+++ /dev/null
-/*
- * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
- * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License, version 2 only,
- * as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
- */
-
-#define _GNU_SOURCE
-#define _LGPL_SOURCE
-#include <errno.h>
-#include <limits.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/wait.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <unistd.h>
-#include <fcntl.h>
-#include <sched.h>
-#include <sys/signal.h>
-
-#include <common/common.h>
-#include <common/utils.h>
-#include <common/compat/getenv.h>
-#include <common/sessiond-comm/unix.h>
-
-#include "runas.h"
-
-struct run_as_data;
-typedef int (*run_as_fct)(struct run_as_data *data);
-
-struct run_as_mkdir_data {
- char path[PATH_MAX];
- mode_t mode;
-};
-
-struct run_as_open_data {
- char path[PATH_MAX];
- int flags;
- mode_t mode;
-};
-
-struct run_as_unlink_data {
- char path[PATH_MAX];
-};
-
-struct run_as_rmdir_recursive_data {
- char path[PATH_MAX];
-};
-
-enum run_as_cmd {
- RUN_AS_MKDIR,
- RUN_AS_OPEN,
- RUN_AS_UNLINK,
- RUN_AS_RMDIR_RECURSIVE,
- RUN_AS_MKDIR_RECURSIVE,
-};
-
-struct run_as_data {
- enum run_as_cmd cmd;
- union {
- struct run_as_mkdir_data mkdir;
- struct run_as_open_data open;
- struct run_as_unlink_data unlink;
- struct run_as_rmdir_recursive_data rmdir_recursive;
- } u;
- uid_t uid;
- gid_t gid;
-};
-
-struct run_as_ret {
- int ret;
- int _errno;
-};
-
-struct run_as_worker {
- pid_t pid; /* Worker PID. */
- int sockpair[2];
- char *procname;
-};
-
-/* Single global worker per process (for now). */
-static struct run_as_worker *global_worker;
-/* Lock protecting the worker. */
-static pthread_mutex_t worker_lock = PTHREAD_MUTEX_INITIALIZER;
-
-#ifdef VALGRIND
-static
-int use_clone(void)
-{
- return 0;
-}
-#else
-static
-int use_clone(void)
-{
- return !lttng_secure_getenv("LTTNG_DEBUG_NOCLONE");
-}
-#endif
-
-LTTNG_HIDDEN
-int _utils_mkdir_recursive_unsafe(const char *path, mode_t mode);
-
-/*
- * Create recursively directory using the FULL path.
- */
-static
-int _mkdir_recursive(struct run_as_data *data)
-{
- const char *path;
- mode_t mode;
-
- path = data->u.mkdir.path;
- mode = data->u.mkdir.mode;
-
- /* Safe to call as we have transitioned to the requested uid/gid. */
- return _utils_mkdir_recursive_unsafe(path, mode);
-}
-
-static
-int _mkdir(struct run_as_data *data)
-{
- return mkdir(data->u.mkdir.path, data->u.mkdir.mode);
-}
-
-static
-int _open(struct run_as_data *data)
-{
- return open(data->u.open.path, data->u.open.flags, data->u.open.mode);
-}
-
-static
-int _unlink(struct run_as_data *data)
-{
- return unlink(data->u.unlink.path);
-}
-
-static
-int _rmdir_recursive(struct run_as_data *data)
-{
- return utils_recursive_rmdir(data->u.rmdir_recursive.path);
-}
-
-static
-run_as_fct run_as_enum_to_fct(enum run_as_cmd cmd)
-{
- switch (cmd) {
- case RUN_AS_MKDIR:
- return _mkdir;
- case RUN_AS_OPEN:
- return _open;
- case RUN_AS_UNLINK:
- return _unlink;
- case RUN_AS_RMDIR_RECURSIVE:
- return _rmdir_recursive;
- case RUN_AS_MKDIR_RECURSIVE:
- return _mkdir_recursive;
- default:
- ERR("Unknown command %d", (int) cmd)
- return NULL;
- }
-}
-
-static
-int do_send_fd(struct run_as_worker *worker,
- enum run_as_cmd cmd, int fd)
-{
- ssize_t len;
-
- switch (cmd) {
- case RUN_AS_OPEN:
- break;
- default:
- return 0;
- }
- if (fd < 0) {
- return 0;
- }
- len = lttcomm_send_fds_unix_sock(worker->sockpair[1], &fd, 1);
- if (len < 0) {
- PERROR("lttcomm_send_fds_unix_sock");
- return -1;
- }
- if (close(fd) < 0) {
- PERROR("close");
- return -1;
- }
- return 0;
-}
-
-static
-int do_recv_fd(struct run_as_worker *worker,
- enum run_as_cmd cmd, int *fd)
-{
- ssize_t len;
-
- switch (cmd) {
- case RUN_AS_OPEN:
- break;
- default:
- return 0;
- }
- if (*fd < 0) {
- return 0;
- }
- len = lttcomm_recv_fds_unix_sock(worker->sockpair[0], fd, 1);
- if (!len) {
- return -1;
- } else if (len < 0) {
- PERROR("lttcomm_recv_fds_unix_sock");
- return -1;
- }
- return 0;
-}
-
-/*
- * Return < 0 on error, 0 if OK, 1 on hangup.
