diff options
Diffstat (limited to 'contrib/tcp_wrappers/safe_finger.c')
| -rw-r--r-- | contrib/tcp_wrappers/safe_finger.c | 196 |
1 files changed, 0 insertions, 196 deletions
diff --git a/contrib/tcp_wrappers/safe_finger.c b/contrib/tcp_wrappers/safe_finger.c deleted file mode 100644 index 7b8f3cd638a89..0000000000000 --- a/contrib/tcp_wrappers/safe_finger.c +++ /dev/null @@ -1,196 +0,0 @@ - /* - * safe_finger - finger client wrapper that protects against nasty stuff - * from finger servers. Use this program for automatic reverse finger - * probes, not the raw finger command. - * - * Build with: cc -o safe_finger safe_finger.c - * - * The problem: some programs may react to stuff in the first column. Other - * programs may get upset by thrash anywhere on a line. File systems may - * fill up as the finger server keeps sending data. Text editors may bomb - * out on extremely long lines. The finger server may take forever because - * it is somehow wedged. The code below takes care of all this badness. - * - * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands. - */ - -#ifndef lint -static char sccsid[] = "@(#) safe_finger.c 1.4 94/12/28 17:42:41"; -#endif - -/* System libraries */ - -#include <sys/types.h> -#include <sys/stat.h> -#include <signal.h> -#include <stdio.h> -#include <ctype.h> -#include <pwd.h> - -extern void exit(); - -/* Local stuff */ - -char path[] = "PATH=/bin:/usr/bin:/usr/ucb:/usr/bsd:/etc:/usr/etc:/usr/sbin"; - -#define TIME_LIMIT 60 /* Do not keep listinging forever */ -#define INPUT_LENGTH 100000 /* Do not keep listinging forever */ -#define LINE_LENGTH 128 /* Editors can choke on long lines */ -#define FINGER_PROGRAM "finger" /* Most, if not all, UNIX systems */ -#define UNPRIV_NAME "nobody" /* Preferred privilege level */ -#define UNPRIV_UGID 32767 /* Default uid and gid */ - -int finger_pid; - -void cleanup(sig) -int sig; -{ - kill(finger_pid, SIGKILL); - exit(0); -} - -main(argc, argv) -int argc; -char **argv; -{ - int c; - int line_length = 0; - int finger_status; - int wait_pid; - int input_count = 0; - struct passwd *pwd; - - /* - * First of all, let's don't run with superuser privileges. - */ - if (getuid() == 0 || geteuid() == 0) { - if ((pwd = getpwnam(UNPRIV_NAME)) && pwd->pw_uid > 0) { - setgid(pwd->pw_gid); - setuid(pwd->pw_uid); - } else { - setgid(UNPRIV_UGID); - setuid(UNPRIV_UGID); - } - } - - /* - * Redirect our standard input through the raw finger command. - */ - if (putenv(path)) { - fprintf(stderr, "%s: putenv: out of memory", argv[0]); - exit(1); - } - argv[0] = FINGER_PROGRAM; - finger_pid = pipe_stdin(argv); - - /* - * Don't wait forever (Peter Wemm <peter@gecko.DIALix.oz.au>). - */ - signal(SIGALRM, cleanup); - (void) alarm(TIME_LIMIT); - - /* - * Main filter loop. - */ - while ((c = getchar()) != EOF) { - if (input_count++ >= INPUT_LENGTH) { /* don't listen forever */ - fclose(stdin); - printf("\n\n Input truncated to %d bytes...\n", input_count - 1); - break; - } - if (c == '\n') { /* good: end of line */ - putchar(c); - line_length = 0; - } else { - if (line_length >= LINE_LENGTH) { /* force end of line */ - printf("\\\n"); - line_length = 0; - } - if (line_length == 0) { /* protect left margin */ - putchar(' '); - line_length++; - } - if (isascii(c) && (isprint(c) || isspace(c))) { /* text */ - if (c == '\\') { - putchar(c); - line_length++; - } - putchar(c); - line_length++; - } else { /* quote all other thash */ - printf("\\%03o", c & 0377); - line_length += 4; - } - } - } - - /* - * Wait until the finger child process has terminated and account for its - * exit status. Which will always be zero on most systems. - */ - while ((wait_pid = wait(&finger_status)) != -1 && wait_pid != finger_pid) - /* void */ ; - return (wait_pid != finger_pid || finger_status != 0); -} - -/* perror_exit - report system error text and terminate */ - -void perror_exit(text) -char *text; -{ - perror(text); - exit(1); -} - -/* pipe_stdin - pipe stdin through program (from my ANSI to OLD C converter) */ - -int pipe_stdin(argv) -char **argv; -{ - int pipefds[2]; - int pid; - int i; - struct stat st; - - /* - * The code that sets up the pipe requires that file descriptors 0,1,2 - * are already open. All kinds of mysterious things will happen if that - * is not the case. The following loops makes sure that descriptors 0,1,2 - * are set up properly. - */ - - for (i = 0; i < 3; i++) { - if (fstat(i, &st) == -1 && open("/dev/null", 2) != i) - perror_exit("open /dev/null"); - } - - /* - * Set up the pipe that interposes the command into our standard input - * stream. - */ - - if (pipe(pipefds)) - perror_exit("pipe"); - - switch (pid = fork()) { - case -1: /* error */ - perror_exit("fork"); - /* NOTREACHED */ - case 0: /* child */ - (void) close(pipefds[0]); /* close reading end */ - (void) close(1); /* connect stdout to pipe */ - if (dup(pipefds[1]) != 1) - perror_exit("dup"); - (void) close(pipefds[1]); /* close redundant fd */ - (void) execvp(argv[0], argv); - perror_exit(argv[0]); - /* NOTREACHED */ - default: /* parent */ - (void) close(pipefds[1]); /* close writing end */ - (void) close(0); /* connect stdin to pipe */ - if (dup(pipefds[0]) != 0) - perror_exit("dup"); - (void) close(pipefds[0]); /* close redundant fd */ - return (pid); - } -} |