diff options
| author |   miod <miod@openbsd.org> | 2015-02-09 11:52:47 +0000 |
|---|---|---|
| committer | miod <miod@openbsd.org> | 2015-02-09 11:52:47 +0000 |
| commit | 2bda40dc64ded01f64f2729a3910b84c37f10acb (patch) | |
| tree | 3b6464215676047198719b1a9a49ead146e64453 /sys/kern/exec_subr.c | |
| parent | Oups forgot to remove the enums (diff) | |
| download | wireguard-openbsd-2bda40dc64ded01f64f2729a3910b84c37f10acb.tar.xz wireguard-openbsd-2bda40dc64ded01f64f2729a3910b84c37f10acb.zip | |
Change the way stackgap_random is applied. Instead of applying it within the
fixed stack area of the exec'd image, and risking hitting process limits,
should we want to increase stackgap_random, the randomness is applied to the
stack region in the process' vmspace.
Diffstat (limited to 'sys/kern/exec_subr.c')
| -rw-r--r-- | sys/kern/exec_subr.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/sys/kern/exec_subr.c b/sys/kern/exec_subr.c index e51b6af910f..1e34ed57b50 100644 --- a/sys/kern/exec_subr.c +++ b/sys/kern/exec_subr.c @@ -1,4 +1,4 @@ -/* $OpenBSD: exec_subr.c,v 1.47 2015/02/06 23:58:12 deraadt Exp $ */ +/* $OpenBSD: exec_subr.c,v 1.48 2015/02/09 11:52:47 miod Exp $ */ /* $NetBSD: exec_subr.c,v 1.9 1994/12/04 03:10:42 mycroft Exp $ */ /* @@ -330,6 +330,7 @@ vmcmd_randomize(struct proc *p, struct exec_vmcmd *cmd) int exec_setup_stack(struct proc *p, struct exec_package *epp) { + vaddr_t sgap; #ifdef MACHINE_STACK_GROWS_UP epp->ep_maxsaddr = USRSTACK; @@ -340,6 +341,14 @@ exec_setup_stack(struct proc *p, struct exec_package *epp) #endif epp->ep_ssize = round_page(p->p_rlimit[RLIMIT_STACK].rlim_cur); + if (stackgap_random != 0) { + sgap = arc4random() & (stackgap_random - 1); + sgap = trunc_page(sgap); + + epp->ep_maxsaddr -= sgap; + epp->ep_minsaddr -= sgap; + } + /* * set up commands for stack. note that this takes *two*, one to * map the part of the stack which we can access, and one to map |