/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
* All rights reserved.
*
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* The implementation was written so as to conform with Netscapes SSL.
*
* This library is free for commercial and non-commercial use as long as
* the following conditions are aheared to. The following conditions
* apply to all code found in this distribution, be it the RC4, RSA,
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
* included with this distribution is covered by the same copyright terms
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
*
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed.
* If this package is used in a product, Eric Young should be given attribution
* as the author of the parts of the library used.
* This can be in the form of a textual message at program startup or
* in documentation (online or textual) provided with the package.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* "This product includes cryptographic software written by
* Eric Young (eay@cryptsoft.com)"
* The word 'cryptographic' can be left out if the rouines from the library
* being used are not cryptographic related :-).
* 4. If you include any Windows specific code (or a derivative thereof) from
* the apps directory (application code) you must include an acknowledgement:
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
*
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``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 AUTHOR 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.
*
* The licence and distribution terms for any publically available version or
* derivative of this code cannot be changed. i.e. this code cannot simply be
* copied and put under another distribution licence
* [including the GNU Public Licence.] */
#include <openssl/base64.h>
#include <assert.h>
#include <limits.h>
#include <string.h>
#include <openssl/type_check.h>
#include "../internal.h"
// constant_time_lt_args_8 behaves like |constant_time_lt_8| but takes |uint8_t|
// arguments for a slightly simpler implementation.
static inline uint8_t constant_time_lt_args_8(uint8_t a, uint8_t b) {
crypto_word_t aw = a;
crypto_word_t bw = b;
// |crypto_word_t| is larger than |uint8_t|, so |aw| and |bw| have the same
// MSB. |aw| < |bw| iff MSB(|aw| - |bw|) is 1.
return constant_time_msb_w(aw - bw);
}
// constant_time_in_range_8 returns |CONSTTIME_TRUE_8| if |min| <= |a| <= |max|
// and |CONSTTIME_FALSE_8| otherwise.
static inline uint8_t constant_time_in_range_8(uint8_t a, uint8_t min,
uint8_t max) {
a -= min;
return constant_time_lt_args_8(a, max - min + 1);
}
// Encoding.
static uint8_t conv_bin2ascii(uint8_t a) {
// Since PEM is sometimes used to carry private keys, we encode base64 data
// itself in constant-time.
a &= 0x3f;
uint8_t ret = constant_time_select_8(constant_time_eq_8(a, 62), '+', '/');
ret =
constant_time_select_8(constant_time_lt_args_8(a, 62), a - 52 + '0', ret);
ret =
constant_time_select_8(constant_time_lt_args_8(a, 52), a - 26 + 'a', ret);
ret = constant_time_select_8(constant_time_lt_args_8(a, 26), a + 'A', ret);
return ret;
}
OPENSSL_STATIC_ASSERT(sizeof(((EVP_ENCODE_CTX *)(NULL))->data) % 3 == 0,
"data length must be a multiple of base64 chunk size");
int EVP_EncodedLength(size_t *out_len, size_t len) {
if (len + 2 < len) {
return 0;
}
len += 2;
len /= 3;
if (((len << 2) >> 2) != len) {
return 0;
}
len <<= 2;
if (len + 1 < len) {
return 0;
}
len++;
*out_len = len;
return 1;
}
void EVP_EncodeInit(EVP_ENCODE_CTX *ctx) {
OPENSSL_memset(ctx, 0, sizeof(EVP_ENCODE_CTX));
}
void EVP_EncodeUpdate(EVP_ENCODE_CTX *ctx, uint8_t *out, int *out_len,
const uint8_t *in, size_t in_len) {
size_t total = 0;
*out_len = 0;
if (in_len == 0) {
return;
}
assert(ctx->data_used < sizeof(ctx->data));
if (sizeof(ctx->data) - ctx->data_used > in_len) {
OPENSSL_memcpy(&ctx->data[ctx->data_used], in, in_len);
ctx->data_used += (unsigned)in_len;
return;
}
if (ctx->data_used != 0) {
const size_t todo = sizeof(ctx->data) - ctx->data_used;
OPENSSL_memcpy(&ctx->data[ctx->data_used], in, todo);
in += todo;
in_len -= todo;
size_t encoded = EVP_EncodeBlock(out, ctx->data, sizeof(ctx->data));
ctx->data_used = 0;
out += encoded;
*(out++) = '\n';
*out = '\0';
total = encoded + 1;
}
while (in_len >= sizeof(ctx->data)) {
size_t encoded = EVP_EncodeBlock(out, in, sizeof(ctx->data));
in += sizeof(ctx->data);
in_len -= sizeof(ctx->data);
out += encoded;
*(out++) = '\n';
*out = '\0';
if (total + encoded + 1 < total) {
*out_len = 0;
return;
}
total += encoded + 1;
}
if (in_len != 0) {
OPENSSL_memcpy(ctx->data, in, in_len);
}
ctx->data_used = (unsigned)in_len;
if (total > INT_MAX) {
// We cannot signal an error, but we can at least avoid making *out_len
// negative.
