** Merge proposal linked: https://code.launchpad.net/~lucaskanashiro/ubuntu/+source/openldap/+git/openldap/+merge/371147
-- 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/1838370 Title: slapd segfault on filter parse error Status in openldap: Fix Released Status in openldap package in Ubuntu: Fix Released Status in openldap source package in Xenial: Confirmed Status in openldap source package in Bionic: Confirmed Status in openldap source package in Disco: Confirmed Bug description: Impact ------ Users willing to use the slapd rwm overlay will face a slapd segmentation fault when trying to rewrite some rules. Backporting this fix will allow users using stable releases to take advantage of this feature without crashing slapd. This issue was fixed by upstream not freeing the rwm overlay filter memory without prior checking. Test Case --------- In this test case, the rwm overlay will be used and a rule will be created to deny any search request for uid=root, then the 'ldapsearch' will be invoked to trigger the failure. It is important to mention that the 'ldapsearch' command should fail regardless the presence of the bug in the package, the target here is the slapd crash. To reproduce this bug one can follow the procedure below in Ubuntu xenial, bionic or disco: $ sudo apt-get update $ sudo apt-get install slapd ldap-utils -y Reconfigure the slapd package. When asked about a domain, use "example.com". Choose a password you want (or just leave it blank), and accept defaults for everything else: $ sudo dpkg-reconfigure slapd Create a file called 'add-rwm.ldif' with the following content: $ cat add-rwm.ldif dn: cn=module{0},cn=config changetype: modify add: olcModuleLoad olcModuleLoad: rwm dn: olcOverlay=rwm,olcDatabase={1}mdb,cn=config changetype: add objectClass: olcOverlayConfig objectClass: olcRwmConfig olcOverlay: rwm olcRwmRewrite: {0} rwm-rewriteEngine "on" olcRwmRewrite: {1} rwm-rewriteContext "searchFilter" olcRwmRewrite: {2} rwm-rewriteRule "(.*)(uid=root)(.*)" "$1$2$3" "#" With this file in place, run: $ sudo ldapadd -Q -Y EXTERNAL -H ldapi:/// -f add-rwm.ldif Now, to trigger the crash: $ ldapsearch -x -h localhost -b dc=example,dc=com -LLL uid=root Server is unwilling to perform (53) Additional information: searchFilter/searchFilterAttrDN massage error slapd process will die, and /var/crash will have a crash file for slapd. You can run the following command to confirm the error: $ cat /var/log/syslog | grep filter_free Aug 9 19:51:05 popular-gorilla slapd[1479]: filter_free: unknown filter type=28530 Regression Potential -------------------- Since the fix is a patch provided by upstream (reviewed by maintainers and us) simple mistakes like typos are not expected. The patch impacts only the rwm module which is not loaded by default. So any regression would affect only the users that make use of this overlay. If an user is not using rwm overlay and is facing any issue, it should be related to other problems related to LDAP directory services. [Original message] Hello! We have faced slapd crash, seems an attacker was trying to brute force one of our services and uid parsing failures caused slapd crash: Jul 26 18:59:47 slapd[1252]: conn=1466 op=13 SRCH base="ou=test,dc=test,dc=com" scope=2 deref=0 filter="(&(uid=aistar123<>!n)(objectClass=posixAccount)(uid=*)(&(uidNumber=*)(!(uidNumber=0))))" Jul 26 18:59:47 slapd[1252]: conn=1466 op=13 SRCH attr=objectClass uid userPassword uidNumber gidNumber gecos homeDirectory loginShell krbPrincipalName cn memberOf modifyTimestamp modifyTimestamp shadowLastChange shadowMin shadow Max shadowWarning shadowInactive shadowExpire shadowFlag krbLastPwdChange krbPasswordExpiration pwdAttribute authorizedService accountExpires userAccountControl nsAccountLock host loginDisabled loginExpirationTime loginAllowedTimeMap sshPublic Key Jul 26 18:59:47 slapd[1252]: conn=1466 op=13 SEARCH RESULT tag=101 err=0 nentries=0 text=massaged filter parse error Jul 26 18:59:47 kernel: [ 9441.554161] slapd[2367]: segfault at 18 ip 00007fc8d18ec512 sp 00007fc8889e2810 error 4 in libc-2.23.so [7fc8d1868000+1c0000] Another faulty filter example: filter="(&(uid=sql<>?)(objectClass=posixAccount)(&(uidNumber=*)(!(uidNumber=0))))" filter="(&(uid=fugeone<>?123)(objectClass=posixAccount)(uid=*)(&(uidNumber=*)(!(uidNumber=0))))" $ lsb_release -rd Description: Ubuntu 16.04.5 LTS Release: 16.04 $ slapd -VVV @(#) $OpenLDAP: slapd (Ubuntu) (May 22 2018 13:54:12) $ buildd@lcy01-amd64-019 :/build/openldap-t_Ta0O/openldap-2.4.42+dfsg/debian/build/servers/slapd Included static backends: config ldif $ apt-cache policy slapd slapd: Installed: 2.4.42+dfsg-2ubuntu3.3 Candidate: 2.4.42+dfsg-2ubuntu3.5 Version table: 2.4.42+dfsg-2ubuntu3.5 500 500 http://nl.archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages *** 2.4.42+dfsg-2ubuntu3.3 100 100 /var/lib/dpkg/status 2.4.42+dfsg-2ubuntu3.2 500 500 http://security.ubuntu.com/ubuntu xenial-security/main amd64 Packages 2.4.42+dfsg-2ubuntu3 500 500 http://nl.archive.ubuntu.com/ubuntu xenial/main amd64 Packages affects ubuntu/openldap To manage notifications about this bug go to: https://bugs.launchpad.net/openldap/+bug/1838370/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
