \sa isNull()
> + */
> + bool QSslCertificate::isValid() const
> + {
> +     const QDateTime currentTime = QDateTime::currentDateTime();
> +-    return currentTime >= d->notValidBefore && currentTime <= d->notValidAfter;
> ++    return currentTime >= d->notValidBefore &&
> ++            currentTime <= d->notValidAfter &&
> ++            ! QSslCertificatePrivate::isBlacklisted(*this);
> + }
> + 
> + /*!
> +@@ -798,6 +800,30 @@ QList<QSslCertificate> QSslCertificatePrivate::certificatesFromDer(const QByteAr
> +     return certificates;
> + }
> + 
> ++// These certificates are known to be fraudulent and were created during the comodo
> ++// compromise. See http://www.comodo.com/Comodo-Fraud-Incident-2011-03-23.html
> ++static const char *certificate_blacklist[] = {
> ++    "04:7e:cb:e9:fc:a5:5f:7b:d0:9e:ae:36:e1:0c:ae:1e",
> ++    "f5:c8:6a:f3:61:62:f1:3a:64:f5:4f:6d:c9:58:7c:06",
> ++    "d7:55:8f:da:f5:f1:10:5b:b2:13:28:2b:70:77:29:a3",
> ++    "39:2a:43:4f:0e:07:df:1f:8a:a3:05:de:34:e0:c2:29",
> ++    "3e:75:ce:d4:6b:69:30:21:21:88:30:ae:86:a8:2a:71",
> ++    "e9:02:8b:95:78:e4:15:dc:1a:71:0a:2b:88:15:44:47",
> ++    "92:39:d5:34:8f:40:d1:69:5a:74:54:70:e1:f2:3f:43",
> ++    "b0:b7:13:3e:d0:96:f9:b5:6f:ae:91:c8:74:bd:3a:c0",
> ++    "d8:f3:5f:4e:b7:87:2b:2d:ab:06:92:e3:15:38:2f:b0",
> ++    0
> ++};
> ++
> ++bool QSslCertificatePrivate::isBlacklisted(const QSslCertificate &certificate)
> ++{
> ++    for (int a = 0; certificate_blacklist[a] != 0; a++) {
> ++        if (certificate.serialNumber() == certificate_blacklist[a])
> ++            return true;
> ++    }
> ++    return false;
> ++}
> ++
> + #ifndef QT_NO_DEBUG_STREAM
> + QDebug operator<<(QDebug debug, const QSslCertificate &certificate)
> + {
> +diff --git a/src/network/ssl/qsslcertificate_p.h b/src/network/ssl/qsslcertificate_p.h
> +index cdceb0f..1ce33d3 100644
> +--- a/src/network/ssl/qsslcertificate_p.h
> ++++ b/src/network/ssl/qsslcertificate_p.h
> +@@ -96,6 +96,7 @@ public:
> +     static QSslCertificate QSslCertificate_from_X509(X509 *x509);
> +     static QList<QSslCertificate> certificatesFromPem(const QByteArray &pem, int count = -1);
> +     static QList<QSslCertificate> certificatesFromDer(const QByteArray &der, int count = -1);
> ++    static bool isBlacklisted(const QSslCertificate &certificate);
> + 
> +     friend class QSslSocketBackendPrivate;
> + 
> +diff --git a/src/network/ssl/qsslsocket_openssl.cpp b/src/network/ssl/qsslsocket_openssl.cpp
> +index 0866534..2427193 100644
> +--- a/src/network/ssl/qsslsocket_openssl.cpp
> ++++ b/src/network/ssl/qsslsocket_openssl.cpp
> +@@ -1193,6 +1193,13 @@ bool QSslSocketBackendPrivate::startHandshake()
> +     X509 *x509 = q_SSL_get_peer_certificate(ssl);
> +     configuration.peerCertificate = QSslCertificatePrivate::QSslCertificate_from_X509(x509);
> +     q_X509_free(x509);
> ++    if (QSslCertificatePrivate::isBlacklisted(configuration.peerCertificate)) {
> ++        q->setErrorString(QSslSocket::tr("The peer certificate is blacklisted"));
> ++        q->setSocketError(QAbstractSocket::SslHandshakeFailedError);
> ++        emit q->error(QAbstractSocket::SslHandshakeFailedError);
> ++        plainSocket->disconnectFromHost();
> ++        return false;
> ++    }
> + 
> +     // Start translating errors.
