chacha20: fix bug in starts() and add test for it

Previously the streaming API would fail when encrypting multiple messages with
the same key.
This commit is contained in:
Manuel Pégourié-Gonnard 2018-05-09 12:37:58 +02:00
parent 7296771194
commit 55c0d096b7
2 changed files with 42 additions and 1 deletions

View File

@ -243,6 +243,12 @@ int mbedtls_chacha20_starts( mbedtls_chacha20_context* ctx,
ctx->initial_state[14] = BYTES_TO_U32_LE( nonce, 4 ); ctx->initial_state[14] = BYTES_TO_U32_LE( nonce, 4 );
ctx->initial_state[15] = BYTES_TO_U32_LE( nonce, 8 ); ctx->initial_state[15] = BYTES_TO_U32_LE( nonce, 8 );
mbedtls_zeroize( ctx->working_state, sizeof( ctx->working_state ) );
mbedtls_zeroize( ctx->keystream8, sizeof( ctx->keystream8 ) );
/* Initially, there's no keystream bytes available */
ctx->keystream_bytes_used = CHACHA20_BLOCK_SIZE_BYTES;
return( 0 ); return( 0 );
} }

View File

@ -23,6 +23,7 @@ void chacha20_crypt( char *hex_key_string,
size_t nonce_len; size_t nonce_len;
size_t src_len; size_t src_len;
size_t dst_len; size_t dst_len;
mbedtls_chacha20_context ctx;
memset( key_str, 0x00, sizeof( key_str ) ); memset( key_str, 0x00, sizeof( key_str ) );
memset( nonce_str, 0x00, sizeof( nonce_str ) ); memset( nonce_str, 0x00, sizeof( nonce_str ) );
@ -39,11 +40,45 @@ void chacha20_crypt( char *hex_key_string,
TEST_ASSERT( key_len == 32U ); TEST_ASSERT( key_len == 32U );
TEST_ASSERT( nonce_len == 12U ); TEST_ASSERT( nonce_len == 12U );
/*
* Test the integrated API
*/
TEST_ASSERT( mbedtls_chacha20_crypt( key_str, nonce_str, counter, src_len, src_str, output ) == 0 ); TEST_ASSERT( mbedtls_chacha20_crypt( key_str, nonce_str, counter, src_len, src_str, output ) == 0 );
hexify( dst_str, output, src_len ); hexify( dst_str, output, src_len );
TEST_ASSERT( strcmp( (char*) dst_str, hex_dst_string ) == 0 ); TEST_ASSERT( strcmp( (char*) dst_str, hex_dst_string ) == 0 );
/*
* Test the streaming API
*/
mbedtls_chacha20_init( &ctx );
TEST_ASSERT( mbedtls_chacha20_setkey( &ctx, key_str ) == 0 );
TEST_ASSERT( mbedtls_chacha20_starts( &ctx, nonce_str, counter ) == 0 );
memset( output, 0x00, sizeof( output ) );
TEST_ASSERT( mbedtls_chacha20_update( &ctx, src_len, src_str, output ) == 0 );
hexify( dst_str, output, src_len );
TEST_ASSERT( strcmp( (char*) dst_str, hex_dst_string ) == 0 );
/*
* Test the streaming API again, piecewise
*/
/* Don't reset the context of key, in order to test that starts() do the
* right thing. */
TEST_ASSERT( mbedtls_chacha20_starts( &ctx, nonce_str, counter ) == 0 );
memset( output, 0x00, sizeof( output ) );
TEST_ASSERT( mbedtls_chacha20_update( &ctx, 1, src_str, output ) == 0 );
TEST_ASSERT( mbedtls_chacha20_update( &ctx, src_len - 1, src_str + 1, output + 1 ) == 0 );
hexify( dst_str, output, src_len );
TEST_ASSERT( strcmp( (char*) dst_str, hex_dst_string ) == 0 );
mbedtls_chacha20_free( &ctx );
} }
/* END_CASE */ /* END_CASE */