xref: /qemu/util/base64.c (revision 7a4e543d)
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 }
62