- */
-static
-int handle_one_cmd(struct run_as_worker *worker)
-{
- int ret = 0;
- struct run_as_data data;
- ssize_t readlen, writelen;
- struct run_as_ret sendret;
- run_as_fct cmd;
- uid_t prev_euid;
-
- /* Read data */
- readlen = lttcomm_recv_unix_sock(worker->sockpair[1], &data,
- sizeof(data));
- if (readlen == 0) {
- /* hang up */
- ret = 1;
- goto end;
- }
- if (readlen < sizeof(data)) {
- PERROR("lttcomm_recv_unix_sock error");
- ret = -1;
- goto end;
- }
-
- cmd = run_as_enum_to_fct(data.cmd);
- if (!cmd) {
- ret = -1;
- goto end;
- }
-
- prev_euid = getuid();
- if (data.gid != getegid()) {
- ret = setegid(data.gid);
- if (ret < 0) {
- PERROR("setegid");
- goto write_return;
- }
- }
- if (data.uid != prev_euid) {
- ret = seteuid(data.uid);
- if (ret < 0) {
- PERROR("seteuid");
- goto write_return;
- }
- }
- /*
- * Also set umask to 0 for mkdir executable bit.
- */
- umask(0);
- ret = (*cmd)(&data);
-
-write_return:
- sendret.ret = ret;
- sendret._errno = errno;
- /* send back return value */
- writelen = lttcomm_send_unix_sock(worker->sockpair[1], &sendret,
- sizeof(sendret));
- if (writelen < sizeof(sendret)) {
- PERROR("lttcomm_send_unix_sock error");
- ret = -1;
- goto end;
- }
- ret = do_send_fd(worker, data.cmd, ret);
- if (ret) {
- PERROR("do_send_fd error");
- ret = -1;
- goto end;
- }
- if (seteuid(prev_euid) < 0) {
- PERROR("seteuid");
- ret = -1;
- goto end;
- }
- ret = 0;
-end:
- return ret;
-}
-
-static
-int run_as_worker(struct run_as_worker *worker)
-{
- int ret;
- ssize_t writelen;
- struct run_as_ret sendret;
- size_t proc_orig_len;
-
- /*
- * Initialize worker. Set a different process cmdline.
- */
- proc_orig_len = strlen(worker->procname);
- memset(worker->procname, 0, proc_orig_len);
- strncpy(worker->procname, DEFAULT_RUN_AS_WORKER_NAME, proc_orig_len);
-
- ret = pthread_setname_np(pthread_self(), DEFAULT_RUN_AS_WORKER_NAME);
- if (ret) {
- errno = ret;
- ret = -1;
- PERROR("pthread_setname_np");
- return EXIT_FAILURE;
- }
-
- sendret.ret = 0;
- sendret._errno = 0;
- writelen = lttcomm_send_unix_sock(worker->sockpair[1], &sendret,
- sizeof(sendret));
- if (writelen < sizeof(sendret)) {
- PERROR("lttcomm_send_unix_sock error");
- ret = EXIT_FAILURE;
- goto end;
- }
-
- for (;;) {
- ret = handle_one_cmd(worker);
- if (ret < 0) {
- ret = EXIT_FAILURE;
- goto end;
- } else if (ret > 0) {
- break;
- } else {
- continue; /* Next command. */
- }
- }
- ret = EXIT_SUCCESS;
-end:
- return ret;
-}
-
-static
-int run_as_cmd(struct run_as_worker *worker,
- enum run_as_cmd cmd,
- struct run_as_data *data,
- uid_t uid, gid_t gid)
-{
- ssize_t readlen, writelen;
- struct run_as_ret recvret;
-
- pthread_mutex_lock(&worker_lock);
- /*
- * If we are non-root, we can only deal with our own uid.
