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/*
*
* Copyright 2015, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include "src/core/security/base64.h"
#include <string.h>
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <grpc/support/useful.h>
/* --- Constants. --- */
static const char base64_bytes[] = {
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, 0x3E, -1, -1, -1, 0x3F,
0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, 0x3D, -1, -1,
-1, 0x7F, -1, -1, -1, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12,
0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, -1, -1, -1, -1, -1,
-1, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, 0x23, 0x24,
0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F, 0x30,
0x31, 0x32, 0x33, -1, -1, -1, -1, -1};
static const char base64_url_unsafe_chars[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static const char base64_url_safe_chars[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
#define GRPC_BASE64_PAD_CHAR '='
#define GRPC_BASE64_PAD_BYTE 0x7F
#define GRPC_BASE64_MULTILINE_LINE_LEN 76
#define GRPC_BASE64_MULTILINE_NUM_BLOCKS (GRPC_BASE64_MULTILINE_LINE_LEN / 4)
/* --- base64 functions. --- */
char *grpc_base64_encode(const void *vdata, size_t data_size, int url_safe,
int multiline) {
const unsigned char *data = vdata;
const char *base64_chars =
url_safe ? base64_url_safe_chars : base64_url_unsafe_chars;
size_t result_projected_size =
4 * ((data_size + 3) / 3) +
2 * (multiline ? (data_size / (3 * GRPC_BASE64_MULTILINE_NUM_BLOCKS))
: 0) +
1;
char *result = gpr_malloc(result_projected_size);
char *current = result;
size_t num_blocks = 0;
size_t i = 0;
/* Encode each block. */
while (data_size >= 3) {
*current++ = base64_chars[(data[i] >> 2) & 0x3F];
*current++ =
base64_chars[((data[i] & 0x03) << 4) | ((data[i + 1] >> 4) & 0x0F)];
*current++ =
base64_chars[((data[i + 1] & 0x0F) << 2) | ((data[i + 2] >> 6) & 0x03)];
*current++ = base64_chars[data[i + 2] & 0x3F];
data_size -= 3;
i += 3;
if (multiline && (++num_blocks == GRPC_BASE64_MULTILINE_NUM_BLOCKS)) {
*current++ = '\r';
*current++ = '\n';
num_blocks = 0;
}
}
/* Take care of the tail. */
if (data_size == 2) {
*current++ = base64_chars[(data[i] >> 2) & 0x3F];
*current++ =
base64_chars[((data[i] & 0x03) << 4) | ((data[i + 1] >> 4) & 0x0F)];
*current++ = base64_chars[(data[i + 1] & 0x0F) << 2];
*current++ = GRPC_BASE64_PAD_CHAR;
} else if (data_size == 1) {
*current++ = base64_chars[(data[i] >> 2) & 0x3F];
*current++ = base64_chars[(data[i] & 0x03) << 4];
*current++ = GRPC_BASE64_PAD_CHAR;
*current++ = GRPC_BASE64_PAD_CHAR;
}
GPR_ASSERT(current >= result);
GPR_ASSERT((gpr_uintptr)(current - result) < result_projected_size);
result[current - result] = '\0';
return result;
}
gpr_slice grpc_base64_decode(const char *b64, int url_safe) {
size_t b64_len = strlen(b64);
gpr_slice result = gpr_slice_malloc(b64_len);
unsigned char *current = GPR_SLICE_START_PTR(result);
size_t result_size = 0;
unsigned char codes[4];
size_t num_codes = 0;
while (b64_len--) {
unsigned char c = *b64++;
signed char code;
if (c >= GPR_ARRAY_SIZE(base64_bytes)) continue;
if (url_safe) {
if (c == '+' || c == '/') {
gpr_log(GPR_ERROR, "Invalid character for url safe base64 %c", c);
goto fail;
}
if (c == '-') {
c = '+';
} else if (c == '_') {
c = '/';
}
}
code = base64_bytes[c];
if (code == -1) {
if (c != '\r' && c != '\n') {
gpr_log(GPR_ERROR, "Invalid character %c", c);
goto fail;
}
} else {
codes[num_codes++] = code;
if (num_codes == 4) {
if (codes[0] == GRPC_BASE64_PAD_BYTE ||
codes[1] == GRPC_BASE64_PAD_BYTE) {
gpr_log(GPR_ERROR, "Invalid padding detected.");
goto fail;
}
if (codes[2] == GRPC_BASE64_PAD_BYTE) {
if (codes[3] == GRPC_BASE64_PAD_BYTE) {
/* Double padding. */
gpr_uint32 packed = (codes[0] << 2) | (codes[1] >> 4);
current[result_size++] = (unsigned char)packed;
} else {
gpr_log(GPR_ERROR, "Invalid padding detected.");
goto fail;
}
} else if (codes[3] == GRPC_BASE64_PAD_BYTE) {
/* Single padding. */
gpr_uint32 packed =
(codes[0] << 10) | (codes[1] << 4) | (codes[2] >> 2);
current[result_size++] = (unsigned char)(packed >> 8);
current[result_size++] = (unsigned char)(packed);
} else {
/* No padding. */
gpr_uint32 packed =
(codes[0] << 18) | (codes[1] << 12) | (codes[2] << 6) | codes[3];
current[result_size++] = (unsigned char)(packed >> 16);
current[result_size++] = (unsigned char)(packed >> 8);
current[result_size++] = (unsigned char)(packed);
}
num_codes = 0;
}
}
}
if (num_codes != 0) {
gpr_log(GPR_ERROR, "Invalid base64.");
gpr_slice_unref(result);
return gpr_empty_slice();
}
GPR_SLICE_SET_LENGTH(result, result_size);
return result;
fail:
gpr_slice_unref(result);
return gpr_empty_slice();
}
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