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Replace OpenSSL base64 impl with a simple direct impl.

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Unit tests, too.
This commit is contained in:
John Hood
2015-10-04 20:16:25 -04:00
parent 1307dc4a0f
commit db311f92f7
8 changed files with 256 additions and 88 deletions
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src/crypto/base64.cc
+59 -84
View File
@@ -31,103 +31,78 @@
*/
#include <string.h>
#include <openssl/bio.h>
#include <openssl/evp.h>
#include <stdlib.h>
#include "fatal_assert.h"
#include "base64.h"
bool base64_decode( const char *b64, const size_t b64_len,
char *raw, size_t *raw_len )
{
bool ret = false;
static const char table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
/* Reverse maps from an ASCII char to a base64 sixbit value. Returns > 0x3f on failure. */
static unsigned char base64_char_to_sixbit(char c)
{
/*
* Yes, this is slow. But it's also very simple, and easy to verify.
* We don't need performance here.
*/
const char *match = strchr(table, c);
if (!match) {
return 0xff;
}
return match - table;
}
bool base64_decode( const char *b64, const size_t b64_len,
uint8_t *raw, size_t *raw_len )
{
fatal_assert( b64_len == 24 ); /* only useful for Mosh keys */
fatal_assert( *raw_len == 16 );
/* initialize input/output */
BIO_METHOD *b64_method = BIO_f_base64();
fatal_assert( b64_method );
BIO *b64_bio = BIO_new( b64_method );
fatal_assert( b64_bio );
BIO_set_flags( b64_bio, BIO_FLAGS_BASE64_NO_NL );
BIO *mem_bio = BIO_new_mem_buf( (void *) b64, b64_len );
fatal_assert( mem_bio );
BIO *combined_bio = BIO_push( b64_bio, mem_bio );
fatal_assert( combined_bio );
fatal_assert( 1 == BIO_flush( combined_bio ) );
/* read the string */
int bytes_read = BIO_read( combined_bio, raw, *raw_len );
if ( bytes_read <= 0 ) {
goto end;
uint32_t bytes = 0;
for (int i = 0; i < 22; i++) {
unsigned char sixbit = base64_char_to_sixbit(*(b64++));
if (sixbit > 0x3f) {
return false;
}
bytes <<= 6;
bytes |= sixbit;
/* write groups of 3 */
if (i % 4 == 3) {
raw[0] = bytes >> 16;
raw[1] = bytes >> 8;
raw[2] = bytes;
raw += 3;
bytes = 0;
}
}
/* last byte of output */
*raw = bytes >> 4;
if (b64[0] != '=' || b64[1] != '=') {
return false;
}
return true;
}
if ( bytes_read != (int)*raw_len ) {
goto end;
}
fatal_assert( 1 == BIO_flush( combined_bio ) );
/* check if there is more to read */
char extra[ 256 ];
bytes_read = BIO_read( combined_bio, extra, 256 );
if ( bytes_read > 0 ) {
goto end;
}
/* check if mem buf is empty */
if ( !BIO_eof( mem_bio ) ) {
goto end;
}
ret = true;
end:
BIO_free_all( combined_bio );
return ret;
}
void base64_encode( const char *raw, const size_t raw_len,
void base64_encode( const uint8_t *raw, const size_t raw_len,
char *b64, const size_t b64_len )
{
fatal_assert( b64_len == 24 ); /* only useful for Mosh keys */
fatal_assert( raw_len == 16 );
/* initialize input/output */
BIO_METHOD *b64_method = BIO_f_base64(), *mem_method = BIO_s_mem();
fatal_assert( b64_method );
fatal_assert( mem_method );
BIO *b64_bio = BIO_new( b64_method ), *mem_bio = BIO_new( mem_method );
fatal_assert( b64_bio );
fatal_assert( mem_bio );
BIO_set_flags( b64_bio, BIO_FLAGS_BASE64_NO_NL );
BIO *combined_bio = BIO_push( b64_bio, mem_bio );
fatal_assert( combined_bio );
/* write the string */
int bytes_written = BIO_write( combined_bio, raw, raw_len );
fatal_assert( bytes_written >= 0 );
fatal_assert( bytes_written == (int)raw_len );
fatal_assert( 1 == BIO_flush( combined_bio ) );
/* check if mem buf has desired length */
fatal_assert( BIO_pending( mem_bio ) == (int)b64_len );
char *mem_ptr;
BIO_get_mem_data( mem_bio, &mem_ptr );
memcpy( b64, mem_ptr, b64_len );
BIO_free_all( combined_bio );
/* first 15 bytes of input */
for (int i = 0; i < 5; i++) {
uint32_t bytes = (raw[0] << 16) | (raw[1] << 8) | raw[2];
b64[0] = table[(bytes >> 18) & 0x3f];
b64[1] = table[(bytes >> 12) & 0x3f];
b64[2] = table[(bytes >> 6) & 0x3f];
b64[3] = table[(bytes) & 0x3f];
raw += 3;
b64 += 4;
}
/* last byte of input, last 4 of output */
b64[0] = table[*raw >> 2];
b64[1] = table[(*raw << 4) & 0x3f];
b64[2] = '=';
b64[3] = '=';
}
src/crypto/base64.h
+5 -3
View File
@@ -30,8 +30,10 @@
also delete it here.
