On 05/09/2013 05:50 PM, Alex Rousskov wrote: > Hello, > > According to the squid-user exchange below, OpenSSL v0.9.8y is also > vulnerable. However, it is possible that the stock v0.9.8y is not > vulnerable, but FreeBSD patched it to make it vulnerable, I guess.
Nope, this is not FreeBSD problem. This openSSL release has this bug too.. > Christos, can you reproduce the crash with stock v0.9.8y on Linux (if > you do not have FreeBSD)? Yep. > > I wonder if we should change strategy from compile-time OpenSSL version > checks to something like this: > > // Temporary ssl for getting X509 certificate from SSL_CTX. > Ssl::SSL_Pointer ssl(SSL_new(sslContext)); > // Various OpenSSL versions crash on a SSL_get_certificate() call: > // http://bugs.squid-cache.org/show_bug.cgi?id=3816#c16 > // so we avoid that call by extracting certificate directly: > X509 *cert = ssl->cert ? ssl->cert->key->x509 : NULL; > if (!cert) > return false; The ssl->cert is of type CERT ("struct cert_st") and it is defined in a header file which is not available to the public openSSL SDK... So the above (ssl->cert->key->x509) can not be used unless we copy the "struct cert_st" definition inside squid... This is why I used the following to get the X509 object: X509 ***pCert = (X509 ***)sslContext->cert; > > If the "ssl->cert->key->x509" expression is not portable across OpenSSL > versions, perhaps we can detect that at ./configure time and add an > #ifdef guard for _that_ (as opposed to OpenSSL version guards)? I can reporoduce the bug with the following simple program: int main(int argc, char *argv[]) { SSLeay_add_ssl_algorithms(); SSL_CTX *sslContext = SSL_CTX_new(SSLv3_method()); SSL *ssl = SSL_new(sslContext); X509 * cert = SSL_get_certificate(ssl); return 0; } This program crashes inside a function called by SSL_get_certificate. I suppose we can check if the program exited normally or not, to decide if the openSSL SDK is OK or have the bug. > > > Thank you, > > Alex. > > > On 05/09/2013 08:19 AM, Guy Helmer wrote: >> >> On May 8, 2013, at 10:55 PM, Alex Rousskov >> <rouss...@measurement-factory.com> wrote: >> >>> On 05/08/2013 04:31 PM, Guy Helmer wrote: >>> >>>> I was using squid 3.3.4 on FreeBSD 8.3 with transparent interception >>>> (via ipfw) and ssl bump with success. >>> >>>> After upgrading FreeBSD to 9.1 [...] squid is failing with >>>> segmentation violations and the ssl_crtd helpers are dying. >>> >>>> #7 0xbfbff044 in ?? () >>>> #8 0x0000000b in ?? () >>>> #9 0x484eb5c8 in ssl_get_server_send_pkey () from /usr/lib/libssl.so.6 >>>> #10 0x484eb68d in ssl_get_server_send_cert () from /usr/lib/libssl.so.6 >>>> #11 0x484eb6c4 in SSL_get_certificate () from /usr/lib/libssl.so.6 >>>> #12 0x083cb5ef in Ssl::verifySslCertificate (sslContext=0x4a259340, >>>> properties=@0xbfbfd9d8) at support.cc:1422 >>>> #13 0x0813d20d in ConnStateData::getSslContextStart (this=0x4a257cd0) >>>> at client_side.cc:3820 >>>> #14 0x0814a89e in ConnStateData::httpsPeeked (this=0x4a257cd0, >>>> serverConnection=@0xbfbfdadc) at client_side.cc:3968 >>> >>> Smells like an OpenSSL bug that we thought we had a workaround for: >>> http://bugs.squid-cache.org/show_bug.cgi?id=3816 >>> >>> The workaround should be in v3.3.4 that you are running but, apparently, >>> it is not sufficient, or our OpenSSL version detection code is failing >>> in your environment. We thought the bug affects OpenSSL versions 1.0.1d >>> and 1.0.1e only. >>> >>> Which OpenSSL version are you building Squid with? >>> >>> What is the OPENSSL_VERSION_NUMBER constant in OpenSSL header files >>> where you build Squid? You can probably run something like "fgrep -RI >>> OPENSSL_VERSION_NUMBER /usr/include/openssl" to figure that out. >>> >>> Which OpenSSL version are you running Squid with? >> >> Under FreeBSD 8.3, it was built and running with OpenSSL 0.9.8q >> (OPENSSL_VERSION_NUMBER 0x0090811f). >> >> Under FreeBSD 9.1 (stable branch checkout as of 2013-04-10), it is built and >> running with OpenSSL 0.9.8y (OPENSSL_VERSION_NUMBER 0x0090819fL). >> >> I made this little change to support.cc, rebuilt squid and ssl_crtd, and it >> seems to be working OK with transparent SSL bumping: >> >> --- src/ssl/support.cc.orig 2013-05-09 08:59:19.000000000 -0500 >> +++ src/ssl/support.cc 2013-05-09 09:00:25.000000000 -0500 >> @@ -1413,7 +1413,7 @@ >> { >> // SSL_get_certificate is buggy in openssl versions 1.0.1d and 1.0.1e >> // Try to retrieve certificate directly from SSL_CTX object >> -#if OPENSSL_VERSION_NUMBER == 0x1000105fL || OPENSSL_VERSION_NUMBER == >> 0x1000104fL >> +#if OPENSSL_VERSION_NUMBER == 0x1000105fL || OPENSSL_VERSION_NUMBER == >> 0x1000104fL || OPENSSL_VERSION_NUMBER == 0x0090819fL >> X509 ***pCert = (X509 ***)sslContext->cert; >> X509 * cert = pCert && *pCert ? **pCert : NULL; >> #else >> >> Thanks for the pointer, Alex! >> >> Guy >> > >
