xref: /illumos-gate/usr/src/cmd/mail/createmf.c (revision 7c478bd9)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 1995 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 #pragma ident	"%Z%%M%	%I%	%E% SMI"
31 
32 #include "mail.h"
33 /*
34 	If mail file does not exist create it
35 */
36 #ifdef OLD
createmf(uid,file)37 void createmf(uid, file)
38 uid_t uid;
39 char *file;
40 {
41 	int fd;
42 
43 	void (*istat)(), (*qstat)(), (*hstat)();
44 
45 	if (access(file, A_EXIST) == CERROR) {
46 		istat = signal(SIGINT, SIG_IGN);
47 		qstat = signal(SIGQUIT, SIG_IGN);
48 		hstat = signal(SIGHUP, SIG_IGN);
49 		umask(0);
50 		if ((fd = creat(file, MFMODE)) == -1)
51 			sav_errno = errno;
52 		else
53 			close(fd);
54 		umask(7);
55 		(void) signal(SIGINT, istat);
56 		(void) signal(SIGQUIT, qstat);
57 		(void) signal(SIGHUP, hstat);
58 	}
59 }
60 #else
61 
62 #include <sys/stat.h>
63 #include <fcntl.h>
64 #include <stdio.h>
65 
accessmf(path)66 int accessmf(path)
67 char *path;
68 {
69 
70 struct stat fsb,sb;
71 int mbfd;
72 tryagain:
73 	if (lstat(path, &sb)) {
74 		/* file/symlink does not exist, so create one */
75 		mbfd = open(path,
76 		    O_APPEND|O_CREAT|O_EXCL|O_WRONLY, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP);
77 		chmod(path, 0660);
78 		/* if someone create a symlink/file just ahead */
79 		/* of us, the create will failed with EEXIST   */
80 		/* This is what we want, because we do not     */
81 		/* want someone to re-direct our "create"      */
82 	        /* request to a another location.              */
83 		if (mbfd == -1) {
84 			if (errno == EEXIST)
85 				goto tryagain;
86 		}
87 
88 	/* file/symlink  exist, make sure it is not linked */
89 	} else if (sb.st_nlink != 1 || S_ISLNK(sb.st_mode)) {
90 		fprintf(stderr,
91 "%s: security violation, '%s' should not be linked to other file\n", program, path);
92 		sav_errno = errno;
93 		return -1;
94 	} else {
95 		/* if we get here, there is a pre-existing file, */
96 		/* and it is not a symlink...			 */
97 		/* open it, and make sure it is the same file    */
98 		/* we lstat() before...                          */
99 		/* this is to guard against someone deleting the */
100 		/* old file and creat a new symlink in its place */
101 		/* We are not createing a new file here, but we  */
102 		/* do not want append to the worng file either   */
103 		mbfd = open(path, O_APPEND|O_WRONLY, 0);
104 		if (mbfd != -1 &&
105 		    (fstat(mbfd, &fsb) || fsb.st_nlink != 1 ||
106 		    S_ISLNK(fsb.st_mode) || sb.st_dev != fsb.st_dev ||
107 		    sb.st_ino != fsb.st_ino)) {
108 			/*  file changed after open */
109 			fprintf(stderr, "%s: security violation, '%s' inode changed after open\n", program, path);
110 			(void)close(mbfd);
111 			return -1;
112 		}
113 	}
114 
115 	if (mbfd == -1) {
116 		sav_errno = errno;
117 		return -1;
118 	}
119 
120 	return mbfd;
121 }
122 #endif
123