> +     QList<QSslError> errors;
> diff --git a/recipes/qt4/qt-4.6.3.inc b/recipes/qt4/qt-4.6.3.inc
> index 5b91116..77c5cf6 100644
> --- a/recipes/qt4/qt-4.6.3.inc
> +++ b/recipes/qt4/qt-4.6.3.inc
> @@ -1,11 +1,14 @@
>  DEFAULT_PREFERENCE = "-1"
> +LICENSE = "LGPLv2.1 GPLv3"
>  
>  FILESPATHPKG .= ":qt-${PV}"
>  
>  SRC_URI = "ftp://ftp.trolltech.com/qt/source/qt-everywhere-opensource-src-${PV}.tar.gz \
> +           file://blacklist-fraudulent-comodo-certificates-patch.diff \
>             file://0001-cross-compile.patch \
>             file://0002-fix-resinit-declaration.patch \
>             file://0004-no-qmake.patch \
> +           file://hack-out-pg_config.patch \
>             file://0006-freetype-host-includes.patch \
>             file://0008-qt-lib-infix.patch \
>             file://0009-support-2bpp.patch \
> @@ -64,10 +67,5 @@ do_install_append() {
>  	fi
>  }
>  
> -LICENSE = "LGPLv2.1 GPLv3"
> -SRC_URI += " \
> -            file://hack-out-pg_config.patch"
> -
>  SRC_URI[md5sum] = "5c69f16d452b0bb3d44bc3c10556c072"
>  SRC_URI[sha256sum] = "f4e0ada8d4d516bbb8600a3ee7d9046c9c79e38cd781df9ffc46d8f16acd1768"
> -
> diff --git a/recipes/qt4/qt-4.7.2.inc b/recipes/qt4/qt-4.7.2.inc
> index 282bc82..e6a7b90 100644
> --- a/recipes/qt4/qt-4.7.2.inc
> +++ b/recipes/qt4/qt-4.7.2.inc
> @@ -5,8 +5,9 @@ FILESPATHPKG =. "qt-${PV}:"
>  
>  SRC_URI = "\
>  	ftp://ftp.trolltech.com/qt/source/qt-everywhere-opensource-src-${PV}.tar.gz \
> +	file://blacklist-fraudulent-comodo-certificates-patch.diff \
>  	file://0004-no-qmake.patch \
> -    file://hack-out-pg2-4.7.0.patch \
> +	file://hack-out-pg2-4.7.0.patch \
>  	file://0006-freetype-host-includes.patch \
>  	file://0001-Added-Openembedded-crossarch-option.patch \
>  	file://0010-phonon-gstreamer-rgb-endianess.patch \
> diff --git a/recipes/qt4/qt4-embedded_4.6.3.bb b/recipes/qt4/qt4-embedded_4.6.3.bb
> index 13f3f00..fe49fdb 100644
> --- a/recipes/qt4/qt4-embedded_4.6.3.bb
> +++ b/recipes/qt4/qt4-embedded_4.6.3.bb
> @@ -1,6 +1,6 @@
>  require qt4-embedded.inc
>  
> -PR = "${INC_PR}.1"
> +PR = "${INC_PR}.2"
>  
>  QT_CONFIG_FLAGS_append_armv6 = " -no-neon "
>  
> diff --git a/recipes/qt4/qt4-embedded_4.7.2.bb b/recipes/qt4/qt4-embedded_4.7.2.bb
> index 1cd43a6..7e3d4b8 100644
> --- a/recipes/qt4/qt4-embedded_4.7.2.bb
> +++ b/recipes/qt4/qt4-embedded_4.7.2.bb
> @@ -2,7 +2,7 @@ DEFAULT_PREFERENCE = "-1"
>  
>  require qt4-embedded.inc
>  
> -PR = "${INC_PR}.0"
> +PR = "${INC_PR}.1"
>  
>  QT_CONFIG_FLAGS_append_armv6 = " -no-neon "
>  
> -- 
> 1.7.0.4
> 
> 
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