COMMAND
tcsh
SYSTEMS AFFECTED
RedHat 5.2 and others using tcsh 6.07.09-1
PROBLEM
arkth posted following about another overflow in tcsh-6.07.09-1.
The problem is in too long $HOME evironment variable (very old
thing - zgv overflow). It's not a dangerous problem, but like
someone said this shell can be used in some kind of script with
SUID, etc. Example:
$ HOME=AAAAAAAAAAAAAAA...AAA
$ export HOME
$ tcsh
Segmentation fault (core dumped)
$ gdb tcsh core
GNU gdb 4.17.0.4 with Linux/x86 hardware watchpoint and FPU support
Copyright 1998 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB. Type "show warranty" for details.
This GDB was configured as "i386-redhat-linux"...
(no debugging symbols found)...
Core was generated by `-csh'.
Program terminated with signal 11, Segmentation fault.
Reading symbols from /lib/libnsl.so.1...done.
Reading symbols from /lib/libtermcap.so.2...done.
Reading symbols from /lib/libcrypt.so.1...done.
Reading symbols from /lib/libc.so.6...done.
Reading symbols from /lib/ld-linux.so.2...done.
Reading symbols from /lib/libnss_files.so.1...done.
#0 0x410041 in ?? ()
(gdb)
SOLUTION
V6.07.12 fixed it. However, the "exploit" given using tcsh
6.08.04 will result that tcsh still crashes, but this time with a
SIGABRT rather than SIGSEGV.