total = 0;
}
*out_len = (int)total;
}
void EVP_EncodeFinal(EVP_ENCODE_CTX *ctx, uint8_t *out, int *out_len) {
if (ctx->data_used == 0) {
*out_len = 0;
return;
}
size_t encoded = EVP_EncodeBlock(out, ctx->data, ctx->data_used);
out[encoded++] = '\n';
out[encoded] = '\0';
ctx->data_used = 0;
// ctx->data_used is bounded by sizeof(ctx->data), so this does not
// overflow.
assert(encoded <= INT_MAX);
*out_len = (int)encoded;
}
size_t EVP_EncodeBlock(uint8_t *dst, const uint8_t *src, size_t src_len) {
uint32_t l;
size_t remaining = src_len, ret = 0;
while (remaining) {
if (remaining >= 3) {
l = (((uint32_t)src[0]) << 16L) | (((uint32_t)src[1]) << 8L) | src[2];
*(dst++) = conv_bin2ascii(l >> 18L);
*(dst++) = conv_bin2ascii(l >> 12L);
*(dst++) = conv_bin2ascii(l >> 6L);
*(dst++) = conv_bin2ascii(l);
remaining -= 3;
} else {
l = ((uint32_t)src[0]) << 16L;
if (remaining == 2) {
l |= ((uint32_t)src[1] << 8L);
}
*(dst++) = conv_bin2ascii(l >> 18L);
*(dst++) = conv_bin2ascii(l >> 12L);
*(dst++) = (remaining == 1) ? '=' : conv_bin2ascii(l >> 6L);
*(dst++) = '=';
remaining = 0;
}
ret += 4;
src += 3;
}
*dst = '\0';
return ret;
}
// Decoding.
int EVP_DecodedLength(size_t *out_len, size_t len) {
if (len % 4 != 0) {
return 0;
}
*out_len = (len / 4) * 3;
return 1;
}
void EVP_DecodeInit(EVP_ENCODE_CTX *ctx) {
OPENSSL_memset(ctx, 0, sizeof(EVP_ENCODE_CTX));
}
static uint8_t base64_ascii_to_bin(uint8_t a) {
// Since PEM is sometimes used to carry private keys, we decode base64 data
// itself in constant-time.
const uint8_t is_upper = constant_time_in_range_8(a, 'A', 'Z');
const uint8_t is_lower = constant_time_in_range_8(a, 'a', 'z');
const uint8_t is_digit = constant_time_in_range_8(a, '0', '9');
const uint8_t is_plus = constant_time_eq_8(a, '+');
const uint8_t is_slash = constant_time_eq_8(a, '/');
const uint8_t is_equals = constant_time_eq_8(a, '=');
uint8_t ret = 0xff; // 0xff signals invalid.
ret = constant_time_select_8(is_upper, a - 'A', ret); // [0,26)
ret = constant_time_select_8(is_lower, a - 'a' + 26, ret); // [26,52)
ret = constant_time_select_8(is_digit, a - '0' + 52, ret); // [52,62)
ret = constant_time_select_8(is_plus, 62, ret);
ret = constant_time_select_8(is_slash, 63, ret);
// Padding maps to zero, to be further handled by the caller.
ret = constant_time_select_8(is_equals, 0, ret);
return ret;
}
// base64_decode_quad decodes a single “quad” (i.e. four characters) of base64
// data and writes up to three bytes to |out|. It sets |*out_num_bytes| to the
// number of bytes written, which will be less than three if the quad ended
// with padding. It returns one on success or zero on error.
