IABSD.fr/src/libexec/talkd/announce.c

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• Author : deraadt
  Date : 2019-06-28 13:32:41
  Hash : df69c215
  Message : When system calls indicate an error they return -1, not some arbitrary value < 0. errno is only updated in this case. Change all (most?) callers of syscalls to follow this better, and let's see if this strictness helps us in the future.

• libexec/talkd/announce.c

• /*	$OpenBSD: announce.c,v 1.25 2019/06/28 13:32:53 deraadt Exp $	*/
  
  /*
   * Copyright (c) 1983 Regents of the University of California.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Neither the name of the University nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   */
  
  #include <sys/stat.h>
  #include <protocols/talkd.h>
  
  #include <limits.h>
  #include <paths.h>
  #include <stdio.h>
  #include <string.h>
  #include <unistd.h>
  #include <vis.h>
  
  #include "talkd.h"
  
  static void	print_mesg(FILE *,CTL_MSG *,char *);
  
  /*
   * Announce an invitation to talk.  If the user is
   * accepting messages, announce that a talk is requested.
   */
  int
  announce(CTL_MSG *request, char *remote_machine)
  {
  	char full_tty[PATH_MAX];
  	FILE *tf;
  	struct stat stbuf;
  
  	(void)snprintf(full_tty, sizeof(full_tty), "%s/%s", _PATH_DEV,
  	    request->r_tty);
  	if (access(full_tty, 0) != 0)
  		return (FAILED);
  	if ((tf = fopen(full_tty, "w")) == NULL)
  		return (PERMISSION_DENIED);
  	if (fstat(fileno(tf), &stbuf) == -1) {
  		fclose(tf);
  		return (PERMISSION_DENIED);
  	}
  	if ((stbuf.st_mode & S_IWGRP) == 0) {
  		fclose(tf);
  		return (PERMISSION_DENIED);
  	}
  	print_mesg(tf, request, remote_machine);
  	fclose(tf);
  	return (SUCCESS);
  }
  
  #define max(a,b) ( (a) > (b) ? (a) : (b) )
  #define N_LINES 5
  #define N_CHARS 120
  
  /*
   * Build a block of characters containing the message.
   * It is sent blank filled and in a single block to
   * try to keep the message in one piece if the recipient
   * is in vi at the time
   */
  static void
  print_mesg(FILE *tf, CTL_MSG *request, char *remote_machine)
  {
  	time_t clocktime;
  	struct tm *localclock;
  	char line_buf[N_LINES][N_CHARS];
  	int sizes[N_LINES];
  	char big_buf[(N_LINES + 1) * N_CHARS];
  	char *bptr, *lptr, vis_user[sizeof(request->l_name) * 4];
  	int i, j, max_size;
  
  	i = 0;
  	max_size = 0;
  	time(&clocktime);
  	localclock = localtime(&clocktime);
  	(void)snprintf(line_buf[i], N_CHARS, " ");
  	sizes[i] = strlen(line_buf[i]);
  	max_size = max(max_size, sizes[i]);
  	i++;
  	(void)snprintf(line_buf[i], N_CHARS,
  	    "Message from Talk_Daemon@%s at %d:%02d ...",
  	    hostname, localclock->tm_hour , localclock->tm_min );
  	sizes[i] = strlen(line_buf[i]);
  	max_size = max(max_size, sizes[i]);
  	i++;
  	strvis(vis_user, request->l_name, VIS_CSTYLE);
  	(void)snprintf(line_buf[i], N_CHARS,
  	    "talk: connection requested by %s@%s.",
  	    vis_user, remote_machine);
  	sizes[i] = strlen(line_buf[i]);
  	max_size = max(max_size, sizes[i]);
  	i++;
  	(void)snprintf(line_buf[i], N_CHARS, "talk: respond with:  talk %s@%s",
  	    vis_user, remote_machine);
  	sizes[i] = strlen(line_buf[i]);
  	max_size = max(max_size, sizes[i]);
  	i++;
  	(void)snprintf(line_buf[i], N_CHARS, " ");
  	sizes[i] = strlen(line_buf[i]);
  	max_size = max(max_size, sizes[i]);
  	i++;
  	bptr = big_buf;
  	*bptr++ = '\007'; /* send something to wake them up */
  	*bptr++ = '\r';	/* add a \r in case of raw mode */
  	*bptr++ = '\n';
  	for (i = 0; i < N_LINES; i++) {
  		/* copy the line into the big buffer */
  		lptr = line_buf[i];
  		while (*lptr != '\0')
  			*(bptr++) = *(lptr++);
  		/* pad out the rest of the lines with blanks */
  		for (j = sizes[i]; j < max_size + 2; j++)
  			*(bptr++) = ' ';
  		*(bptr++) = '\r';	/* add a \r in case of raw mode */
  		*(bptr++) = '\n';
  	}
  	*bptr = '\0';
  	fprintf(tf, "%s", big_buf);
  	fflush(tf);
  }