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 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