On 04/07/2015 01:32 PM, Oleg Strikov wrote: > Client may crash itself > by passing incorrect cipher suite to the API. While that's sad, it > doesn't crash slapd itself To the contrary, it certainly does crash slapd itself. Anyone upgrading will at some point silently switch from a slapd that used openssl to gnutls --- without the package warning about nor updating the apropos config string. As a result, "apt-get update;apt-get upgrade" results in slapd crashing with a double free as it loads the previous conf file. Most package maintainers would refer to this as a regression inasmuch as the typical upgrade process fails to start and without any obvious warning. The answer may be found by spending many hours googling for 'what the heck'. For over a year this has gone unfixed.
At least improve the upgrade script to warn the installer and prevent slapd from starting until some flag is set noting the user has corrected the string and is aware the developers won't fix the issue. In the alternative, I think a much better approach is to put a versions of all these and related packages compiled against openSSL in the appropriate repository. It is not material to me whether this is fixed or not as I've removed all packages using gnutls until it's more mature, and won't revisit this again for at least four years. In fact I'm looking for other distros like Mint that actually check whether upgrades generate regressions and classify risk assessments that allow only proven upgrades to succeed. It's really quite an eye-opener to me that a distro aiming to be deployed outside the sole-user world doesn't see this as a problem. -- Harry G Coin Quiet Fountain LLC 2118 Lundy Ln Bettendorf, Iowa 52722 -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to openldap in Ubuntu. https://bugs.launchpad.net/bugs/1103353 Title: Invalid GnuTLS cipher suite strings causes libldap to crash Status in openldap package in Ubuntu: Fix Released Status in openldap source package in Precise: In Progress Status in openldap source package in Trusty: In Progress Status in openldap package in Debian: Fix Released Bug description: If the cipher suite string is unacceptable to GnuTLS, libldap_r-2.4 crashes due to a double free. GnuTLS is extremely picky about the cipher suite strings it accepts; as a first measure, try LDAP cipher suite string "SECURE256" or "NORMAL". If that stops the crash, then you have encountered this bug. Typically, the crash report begins with something like *** glibc detected *** APPLICATION: double free or corruption (!prev) /lib/x86_64-linux-gnu/libc.so.6(+0x7eb96)[0x7fc68cff0b96] /usr/lib/x86_64-linux-gnu/libldap_r-2.4.so.2(+0x38769)[0x7fc68bb13769] /usr/lib/x86_64-linux-gnu/libldap_r-2.4.so.2(+0x3570e)[0x7fc68bb1070e] /usr/lib/x86_64-linux-gnu/libldap_r-2.4.so.2(ldap_pvt_tls_init_def_ctx+0x1d)[0x7fc68bb108ed] /usr/lib/x86_64-linux-gnu/libldap_r-2.4.so.2(+0x35965)[0x7fc68bb10965] /usr/lib/x86_64-linux-gnu/libldap_r-2.4.so.2(+0x35a6d)[0x7fc68bb10a6d] /usr/lib/x86_64-linux-gnu/libldap_r-2.4.so.2(ldap_int_tls_start+0x5d)[0x7fc68bb1149d] The actual double free happens in openldap/libraries/libldap/tls2.c:ldap_int_tls_init_ctx(), in the ldap_pvt_tls_ctx_free(lo->ldo_tls_ctx); call in the error_exit: path. The root cause of the double free is lack of GnuTLS return value checks when calling gnutls_priority*() functions. The code simply assumes they succeed, and when GnuTLS fails to provide a valid context due to those failures, ldap_int_tls_init_ctx() tries to free the never-fully-initialized context. A simple fix is to create GnuTLS security contexts using the configured cipher suite string, instead of "NORMAL" as openldap/libraries/libldap/tls_g.c now does. If the cipher suite string is invalid, then do not create the context at all. This is caught earlier in ldap_int_tls_init_ctx(), and avoids the crash. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/openldap/+bug/1103353/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
