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 "qapi/error.h"
  23 #include "qemu/base64.h"
  24
  25 static const char *base64_valid_chars =
  26     "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=\n";
  27
  28 uint8_t *qbase64_decode(const char *input,
  29                         size_t in_len,
  30                         size_t *out_len,
  31                         Error **errp)
  32 {
  33     *out_len = 0;
  34
  35     if (in_len != -1) {
  36         /* Lack of NUL terminator is an error */
  37         if (input[in_len] != '\0') {
  38             error_setg(errp, "Base64 data is not NUL terminated");
  39             return NULL;
  40         }
  41         /* Check there's no NULs embedded since we expect
  42          * this to be valid base64 data */
  43         if (memchr(input, '\0', in_len) != NULL) {
  44             error_setg(errp, "Base64 data contains embedded NUL characters");
  45             return NULL;
  46         }
  47
  48         /* Now we know its a valid nul terminated string
  49          * strspn is safe to use... */
  50     } else {
  51         in_len = strlen(input);
  52     }
  53
  54     if (strspn(input, base64_valid_chars) != in_len) {
  55         error_setg(errp, "Base64 data contains invalid characters");
  56         return NULL;
  57     }
  58
  59     return g_base64_decode(input, out_len);
  60 }