[Pkg-shadow-devel] Bug#396241: login: Executing su cause an "invalid pointer" error

[Frederic Schutz]

Package: login
Version: 1:4.0.18.1-5
Severity: important

Executing "su" yields an "invalid pointer" error. This is what happens
if the password entered is correct:

  schutz at sib-pc17:~$ su - root
  Password:
  
  *** glibc detected *** free(): invalid pointer: 0xbfec0120 ***
  *** glibc detected *** free(): invalid pointer: 0xbfec0120 ***
  Aborted
  schutz at sib-pc17:~$

and if the password is incorrect:

  schutz at sib-pc17:~$ su - root
  Password:
  Password:
  su: Authentication failure
  *** glibc detected *** free(): invalid pointer: 0xbf8a02a0 ***
  Aborted
  schutz at sib-pc17:~$

The same happens if I try to "su" to another user than root; however,
logging into root (using ssh) and "su" to another user works. I realise
that su may not be at fault, and that another program (such as pam) may
be the culprit, but I don't have any lead so far.

Setting the environement variable MALLOC_CHECK_=1, as indicated on
several web pages after googling for the error, did not help at all.

I almost picked an RC severity for this bug, but did not (for now) because
I can still login using ssh.

This originally happenend with testing; however, I updated the libraries
piecewise to unstable to see if it made any difference.

Any help welcome !

Thanks in advance,

Frédéric

-- System Information:
Debian Release: testing/unstable
  APT prefers unstable
  APT policy: (500, 'unstable'), (500, 'testing')
Architecture: i386 (i686)
Shell:  /bin/sh linked to /bin/bash
Kernel: Linux 2.6.17-2-686-bigmem
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)

Versions of packages login depends on:
ii  libc6                        2.3.6.ds1-7 GNU C Library: Shared libraries
ii  libpam-modules               0.79-4      Pluggable Authentication Modules f
ii  libpam-runtime               0.79-4      Runtime support for the PAM librar
ii  libpam0g                     0.79-4      Pluggable Authentication Modules l

login recommends no packages.

-- no debconf information