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1 /* $OpenBSD: sandbox-rlimit.c,v 1.3 2011/06/23 09:34:13 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/param.h>
24 #include <sys/time.h>
25 #include <sys/resource.h>
26 
27 #include <errno.h>
28 #include <stdarg.h>
29 #include <stdio.h>
30 #include <stdlib.h>
31 #include <string.h>
32 #include <unistd.h>
33 
34 #include "log.h"
35 #include "ssh-sandbox.h"
36 #include "xmalloc.h"
37 
38 /* Minimal sandbox that sets zero nfiles, nprocs and filesize rlimits */
39 
40 struct ssh_sandbox {
41 	pid_t child_pid;
42 };
43 
44 struct ssh_sandbox *
ssh_sandbox_init(void)45 ssh_sandbox_init(void)
46 {
47 	struct ssh_sandbox *box;
48 
49 	/*
50 	 * Strictly, we don't need to maintain any state here but we need
51 	 * to return non-NULL to satisfy the API.
52 	 */
53 	debug3("%s: preparing rlimit sandbox", __func__);
54 	box = xcalloc(1, sizeof(*box));
55 	box->child_pid = 0;
56 
57 	return box;
58 }
59 
60 void
ssh_sandbox_child(struct ssh_sandbox * box)61 ssh_sandbox_child(struct ssh_sandbox *box)
62 {
63 	struct rlimit rl_zero;
64 
65 	rl_zero.rlim_cur = rl_zero.rlim_max = 0;
66 
67 	if (setrlimit(RLIMIT_FSIZE, &rl_zero) == -1)
68 		fatal("%s: setrlimit(RLIMIT_FSIZE, { 0, 0 }): %s",
69 			__func__, strerror(errno));
70 	if (setrlimit(RLIMIT_NOFILE, &rl_zero) == -1)
71 		fatal("%s: setrlimit(RLIMIT_NOFILE, { 0, 0 }): %s",
72 			__func__, strerror(errno));
73 #ifdef HAVE_RLIMIT_NPROC
74 	if (setrlimit(RLIMIT_NPROC, &rl_zero) == -1)
75 		fatal("%s: setrlimit(RLIMIT_NPROC, { 0, 0 }): %s",
76 			__func__, strerror(errno));
77 #endif
78 }
79 
80 void
ssh_sandbox_parent_finish(struct ssh_sandbox * box)81 ssh_sandbox_parent_finish(struct ssh_sandbox *box)
82 {
83 	free(box);
84 	debug3("%s: finished", __func__);
85 }
86 
87 void
ssh_sandbox_parent_preauth(struct ssh_sandbox * box,pid_t child_pid)88 ssh_sandbox_parent_preauth(struct ssh_sandbox *box, pid_t child_pid)
89 {
90 	box->child_pid = child_pid;
91 }
92 
93 #endif /* SANDBOX_RLIMIT */
94