*/
bool base64_decode( const char *b64, const size_t b64_len,
char *raw, size_t *raw_len );
#include <stdint.h>
void base64_encode( const char *raw, const size_t raw_len,
bool base64_decode( const char *b64, const size_t b64_len,
uint8_t *raw, size_t *raw_len );
void base64_encode( const uint8_t *raw, const size_t raw_len,
char *b64, const size_t b64_len );
src/crypto/crypto.cc
+7 -2
View File
@@ -105,7 +105,7 @@ Base64Key::Base64Key( string printable_key )
string base64 = printable_key + "==";
size_t len = 16;
if ( !base64_decode( base64.data(), 24, (char *)&key[ 0 ], &len ) ) {
if ( !base64_decode( base64.data(), 24, key, &len ) ) {
throw CryptoException( "Key must be well-formed base64." );
}
@@ -124,11 +124,16 @@ Base64Key::Base64Key()
PRNG().fill( key, sizeof( key ) );
}
Base64Key::Base64Key(PRNG &prng)
{
prng.fill( key, sizeof( key ) );
}
string Base64Key::printable_key( void ) const
{
char base64[ 24 ];
base64_encode( (char *)key, 16, base64, 24 );
base64_encode( key, 16, base64, 24 );
if ( (base64[ 23 ] != '=')
|| (base64[ 22 ] != '=') ) {
src/crypto/crypto.h
+4
View File
@@ -44,7 +44,10 @@ using std::string;
long int myatoi( const char *str );
class PRNG;
namespace Crypto {
class CryptoException : public std::exception {
public:
string text;
@@ -84,6 +87,7 @@ namespace Crypto {
public:
Base64Key(); /* random key */
Base64Key(PRNG &prng);
Base64Key( string printable_key );
string printable_key( void ) const;
unsigned char *data( void ) { return key; }
src/tests/Makefile.am
+12 -2
View File
@@ -16,12 +16,16 @@ displaytests = \
unicode-combine-fallback-assert.test \
unicode-later-combining.test
check_PROGRAMS = ocb-aes encrypt-decrypt
TESTS = ocb-aes encrypt-decrypt $(displaytests)
check_PROGRAMS = ocb-aes encrypt-decrypt base64
TESTS = ocb-aes encrypt-decrypt base64 $(displaytests)
XFAIL_TESTS = \
e2e-failure.test \
emulation-back-tab.test
base64_vector.cc: $(srcdir)/genbase64.pl
$(AM_V_GEN)echo '#include "base64_vector.h"' > base64_vector.cc || rm base64_vector.cc
$(AM_V_GEN)perl $(srcdir)/genbase64.pl >> base64_vector.cc || rm base64_vector.cc
ocb_aes_SOURCES = ocb-aes.cc test_utils.cc test_utils.h
ocb_aes_CPPFLAGS = -I$(srcdir)/../crypto -I$(srcdir)/../util
ocb_aes_LDADD = ../crypto/libmoshcrypto.a ../util/libmoshutil.a $(OPENSSL_LIBS)
@@ -30,7 +34,13 @@ encrypt_decrypt_SOURCES = encrypt-decrypt.cc test_utils.cc test_utils.h
encrypt_decrypt_CPPFLAGS = -I$(srcdir)/../crypto -I$(srcdir)/../util
encrypt_decrypt_LDADD = ../crypto/libmoshcrypto.a ../util/libmoshutil.a $(OPENSSL_LIBS)
base64_SOURCES = base64.cc base64_vector.cc base64_vector.h genbase64.pl
base64_CPPFLAGS = $(ocb_aes_CPPFLAGS)
base64_LDADD = $(ocb_aes_LDADD)
clean-local: clean-local-check
.PHONY: clean-local-check
clean-local-check:
-for i in $(displaytests); do rm -rf $$i.d/; done
CLEANFILES = base64_vector.cc
src/tests/base64.cc
+141
View File
@@ -0,0 +1,141 @@
/*
Mosh: the mobile shell
Copyright 2012 Keith Winstein
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
In addition, as a special exception, the copyright holders give
permission to link the code of portions of this program with the
OpenSSL library under certain conditions as described in each
individual source file, and distribute linked combinations including
the two.
You must obey the GNU General Public License in all respects for all
of the code used other than OpenSSL. If you modify file(s) with this
exception, you may extend this exception to your version of the
file(s), but you are not obligated to do so. If you do not wish to do
so, delete this exception statement from your version. If you delete
this exception statement from all source files in the program, then
also delete it here.
