diff options
Diffstat (limited to 'sandbox-capsicum.c')
-rw-r--r-- | sandbox-capsicum.c | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/sandbox-capsicum.c b/sandbox-capsicum.c new file mode 100644 index 0000000..1104525 --- /dev/null +++ b/sandbox-capsicum.c @@ -0,0 +1,128 @@ +/* + * Copyright (c) 2011 Dag-Erling Smorgrav + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +#include "includes.h" + +#ifdef SANDBOX_CAPSICUM + +#include <sys/types.h> +#include <sys/time.h> +#include <sys/resource.h> +#include <sys/capsicum.h> + +#include <errno.h> +#include <stdarg.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#ifdef HAVE_CAPSICUM_HELPERS_H +#include <capsicum_helpers.h> +#endif + +#include "log.h" +#include "monitor.h" +#include "ssh-sandbox.h" +#include "xmalloc.h" + +/* + * Capsicum sandbox that sets zero nfiles, nprocs and filesize rlimits, + * limits rights on stdout, stdin, stderr, monitor and switches to + * capability mode. + */ + +struct ssh_sandbox { + struct monitor *monitor; + pid_t child_pid; +}; + +struct ssh_sandbox * +ssh_sandbox_init(struct monitor *monitor) +{ + struct ssh_sandbox *box; + + /* + * Strictly, we don't need to maintain any state here but we need + * to return non-NULL to satisfy the API. + */ + debug3("%s: preparing capsicum sandbox", __func__); + box = xcalloc(1, sizeof(*box)); + box->monitor = monitor; + box->child_pid = 0; + + return box; +} + +void +ssh_sandbox_child(struct ssh_sandbox *box) +{ + struct rlimit rl_zero; + cap_rights_t rights; + +#ifdef HAVE_CAPH_CACHE_TZDATA + caph_cache_tzdata(); +#endif + + rl_zero.rlim_cur = rl_zero.rlim_max = 0; + + if (setrlimit(RLIMIT_FSIZE, &rl_zero) == -1) + fatal("%s: setrlimit(RLIMIT_FSIZE, { 0, 0 }): %s", + __func__, strerror(errno)); +#ifndef SANDBOX_SKIP_RLIMIT_NOFILE + if (setrlimit(RLIMIT_NOFILE, &rl_zero) == -1) + fatal("%s: setrlimit(RLIMIT_NOFILE, { 0, 0 }): %s", + __func__, strerror(errno)); +#endif + if (setrlimit(RLIMIT_NPROC, &rl_zero) == -1) + fatal("%s: setrlimit(RLIMIT_NPROC, { 0, 0 }): %s", + __func__, strerror(errno)); + + cap_rights_init(&rights); + + if (cap_rights_limit(STDIN_FILENO, &rights) < 0 && errno != ENOSYS) + fatal("can't limit stdin: %m"); + if (cap_rights_limit(STDOUT_FILENO, &rights) < 0 && errno != ENOSYS) + fatal("can't limit stdout: %m"); + if (cap_rights_limit(STDERR_FILENO, &rights) < 0 && errno != ENOSYS) + fatal("can't limit stderr: %m"); + + cap_rights_init(&rights, CAP_READ, CAP_WRITE); + if (cap_rights_limit(box->monitor->m_recvfd, &rights) < 0 && + errno != ENOSYS) + fatal("%s: failed to limit the network socket", __func__); + cap_rights_init(&rights, CAP_WRITE); + if (cap_rights_limit(box->monitor->m_log_sendfd, &rights) < 0 && + errno != ENOSYS) + fatal("%s: failed to limit the logging socket", __func__); + if (cap_enter() < 0 && errno != ENOSYS) + fatal("%s: failed to enter capability mode", __func__); + +} + +void +ssh_sandbox_parent_finish(struct ssh_sandbox *box) +{ + free(box); + debug3("%s: finished", __func__); +} + +void +ssh_sandbox_parent_preauth(struct ssh_sandbox *box, pid_t child_pid) +{ + box->child_pid = child_pid; +} + +#endif /* SANDBOX_CAPSICUM */ |