#include <common/common.h>
#include <common/utils.h>
-#include <common/compat/mman.h>
-#include <common/compat/clone.h>
#include <common/compat/getenv.h>
+#include <common/sessiond-comm/unix.h>
#include "runas.h"
-#define RUNAS_CHILD_STACK_SIZE 10485760
-
-#ifndef MAP_STACK
-#define MAP_STACK 0
-#endif
-
-#ifdef __FreeBSD__
-/* FreeBSD MAP_STACK always return -ENOMEM */
-#define LTTNG_MAP_STACK 0
-#else
-#define LTTNG_MAP_STACK MAP_STACK
-#endif
-
-#ifndef MAP_GROWSDOWN
-#define MAP_GROWSDOWN 0
-#endif
-
-#ifndef MAP_ANONYMOUS
-#define MAP_ANONYMOUS MAP_ANON
-#endif
-
-struct run_as_data {
- int (*cmd)(void *data);
- void *data;
- uid_t uid;
- gid_t gid;
- int retval_pipe;
-};
+struct run_as_data;
+typedef int (*run_as_fct)(struct run_as_data *data);
struct run_as_mkdir_data {
- const char *path;
+ char path[PATH_MAX];
mode_t mode;
};
struct run_as_open_data {
- const char *path;
+ char path[PATH_MAX];
int flags;
mode_t mode;
};
struct run_as_unlink_data {
- const char *path;
+ char path[PATH_MAX];
};
-struct run_as_recursive_rmdir_data {
- const char *path;
+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 _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)
* Create recursively directory using the FULL path.
*/
static
-int _mkdir_recursive(void *_data)
+int _mkdir_recursive(struct run_as_data *data)
{
- struct run_as_mkdir_data *data = _data;
const char *path;
mode_t mode;
- path = data->path;
- mode = data->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(void *_data)
+int _mkdir(struct run_as_data *data)
{
- struct run_as_mkdir_data *data = _data;
+ return mkdir(data->u.mkdir.path, data->u.mkdir.mode);
+}
- return mkdir(data->path, data->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 _open(void *_data)
+int _rmdir_recursive(struct run_as_data *data)
{
- struct run_as_open_data *data = _data;
+ return utils_recursive_rmdir(data->u.rmdir_recursive.path);
+}
- return open(data->path, data->flags, data->mode);
+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 _unlink(void *_data)
+int do_send_fd(struct run_as_worker *worker,
+ enum run_as_cmd cmd, int fd)
{
- struct run_as_unlink_data *data = _data;
+ ssize_t len;
- return unlink(data->path);
+ 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 _recursive_rmdir(void *_data)
+int do_recv_fd(struct run_as_worker *worker,
+ enum run_as_cmd cmd, int *fd)
{
- struct run_as_recursive_rmdir_data *data = _data;
+ ssize_t len;
- return utils_recursive_rmdir(data->path);
+ 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 < 0) {
+ PERROR("lttcomm_recv_fds_unix_sock");
+ return -1;
+ }
+ return 0;
}
+/*
+ * Return < 0 on error, 0 if OK, 1 on hangup.
+ */
static
-int child_run_as(void *_data)
+int handle_one_cmd(struct run_as_worker *worker)
{
- int ret;
- struct run_as_data *data = _data;
- ssize_t writelen;
+ 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;
+ }
- /*
- * Child: it is safe to drop egid and euid while sharing the
- * file descriptors with the parent process, since we do not
- * drop "uid": therefore, the user we are dropping egid/euid to
- * cannot attach to this process with, e.g. ptrace, nor map this
- * process memory.
- */
- if (data->gid != getegid()) {
- ret = setegid(data->gid);
+ 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 != geteuid()) {
- ret = seteuid(data->uid);
+ 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 = (*data->cmd)(data->data);
+ ret = (*cmd)(&data);
write_return:
sendret.ret = ret;
sendret._errno = errno;
/* send back return value */
- writelen = lttng_write(data->retval_pipe, &sendret, sizeof(sendret));
+ writelen = lttcomm_send_unix_sock(worker->sockpair[1], &sendret,
+ sizeof(sendret));
if (writelen < sizeof(sendret)) {
- PERROR("lttng_write error");
+ 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;
- } else {
- return EXIT_SUCCESS;
}
+
+ 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_clone(int (*cmd)(void *data), void *data, uid_t uid, gid_t gid)
+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)
{
- struct run_as_data run_as_data;
- int ret = 0;
- ssize_t readlen;
- int status;
- pid_t pid;
- int retval_pipe[2];
- void *child_stack;
+ 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.
