diff options
Diffstat (limited to 'sys/kern')
| -rw-r--r-- | sys/kern/kern_exec.c | 21 |
1 files changed, 10 insertions, 11 deletions
diff --git a/sys/kern/kern_exec.c b/sys/kern/kern_exec.c index 68b237ef786..a6faedd19fe 100644 --- a/sys/kern/kern_exec.c +++ b/sys/kern/kern_exec.c @@ -1,4 +1,4 @@ -/* $OpenBSD: kern_exec.c,v 1.137 2014/01/21 01:48:44 tedu Exp $ */ +/* $OpenBSD: kern_exec.c,v 1.138 2014/03/19 00:01:56 deraadt Exp $ */ /* $NetBSD: kern_exec.c,v 1.75 1996/02/09 18:59:28 christos Exp $ */ /*- @@ -81,9 +81,8 @@ int exec_sigcode_map(struct proc *, struct emul *); /* - * stackgap_random specifies if the stackgap should have a random size added - * to it. Must be a n^2. If non-zero, the stack gap will be calculated as: - * (arc4random() * ALIGNBYTES) & (stackgap_random - 1) + STACKGAPLEN. + * If non-zero, stackgap_random specifies the upper limit of the random gap size + * added to the fixed stack gap. Must be n^2. */ int stackgap_random = STACKGAP_RANDOM; @@ -391,19 +390,19 @@ sys_execve(struct proc *p, void *v, register_t *retval) } } - dp = (char *)ALIGN(dp); + dp = (char *)(((long)dp + _STACKALIGNBYTES) & ~_STACKALIGNBYTES); sgap = STACKGAPLEN; - if (stackgap_random != 0) - sgap += (arc4random() * ALIGNBYTES) & (stackgap_random - 1); -#ifdef MACHINE_STACK_GROWS_UP - sgap = ALIGN(sgap); -#endif + if (stackgap_random != 0) { + sgap += arc4random() & (stackgap_random - 1); + sgap = (sgap + _STACKALIGNBYTES) & ~_STACKALIGNBYTES; + } + /* Now check if args & environ fit into new stack */ len = ((argc + envc + 2 + pack.ep_emul->e_arglen) * sizeof(char *) + sizeof(long) + dp + sgap + sizeof(struct ps_strings)) - argp; - len = ALIGN(len); /* make the stack "safely" aligned */ + len = (len + _STACKALIGNBYTES) &~ _STACKALIGNBYTES; if (len > pack.ep_ssize) { /* in effect, compare to initial limit */ error = ENOMEM; |