IABSD.fr/xenocara/app/cwm/util.c

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• Author : tobias
  Date : 2020-04-16 17:12:49
  Hash : 493e33f3
  Message : Prevent out of boundary write with configuration files in which too many quoted arguments are stored for other window managers. The quotation handling happens within the while loop without checking if the "end" limit has been already reached. If this happens, the final NULL assignment leads to an out of boundary write on stack. OK okan@

• app/cwm/util.c

• /*
   * calmwm - the calm window manager
   *
   * Copyright (c) 2004 Marius Aamodt Eriksen <marius@monkey.org>
   *
   * Permission to use, copy, modify, and distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
   * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   *
   * $OpenBSD: util.c,v 1.26 2020/04/16 17:12:49 tobias Exp $
   */
  
  #include <sys/types.h>
  #include <sys/queue.h>
  
  #include <err.h>
  #include <errno.h>
  #include <limits.h>
  #include <stdarg.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <unistd.h>
  
  #include "calmwm.h"
  
  static void	 log_msg(const char *, va_list);
  
  void
  u_spawn(char *argstr)
  {
  	switch (fork()) {
  	case 0:
  		u_exec(argstr);
  		exit(1);
  	case -1:
  		warn("fork");
  	default:
  		break;
  	}
  }
  
  void
  u_exec(char *argstr)
  {
  #define MAXARGLEN 20
  	char	*args[MAXARGLEN], **ap = args;
  	char	**end = &args[MAXARGLEN - 2], *tmp;
  	char	*s = argstr;
  
  	while (ap < end && (*ap = strsep(&argstr, " \t")) != NULL) {
  		if (**ap == '\0')
  			continue;
  		ap++;
  		if (argstr != NULL) {
  			/* deal with quoted strings */
  			switch(argstr[0]) {
  			case '"':
  			case '\'':
  				if ((tmp = strchr(argstr + 1, argstr[0]))
  				    != NULL) {
  					*(tmp++) = '\0';
  					*(ap++) = ++argstr;
  					argstr = tmp;
  				}
  				break;
  			default:
  				break;
  			}
  		}
  	}
  	*ap = NULL;
  
  	(void)setsid();
  	(void)execvp(args[0], args);
  	warn("%s", s);
  }
  
  char *
  u_argv(char * const *argv)
  {
  	size_t	 siz = 0;
  	int	 i;
  	char	*p;
  
  	if (argv == 0)
  		return NULL;
  
  	for (i = 0; argv[i]; i++)
  		siz += strlen(argv[i]) + 1;
  	if (siz == 0)
  		return NULL;
  
  	p = xmalloc(siz);
  	strlcpy(p, argv[0], siz);
  	for (i = 1; argv[i]; i++) {
  		strlcat(p, " ", siz);
  		strlcat(p, argv[i], siz);
  	}
  	return p;
  }
  
  static void
  log_msg(const char *msg, va_list ap)
  {
  	char	*fmt;
  
  	if (asprintf(&fmt, "%s\n", msg) == -1) {
  		vfprintf(stderr, msg, ap);
  		fprintf(stderr, "\n");
  	} else {
  		vfprintf(stderr, fmt, ap);
  		free(fmt);
  	}
  	fflush(stderr);
  }
  
  void
  log_debug(int level, const char *func, const char *msg, ...)
  {
  	char	*fmt;
  	va_list	 ap;
  
  	if (Conf.debug < level)
  		return;
  
  	va_start(ap, msg);
  	xasprintf(&fmt, "debug%d: %s: %s", level, func, msg);
  	log_msg(fmt, ap);
  	free(fmt);
  	va_end(ap);
  }