source: vendor/current/source3/lib/util_ea.c

/*
   Unix SMB/CIFS implementation.
   SMB Extended attribute buffer handling
   Copyright (C) Jeremy Allison                 2005-2013
   Copyright (C) Tim Prouty                     2008

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"
#include "lib/util_ea.h"

/****************************************************************************
 Read one EA list entry from the buffer.
****************************************************************************/

struct ea_list *read_ea_list_entry(TALLOC_CTX *ctx, const char *pdata, size_t data_size, size_t *pbytes_used)
{
        struct ea_list *eal = talloc_zero(ctx, struct ea_list);
        uint16_t val_len;
        unsigned int namelen;
        size_t converted_size;

        if (!eal) {
                return NULL;
        }

        if (data_size < 6) {
                return NULL;
        }

        eal->ea.flags = CVAL(pdata,0);
        namelen = CVAL(pdata,1);
        val_len = SVAL(pdata,2);

        if (4 + namelen + 1 + val_len > data_size) {
                return NULL;
        }

        /* Ensure the name is null terminated. */
        if (pdata[namelen + 4] != '\0') {
                return NULL;
        }
        if (!pull_ascii_talloc(ctx, &eal->ea.name, pdata + 4, &converted_size)) {
                DEBUG(0,("read_ea_list_entry: pull_ascii_talloc failed: %s",
                        strerror(errno)));
        }
        if (!eal->ea.name) {
                return NULL;
        }

        eal->ea.value = data_blob_talloc(eal, NULL, (size_t)val_len + 1);
        if (!eal->ea.value.data) {
                return NULL;
        }

        memcpy(eal->ea.value.data, pdata + 4 + namelen + 1, val_len);

        /* Ensure we're null terminated just in case we print the value. */
        eal->ea.value.data[val_len] = '\0';
        /* But don't count the null. */
        eal->ea.value.length--;

        if (pbytes_used) {
                *pbytes_used = 4 + namelen + 1 + val_len;
        }

        DEBUG(10,("read_ea_list_entry: read ea name %s\n", eal->ea.name));
        dump_data(10, eal->ea.value.data, eal->ea.value.length);

        return eal;
}

/****************************************************************************
 Read a list of EA names and data from an incoming data buffer. Create an ea_list with them.
****************************************************************************/

struct ea_list *read_nttrans_ea_list(TALLOC_CTX *ctx, const char *pdata, size_t data_size)
{
        struct ea_list *ea_list_head = NULL;
        size_t offset = 0;

        if (data_size < 4) {
                return NULL;
        }

        while (offset + 4 <= data_size) {
                size_t next_offset = IVAL(pdata,offset);
                struct ea_list *eal = read_ea_list_entry(ctx, pdata + offset + 4, data_size - offset - 4, NULL);

                if (!eal) {
                        return NULL;
                }

                DLIST_ADD_END(ea_list_head, eal);
                if (next_offset == 0) {
                        break;
                }

                /* Integer wrap protection for the increment. */
                if (offset + next_offset < offset) {
                        break;
                }

                offset += next_offset;

                /* Integer wrap protection for while loop. */
                if (offset + 4 < offset) {
                        break;
                }

        }

        return ea_list_head;
}