alpine/osdep/fltrname.c

   1 #if !defined(lint) && !defined(DOS)
   2 static char rcsid[] = "$Id: fltrname.c 769 2007-10-24 00:15:40Z hubert@u.washington.edu $";
   3 #endif
   4
   5 /*
   6  * ========================================================================
   7  * Copyright 2006-2007 University of Washington
   8  * Copyright 2013-2017 Eduardo Chappa
   9  *
  10  * Licensed under the Apache License, Version 2.0 (the "License");
  11  * you may not use this file except in compliance with the License.
  12  * You may obtain a copy of the License at
  13  *
  14  *     http://www.apache.org/licenses/LICENSE-2.0
  15  *
  16  * ========================================================================
  17  */
  18
  19 #include "../c-client/mail.h"   /* for MAILSTREAM */
  20 #undef ERROR
  21
  22 #include <system.h>
  23 #include <general.h>
  24
  25 #include "../../pith/osdep/writ_dir.h"
  26 #include "../../pith/osdep/bldpath.h"
  27
  28 #include "fltrname.h"
  29
  30
  31 /*----------------------------------------------------------------------
  32     Filter file names for strange characters
  33
  34    Args:  file  -- the file name to check
  35
  36  Result: Returns NULL if file name is OK
  37          Returns formatted error message if it is not
  38   ----*/
  39 char *
  40 filter_filename(char *file, int *fatal, int strict)
  41 {
  42 #define ERRORLEN 100
  43 #define ALLOW_WEIRD 1
  44 #ifdef ALLOW_WEIRD
  45     static char illegal[] = {'\177', '\0'};
  46 #else
  47 #ifdef  _WINDOWS
  48     static char illegal[] = {'"', '#', '$', '%', '&', /*'/',*/ '(', ')','*',
  49                           ',', ';', '<', '=', '>', '?', '[', ']',
  50                           '^', '|', '\177', '\0'};
  51 #else   /* UNIX */
  52     static char illegal[] = {'"', '#', '$', '%', '&', '\'','(', ')','*',
  53                           ',', ':', ';', '<', '=', '>', '?', '[', ']',
  54                           '\\', '^', '|', '\177', '\0'};
  55 #endif  /* UNIX */
  56 #endif
  57     static char error[ERRORLEN];
  58     char ill_file[MAXPATH+1], *ill_char, *ptr, e2[20];
  59     int i;
  60
  61     for(ptr = file; *ptr == ' '; ptr++) ; /* leading spaces gone */
  62
  63     while(*ptr && (unsigned char)(*ptr) >= ' ' && strchr(illegal, *ptr) == 0)
  64       ptr++;
  65
  66     *fatal = TRUE;
  67     if(*ptr != '\0') {
  68         if(*ptr == '\n') {
  69             ill_char = "<newline>";
  70         } else if(*ptr == '\r') {
  71             ill_char = "<carriage return>";
  72         } else if(*ptr == '\t') {
  73             ill_char = "<tab>";
  74             *fatal = FALSE;             /* just whitespace */
  75         } else if(*ptr < ' ') {
  76             snprintf(e2, sizeof(e2), "control-%c", *ptr + '@');
  77             ill_char = e2;
  78         } else if (*ptr == '\177') {
  79             ill_char = "<del>";
  80         } else {
  81             e2[0] = *ptr;
  82             e2[1] = '\0';
  83             ill_char = e2;
  84             *fatal = FALSE;             /* less offensive? */
  85         }
  86         if(!*fatal){
  87             strncpy(error, ill_char, sizeof(error)-1);
  88             error[sizeof(error)-1] = '\0';
  89         }
  90         else if(ptr != file) {
  91             strncpy(ill_file, file, MIN(ptr-file,sizeof(ill_file)-1));
  92             ill_file[MIN(ptr-file,sizeof(ill_file)-1)] = '\0';
  93             snprintf(error, sizeof(error),
  94                     "Character \"%s\" after \"%.*s\" not allowed in file name",
  95                     ill_char, ERRORLEN-50, ill_file);
  96         } else {
  97             snprintf(error, sizeof(error),
  98                     "First character, \"%s\", not allowed in file name",
  99                     ill_char);
 100         }
 101
 102         return(error);
 103     }
 104
 105     if((i=is_writable_dir(file)) == 0 || i == 1){
 106         snprintf(error, sizeof(error), "\"%.*s\" is a directory", ERRORLEN-50, file);
 107         return(error);
 108     }
 109
 110     if(strict){
 111         for(ptr = file; *ptr == ' '; ptr++) ;   /* leading spaces gone */
 112
 113         if((ptr[0] == '.' && ptr[1] == '.') || filename_parent_ref(ptr)){
 114             snprintf(error, sizeof(error), "\"..\" not allowed in filename");
 115             return(error);
 116         }
 117     }
 118
 119     return((char *)NULL);
 120 }