*/
/* Test suite for the OCB-AES reference implementation included with Mosh.
This tests cryptographic primitives implemented by others. It uses the
same interfaces and indeed the same compiled object code as the Mosh
client and server. It does not particularly test any code written for
the Mosh project. */
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include "base64.h"
#include "base64_vector.h"
#include "crypto.h"
#include "prng.h"
#include "fatal_assert.h"
// #include "test_utils.h"
#define KEY_LEN 16
#define NONCE_LEN 12
#define TAG_LEN 16
bool verbose = false;
static void test_base64( void ) {
/* run through a test vector */
char encoded[25];
uint8_t decoded[16];
size_t b64_len = 24;
size_t raw_len = 16;
for ( base64_test_row *row = static_base64_vector; *row->native != '\0'; row++ ) {
memset(encoded, '\0', sizeof encoded);
memset(decoded, '\0', sizeof decoded);
base64_encode(static_cast<const uint8_t *>(row->native), raw_len, encoded, b64_len);
fatal_assert( b64_len == 24 );
fatal_assert( !memcmp(row->encoded, encoded, sizeof encoded));
fatal_assert( base64_decode(row->encoded, b64_len, decoded, &raw_len ));
fatal_assert( raw_len == 16 );
fatal_assert( !memcmp(row->native, decoded, sizeof decoded));
}
if ( verbose ) {
printf( "validation PASSED\n" );
}
/* try 0..255 in the last byte; make sure the final two characters are output properly */
uint8_t source[16];
memset(source, '\0', sizeof source);
for ( int i = 0; i < 256; i++ ) {
source[15] = i;
base64_encode(source, raw_len, encoded, b64_len);
fatal_assert( b64_len == 24 );
fatal_assert( base64_decode(encoded, b64_len, decoded, &raw_len ));
fatal_assert( raw_len == 16 );
fatal_assert( !memcmp(source, decoded, sizeof decoded));
}
if ( verbose ) {
printf( "last-byte PASSED\n" );
}
/* randomly try keys */
PRNG prng;
for ( int i = 0; i < ( 1<<17 ); i++ ) {
Base64Key key1(prng);
Base64Key key2(key1.printable_key());
fatal_assert( key1.printable_key() == key2.printable_key() && !memcmp(key1.data(), key2.data(), 16 ));
}
if ( verbose ) {
printf( "random PASSED\n" );
}
/* test bad keys */
const char *bad_keys[] = {
"",
"AAAAAAAAAAAAAAAAAAAAAA",
"AAAAAAAAAAAAAAAAAAAAAA=",
"AAAAAAAAAAAAAAAAAAAAA==",
"AAAAAAAAAAAAAAAAAAAAAAA==",
"AAAAAAAAAAAAAAAAAAAAAAAA==",
"AAAAAAAAAAAAAAAAAAAAAA~=",
"AAAAAAAAAAAAAAAAAAAAAA=~",
"~AAAAAAAAAAAAAAAAAAAAA==",
"AAAAAAAAAAAAAAAAAAAA~A==",
"AAAAAAAAAAAAAAAAAAAAA~==",
"AAAAAAAAAA~AAAAAAAAAAA==",
"AAAAAAAAAA==",
NULL,
};
for ( const char **key = bad_keys; *key != NULL; key++ ) {
b64_len = 24;
raw_len = 16;
fatal_assert( !base64_decode(*key, b64_len, decoded, &raw_len ));
}
if ( verbose ) {
printf( "bad-keys PASSED\n" );
}
}
int main( int argc, char *argv[] )
{
if ( argc >= 2 && strcmp( argv[ 1 ], "-v" ) == 0 ) {
verbose = true;
}
test_base64();
return 0;
}
src/tests/base64_vector.h
+3
View File
@@ -0,0 +1,3 @@
struct base64_test_row { const unsigned char native[17]; const char encoded[25]; };
typedef base64_test_row *base64_test_vector;
extern base64_test_row static_base64_vector[];
src/tests/genbase64.pl
Executable
+28
View File
@@ -0,0 +1,28 @@
#!/usr/bin/perl
use strict;
use warnings;
use MIME::Base64;
my @vectors = (
"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff",
"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xff",
"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\x00",
"\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa",
"\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\x55\x55\x55\x55\x55\x55\x55\x55",
"\x55\x55\x55\x55\x55\x55\x55\x55\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa",
"\x01\x02\x04\x08\x10\x20\x40\x80\xfe\xfd\xfb\xf7\xef\xdf\xbf\x7f",
);
print 'base64_test_row static_base64_vector[] = {' . "\n";
for my $v (@vectors) {
print ' { "';
my @chars = split '', $v;
for my $c (@chars) {
printf "\\x%02x", ord($c);
}
print '", "' . encode_base64($v, "") . '" },' . "\n";
}
print ' { "", "" }' . "\n";
print "};\n";