source3/lib/util_ea.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    SMB Extended attribute buffer handling
   4    Copyright (C) Jeremy Allison                 2005-2013
   5    Copyright (C) Tim Prouty                     2008
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "includes.h"
  22 #include "lib/util_ea.h"
  23
  24 /****************************************************************************
  25  Read one EA list entry from the buffer.
  26 ****************************************************************************/
  27
  28 struct ea_list *read_ea_list_entry(TALLOC_CTX *ctx, const char *pdata, size_t data_size, size_t *pbytes_used)
  29 {
  30         struct ea_list *eal = talloc_zero(ctx, struct ea_list);
  31         uint16_t val_len;
  32         unsigned int namelen;
  33         size_t converted_size;
  34
  35         if (!eal) {
  36                 return NULL;
  37         }
  38
  39         if (data_size < 6) {
  40                 return NULL;
  41         }
  42
  43         eal->ea.flags = CVAL(pdata,0);
  44         namelen = CVAL(pdata,1);
  45         val_len = SVAL(pdata,2);
  46
  47         if (4 + namelen + 1 + val_len > data_size) {
  48                 return NULL;
  49         }
  50
  51         /* Ensure the name is null terminated. */
  52         if (pdata[namelen + 4] != '\0') {
  53                 return NULL;
  54         }
  55         if (!pull_ascii_talloc(ctx, &eal->ea.name, pdata + 4, &converted_size)) {
  56                 DEBUG(0,("read_ea_list_entry: pull_ascii_talloc failed: %s",
  57                         strerror(errno)));
  58         }
  59         if (!eal->ea.name) {
  60                 return NULL;
  61         }
  62
  63         eal->ea.value = data_blob_talloc(eal, NULL, (size_t)val_len + 1);
  64         if (!eal->ea.value.data) {
  65                 return NULL;
  66         }
  67
  68         memcpy(eal->ea.value.data, pdata + 4 + namelen + 1, val_len);
  69
  70         /* Ensure we're null terminated just in case we print the value. */
  71         eal->ea.value.data[val_len] = '\0';
  72         /* But don't count the null. */
  73         eal->ea.value.length--;
  74
  75         if (pbytes_used) {
  76                 *pbytes_used = 4 + namelen + 1 + val_len;
  77         }
  78
  79         DEBUG(10,("read_ea_list_entry: read ea name %s\n", eal->ea.name));
  80         dump_data(10, eal->ea.value.data, eal->ea.value.length);
  81
  82         return eal;
  83 }
  84
  85 /****************************************************************************
  86  Read a list of EA names and data from an incoming data buffer. Create an ea_list with them.
  87 ****************************************************************************/
  88
  89 struct ea_list *read_nttrans_ea_list(TALLOC_CTX *ctx, const char *pdata, size_t data_size)
  90 {
  91         struct ea_list *ea_list_head = NULL;
  92         size_t offset = 0;
  93
  94         if (data_size < 4) {
  95                 return NULL;
  96         }
  97
  98         while (offset + 4 <= data_size) {
  99                 size_t next_offset = IVAL(pdata,offset);
 100                 struct ea_list *eal = read_ea_list_entry(ctx, pdata + offset + 4, data_size - offset - 4, NULL);
 101
 102                 if (!eal) {
 103                         return NULL;
 104                 }
 105
 106                 DLIST_ADD_END(ea_list_head, eal, struct ea_list *);
 107                 if (next_offset == 0) {
 108                         break;
 109                 }
 110
 111                 /* Integer wrap protection for the increment. */
 112                 if (offset + next_offset < offset) {
 113                         break;
 114                 }
 115
 116                 offset += next_offset;
 117
 118                 /* Integer wrap protection for while loop. */
 119                 if (offset + 4 < offset) {
 120                         break;
 121                 }
 122
 123         }
 124
 125         return ea_list_head;
 126 }