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- djm@cvs.openbsd.org 2011/07/29 14:42:45

Browse Source 
[sandbox-systrace.c]
     fail open(2) with EPERM rather than SIGKILLing the whole process. libc
     will call open() to do strerror() when NLS is enabled;
     feedback and ok markus@
This commit is contained in:
Damien Miller 2011-08-06 06:16:23 +10:00
parent 6ea5e44871
commit 35e48198a8
2 changed files with 49 additions and 34 deletions
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5
ChangeLog
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@ -8,6 +8,11 @@
bzero the agent address. the kernel was for a while very cranky about
these things. evne though that's fixed, always good to initialize
memory. ok deraadt djm
- djm@cvs.openbsd.org 2011/07/29 14:42:45
[sandbox-systrace.c]
fail open(2) with EPERM rather than SIGKILLing the whole process. libc
will call open() to do strerror() when NLS is enabled;
feedback and ok markus@
20110624
- (djm) [configure.ac Makefile.in sandbox-darwin.c] Add a sandbox for

78
sandbox-systrace.c
View File

@ -1,4 +1,4 @@
/* $OpenBSD: sandbox-systrace.c,v 1.3 2011/06/23 09:34:13 djm Exp $ */
/* $OpenBSD: sandbox-systrace.c,v 1.4 2011/07/29 14:42:45 djm Exp $ */
/*
* Copyright (c) 2011 Damien Miller <djm@mindrot.org>
*
@ -41,22 +41,30 @@
#include "ssh-sandbox.h"
#include "xmalloc.h"
static const int preauth_policy[] = {
SYS___sysctl,
SYS_close,
SYS_exit,
SYS_getpid,
SYS_gettimeofday,
SYS_madvise,
SYS_mmap,
SYS_mprotect,
SYS_poll,
SYS_munmap,
SYS_read,
SYS_select,
SYS_sigprocmask,
SYS_write,
-1
struct sandbox_policy {
int syscall;
int action;
};
/* Permitted syscalls in preauth. Unlisted syscalls get SYSTR_POLICY_KILL */
static const struct sandbox_policy preauth_policy[] = {
{ SYS_open, SYSTR_POLICY_NEVER },
{ SYS___sysctl, SYSTR_POLICY_PERMIT },
{ SYS_close, SYSTR_POLICY_PERMIT },
{ SYS_exit, SYSTR_POLICY_PERMIT },
{ SYS_getpid, SYSTR_POLICY_PERMIT },
{ SYS_gettimeofday, SYSTR_POLICY_PERMIT },
{ SYS_madvise, SYSTR_POLICY_PERMIT },
{ SYS_mmap, SYSTR_POLICY_PERMIT },
{ SYS_mprotect, SYSTR_POLICY_PERMIT },
{ SYS_poll, SYSTR_POLICY_PERMIT },
{ SYS_munmap, SYSTR_POLICY_PERMIT },
{ SYS_read, SYSTR_POLICY_PERMIT },
{ SYS_select, SYSTR_POLICY_PERMIT },
{ SYS_sigprocmask, SYSTR_POLICY_PERMIT },
{ SYS_write, SYSTR_POLICY_PERMIT },
{ -1, -1 }
};
struct ssh_sandbox {
@ -64,7 +72,6 @@ struct ssh_sandbox {
int parent_sock;
int systrace_fd;
pid_t child_pid;
struct systrace_policy policy;
};
struct ssh_sandbox *
@ -104,10 +111,11 @@ ssh_sandbox_child(struct ssh_sandbox *box)
static void
ssh_sandbox_parent(struct ssh_sandbox *box, pid_t child_pid,
const int *allowed_syscalls)
const struct sandbox_policy *allowed_syscalls)
{
int dev_systrace, i, j, found;
char whatever = 0;
struct systrace_policy policy;
debug3("%s: wait for child %ld", __func__, (long)child_pid);
box->child_pid = child_pid;
@ -131,33 +139,35 @@ ssh_sandbox_parent(struct ssh_sandbox *box, pid_t child_pid,
box->systrace_fd, child_pid, strerror(errno));
/* Allocate and assign policy */
bzero(&box->policy, sizeof(box->policy));
box->policy.strp_op = SYSTR_POLICY_NEW;
box->policy.strp_maxents = SYS_MAXSYSCALL;
if (ioctl(box->systrace_fd, STRIOCPOLICY, &box->policy) == -1)
bzero(&policy, sizeof(policy));
policy.strp_op = SYSTR_POLICY_NEW;
policy.strp_maxents = SYS_MAXSYSCALL;
if (ioctl(box->systrace_fd, STRIOCPOLICY, &policy) == -1)
fatal("%s: ioctl(%d, STRIOCPOLICY (new)): %s", __func__,
box->systrace_fd, strerror(errno));
box->policy.strp_op = SYSTR_POLICY_ASSIGN;
box->policy.strp_pid = box->child_pid;
if (ioctl(box->systrace_fd, STRIOCPOLICY, &box->policy) == -1)
policy.strp_op = SYSTR_POLICY_ASSIGN;
policy.strp_pid = box->child_pid;
if (ioctl(box->systrace_fd, STRIOCPOLICY, &policy) == -1)
fatal("%s: ioctl(%d, STRIOCPOLICY (assign)): %s",
__func__, box->systrace_fd, strerror(errno));
/* Set per-syscall policy */
for (i = 0; i < SYS_MAXSYSCALL; i++) {
for (j = found = 0; allowed_syscalls[j] != -1 && !found; j++) {
if (allowed_syscalls[j] == i)
found = 0;
for (j = 0; allowed_syscalls[j].syscall != -1; j++) {
if (allowed_syscalls[j].syscall == i) {
found = 1;
break;
}
}
box->policy.strp_op = SYSTR_POLICY_MODIFY;
box->policy.strp_code = i;
box->policy.strp_policy = found ?
SYSTR_POLICY_PERMIT : SYSTR_POLICY_KILL;
policy.strp_op = SYSTR_POLICY_MODIFY;
policy.strp_code = i;
policy.strp_policy = found ?
allowed_syscalls[j].action : SYSTR_POLICY_KILL;
if (found)
debug3("%s: policy: enable syscall %d", __func__, i);
if (ioctl(box->systrace_fd, STRIOCPOLICY,
&box->policy) == -1)
if (ioctl(box->systrace_fd, STRIOCPOLICY, &policy) == -1)
fatal("%s: ioctl(%d, STRIOCPOLICY (modify)): %s",
__func__, box->systrace_fd, strerror(errno));
}