1 /* $OpenBSD: sandbox-rlimit.c,v 1.5 2020/10/18 11:32:01 djm Exp $ */
2 /*
3 * Copyright (c) 2011 Damien Miller <djm@mindrot.org>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18 #include "includes.h"
19 __RCSID("$NetBSD: sandbox-rlimit.c,v 1.7 2021/03/05 17:47:16 christos Exp $");
20 #include <sys/types.h>
21 #include <sys/time.h>
22 #include <sys/resource.h>
23
24 #include <errno.h>
25 #include <stdarg.h>
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <unistd.h>
30
31 #include "log.h"
32 #include "ssh-sandbox.h"
33 #include "xmalloc.h"
34
35 /* Minimal sandbox that sets zero nfiles, nprocs and filesize rlimits */
36
37 struct ssh_sandbox {
38 pid_t child_pid;
39 };
40
41 struct ssh_sandbox *
ssh_sandbox_init(void)42 ssh_sandbox_init(void)
43 {
44 struct ssh_sandbox *box;
45
46 /*
47 * Strictly, we don't need to maintain any state here but we need
48 * to return non-NULL to satisfy the API.
49 */
50 debug3_f("preparing rlimit sandbox");
51 box = xcalloc(1, sizeof(*box));
52 box->child_pid = 0;
53
54 return box;
55 }
56
57 void
ssh_sandbox_child(struct ssh_sandbox * box)58 ssh_sandbox_child(struct ssh_sandbox *box)
59 {
60 struct rlimit rl_zero;
61
62 rl_zero.rlim_cur = rl_zero.rlim_max = 0;
63
64 if (setrlimit(RLIMIT_FSIZE, &rl_zero) == -1)
65 fatal_f("setrlimit(RLIMIT_FSIZE, { 0, 0 }): %s",
66 strerror(errno));
67 if (setrlimit(RLIMIT_NOFILE, &rl_zero) == -1)
68 fatal_f("setrlimit(RLIMIT_NOFILE, { 0, 0 }): %s",
69 strerror(errno));
70 if (setrlimit(RLIMIT_NPROC, &rl_zero) == -1)
71 fatal_f("setrlimit(RLIMIT_NPROC, { 0, 0 }): %s",
72 strerror(errno));
73 }
74
75 void
ssh_sandbox_parent_finish(struct ssh_sandbox * box)76 ssh_sandbox_parent_finish(struct ssh_sandbox *box)
77 {
78 free(box);
79 debug3_f("finished");
80 }
81
82 void
ssh_sandbox_parent_preauth(struct ssh_sandbox * box,pid_t child_pid)83 ssh_sandbox_parent_preauth(struct ssh_sandbox *box, pid_t child_pid)
84 {
85 box->child_pid = child_pid;
86 /* Nothing to do here */
87 }
88
89