tree ed3bc6912a5dabd756f01e5cbafe49259cca1b2f
parent 64b1641d7c7b9a65619522a11ce4abe9b8fd2d9c
author Vasiliy Kulikov <segoon@openwall.com> 1308917318 +0400
committer Greg Kroah-Hartman <gregkh@suse.de> 1312400571 -0700

proc: restrict access to /proc/PID/io

commit 1d1221f375c94ef961ba8574ac4f85c8870ddd51 upstream.

/proc/PID/io may be used for gathering private information.  E.g.  for
openssh and vsftpd daemons wchars/rchars may be used to learn the
precise password length.  Restrict it to processes being able to ptrace
the target process.

ptrace_may_access() is needed to prevent keeping open file descriptor of
"io" file, executing setuid binary and gathering io information of the
setuid'ed process.

Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>