static int base64_decode_quad(uint8_t *out, size_t *out_num_bytes,
const uint8_t *in) {
const uint8_t a = base64_ascii_to_bin(in[0]);
const uint8_t b = base64_ascii_to_bin(in[1]);
const uint8_t c = base64_ascii_to_bin(in[2]);
const uint8_t d = base64_ascii_to_bin(in[3]);
if (a == 0xff || b == 0xff || c == 0xff || d == 0xff) {
return 0;
}
const uint32_t v = ((uint32_t)a) << 18 | ((uint32_t)b) << 12 |
((uint32_t)c) << 6 | (uint32_t)d;
const unsigned padding_pattern = (in[0] == '=') << 3 |
(in[1] == '=') << 2 |
(in[2] == '=') << 1 |
(in[3] == '=');
switch (padding_pattern) {
case 0:
// The common case of no padding.
*out_num_bytes = 3;
out[0] = v >> 16;
out[1] = v >> 8;
out[2] = v;
break;
case 1: // xxx=
*out_num_bytes = 2;
out[0] = v >> 16;
out[1] = v >> 8;
break;
case 3: // xx==
*out_num_bytes = 1;
out[0] = v >> 16;
break;
default:
return 0;
}
return 1;
}
int EVP_DecodeUpdate(EVP_ENCODE_CTX *ctx, uint8_t *out, int *out_len,
const uint8_t *in, size_t in_len) {
*out_len = 0;
if (ctx->error_encountered) {
return -1;
}
size_t bytes_out = 0, i;
for (i = 0; i < in_len; i++) {
const char c = in[i];
switch (c) {
case ' ':
case '\t':
case '\r':
case '\n':
continue;
}
if (ctx->eof_seen) {
ctx->error_encountered = 1;
return -1;
}
ctx->data[ctx->data_used++] = c;
if (ctx->data_used == 4) {
size_t num_bytes_resulting;
if (!base64_decode_quad(out, &num_bytes_resulting, ctx->data)) {
ctx->error_encountered = 1;
return -1;
}
ctx->data_used = 0;
bytes_out += num_bytes_resulting;
out += num_bytes_resulting;
if (num_bytes_resulting < 3) {
ctx->eof_seen = 1;
}
}
}
if (bytes_out > INT_MAX) {
ctx->error_encountered = 1;
*out_len = 0;
return -1;
}
*out_len = (int)bytes_out;
if (ctx->eof_seen) {
return 0;
}
return 1;
}
int EVP_DecodeFinal(EVP_ENCODE_CTX *ctx, uint8_t *out, int *out_len) {
*out_len = 0;
if (ctx->error_encountered || ctx->data_used != 0) {
return -1;
}
return 1;
}
int EVP_DecodeBase64(uint8_t *out, size_t *out_len, size_t max_out,
const uint8_t *in, size_t in_len) {
*out_len = 0;
if (in_len % 4 != 0) {
return 0;
}
size_t max_len;
if (!EVP_DecodedLength(&max_len, in_len) ||
max_out < max_len) {
return 0;
}
size_t i, bytes_out = 0;
for (i = 0; i < in_len; i += 4) {
size_t num_bytes_resulting;
if (!base64_decode_quad(out, &num_bytes_resulting, &in[i])) {
return 0;
}
bytes_out += num_bytes_resulting;
out += num_bytes_resulting;
if (num_bytes_resulting != 3 && i != in_len - 4) {
return 0;
}
}
*out_len = bytes_out;
return 1;
}
int EVP_DecodeBlock(uint8_t *dst, const uint8_t *src, size_t src_len) {
// Trim spaces and tabs from the beginning of the input.
while (src_len > 0) {
if (src[0] != ' ' && src[0] != '\t') {
break;
}
src++;
src_len--;
}
// Trim newlines, spaces and tabs from the end of the line.
while (src_len > 0) {
switch (src[src_len-1]) {
case ' ':
case '\t':
case '\r':
case '\n':
src_len--;
continue;
}
break;
}
size_t dst_len;
if (!EVP_DecodedLength(&dst_len, src_len) ||
dst_len > INT_MAX ||
!EVP_DecodeBase64(dst, &dst_len, dst_len, src, src_len)) {
return -1;
}
// EVP_DecodeBlock does not take padding into account, so put the
// NULs back in... so the caller can strip them back out.
while (dst_len % 3 != 0) {
dst[dst_len++] = '\0';
}
assert(dst_len <= INT_MAX);
return (int)dst_len;
}