Module Name: src
Committed By: christos
Date: Mon Aug 23 20:53:08 UTC 2010
Modified Files:
src/sys/kern: exec_subr.c kern_pax.c
Log Message:
Fix issues with stack allocation and pax aslr:
- since the size is unsigned, don't check just that it is > 0, but limit
it to the MAXSSIZ
- if the stack size is reduced because of aslr, make sure we reduce the
actual allocation by the same size so that the size does not wrap around.
NB: Must be pulled up to 5.x!
To generate a diff of this commit:
cvs rdiff -u -r1.64 -r1.65 src/sys/kern/exec_subr.c
cvs rdiff -u -r1.23 -r1.24 src/sys/kern/kern_pax.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/exec_subr.c
diff -u src/sys/kern/exec_subr.c:1.64 src/sys/kern/exec_subr.c:1.65
--- src/sys/kern/exec_subr.c:1.64 Thu Jun 24 09:03:11 2010
+++ src/sys/kern/exec_subr.c Mon Aug 23 16:53:08 2010
@@ -1,4 +1,4 @@
-/* $NetBSD: exec_subr.c,v 1.64 2010/06/24 13:03:11 hannken Exp $ */
+/* $NetBSD: exec_subr.c,v 1.65 2010/08/23 20:53:08 christos Exp $ */
/*
* Copyright (c) 1993, 1994, 1996 Christopher G. Demetriou
@@ -31,7 +31,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: exec_subr.c,v 1.64 2010/06/24 13:03:11 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: exec_subr.c,v 1.65 2010/08/23 20:53:08 christos Exp $");
#include "opt_pax.h"
@@ -388,6 +388,7 @@
epp->ep_minsaddr = USRSTACK;
max_stack_size = MAXSSIZ;
}
+ epp->ep_ssize = l->l_proc->p_rlimit[RLIMIT_STACK].rlim_cur;
#ifdef PAX_ASLR
pax_aslr_stack(l, epp, &max_stack_size);
@@ -397,7 +398,6 @@
epp->ep_maxsaddr = (vaddr_t)STACK_GROW(epp->ep_minsaddr,
max_stack_size);
- epp->ep_ssize = l->l_proc->p_rlimit[RLIMIT_STACK].rlim_cur;
/*
* set up commands for stack. note that this takes *two*, one to
@@ -412,11 +412,11 @@
noaccess_size = max_stack_size - access_size;
noaccess_linear_min = (vaddr_t)STACK_ALLOC(STACK_GROW(epp->ep_minsaddr,
access_size), noaccess_size);
- if (noaccess_size > 0) {
+ if (noaccess_size > 0 && noaccess_size <= MAXSSIZ) {
NEW_VMCMD2(&epp->ep_vmcmds, vmcmd_map_zero, noaccess_size,
noaccess_linear_min, NULL, 0, VM_PROT_NONE, VMCMD_STACK);
}
- KASSERT(access_size > 0);
+ KASSERT(access_size > 0 && access_size <= MAXSSIZ);
NEW_VMCMD2(&epp->ep_vmcmds, vmcmd_map_zero, access_size,
access_linear_min, NULL, 0, VM_PROT_READ | VM_PROT_WRITE,
VMCMD_STACK);
Index: src/sys/kern/kern_pax.c
diff -u src/sys/kern/kern_pax.c:1.23 src/sys/kern/kern_pax.c:1.24
--- src/sys/kern/kern_pax.c:1.23 Mon Mar 15 16:35:20 2010
+++ src/sys/kern/kern_pax.c Mon Aug 23 16:53:08 2010
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_pax.c,v 1.23 2010/03/15 20:35:20 christos Exp $ */
+/* $NetBSD: kern_pax.c,v 1.24 2010/08/23 20:53:08 christos Exp $ */
/*-
* Copyright (c) 2006 Elad Efrat <e...@netbsd.org>
@@ -28,7 +28,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_pax.c,v 1.23 2010/03/15 20:35:20 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_pax.c,v 1.24 2010/08/23 20:53:08 christos Exp $");
#include "opt_pax.h"
@@ -353,6 +353,8 @@
#endif
epp->ep_minsaddr -= d;
*max_stack_size -= d;
+ if (epp->ep_ssize > *max_stack_size)
+ epp->ep_ssize = *max_stack_size;
}
}
#endif /* PAX_ASLR */
