source3/smbd/srvstr.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    server specific string routines
   4    Copyright (C) Andrew Tridgell 2001
   5    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2003
   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 extern int max_send;
  23
  24 /* Make sure we can't write a string past the end of the buffer */
  25
  26 size_t srvstr_push_fn(const char *function, unsigned int line,
  27                       const char *base_ptr, uint16 smb_flags2, void *dest,
  28                       const char *src, int dest_len, int flags)
  29 {
  30         size_t buf_used = PTR_DIFF(dest, base_ptr);
  31         if (dest_len == -1) {
  32                 if (((ptrdiff_t)dest < (ptrdiff_t)base_ptr) || (buf_used > (size_t)max_send)) {
  33 #if 0
  34                         DEBUG(0, ("Pushing string of 'unlimited' length into non-SMB buffer!\n"));
  35 #endif
  36                         return push_string_fn(function, line, base_ptr,
  37                                               smb_flags2, dest, src, -1,
  38                                               flags);
  39                 }
  40                 return push_string_fn(function, line, base_ptr, smb_flags2,
  41                                       dest, src, max_send - buf_used, flags);
  42         }
  43
  44         /* 'normal' push into size-specified buffer */
  45         return push_string_fn(function, line, base_ptr, smb_flags2, dest, src,
  46                               dest_len, flags);
  47 }
  48
  49 /*******************************************************************
  50  Add a string to the end of a smb_buf, adjusting bcc and smb_len.
  51  Return the bytes added
  52 ********************************************************************/
  53
  54 ssize_t message_push_string(uint8 **outbuf, const char *str, int flags)
  55 {
  56         size_t buf_size = smb_len(*outbuf) + 4;
  57         size_t grow_size;
  58         size_t result;
  59         uint8 *tmp;
  60
  61         /*
  62          * We need to over-allocate, now knowing what srvstr_push will
  63          * actually use. This is very generous by incorporating potential
  64          * padding, the terminating 0 and at most 4 chars per UTF-16 code
  65          * point.
  66          */
  67         grow_size = (strlen(str) + 2) * 4;
  68
  69         if (!(tmp = TALLOC_REALLOC_ARRAY(NULL, *outbuf, uint8,
  70                                          buf_size + grow_size))) {
  71                 DEBUG(0, ("talloc failed\n"));
  72                 return -1;
  73         }
  74
  75         result = srvstr_push((char *)tmp, SVAL(tmp, smb_flg2),
  76                              tmp + buf_size, str, grow_size, flags);
  77
  78         if (result == (size_t)-1) {
  79                 DEBUG(0, ("srvstr_push failed\n"));
  80                 return -1;
  81         }
  82         set_message_bcc((char *)tmp, smb_buflen(tmp) + result);
  83
  84         *outbuf = tmp;
  85
  86         return result;
  87 }