1 /* $OpenBSD: isexec.c,v 1.13 2021/10/24 21:24:17 deraadt Exp $ */
2
3 /*
4 * Copyright (c) 1983 Regents of the University of California.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include <sys/types.h>
33 #include <elf.h>
34 #include <fcntl.h>
35 #include <unistd.h>
36
37 #include "client.h"
38
39 /*
40 * Determine whether 'file' is a binary executable or not.
41 */
42 int
isexec(char * file,struct stat * statp)43 isexec(char *file, struct stat *statp)
44 {
45 Elf32_Ehdr hdr;
46 int fd, r;
47
48 /*
49 * Must be a regular file that has some executable mode bit on
50 */
51 if (!S_ISREG(statp->st_mode) ||
52 !(statp->st_mode & (S_IXUSR|S_IXGRP|S_IXOTH)))
53 return(FALSE);
54
55 if ((fd = open(file, O_RDONLY)) == -1)
56 return(FALSE);
57
58 r = read(fd, &hdr, sizeof(hdr)) == sizeof(hdr) &&
59 IS_ELF(hdr) && hdr.e_type == ET_EXEC;
60 close(fd);
61
62 return (r);
63 }
64