1*2ce65aaeSmillert /* $OpenBSD: __mktemp4.c,v 1.1 2024/01/19 19:45:02 millert Exp $ */
2*2ce65aaeSmillert /*
3*2ce65aaeSmillert * Copyright (c) 1996-1998, 2008 Theo de Raadt
4*2ce65aaeSmillert * Copyright (c) 1997, 2008-2009, 2024 Todd C. Miller
5*2ce65aaeSmillert *
6*2ce65aaeSmillert * Permission to use, copy, modify, and distribute this software for any
7*2ce65aaeSmillert * purpose with or without fee is hereby granted, provided that the above
8*2ce65aaeSmillert * copyright notice and this permission notice appear in all copies.
9*2ce65aaeSmillert *
10*2ce65aaeSmillert * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11*2ce65aaeSmillert * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12*2ce65aaeSmillert * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13*2ce65aaeSmillert * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14*2ce65aaeSmillert * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15*2ce65aaeSmillert * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16*2ce65aaeSmillert * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17*2ce65aaeSmillert */
18*2ce65aaeSmillert
19*2ce65aaeSmillert #include <errno.h>
20*2ce65aaeSmillert #include <limits.h>
21*2ce65aaeSmillert #include <stdlib.h>
22*2ce65aaeSmillert #include <string.h>
23*2ce65aaeSmillert
24*2ce65aaeSmillert #define TEMPCHARS "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
25*2ce65aaeSmillert #define NUM_CHARS (sizeof(TEMPCHARS) - 1)
26*2ce65aaeSmillert #define MIN_X 6
27*2ce65aaeSmillert
28*2ce65aaeSmillert #ifndef nitems
29*2ce65aaeSmillert #define nitems(_a) (sizeof((_a)) / sizeof((_a)[0]))
30*2ce65aaeSmillert #endif
31*2ce65aaeSmillert
32*2ce65aaeSmillert /*
33*2ce65aaeSmillert * Internal driver for the mktemp(3) family of functions.
34*2ce65aaeSmillert * The supplied callback does the actual work of testing or
35*2ce65aaeSmillert * creating the file/directory.
36*2ce65aaeSmillert */
37*2ce65aaeSmillert int
__mktemp4(char * path,int slen,int flags,int (* cb)(const char *,int))38*2ce65aaeSmillert __mktemp4(char *path, int slen, int flags, int (*cb)(const char *, int))
39*2ce65aaeSmillert {
40*2ce65aaeSmillert char *start, *cp, *ep;
41*2ce65aaeSmillert const char tempchars[] = TEMPCHARS;
42*2ce65aaeSmillert unsigned int tries;
43*2ce65aaeSmillert size_t len;
44*2ce65aaeSmillert int ret;
45*2ce65aaeSmillert
46*2ce65aaeSmillert len = strlen(path);
47*2ce65aaeSmillert if (len < MIN_X || slen < 0 || (size_t)slen > len - MIN_X) {
48*2ce65aaeSmillert errno = EINVAL;
49*2ce65aaeSmillert return -1;
50*2ce65aaeSmillert }
51*2ce65aaeSmillert ep = path + len - slen;
52*2ce65aaeSmillert
53*2ce65aaeSmillert for (start = ep; start > path && start[-1] == 'X'; start--)
54*2ce65aaeSmillert ;
55*2ce65aaeSmillert if (ep - start < MIN_X) {
56*2ce65aaeSmillert errno = EINVAL;
57*2ce65aaeSmillert return -1;
58*2ce65aaeSmillert }
59*2ce65aaeSmillert
60*2ce65aaeSmillert tries = INT_MAX;
61*2ce65aaeSmillert do {
62*2ce65aaeSmillert cp = start;
63*2ce65aaeSmillert do {
64*2ce65aaeSmillert unsigned short rbuf[16];
65*2ce65aaeSmillert unsigned int i;
66*2ce65aaeSmillert
67*2ce65aaeSmillert /*
68*2ce65aaeSmillert * Avoid lots of arc4random() calls by using
69*2ce65aaeSmillert * a buffer sized for up to 16 Xs at a time.
70*2ce65aaeSmillert */
71*2ce65aaeSmillert arc4random_buf(rbuf, sizeof(rbuf));
72*2ce65aaeSmillert for (i = 0; i < nitems(rbuf) && cp != ep; i++)
73*2ce65aaeSmillert *cp++ = tempchars[rbuf[i] % NUM_CHARS];
74*2ce65aaeSmillert } while (cp != ep);
75*2ce65aaeSmillert
76*2ce65aaeSmillert ret = cb(path, flags);
77*2ce65aaeSmillert if (ret != -1 || errno != EEXIST)
78*2ce65aaeSmillert return ret;
79*2ce65aaeSmillert } while (--tries);
80*2ce65aaeSmillert
81*2ce65aaeSmillert errno = EEXIST;
82*2ce65aaeSmillert return -1;
83*2ce65aaeSmillert }
84