Files
lbmk/util/libreboot-utils/mkhtemp.c
T
Leah Rowe 3d3193bb80 mkhtemp readme
Signed-off-by: Leah Rowe <leah@libreboot.org>
2026-03-26 06:59:42 +00:00

163 lines
3.5 KiB
C

/* SPDX-License-Identifier: MIT
* Copyright (c) 2026 Leah Rowe <leah@libreboot.org>
*
* Hardened mktemp (mkhtemp!)
*
* WORK IN PROGRESS (proof of concept), or, v0.0000001
* DO NOT PUT THIS IN YOUR LINUX DISTRO YET.
*
* I will remove this notice when the code is mature, and
* probably contact several of your projects myself.
*
* See README. This is an ongoing project; no proper docs
* yet, and no manpage (yet!) - the code is documentation,
* while the specification that it implements evolves.
*/
#if defined(__linux__) && !defined(_GNU_SOURCE)
/* for openat2 on linux */
#define _GNU_SOURCE 1
#endif
#ifdef __OpenBSD__
#include <sys/param.h> /* pledge(2) */
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "include/common.h"
int
main(int argc, char *argv[])
{
#if defined (PATH_LEN) && \
(PATH_LEN) >= 256
size_t maxlen = PATH_LEN;
#else
size_t maxlen = 4096;
#endif
size_t len;
size_t tlen;
size_t xc = 0;
char *tmpdir = NULL;
char *template = NULL;
char *p;
char *s = NULL;
char *rp;
char resolved[maxlen];
char c;
int fd = -1;
int type = MKHTEMP_FILE;
int stfu = 0; /* -q option */
if (lbgetprogname(argv[0]) == NULL)
err_no_cleanup(stfu, errno, "could not set progname");
/* https://man.openbsd.org/pledge.2 */
#if defined(__OpenBSD__) && defined(OpenBSD)
#if (OpenBSD) >= 509
if (pledge("stdio flock rpath wpath cpath", NULL) == -1)
goto err_usage;
#endif
#endif
while ((c =
getopt(argc, argv, "qdp:")) != -1) {
switch (c) {
case 'd':
type = MKHTEMP_DIR;
break;
case 'p':
tmpdir = optarg;
break;
case 'q': /* don't print errors */
/* (exit status unchanged) */
stfu = 1;
break;
default:
goto err_usage;
}
}
if (optind < argc)
template = argv[optind];
if (optind + 1 < argc)
goto err_usage;
/* custom template e.g. foo.XXXXXXXXXXXXXXXXXXXXX */
if (template != NULL) {
if (slen(template, maxlen, &tlen) < 0)
err_no_cleanup(stfu, EINVAL,
"invalid template");
for (p = template + tlen;
p > template && *--p == 'X'; xc++);
if (xc < 3) /* the gnu mktemp errs on less than 3 */
err_no_cleanup(stfu, EINVAL,
"template must have 3 X or more on end (12+ advised");
}
/* user supplied -p PATH - WARNING:
* this permits symlinks, but only here,
* not in the library, so they are resolved
* here first, and *only here*. the mkhtemp
* library blocks them. be careful
* when using -p
*/
if (tmpdir != NULL) {
rp = realpath(tmpdir, resolved);
if (rp == NULL)
err_no_cleanup(stfu, errno, "%s", tmpdir);
tmpdir = resolved;
}
if (new_tmp_common(&fd, &s, type,
tmpdir, template) < 0)
err_no_cleanup(stfu, errno, "%s", s);
#if defined(__OpenBSD__) && defined(OpenBSD)
#if (OpenBSD) >= 509
if (pledge("stdio", NULL) == -1)
err_no_cleanup(stfu, errno, "pledge, exit");
#endif
#endif
if (s == NULL)
err_no_cleanup(stfu, EFAULT, "bad string initialisation");
if (*s == '\0')
err_no_cleanup(stfu, EFAULT, "empty string initialisation");
if (slen(s, maxlen, &len) < 0)
err_no_cleanup(stfu, EFAULT, "unterminated string initialisiert");
printf("%s\n", s);
return EXIT_SUCCESS;
err_usage:
err_no_cleanup(stfu, EINVAL,
"usage: %s [-d] [-p dir] [template]\n", getnvmprogname());
}/*
( >:3 )
/| |\
/ \ */