1 /*
2 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
3 * Use is subject to license terms.
4 */
5
6 /*
7 * percent_x() takes a string and performs %<char> expansions. It aborts the
8 * program when the expansion would overflow the output buffer. The result
9 * of %<char> expansion may be passed on to a shell process. For this
10 * reason, characters with a special meaning to shells are replaced by
11 * underscores.
12 *
13 * Diagnostics are reported through syslog(3).
14 *
15 * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
16 */
17
18 #ifndef lint
19 static char sccsid[] = "@(#) percent_x.c 1.4 94/12/28 17:42:37";
20 #endif
21
22 /* System libraries. */
23
24 #include <stdio.h>
25 #include <stdlib.h>
26 #include <unistd.h>
27 #include <syslog.h>
28 #include <string.h>
29
30 extern void exit();
31
32 /* Local stuff. */
33
34 #include "tcpd.h"
35
36 /* percent_x - do %<char> expansion, abort if result buffer is too small */
37
percent_x(result,result_len,string,request)38 char *percent_x(result, result_len, string, request)
39 char *result;
40 int result_len;
41 char *string;
42 struct request_info *request;
43 {
44 char *bp = result;
45 char *end = result + result_len - 1; /* end of result buffer */
46 char *expansion;
47 int expansion_len;
48 static char ok_chars[] = "1234567890!@%-_=+:,./\
49 abcdefghijklmnopqrstuvwxyz\
50 ABCDEFGHIJKLMNOPQRSTUVWXYZ";
51 char *str = string;
52 char *cp;
53 int ch;
54
55 /*
56 * Warning: we may be called from a child process or after pattern
57 * matching, so we cannot use clean_exit() or tcpd_jump().
58 */
59
60 while (*str) {
61 if (*str == '%' && (ch = str[1]) != 0) {
62 str += 2;
63 expansion =
64 ch == 'a' ? eval_hostaddr(request->client) :
65 ch == 'A' ? eval_hostaddr(request->server) :
66 ch == 'c' ? eval_client(request) :
67 ch == 'd' ? eval_daemon(request) :
68 ch == 'h' ? eval_hostinfo(request->client) :
69 ch == 'H' ? eval_hostinfo(request->server) :
70 ch == 'n' ? eval_hostname(request->client) :
71 ch == 'N' ? eval_hostname(request->server) :
72 ch == 'p' ? eval_pid(request) :
73 ch == 's' ? eval_server(request) :
74 ch == 'u' ? eval_user(request) :
75 ch == '%' ? "%" : (tcpd_warn("unrecognized %%%c", ch), "");
76 for (cp = expansion; *(cp += strspn(cp, ok_chars)); /* */ )
77 *cp = '_';
78 expansion_len = cp - expansion;
79 } else {
80 expansion = str++;
81 expansion_len = 1;
82 }
83 if (bp + expansion_len >= end) {
84 tcpd_warn("percent_x: expansion too long: %.30s...", result);
85 sleep(5);
86 exit(0);
87 }
88 memcpy(bp, expansion, expansion_len);
89 bp += expansion_len;
90 }
91 *bp = 0;
92 return (result);
93 }
94