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Diffstat (limited to 'src/core/lib/security/util/b64.c')
| -rw-r--r-- | src/core/lib/security/util/b64.c | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/src/core/lib/security/util/b64.c b/src/core/lib/security/util/b64.c new file mode 100644 index 0000000000..9da42e4e73 --- /dev/null +++ b/src/core/lib/security/util/b64.c @@ -0,0 +1,233 @@ +/* + * + * 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/lib/security/util/b64.h" + +#include <stdint.h> +#include <string.h> + +#include <grpc/support/alloc.h> +#include <grpc/support/log.h> +#include <grpc/support/useful.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) { + 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((uintptr_t)(current - result) < result_projected_size); + result[current - result] = '\0'; + return result; +} + +gpr_slice grpc_base64_decode(const char *b64, int url_safe) { + return grpc_base64_decode_with_len(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; +} + +gpr_slice grpc_base64_decode_with_len(const char *b64, size_t b64_len, + int url_safe) { + 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 = (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; + } + GPR_SLICE_SET_LENGTH(result, result_size); + return result; + +fail: + gpr_slice_unref(result); + return gpr_empty_slice(); +} |