diff options
| author |   bcook <bcook@openbsd.org> | 2016-01-04 02:04:56 +0000 |
|---|---|---|
| committer | bcook <bcook@openbsd.org> | 2016-01-04 02:04:56 +0000 |
| commit | 16ddbd421970f0a6f0310bb7de7893b213ea14d8 (patch) | |
| tree | d7779a681ae6363637ddf8c648afbe4dc55769e8 | |
| parent | Do proper termination of VMs by doing proper VCPU run state management. (diff) | |
| download | wireguard-openbsd-16ddbd421970f0a6f0310bb7de7893b213ea14d8.tar.xz wireguard-openbsd-16ddbd421970f0a6f0310bb7de7893b213ea14d8.zip | |
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@
| -rw-r--r-- | lib/libcrypto/arc4random/arc4random_linux.h | 5 | ||||
| -rw-r--r-- | lib/libcrypto/crypto/arc4random_linux.h | 5 |
2 files changed, 6 insertions, 4 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) diff --git a/lib/libcrypto/crypto/arc4random_linux.h b/lib/libcrypto/crypto/arc4random_linux.h index 3296fdeca17..303deb57861 100644 --- a/lib/libcrypto/crypto/arc4random_linux.h +++ b/lib/libcrypto/crypto/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) |