diff options
| author | Brent Cook <bcook@cvs.openbsd.org> | 2016-01-04 02:04:57 +0000 |
|---|---|---|
| committer | Brent Cook <bcook@cvs.openbsd.org> | 2016-01-04 02:04:57 +0000 |
| commit | 51ba3d277d2aaf6c936db2ad0155291df06e0d4e (patch) | |
| tree | 06bc0be4c0dc0eb3536d3057f10317f8fce148e1 /lib/libcrypto/arc4random | |
| parent | d83b5378ef7949036592dff377f4c457e302354e (diff) | |
Calling clone(2) with CLONE_NEWPID yields multiple processes with pid=1.
Work around this particular case by reseeding whenever pid=1, but as guenther@
notes, directly calling clone(2), and then forking to match another pid,
provides other ways to bypass new process detection on Linux.
Hopefully at some point Linux implements something like MAP_INHERIT_ZERO, and
does not invent a corresponding mechanism to subvert it.
Noted by Sebastian Krahmer and the opmsg team.
See http://stealth.openwall.net/crypto/randup.c for a test program.
ok beck@
Diffstat (limited to 'lib/libcrypto/arc4random')
| -rw-r--r-- | lib/libcrypto/arc4random/arc4random_linux.h | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/lib/libcrypto/arc4random/arc4random_linux.h b/lib/libcrypto/arc4random/arc4random_linux.h index 3296fdeca17..303deb57861 100644 --- a/lib/libcrypto/arc4random/arc4random_linux.h +++ b/lib/libcrypto/arc4random/arc4random_linux.h @@ -1,4 +1,4 @@ -/* $OpenBSD: arc4random_linux.h,v 1.9 2015/01/15 06:57:18 deraadt Exp $ */ +/* $OpenBSD: arc4random_linux.h,v 1.10 2016/01/04 02:04:56 bcook Exp $ */ /* * Copyright (c) 1996, David Mazieres <dm@uun.org> @@ -60,7 +60,8 @@ _rs_forkdetect(void) static pid_t _rs_pid = 0; pid_t pid = getpid(); - if (_rs_pid == 0 || _rs_pid != pid || _rs_forked) { + /* XXX unusual calls to clone() can bypass checks */ + if (_rs_pid == 0 || _rs_pid == 1 || _rs_pid != pid || _rs_forked) { _rs_pid = pid; _rs_forked = 0; if (rs) |