xref: /openbmc/qemu/util/base64.c (revision fc8c745d)
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 2.1 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 }
61