[Pkg-shadow-devel] Bug#524193: login: segfaults if run from already logged in user

[Sven Joachim]

Package: login
Version: 1:4.1.3-1

While examining #524139, I noticed a null pointer dereference if login
is run without arguments:

,----
| # gdb login
| GNU gdb 6.8-debian
| Copyright (C) 2008 Free Software Foundation, Inc.
| License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
| This is free software: you are free to change and redistribute it.
| There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
| and "show warranty" for details.
| This GDB was configured as "i486-linux-gnu"...
| (gdb) run
| Starting program: /usr/local/src/deb-src/shadow/shadow-4.1.3/src/login 
| 
| Program received signal SIGSEGV, Segmentation fault.
| 0x0804a557 in main (argc=1, argv=0xffee4544) at login.c:679
| 679                     if (pam_user[0] == '\0') {
| (gdb) bt
| #0  0x0804a557 in main (argc=1, argv=0xffee4544) at login.c:679
| (gdb) print pam_user 
| $1 = 0x0
| (gdb) quit
| The program is running.  Exit anyway? (y or n) y
`----

Version 1:4.1.1-6 does not have this problem.


-- System Information:
Debian Release: squeeze/sid
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: i386 (x86_64)

Kernel: Linux 2.6.28.9-amd64 (SMP w/2 CPU cores)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages login depends on:
ii  libc6                         2.9-7      GNU C Library: Shared libraries
ii  libpam-modules                1.0.1-9    Pluggable Authentication Modules f
ii  libpam-runtime                1.0.1-9    Runtime support for the PAM librar
ii  libpam0g                      1.0.1-9    Pluggable Authentication Modules l

login recommends no packages.

login suggests no packages.

-- no debconf information