News
Vigil@nce - Linux kernel: memory corruption via n_tty_write
May 2014 by Vigil@nce
This bulletin was written by Vigil@nce : http://vigilance.fr/offer
SYNTHESIS OF THE VULNERABILITY
A local attacker can generate a memory corruption in the
n_tty_write() function of the Linux kernel, in order to trigger a
denial of service, and possibly to execute code.
– Impacted products: Debian, Fedora, Linux, openSUSE, RHEL, SUSE
Linux Enterprise Desktop, SLES, Ubuntu
– Severity: 2/4
– Creation date: 05/05/2014
DESCRIPTION OF THE VULNERABILITY
The drivers/tty/n_tty.c file of the Linux kernel implements a
driver for terminals (tty).
The c_lflags field of the termios structure uses the ECHO flag to
indicate to display received characters. The c_oflag field uses
the OPOST flag to indicate to post-process the output (management
of Unix/Dos line feeds).
The n_tty_write() function writes on a tty. However, if ECHO and
OPOST are set, and if two processes simultaneously write on the
tty, the access to a memory area is not locked.
A local attacker can therefore generate a memory corruption in the
n_tty_write() function of the Linux kernel, in order to trigger a
denial of service, and possibly to execute code.
ACCESS TO THE COMPLETE VIGIL@NCE BULLETIN
http://vigilance.fr/vulnerability/Linux-kernel-memory-corruption-via-n-tty-write-14698
