summaryrefslogtreecommitdiffstats
path: root/core/jni/android_util_Base64.cpp
blob: bc69747c1bcfe28be84fc2c1db4670aa414c5361 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
/* //device/libs/android_runtime/android_util_Base64.cpp
**
** Copyright 2008, The Android Open Source Project
**
** Licensed under the Apache License, Version 2.0 (the "License"); 
** you may not use this file except in compliance with the License. 
** You may obtain a copy of the License at 
**
**     http://www.apache.org/licenses/LICENSE-2.0 
**
** Unless required by applicable law or agreed to in writing, software 
** distributed under the License is distributed on an "AS IS" BASIS, 
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
** See the License for the specific language governing permissions and 
** limitations under the License.
*/

/*********************************************************
*
* This code was copied from
* system/extra/ssh/dropbear-0.49/libtomcrypt/src/misc/base64/base64_decode.c
*
*********************************************************/

#define LOG_TAG "Base64"

#include <utils/Log.h>

#include <android_runtime/AndroidRuntime.h>

#include "JNIHelp.h"

#include <sys/errno.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include <signal.h>

namespace android {

static const unsigned char map[256] = {
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255,  62, 255, 255, 255,  63,
 52,  53,  54,  55,  56,  57,  58,  59,  60,  61, 255, 255,
255, 254, 255, 255, 255,   0,   1,   2,   3,   4,   5,   6,
  7,   8,   9,  10,  11,  12,  13,  14,  15,  16,  17,  18,
 19,  20,  21,  22,  23,  24,  25, 255, 255, 255, 255, 255,
255,  26,  27,  28,  29,  30,  31,  32,  33,  34,  35,  36,
 37,  38,  39,  40,  41,  42,  43,  44,  45,  46,  47,  48,
 49,  50,  51, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255 };

/**
   base64 decode a block of memory
   @param in       The base64 data to decode
   @param inlen    The length of the base64 data
   @param out      [out] The destination of the binary decoded data
   @param outlen   [in/out] The max size and resulting size of the decoded data
   @return 0 if successful
*/
int base64_decode(const unsigned char *in,  unsigned long inlen, 
                        unsigned char *out, unsigned long *outlen)
{
   unsigned long t, x, y, z;
   unsigned char c;
   int           g;

   g = 3;
   for (x = y = z = t = 0; x < inlen; x++) {
       c = map[in[x]&0xFF];
       if (c == 255) continue;
       /* the final = symbols are read and used to trim the remaining bytes */
       if (c == 254) { 
          c = 0; 
          /* prevent g < 0 which would potentially allow an overflow later */
          if (--g < 0) {
             return -3;
          }
       } else if (g != 3) {
          /* we only allow = to be at the end */
          return -4;
       }

       t = (t<<6)|c;

       if (++y == 4) {
          if (z + g > *outlen) { 
             return -2; 
          }
          out[z++] = (unsigned char)((t>>16)&255);
          if (g > 1) out[z++] = (unsigned char)((t>>8)&255);
          if (g > 2) out[z++] = (unsigned char)(t&255);
          y = t = 0;
       }
   }
   if (y != 0) {
       return -5;
   }
   *outlen = z;
   return 0;
}

static jbyteArray decodeBase64(JNIEnv *env, jobject jobj, jstring jdata)
{
    const char * rawData = env->GetStringUTFChars(jdata, NULL);
    int stringLength = env->GetStringUTFLength(jdata);

    int resultLength = stringLength / 4 * 3;
    if (rawData[stringLength-1] == '=') {
        resultLength -= 1;
        if (rawData[stringLength-2] == '=') {
            resultLength -= 1;
        }
    }

    jbyteArray byteArray = env->NewByteArray(resultLength);
    jbyte* byteArrayData = env->GetByteArrayElements(byteArray, NULL);

    unsigned long outlen = resultLength;
    int result = base64_decode((const unsigned char*)rawData, stringLength, (unsigned char *)byteArrayData, &outlen);
    if (result != 0)
        memset((unsigned char *)byteArrayData, -result, resultLength);
    
    env->ReleaseStringUTFChars(jdata, rawData);
    env->ReleaseByteArrayElements(byteArray, byteArrayData, 0);

    return byteArray;
}

static const JNINativeMethod methods[] = {
  {"decodeBase64Native", "(Ljava/lang/String;)[B", (void*)decodeBase64 }
};

static const char* const kBase64PathName = "android/os/Base64Utils";

int register_android_util_Base64(JNIEnv* env)
{
    jclass clazz;

    clazz = env->FindClass(kBase64PathName);
    LOG_FATAL_IF(clazz == NULL, "Unable to find class android.os.Base64Utils");

    return AndroidRuntime::registerNativeMethods(
        env, kBase64PathName,
        methods, NELEM(methods));
}

}