crypto/openssh/sandbox-rlimit.c

   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 *
  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
  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
  84 ssh_sandbox_parent_finish(struct ssh_sandbox *box)
  85 {
  86         free(box);
  87         debug3_f("finished");
  88 }
  89
  90 void
  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 */