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
20 #ifdef SANDBOX_RLIMIT
21
22 #include <sys/types.h>
23 #include <sys/time.h>
24 #include <sys/resource.h>
25
26 #include <errno.h>
27 #include <stdarg.h>
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <unistd.h>
32
33 #include "log.h"
34 #include "ssh-sandbox.h"
35 #include "xmalloc.h"
36
37 /* Minimal sandbox that sets zero nfiles, nprocs and filesize rlimits */
38
39 struct ssh_sandbox {
40 pid_t child_pid;
41 };
42
43 struct ssh_sandbox *
ssh_sandbox_init(struct monitor * monitor)44 ssh_sandbox_init(struct monitor *monitor)
45 {
46 struct ssh_sandbox *box;
47
48 /*
49 * Strictly, we don't need to maintain any state here but we need
50 * to return non-NULL to satisfy the API.
51 */
52 debug3_f("preparing rlimit sandbox");
53 box = xcalloc(1, sizeof(*box));
54 box->child_pid = 0;
55
56 return box;
57 }
58
59 void
ssh_sandbox_child(struct ssh_sandbox * box)60 ssh_sandbox_child(struct ssh_sandbox *box)
61 {
62 struct rlimit rl_zero;
63
64 rl_zero.rlim_cur = rl_zero.rlim_max = 0;
65
66 #ifndef SANDBOX_SKIP_RLIMIT_FSIZE
67 if (setrlimit(RLIMIT_FSIZE, &rl_zero) == -1)
68 fatal_f("setrlimit(RLIMIT_FSIZE, { 0, 0 }): %s",
69 strerror(errno));
70 #endif
71 #ifndef SANDBOX_SKIP_RLIMIT_NOFILE
72 if (setrlimit(RLIMIT_NOFILE, &rl_zero) == -1)
73 fatal_f("setrlimit(RLIMIT_NOFILE, { 0, 0 }): %s",
74 strerror(errno));
75 #endif
76 #ifdef HAVE_RLIMIT_NPROC
77 if (setrlimit(RLIMIT_NPROC, &rl_zero) == -1)
78 fatal_f("setrlimit(RLIMIT_NPROC, { 0, 0 }): %s",
79 strerror(errno));
80 #endif
81 }
82
83 void
ssh_sandbox_parent_finish(struct ssh_sandbox * box)84 ssh_sandbox_parent_finish(struct ssh_sandbox *box)
85 {
86 free(box);
87 debug3_f("finished");
88 }
89
90 void
ssh_sandbox_parent_preauth(struct ssh_sandbox * box,pid_t child_pid)91 ssh_sandbox_parent_preauth(struct ssh_sandbox *box, pid_t child_pid)
92 {
93 box->child_pid = child_pid;
94 }
95
96 #endif /* SANDBOX_RLIMIT */
97