[Bug 423252] Re: NSS using LDAP+SSL breaks setuid applications like su, sudo, apache2 suexec, and atd

[Howard Chu]

This additional patch fixes the crash in bug#1013798.

** Attachment added: "Addition to the patch in comment#73"
   https://bugs.launchpad.net/ubuntu/+source/sudo/+bug/423252/+attachment/3328846/+files/dif.txt

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https://bugs.launchpad.net/bugs/423252

Title:
  NSS using LDAP+SSL breaks setuid applications like su, sudo, apache2
  suexec, and atd

Status in Release Notes for Ubuntu:
  Fix Released
Status in “eglibc” package in Ubuntu:
  Invalid
Status in “libgcrypt11” package in Ubuntu:
  Fix Released
Status in “libnss-ldap” package in Ubuntu:
  Invalid
Status in “sudo” package in Ubuntu:
  Invalid
Status in “eglibc” source package in Lucid:
  Invalid
Status in “libgcrypt11” source package in Lucid:
  Fix Released
Status in “libnss-ldap” source package in Lucid:
  Invalid
Status in “sudo” source package in Lucid:
  Invalid
Status in “eglibc” source package in Maverick:
  Invalid
Status in “libgcrypt11” source package in Maverick:
  Won't Fix
Status in “libnss-ldap” source package in Maverick:
  Confirmed
Status in “sudo” source package in Maverick:
  Invalid
Status in “eglibc” source package in Natty:
  New
Status in “libgcrypt11” source package in Natty:
  Fix Committed
Status in “libnss-ldap” source package in Natty:
  New
Status in “sudo” source package in Natty:
  New
Status in “eglibc” source package in Oneiric:
  New
Status in “libgcrypt11” source package in Oneiric:
  Fix Committed
Status in “libnss-ldap” source package in Oneiric:
  New
Status in “sudo” source package in Oneiric:
  New
Status in “eglibc” source package in Precise:
  New
Status in “libgcrypt11” source package in Precise:
  Fix Released
Status in “libnss-ldap” source package in Precise:
  New
Status in “sudo” source package in Precise:
  New
Status in “eglibc” source package in Karmic:
  Invalid
Status in “libgcrypt11” source package in Karmic:
  Won't Fix
Status in “libnss-ldap” source package in Karmic:
  Invalid
Status in “sudo” source package in Karmic:
  Invalid
Status in “gnutls26” package in Debian:
  New
Status in “libgcrypt11” package in Debian:
  Confirmed
Status in “openldap” package in Debian:
  New
Status in “sudo” package in Debian:
  Confirmed
Status in “sudo” package in Kairos Linux:
  Confirmed

Bug description:
  SRU Request:

  [Impact]
  As heavily outlined in the amount of comments in this bug the impact is detrimental to both community and enterprise users alike.

  [Development Fix]
  Howard Chu released a patch in #73 which was later confirmed in #106 & #108 as a resolution.

  [Stable Fix]
  Patch from #73 can be applied cleanly to Lucid and new distributions.

  [Test Case]
  On Karmic (alpha 4 plus updates), changing the nsswitch.conf 'passwd' field to anything with 'ldap' as the first item breaks the ability to become root using 'su' and 'sudo' as anyone but root.

  Default nsswitch.conf:

  passwd:         compat
  group:          compat
  shadow:         compat

  matt at box:~$ sudo uname -a
  [sudo] password for matt:
  Linux box 2.6.31-9-server #29-Ubuntu SMP Sun Aug 30 18:37:42 UTC 2009 x86_64 GNU/Linux

  matt at box:~$ su -
  Password:
  root at box:~#

  Modified nsswitch.conf with 'ldap' before 'compat':

  passwd:         ldap compat
  group:          ldap compat
  shadow:         ldap compat

  matt at box:~$ sudo uname -a
  sudo: setreuid(ROOT_UID, user_uid): Operation not permitted

  matt at box:~$ su -
  Password:
  setgid: Operation not permitted

  Modified nsswitch.conf with 'ldap' after 'compat':

  passwd:         compat ldap
  group:          compat ldap
  shadow:         compat ldap

  matt at box:~$ sudo uname -a
  [sudo] password for matt:
  Linux box 2.6.31-9-server #29-Ubuntu SMP Sun Aug 30 18:37:42 UTC 2009 x86_64 GNU/Linux

  matt at box:~$ su -
  Password:
  root at box:~#

  The same arrangements in nsswitch.conf work as expected in Jaunty and
  earlier releases.

  [Regression Potential]
  This should be minimal as the code change only addresses the duplicating global_init during thread callbacks.

  Lucid Release Note:

  == NSS via LDAP+SSL breaks setuid applications like sudo ==

  Upgrading systems configured to use ldap over ssl as the first service
  in the nss stack (in nsswitch.conf) leads to a broken nss resolution
  for setuid applications after the upgrade to Lucid (for example sudo
  would stop working). There isn't any simple workaround for now. One
  option is to switch to libnss-ldapd in place of libnss-ldap before the
  upgrade. Another one consists in using nscd before the upgrade.

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