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We need VMCMDs for a binary and its interpreter, so make sure we have 

at least one VMCMD. This also prevents the kernel from using an
uninitialized pointer as entry point for the execution.

From me and Christos

ok christos@
This commit is contained in:
maxv 2014-02-19 15:23:20 +00:00
parent 7ca3eda1e9
commit c22b5e2a12
2 changed files with 22 additions and 8 deletions
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23
sys/kern/exec_elf.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: exec_elf.c,v 1.58 2014/02/16 17:46:36 maxv Exp $ */ /* $NetBSD: exec_elf.c,v 1.59 2014/02/19 15:23:20 maxv Exp $ */
/*- /*-
* Copyright (c) 1994, 2000, 2005 The NetBSD Foundation, Inc. * Copyright (c) 1994, 2000, 2005 The NetBSD Foundation, Inc.
@ -57,7 +57,7 @@
*/ */
#include <sys/cdefs.h> #include <sys/cdefs.h>
__KERNEL_RCSID(1, "$NetBSD: exec_elf.c,v 1.58 2014/02/16 17:46:36 maxv Exp $"); __KERNEL_RCSID(1, "$NetBSD: exec_elf.c,v 1.59 2014/02/19 15:23:20 maxv Exp $");
#ifdef _KERNEL_OPT #ifdef _KERNEL_OPT
#include "opt_pax.h" #include "opt_pax.h"
@ -796,6 +796,14 @@ exec_elf_makecmds(struct lwp *l, struct exec_package *epp)
break; break;
} }
} }
if (epp->ep_vmcmds.evs_cmds == NULL) {
/* No VMCMD; there was no PT_LOAD section, or those
* sections were empty */
error = ENOEXEC;
goto bad;
}
if (interp || (epp->ep_flags & EXEC_FORCEAUX) != 0) { if (interp || (epp->ep_flags & EXEC_FORCEAUX) != 0) {
ap = kmem_alloc(sizeof(*ap), KM_SLEEP); ap = kmem_alloc(sizeof(*ap), KM_SLEEP);
ap->arg_interp = (vaddr_t)NULL; ap->arg_interp = (vaddr_t)NULL;
@ -811,7 +819,7 @@ exec_elf_makecmds(struct lwp *l, struct exec_package *epp)
* its interpreter * its interpreter
*/ */
if (interp) { if (interp) {
int j = epp->ep_vmcmds.evs_used; int nused = epp->ep_vmcmds.evs_used;
u_long interp_offset = 0; u_long interp_offset = 0;
if ((error = elf_load_file(l, epp, interp, if ((error = elf_load_file(l, epp, interp,
@ -819,7 +827,14 @@ exec_elf_makecmds(struct lwp *l, struct exec_package *epp)
kmem_free(ap, sizeof(*ap)); kmem_free(ap, sizeof(*ap));
goto bad; goto bad;
} }
ap->arg_interp = epp->ep_vmcmds.evs_cmds[j].ev_addr; if (epp->ep_vmcmds.evs_used == nused) {
/* elf_load_file() has not set up any new VMCMD */
kmem_free(ap, sizeof(*ap));
error = ENOEXEC;
goto bad;
}
ap->arg_interp = epp->ep_vmcmds.evs_cmds[nused].ev_addr;
epp->ep_entry = ap->arg_interp + interp_offset; epp->ep_entry = ap->arg_interp + interp_offset;
PNBUF_PUT(interp); PNBUF_PUT(interp);
} else } else

7
sys/kern/kern_exec.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: kern_exec.c,v 1.376 2014/02/17 19:29:46 maxv Exp $ */ /* $NetBSD: kern_exec.c,v 1.377 2014/02/19 15:23:20 maxv Exp $ */
/*- /*-
* Copyright (c) 2008 The NetBSD Foundation, Inc. * Copyright (c) 2008 The NetBSD Foundation, Inc.
@ -59,7 +59,7 @@
*/ */
#include <sys/cdefs.h> #include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_exec.c,v 1.376 2014/02/17 19:29:46 maxv Exp $"); __KERNEL_RCSID(0, "$NetBSD: kern_exec.c,v 1.377 2014/02/19 15:23:20 maxv Exp $");
#include "opt_exec.h" #include "opt_exec.h"
#include "opt_execfmt.h" #include "opt_execfmt.h"
@ -658,8 +658,7 @@ execve_loadvm(struct lwp *l, const char *path, char * const *args,
data->ed_pack.ep_hdrvalid = 0; data->ed_pack.ep_hdrvalid = 0;
data->ed_pack.ep_emul_arg = NULL; data->ed_pack.ep_emul_arg = NULL;
data->ed_pack.ep_emul_arg_free = NULL; data->ed_pack.ep_emul_arg_free = NULL;
data->ed_pack.ep_vmcmds.evs_cnt = 0; memset(&data->ed_pack.ep_vmcmds, 0, sizeof(data->ed_pack.ep_vmcmds));
data->ed_pack.ep_vmcmds.evs_used = 0;
data->ed_pack.ep_vap = &data->ed_attr; data->ed_pack.ep_vap = &data->ed_attr;
data->ed_pack.ep_flags = 0; data->ed_pack.ep_flags = 0;
MD_TOPDOWN_INIT(&data->ed_pack); MD_TOPDOWN_INIT(&data->ed_pack);