diff options
Diffstat (limited to 'usr.sbin/rtsold/cap_script.c')
| -rw-r--r-- | usr.sbin/rtsold/cap_script.c | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/usr.sbin/rtsold/cap_script.c b/usr.sbin/rtsold/cap_script.c new file mode 100644 index 000000000000..97b7f947532c --- /dev/null +++ b/usr.sbin/rtsold/cap_script.c @@ -0,0 +1,235 @@ +/*- + * SPDX-License-Identifier: BSD-2-Clause + * + * Copyright (c) 2018 The FreeBSD Foundation + * + * This software was developed by Mark Johnston under sponsorship from + * the FreeBSD Foundation. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <sys/types.h> +#include <sys/capsicum.h> +#include <sys/dnv.h> +#include <sys/nv.h> +#include <sys/queue.h> +#include <sys/wait.h> + +#include <net/if.h> +#include <netinet/in.h> + +#include <capsicum_helpers.h> +#include <errno.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +#include <libcasper.h> +#include <libcasper_service.h> + +#include "rtsold.h" + +/* + * Run the script and return the write end of a pipe to the main process. + * Return -1 and set errno on error. + */ +static int +script_run(char **argv) +{ + pid_t pid; + int fd[2], null; + + if (pipe(fd) != 0) + return (-1); + if ((pid = fork()) < 0) + return (-1); + if (pid == 0) { + (void)close(fd[1]); + null = open("/dev/null", O_RDWR); + if (null < 0) + _exit(1); + if (dup2(fd[0], STDIN_FILENO) != STDIN_FILENO) + _exit(1); + + closefrom(3); + (void)execve(argv[0], argv, NULL); + _exit(1); + } else + (void)close(fd[0]); + + return (fd[1]); +} + +int +cap_script_run(cap_channel_t *cap, const char *const *argv) +{ +#ifdef WITH_CASPER + nvlist_t *nvl; + size_t argc; + int error, wfd; + + for (argc = 0; argv[argc] != NULL; argc++) + ; + + nvl = nvlist_create(0); + nvlist_add_string(nvl, "cmd", "script_run"); + nvlist_add_string_array(nvl, "argv", argv, argc); + nvl = cap_xfer_nvlist(cap, nvl); + if (nvl == NULL) + return (-1); + + error = (int)dnvlist_get_number(nvl, "error", 0); + if (error == 0) + wfd = nvlist_take_descriptor(nvl, "fd"); + nvlist_destroy(nvl); + if (error != 0) + errno = error; + return (error == 0 ? wfd : -1); +#else + (void)cap; + return (script_run(__DECONST(char **, argv))); +#endif +} + +/* + * Wait for a child process to exit, and return its status. + * Return -1 and set errno upon error. + */ +static int +script_wait(int *statusp) +{ + int error; + + error = wait(statusp); + return (error >= 0 ? 0 : -1); +} + +int +cap_script_wait(cap_channel_t *cap, int *statusp) +{ +#ifdef WITH_CASPER + nvlist_t *nvl; + int error; + + nvl = nvlist_create(0); + nvlist_add_string(nvl, "cmd", "script_wait"); + nvl = cap_xfer_nvlist(cap, nvl); + if (nvl == NULL) + return (-1); + + error = (int)dnvlist_get_number(nvl, "error", 0); + if (error == 0) + *statusp = (int)nvlist_get_number(nvl, "status"); + nvlist_destroy(nvl); + if (error != 0) + errno = error; + return (error == 0 ? 0 : -1); +#else + (void)cap; + return (script_wait(statusp)); +#endif +} + +#ifdef WITH_CASPER +static int +script_command(const char *cmd, const nvlist_t *limits, nvlist_t *nvlin, + nvlist_t *nvlout) +{ + cap_rights_t rights; + const char *const *iargv, *const *scripts; + char **argv; + size_t argc, i, nscripts; + int error, fd, status; + + if (strcmp(cmd, "script_wait") == 0) { + /* Wait for the result of a previous "script_run" command. */ + if (script_wait(&status) == -1) + return (errno); + nvlist_add_number(nvlout, "status", status); + return (0); + } + if (strcmp(cmd, "script_run") != 0) + return (EINVAL); + + /* + * Validate the argv against the limits specified at initialization + * time. + */ + iargv = nvlist_get_string_array(nvlin, "argv", &argc); + if (argc == 0) + return (EINVAL); + scripts = nvlist_get_string_array(limits, "scripts", &nscripts); + for (i = 0; i < nscripts; i++) + if (strcmp(iargv[0], scripts[i]) == 0) + break; + if (i == nscripts) + return (EINVAL); + + /* + * The nvlist API does not permit NULL pointers in an array, so we have + * to add the nul terminator ourselves. Yuck. + */ + argv = calloc(argc + 1, sizeof(*argv)); + if (argv == NULL) + return (errno); + memcpy(argv, iargv, sizeof(*argv) * argc); + + fd = script_run(argv); + error = errno; + free(argv); + if (fd < 0) + return (error); + + (void)caph_rights_limit(fd, cap_rights_init(&rights, CAP_WRITE)); + nvlist_move_descriptor(nvlout, "fd", fd); + return (0); +} + +static int +script_limit(const nvlist_t *oldlimits, const nvlist_t *newlimits) +{ + const char *name; + void *cookie; + int nvtype; + bool hasscripts; + + /* Limits may only be set once. */ + if (oldlimits != NULL) + return (ENOTCAPABLE); + + cookie = NULL; + hasscripts = false; + while ((name = nvlist_next(newlimits, &nvtype, &cookie)) != NULL) { + if (nvtype == NV_TYPE_STRING_ARRAY && + strcmp(name, "scripts") == 0) + hasscripts = true; + else + return (EINVAL); + } + if (!hasscripts) + return (EINVAL); + return (0); +} + +CREATE_SERVICE("rtsold.script", script_limit, script_command, 0); +#endif /* WITH_CASPER */ |