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122 lines
3.3 KiB
122 lines
3.3 KiB
/* |
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* Copyright (c) 2011 Dag-Erling Smorgrav |
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* |
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* Permission to use, copy, modify, and distribute this software for any |
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* purpose with or without fee is hereby granted, provided that the above |
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* copyright notice and this permission notice appear in all copies. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
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*/ |
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#include "includes.h" |
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#ifdef SANDBOX_CAPSICUM |
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#include <sys/types.h> |
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#include <sys/param.h> |
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#include <sys/time.h> |
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#include <sys/resource.h> |
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#include <sys/capability.h> |
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#include <errno.h> |
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#include <stdarg.h> |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#include <unistd.h> |
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#include "log.h" |
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#include "monitor.h" |
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#include "ssh-sandbox.h" |
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#include "xmalloc.h" |
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/* |
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* Capsicum sandbox that sets zero nfiles, nprocs and filesize rlimits, |
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* limits rights on stdout, stdin, stderr, monitor and switches to |
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* capability mode. |
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*/ |
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struct ssh_sandbox { |
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struct monitor *monitor; |
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pid_t child_pid; |
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}; |
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struct ssh_sandbox * |
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ssh_sandbox_init(struct monitor *monitor) |
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{ |
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struct ssh_sandbox *box; |
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/* |
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* Strictly, we don't need to maintain any state here but we need |
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* to return non-NULL to satisfy the API. |
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*/ |
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debug3("%s: preparing capsicum sandbox", __func__); |
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box = xcalloc(1, sizeof(*box)); |
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box->monitor = monitor; |
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box->child_pid = 0; |
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return box; |
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} |
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void |
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ssh_sandbox_child(struct ssh_sandbox *box) |
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{ |
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struct rlimit rl_zero; |
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cap_rights_t rights; |
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rl_zero.rlim_cur = rl_zero.rlim_max = 0; |
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if (setrlimit(RLIMIT_FSIZE, &rl_zero) == -1) |
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fatal("%s: setrlimit(RLIMIT_FSIZE, { 0, 0 }): %s", |
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__func__, strerror(errno)); |
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#ifndef SANDBOX_SKIP_RLIMIT_NOFILE |
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if (setrlimit(RLIMIT_NOFILE, &rl_zero) == -1) |
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fatal("%s: setrlimit(RLIMIT_NOFILE, { 0, 0 }): %s", |
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__func__, strerror(errno)); |
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#endif |
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if (setrlimit(RLIMIT_NPROC, &rl_zero) == -1) |
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fatal("%s: setrlimit(RLIMIT_NPROC, { 0, 0 }): %s", |
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__func__, strerror(errno)); |
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cap_rights_init(&rights); |
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if (cap_rights_limit(STDIN_FILENO, &rights) < 0 && errno != ENOSYS) |
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fatal("can't limit stdin: %m"); |
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if (cap_rights_limit(STDOUT_FILENO, &rights) < 0 && errno != ENOSYS) |
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fatal("can't limit stdout: %m"); |
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if (cap_rights_limit(STDERR_FILENO, &rights) < 0 && errno != ENOSYS) |
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fatal("can't limit stderr: %m"); |
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cap_rights_init(&rights, CAP_READ, CAP_WRITE); |
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if (cap_rights_limit(box->monitor->m_recvfd, &rights) < 0 && |
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errno != ENOSYS) |
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fatal("%s: failed to limit the network socket", __func__); |
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cap_rights_init(&rights, CAP_WRITE); |
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if (cap_rights_limit(box->monitor->m_log_sendfd, &rights) < 0 && |
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errno != ENOSYS) |
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fatal("%s: failed to limit the logging socket", __func__); |
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if (cap_enter() < 0 && errno != ENOSYS) |
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fatal("%s: failed to enter capability mode", __func__); |
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} |
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void |
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ssh_sandbox_parent_finish(struct ssh_sandbox *box) |
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{ |
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free(box); |
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debug3("%s: finished", __func__); |
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} |
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void |
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ssh_sandbox_parent_preauth(struct ssh_sandbox *box, pid_t child_pid) |
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{ |
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box->child_pid = child_pid; |
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} |
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#endif /* SANDBOX_CAPSICUM */
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