lib/util/util_str_escape.c

   1 /*
   2    Samba string escaping routines
   3
   4    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2017
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "includes.h"
  21 #include "lib/util/util_str_escape.h"
  22
  23
  24 /*
  25  * Calculate the encoded length of a character for log_escape
  26  *
  27  */
  28 static size_t encoded_length(char c)
  29 {
  30         if (c != '\\' &&  c > 0x1F) {
  31                 return 1;
  32         } else {
  33                 switch (c) {
  34                 case '\a':
  35                 case '\b':
  36                 case '\f':
  37                 case '\n':
  38                 case '\r':
  39                 case '\t':
  40                 case '\v':
  41                 case '\\':
  42                         return 2;  /* C escape sequence */
  43                 default:
  44                         return 4;  /* hex escape \xhh   */
  45                 }
  46         }
  47 }
  48
  49 /*
  50  * Escape any control characters in the inputs to prevent them from
  51  * interfering with the log output.
  52  */
  53 char *log_escape(TALLOC_CTX *frame, const char *in)
  54 {
  55         size_t size = 0;        /* Space to allocate for the escaped data */
  56         char *encoded = NULL;   /* The encoded string                     */
  57         const char *c;
  58         char *e;
  59
  60         if (in == NULL) {
  61                 return NULL;
  62         }
  63
  64         /* Calculate the size required for the escaped array */
  65         c = in;
  66         while (*c) {
  67                 size += encoded_length( *c);
  68                 c++;
  69         }
  70         size++;
  71
  72         encoded = talloc_array( frame, char, size);
  73         if (encoded == NULL) {
  74                 DBG_ERR( "Out of memory allocating encoded string");
  75                 return NULL;
  76         }
  77
  78         c = in;
  79         e = encoded;
  80         while (*c) {
  81                 if (*c != '\\' && *c > 0x1F) {
  82                         *e++ = *c++;
  83                 } else {
  84                         switch (*c) {
  85                         case '\a':
  86                                 *e++ = '\\';
  87                                 *e++ = 'a';
  88                                 break;
  89                         case '\b':
  90                                 *e++ = '\\';
  91                                 *e++ = 'b';
  92                                 break;
  93                         case '\f':
  94                                 *e++ = '\\';
  95                                 *e++ = 'f';
  96                                 break;
  97                         case '\n':
  98                                 *e++ = '\\';
  99                                 *e++ = 'n';
 100                                 break;
 101                         case '\r':
 102                                 *e++ = '\\';
 103                                 *e++ = 'r';
 104                                 break;
 105                         case '\t':
 106                                 *e++ = '\\';
 107                                 *e++ = 't';
 108                                 break;
 109                         case '\v':
 110                                 *e++ = '\\';
 111                                 *e++ = 'v';
 112                                 break;
 113                         case '\\':
 114                                 *e++ = '\\';
 115                                 *e++ = '\\';
 116                                 break;
 117                         default:
 118                                 snprintf(e, 5, "\\x%02X", *c);
 119                                 e += 4;
 120                         }
 121                         c++;
 122                 }
 123         }
 124         *e = '\0';
 125         return encoded;
 126 }