- */
- if (geteuid() != 0) {
- if (uid != geteuid()) {
- recvret.ret = -1;
- recvret._errno = EPERM;
- ERR("Client (%d)/Server (%d) UID mismatch (and sessiond is not root)",
- uid, geteuid());
- goto end;
- }
- }
-
- data->cmd = cmd;
- data->uid = uid;
- data->gid = gid;
-
- writelen = lttcomm_send_unix_sock(worker->sockpair[0], data,
- sizeof(*data));
- if (writelen < sizeof(*data)) {
- PERROR("Error writing message to run_as");
- recvret.ret = -1;
- recvret._errno = errno;
- goto end;
- }
-
- /* receive return value */
- readlen = lttcomm_recv_unix_sock(worker->sockpair[0], &recvret,
- sizeof(recvret));
- if (!readlen) {
- ERR("Run-as worker has hung-up during run_as_cmd");
- recvret.ret = -1;
- recvret._errno = EIO;
- goto end;
- } else if (readlen < sizeof(recvret)) {
- PERROR("Error reading response from run_as");
- recvret.ret = -1;
- recvret._errno = errno;
- }
- if (do_recv_fd(worker, cmd, &recvret.ret)) {
- recvret.ret = -1;
- recvret._errno = EIO;
- }
-
-end:
- pthread_mutex_unlock(&worker_lock);
- errno = recvret._errno;
- return recvret.ret;
-}
-
-/*
- * This is for debugging ONLY and should not be considered secure.
- */
-static
-int run_as_noworker(enum run_as_cmd cmd,
- struct run_as_data *data, uid_t uid, gid_t gid)
-{
- int ret, saved_errno;
- mode_t old_mask;
- run_as_fct fct;
-
- fct = run_as_enum_to_fct(cmd);
- if (!fct) {
- errno = -ENOSYS;
- ret = -1;
- goto end;
- }
- old_mask = umask(0);
- ret = fct(data);
- saved_errno = errno;
- umask(old_mask);
- errno = saved_errno;
-end:
- return ret;
-}
-
-static
-int run_as(struct run_as_worker *worker,
- enum run_as_cmd cmd,
- struct run_as_data *data, uid_t uid, gid_t gid)
-{
- int ret;
-
- if (worker) {
- DBG("Using run_as worker");
- ret = run_as_cmd(worker, cmd, data, uid, gid);
- } else {
- DBG("Using run_as without worker");
- ret = run_as_noworker(cmd, data, uid, gid);
- }
- return ret;
-}
-
-LTTNG_HIDDEN
-int run_as_mkdir_recursive(const char *path, mode_t mode, uid_t uid, gid_t gid)
-{
- struct run_as_worker *worker = global_worker;
- struct run_as_data data;
-
- DBG3("mkdir() recursive %s with mode %d for uid %d and gid %d",
- path, mode, uid, gid);
- strncpy(data.u.mkdir.path, path, PATH_MAX - 1);
- data.u.mkdir.path[PATH_MAX - 1] = '\0';
- data.u.mkdir.mode = mode;
- return run_as(worker, RUN_AS_MKDIR_RECURSIVE, &data, uid, gid);
-}
-
-LTTNG_HIDDEN
-int run_as_mkdir(const char *path, mode_t mode, uid_t uid, gid_t gid)
-{
- struct run_as_worker *worker = global_worker;
- struct run_as_data data;
-
- DBG3("mkdir() %s with mode %d for uid %d and gid %d",
- path, mode, uid, gid);
- strncpy(data.u.mkdir.path, path, PATH_MAX - 1);
- data.u.mkdir.path[PATH_MAX - 1] = '\0';
- data.u.mkdir.mode = mode;
- return run_as(worker, RUN_AS_MKDIR, &data, uid, gid);
-}
-
-/*
- * Note: open_run_as is currently not working. We'd need to pass the fd
- * opened in the child to the parent.
