util/base64.c

   1 /*
   2  * QEMU base64 helpers
   3  *
   4  * Copyright (c) 2015 Red Hat, Inc.
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library 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 GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18  *
  19  */
  20
  21 #include "qemu/osdep.h"
  22 #include <config-host.h>
  23
  24 #include "qemu/base64.h"
  25
  26 static const char *base64_valid_chars =
  27     "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=\n";
  28
  29 uint8_t *qbase64_decode(const char *input,
  30                         size_t in_len,
  31                         size_t *out_len,
  32                         Error **errp)
  33 {
  34     *out_len = 0;
  35
  36     if (in_len != -1) {
  37         /* Lack of NUL terminator is an error */
  38         if (input[in_len] != '\0') {
  39             error_setg(errp, "Base64 data is not NUL terminated");
  40             return NULL;
  41         }
  42         /* Check there's no NULs embedded since we expect
  43          * this to be valid base64 data */
  44         if (memchr(input, '\0', in_len) != NULL) {
  45             error_setg(errp, "Base64 data contains embedded NUL characters");
  46             return NULL;
  47         }
  48
  49         /* Now we know its a valid nul terminated string
  50          * strspn is safe to use... */
  51     } else {
  52         in_len = strlen(input);
  53     }
  54
  55     if (strspn(input, base64_valid_chars) != in_len) {
  56         error_setg(errp, "Base64 data contains invalid characters");
  57         return NULL;
  58     }
  59
  60     return g_base64_decode(input, out_len);
  61 }