proc: restrict access to /proc/PID/io
authorVasiliy Kulikov <segoon@openwall.com>
Fri, 24 Jun 2011 12:08:38 +0000 (16:08 +0400)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 28 Jun 2011 16:39:11 +0000 (09:39 -0700)
commit1d1221f375c94ef961ba8574ac4f85c8870ddd51
tree1e05f1c33bef03a88745c55ac9891b8423ae1795
parentb0af8dfdd67699e25083478c63eedef2e72ebd85
proc: restrict access to /proc/PID/io

/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>
fs/proc/base.c