- */
-LTTNG_HIDDEN
-int run_as_open(const char *path, int flags, mode_t mode, uid_t uid, gid_t gid)
-{
- struct run_as_worker *worker = global_worker;
- struct run_as_data data;
-
- DBG3("open() %s with flags %X mode %d for uid %d and gid %d",
- path, flags, mode, uid, gid);
- strncpy(data.u.open.path, path, PATH_MAX - 1);
- data.u.open.path[PATH_MAX - 1] = '\0';
- data.u.open.flags = flags;
- data.u.open.mode = mode;
- return run_as(worker, RUN_AS_OPEN, &data, uid, gid);
-}
-
-LTTNG_HIDDEN
-int run_as_unlink(const char *path, uid_t uid, gid_t gid)
-{
- struct run_as_worker *worker = global_worker;
- struct run_as_data data;
-
- DBG3("unlink() %s with for uid %d and gid %d",
- path, uid, gid);
- strncpy(data.u.unlink.path, path, PATH_MAX - 1);
- data.u.unlink.path[PATH_MAX - 1] = '\0';
- return run_as(worker, RUN_AS_UNLINK, &data, uid, gid);
-}
-
-LTTNG_HIDDEN
-int run_as_rmdir_recursive(const char *path, uid_t uid, gid_t gid)
-{
- struct run_as_worker *worker = global_worker;
- struct run_as_data data;
-
- DBG3("rmdir_recursive() %s with for uid %d and gid %d",
- path, uid, gid);
- strncpy(data.u.rmdir_recursive.path, path, PATH_MAX - 1);
- data.u.rmdir_recursive.path[PATH_MAX - 1] = '\0';
- return run_as(worker, RUN_AS_RMDIR_RECURSIVE, &data, uid, gid);
-}
-
-LTTNG_HIDDEN
-int run_as_create_worker(char *procname)
-{
- pid_t pid;
- int i, ret = 0;
- ssize_t readlen;
- struct run_as_ret recvret;
- struct run_as_worker *worker;
-
- if (!use_clone()) {
- ret = 0;
- goto end;
- }
- worker = zmalloc(sizeof(*worker));
- if (!worker) {
- ret = -ENOMEM;
- goto end;
- }
- worker->procname = procname;
- /* Create unix socket. */
- if (lttcomm_create_anon_unix_socketpair(worker->sockpair) < 0) {
- ret = -1;
- goto error_sock;
- }
- /* Fork worker. */
- pid = fork();
- if (pid < 0) {
- PERROR("fork");
- ret = -1;
- goto error_fork;
- } else if (pid == 0) {
- /* Child */
-
- /* Just close, no shutdown. */
- if (close(worker->sockpair[0])) {
- PERROR("close");
- exit(EXIT_FAILURE);
- }
- worker->sockpair[0] = -1;
- ret = run_as_worker(worker);
- if (lttcomm_close_unix_sock(worker->sockpair[1])) {
- PERROR("close");
- ret = -1;
- }
- worker->sockpair[1] = -1;
- exit(ret ? EXIT_FAILURE : EXIT_SUCCESS);
- } else {
- /* Parent */
-
- /* Just close, no shutdown. */
- if (close(worker->sockpair[1])) {
- PERROR("close");
- ret = -1;
- goto error_fork;
- }
- worker->sockpair[1] = -1;
- worker->pid = pid;
- /* Wait for worker to become ready. */
- readlen = lttcomm_recv_unix_sock(worker->sockpair[0],
- &recvret, sizeof(recvret));
- if (readlen < sizeof(recvret)) {
- ERR("readlen: %zd", readlen);
- PERROR("Error reading response from run_as at creation");
- ret = -1;
- goto error_fork;
- }
- global_worker = worker;
- }
-end:
- return ret;
-
- /* Error handling. */
-error_fork:
- for (i = 0; i < 2; i++) {
- if (worker->sockpair[i] < 0) {
- continue;
- }
- if (lttcomm_close_unix_sock(worker->sockpair[i])) {
- PERROR("close");
- }
- worker->sockpair[i] = -1;
- }
-error_sock:
- free(worker);
- return ret;
-}
-
-LTTNG_HIDDEN
-void run_as_destroy_worker(void)
-{
- struct run_as_worker *worker = global_worker;
- int status;
- pid_t pid;
-
- if (!worker) {
- return;
- }
- /* Close unix socket */
- if (lttcomm_close_unix_sock(worker->sockpair[0])) {
- PERROR("close");
- }
- worker->sockpair[0] = -1;
- /* Wait for worker. */
- pid = waitpid(worker->pid, &status, 0);
- if (pid < 0 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) {
- PERROR("wait");
- }
- free(worker);
- global_worker = NULL;
-}
projects / lttng-tools.git / blobdiff