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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: }