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/*
*
* Copyright 2015 gRPC authors.
*
* 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.
*
*/
#include "src/core/lib/slice/b64.h"
#include <stdint.h>
#include <string.h>
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <grpc/support/useful.h>
#include "src/core/lib/slice/slice_internal.h"
/* --- Constants. --- */
static const int8_t 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) {
size_t result_projected_size =
grpc_base64_estimate_encoded_size(data_size, url_safe, multiline);
char* result = (char*)gpr_malloc(result_projected_size);
grpc_base64_encode_core(result, vdata, data_size, url_safe, multiline);
return result;
}
size_t grpc_base64_estimate_encoded_size(size_t data_size, int url_safe,
int multiline) {
size_t result_projected_size =
4 * ((data_size + 3) / 3) +
2 * (multiline ? (data_size / (3 * GRPC_BASE64_MULTILINE_NUM_BLOCKS))
: 0) +
1;
return result_projected_size;
}
void grpc_base64_encode_core(char* result, const void* vdata, size_t data_size,
int url_safe, int multiline) {
const unsigned char* data = (const unsigned char*)vdata;
const char* base64_chars =
url_safe ? base64_url_safe_chars : base64_url_unsafe_chars;
const size_t result_projected_size =
grpc_base64_estimate_encoded_size(data_size, url_safe, multiline);
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((uintptr_t)(current - result) < result_projected_size);
result[current - result] = '\0';
}
grpc_slice grpc_base64_decode(grpc_exec_ctx* exec_ctx, const char* b64,
int url_safe) {
return grpc_base64_decode_with_len(exec_ctx, b64, strlen(b64), url_safe);
}
static void decode_one_char(const unsigned char* codes, unsigned char* result,
size_t* result_offset) {
uint32_t packed = ((uint32_t)codes[0] << 2) | ((uint32_t)codes[1] >> 4);
result[(*result_offset)++] = (unsigned char)packed;
}
static void decode_two_chars(const unsigned char* codes, unsigned char* result,
size_t* result_offset) {
uint32_t packed = ((uint32_t)codes[0] << 10) | ((uint32_t)codes[1] << 4) |
((uint32_t)codes[2] >> 2);
result[(*result_offset)++] = (unsigned char)(packed >> 8);
result[(*result_offset)++] = (unsigned char)(packed);
}
static int decode_group(const unsigned char* codes, size_t num_codes,
unsigned char* result, size_t* result_offset) {
GPR_ASSERT(num_codes <= 4);
/* Short end groups that may not have padding. */
if (num_codes == 1) {
gpr_log(GPR_ERROR, "Invalid group. Must be at least 2 bytes.");
return 0;
}
if (num_codes == 2) {
decode_one_char(codes, result, result_offset);
return 1;
}
if (num_codes == 3) {
decode_two_chars(codes, result, result_offset);
return 1;
}
/* Regular 4 byte groups with padding or not. */
GPR_ASSERT(num_codes == 4);
if (codes[0] == GRPC_BASE64_PAD_BYTE || codes[1] == GRPC_BASE64_PAD_BYTE) {
gpr_log(GPR_ERROR, "Invalid padding detected.");
return 0;
}
if (codes[2] == GRPC_BASE64_PAD_BYTE) {
if (codes[3] == GRPC_BASE64_PAD_BYTE) {
decode_one_char(codes, result, result_offset);
} else {
gpr_log(GPR_ERROR, "Invalid padding detected.");
return 0;
}
} else if (codes[3] == GRPC_BASE64_PAD_BYTE) {
decode_two_chars(codes, result, result_offset);
} else {
/* No padding. */
uint32_t packed = ((uint32_t)codes[0] << 18) | ((uint32_t)codes[1] << 12) |
((uint32_t)codes[2] << 6) | codes[3];
result[(*result_offset)++] = (unsigned char)(packed >> 16);
result[(*result_offset)++] = (unsigned char)(packed >> 8);
result[(*result_offset)++] = (unsigned char)(packed);
}
return 1;
}
grpc_slice grpc_base64_decode_with_len(grpc_exec_ctx* exec_ctx, const char* b64,
size_t b64_len, int url_safe) {
grpc_slice result = GRPC_SLICE_MALLOC(b64_len);
unsigned char* current = GRPC_SLICE_START_PTR(result);
size_t result_size = 0;
unsigned char codes[4];
size_t num_codes = 0;
while (b64_len--) {
unsigned char c = (unsigned char)(*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++] = (unsigned char)code;
if (num_codes == 4) {
if (!decode_group(codes, num_codes, current, &result_size)) goto fail;
num_codes = 0;
}
}
}
if (num_codes != 0 &&
!decode_group(codes, num_codes, current, &result_size)) {
goto fail;
}
GRPC_SLICE_SET_LENGTH(result, result_size);
return result;
fail:
grpc_slice_unref_internal(exec_ctx, result);
return grpc_empty_slice();
}
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