Annotation of embedaddon/sudo/plugins/sudoers/base64.c, revision 1.1.1.1
1.1 misho 1: /*
2: * Copyright (c) 2013 Todd C. Miller <Todd.Miller@courtesan.com>
3: *
4: * Permission to use, copy, modify, and distribute this software for any
5: * purpose with or without fee is hereby granted, provided that the above
6: * copyright notice and this permission notice appear in all copies.
7: *
8: * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9: * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10: * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11: * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12: * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13: * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14: * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15: * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
16: * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
17: */
18:
19: #include <config.h>
20:
21: #include <sys/types.h>
22: #include <stdio.h>
23: #ifdef STDC_HEADERS
24: # include <stdlib.h>
25: # include <stddef.h>
26: #else
27: # ifdef HAVE_STDLIB_H
28: # include <stdlib.h>
29: # endif
30: #endif /* STDC_HEADERS */
31: #ifdef HAVE_STRING_H
32: # include <string.h>
33: #endif /* HAVE_STRING_H */
34: #ifdef HAVE_STRINGS_H
35: # include <strings.h>
36: #endif /* HAVE_STRINGS_H */
37:
38: #include "missing.h"
39: #include "sudo_debug.h"
40:
41: /*
42: * Decode a NUL-terminated string in base64 format and store the
43: * result in dst.
44: */
45: size_t
46: base64_decode(const char *str, unsigned char *dst, size_t dsize)
47: {
48: static const char b64[] =
49: "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
50: const unsigned char *dst0 = dst;
51: const unsigned char *dend = dst + dsize;
52: unsigned char ch[4];
53: char *pos;
54: int i;
55: debug_decl(base64_decode, SUDO_DEBUG_MATCH)
56:
57: /*
58: * Convert from base64 to binary. Each base64 char holds 6 bits of data
59: * so 4 base64 chars equals 3 chars of data.
60: * Padding (with the '=' char) may or may not be present.
61: */
62: while (*str != '\0') {
63: for (i = 0; i < 4; i++) {
64: switch (*str) {
65: case '=':
66: str++;
67: /* FALLTHROUGH */
68: case '\0':
69: ch[i] = '=';
70: break;
71: default:
72: if ((pos = strchr(b64, *str++)) == NULL)
73: debug_return_size_t((size_t)-1);
74: ch[i] = (unsigned char)(pos - b64);
75: break;
76: }
77: }
78: if (ch[0] == '=' || ch[1] == '=' || dst == dend)
79: break;
80: *dst++ = (ch[0] << 2) | ((ch[1] & 0x30) >> 4);
81: if (ch[2] == '=' || dst == dend)
82: break;
83: *dst++ = ((ch[1] & 0x0f) << 4) | ((ch[2] & 0x3c) >> 2);
84: if (ch[3] == '=' || dst == dend)
85: break;
86: *dst++ = ((ch[2] & 0x03) << 6) | ch[3];
87: }
88: debug_return_size_t((size_t)(dst - dst0));
89: }
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