tree 1e05f1c33bef03a88745c55ac9891b8423ae1795
parent b0af8dfdd67699e25083478c63eedef2e72ebd85
author Vasiliy Kulikov <segoon@openwall.com> 1308917318 +0400
committer Linus Torvalds <torvalds@linux-foundation.org> 1309279151 -0700

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>