diff options
| -rw-r--r-- | tools/virtiofsd/passthrough_ll.c | 34 |
1 files changed, 11 insertions, 23 deletions
diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c index 477e6ee0b5..ff53df4451 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -2393,8 +2393,6 @@ static void setup_wait_parent_capabilities(void) static void setup_namespaces(struct lo_data *lo, struct fuse_session *se) { pid_t child; - char template[] = "virtiofsd-XXXXXX"; - char *tmpdir; /* * Create a new pid namespace for *child* processes. We'll have to @@ -2458,33 +2456,23 @@ static void setup_namespaces(struct lo_data *lo, struct fuse_session *se) exit(1); } - tmpdir = mkdtemp(template); - if (!tmpdir) { - fuse_log(FUSE_LOG_ERR, "tmpdir(%s): %m\n", template); - exit(1); - } - - if (mount("/proc/self/fd", tmpdir, NULL, MS_BIND, NULL) < 0) { - fuse_log(FUSE_LOG_ERR, "mount(/proc/self/fd, %s, MS_BIND): %m\n", - tmpdir); + /* + * We only need /proc/self/fd. Prevent ".." from accessing parent + * directories of /proc/self/fd by bind-mounting it over /proc. Since / was + * previously remounted with MS_REC | MS_SLAVE this mount change only + * affects our process. + */ + if (mount("/proc/self/fd", "/proc", NULL, MS_BIND, NULL) < 0) { + fuse_log(FUSE_LOG_ERR, "mount(/proc/self/fd, MS_BIND): %m\n"); exit(1); } - /* Now we can get our /proc/self/fd directory file descriptor */ - lo->proc_self_fd = open(tmpdir, O_PATH); + /* Get the /proc (actually /proc/self/fd, see above) file descriptor */ + lo->proc_self_fd = open("/proc", O_PATH); if (lo->proc_self_fd == -1) { - fuse_log(FUSE_LOG_ERR, "open(%s, O_PATH): %m\n", tmpdir); + fuse_log(FUSE_LOG_ERR, "open(/proc, O_PATH): %m\n"); exit(1); } - - if (umount2(tmpdir, MNT_DETACH) < 0) { - fuse_log(FUSE_LOG_ERR, "umount2(%s, MNT_DETACH): %m\n", tmpdir); - exit(1); - } - - if (rmdir(tmpdir) < 0) { - fuse_log(FUSE_LOG_ERR, "rmdir(%s): %m\n", tmpdir); - } } /* |