*/
}
}
- ret = pipe(retval_pipe);
- if (ret < 0) {
+ 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;
- PERROR("pipe");
goto end;
}
- run_as_data.data = data;
- run_as_data.cmd = cmd;
- run_as_data.uid = uid;
- run_as_data.gid = gid;
- run_as_data.retval_pipe = retval_pipe[1]; /* write end */
- child_stack = mmap(NULL, RUNAS_CHILD_STACK_SIZE,
- PROT_WRITE | PROT_READ,
- MAP_PRIVATE | MAP_GROWSDOWN | MAP_ANONYMOUS | LTTNG_MAP_STACK,
- -1, 0);
- if (child_stack == MAP_FAILED) {
- recvret.ret = -1;
- recvret._errno = ENOMEM;
- PERROR("mmap");
- goto close_pipe;
- }
- /*
- * Pointing to the middle of the stack to support architectures
- * where the stack grows up (HPPA).
- */
- pid = lttng_clone_files(child_run_as, child_stack + (RUNAS_CHILD_STACK_SIZE / 2),
- &run_as_data);
- if (pid < 0) {
- recvret.ret = -1;
- recvret._errno = errno;
- PERROR("clone");
- goto unmap_stack;
- }
+
/* receive return value */
- readlen = lttng_read(retval_pipe[0], &recvret, sizeof(recvret));
+ readlen = lttcomm_recv_unix_sock(worker->sockpair[0], &recvret,
+ sizeof(recvret));
if (readlen < sizeof(recvret)) {
+ PERROR("Error reading response from run_as");
recvret.ret = -1;
recvret._errno = errno;
}
-
- /*
- * Parent: wait for child to return, in which case the
- * shared memory map will have been created.
- */
- pid = waitpid(pid, &status, 0);
- if (pid < 0 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) {
- recvret.ret = -1;
- recvret._errno = errno;
- PERROR("wait");
- }
-unmap_stack:
- ret = munmap(child_stack, RUNAS_CHILD_STACK_SIZE);
- if (ret < 0) {
- recvret.ret = -1;
- recvret._errno = errno;
- PERROR("munmap");
- }
-close_pipe:
- ret = close(retval_pipe[0]);
- if (ret) {
- recvret.ret = -1;
- recvret._errno = errno;
- PERROR("close");
- }
- ret = close(retval_pipe[1]);
- if (ret) {
+ if (do_recv_fd(worker, cmd, &recvret.ret)) {
recvret.ret = -1;
- recvret._errno = errno;
- PERROR("close");
+ recvret._errno = -EIO;
}
+
end:
+ pthread_mutex_unlock(&worker_lock);
errno = recvret._errno;
return recvret.ret;
}
/*
- * To be used on setups where gdb has issues debugging programs using
- * clone/rfork. Note that this is for debuging ONLY, and should not be
- * considered secure.
+ * This is for debugging ONLY and should not be considered secure.
*/
static
-int run_as_noclone(int (*cmd)(void *data), void *data, uid_t uid, gid_t gid)
+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 = cmd(data);
+ ret = fct(data);
saved_errno = errno;
umask(old_mask);
errno = saved_errno;
-
+end:
return ret;
}
static
-int run_as(int (*cmd)(void *data), void *data, uid_t uid, gid_t gid)
+int run_as(struct run_as_worker *worker,
+ enum run_as_cmd cmd,
+ struct run_as_data *data, uid_t uid, gid_t gid)
{
- if (use_clone()) {
- int ret;
-
- DBG("Using run_as_clone");
- pthread_mutex_lock(<tng_libc_state_lock);
- ret = run_as_clone(cmd, data, uid, gid);
- pthread_mutex_unlock(<tng_libc_state_lock);
- return ret;
+ int ret;
+
+ if (worker) {
+ DBG("Using run_as worker");
+ ret = run_as_cmd(worker, cmd, data, uid, gid);
} else {
- DBG("Using run_as_noclone");
- return run_as_noclone(cmd, data, uid, gid);
+ 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_mkdir_data data;
+ 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);
- data.path = path;
- data.mode = mode;
- return run_as(_mkdir_recursive, &data, 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_mkdir_data data;
+ 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);
- data.path = path;
- data.mode = mode;
- return run_as(_mkdir, &data, 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);
}
/*
LTTNG_HIDDEN
int run_as_open(const char *path, int flags, mode_t mode, uid_t uid, gid_t gid)
{
- struct run_as_open_data data;
+ 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);
- data.path = path;
- data.flags = flags;
- data.mode = mode;
- return run_as(_open, &data, 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_unlink_data data;
+ 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);
- data.path = path;
- return run_as(_unlink, &data, 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_recursive_rmdir(const char *path, uid_t uid, gid_t gid)
+int run_as_rmdir_recursive(const char *path, uid_t uid, gid_t gid)
{
- struct run_as_recursive_rmdir_data data;
+ struct run_as_worker *worker = global_worker;
+ struct run_as_data data;
- DBG3("recursive_rmdir() %s with for uid %d and gid %d",
+ DBG3("rmdir_recursive() %s with for uid %d and gid %d",
path, uid, gid);
- data.path = path;
- return run_as(_recursive_rmdir, &data, 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 / commitdiff
