Merge pull request #4720 from gilles-peskine-arm/gcm-finish-outlen

Add output_length parameter to mbedtls_gcm_finish
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Gilles Peskine 2021-06-24 20:02:40 +02:00 committed by GitHub
commit 1fed4b8324
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4 changed files with 31 additions and 9 deletions

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@ -339,6 +339,10 @@ int mbedtls_gcm_update( mbedtls_gcm_context *ctx,
* then mbedtls_gcm_finish() never produces any output,
* so \p output_size can be \c 0.
* - \p output_size never needs to be more than \c 15.
* \param output_length On success, \p *output_length contains the actual
* length of the output written in \p output.
* On failure, the content of \p *output_length is
* unspecified.
*
* \return \c 0 on success.
* \return #MBEDTLS_ERR_GCM_BAD_INPUT on failure:
@ -347,6 +351,7 @@ int mbedtls_gcm_update( mbedtls_gcm_context *ctx,
*/
int mbedtls_gcm_finish( mbedtls_gcm_context *ctx,
unsigned char *output, size_t output_size,
size_t *output_length,
unsigned char *tag, size_t tag_len );
/**

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@ -1109,9 +1109,14 @@ int mbedtls_cipher_write_tag( mbedtls_cipher_context_t *ctx,
#if defined(MBEDTLS_GCM_C)
if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode )
{
size_t output_length;
/* The code here doesn't yet support alternative implementations
* that can delay up to a block of output. */
return( mbedtls_gcm_finish( (mbedtls_gcm_context *) ctx->cipher_ctx,
NULL, 0,
NULL, 0, &output_length,
tag, tag_len ) );
}
#endif
#if defined(MBEDTLS_CHACHAPOLY_C)
@ -1158,12 +1163,16 @@ int mbedtls_cipher_check_tag( mbedtls_cipher_context_t *ctx,
#if defined(MBEDTLS_GCM_C)
if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode )
{
size_t output_length;
/* The code here doesn't yet support alternative implementations
* that can delay up to a block of output. */
if( tag_len > sizeof( check_tag ) )
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
if( 0 != ( ret = mbedtls_gcm_finish(
(mbedtls_gcm_context *) ctx->cipher_ctx,
NULL, 0,
NULL, 0, &output_length,
check_tag, tag_len ) ) )
{
return( ret );

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@ -532,6 +532,7 @@ int mbedtls_gcm_update( mbedtls_gcm_context *ctx,
int mbedtls_gcm_finish( mbedtls_gcm_context *ctx,
unsigned char *output, size_t output_size,
size_t *output_length,
unsigned char *tag, size_t tag_len )
{
unsigned char work_buf[16];
@ -546,6 +547,7 @@ int mbedtls_gcm_finish( mbedtls_gcm_context *ctx,
* for the sake of alternative implementations. */
(void) output;
(void) output_size;
*output_length = 0;
orig_len = ctx->len * 8;
orig_add_len = ctx->add_len * 8;
@ -616,7 +618,7 @@ int mbedtls_gcm_crypt_and_tag( mbedtls_gcm_context *ctx,
output, length, &olen ) ) != 0 )
return( ret );
if( ( ret = mbedtls_gcm_finish( ctx, NULL, 0, tag, tag_len ) ) != 0 )
if( ( ret = mbedtls_gcm_finish( ctx, NULL, 0, &olen, tag, tag_len ) ) != 0 )
return( ret );
return( 0 );
@ -1068,7 +1070,7 @@ int mbedtls_gcm_self_test( int verbose )
goto exit;
}
ret = mbedtls_gcm_finish( &ctx, NULL, 0, tag_buf, 16 );
ret = mbedtls_gcm_finish( &ctx, NULL, 0, &olen, tag_buf, 16 );
if( ret != 0 )
goto exit;
@ -1140,7 +1142,7 @@ int mbedtls_gcm_self_test( int verbose )
goto exit;
}
ret = mbedtls_gcm_finish( &ctx, NULL, 0, tag_buf, 16 );
ret = mbedtls_gcm_finish( &ctx, NULL, 0, &olen, tag_buf, 16 );
if( ret != 0 )
goto exit;

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@ -50,7 +50,8 @@ static int check_multipart( mbedtls_gcm_context *ctx,
output = NULL;
ASSERT_ALLOC( output, tag->len );
TEST_EQUAL( 0, mbedtls_gcm_finish( ctx, NULL, 0, output, tag->len ) );
TEST_EQUAL( 0, mbedtls_gcm_finish( ctx, NULL, 0, &olen, output, tag->len ) );
TEST_EQUAL( 0, olen );
ASSERT_COMPARE( output, tag->len, tag->x, tag->len );
mbedtls_free( output );
output = NULL;
@ -96,7 +97,8 @@ static void check_cipher_with_empty_ad( mbedtls_gcm_context *ctx,
output = NULL;
ASSERT_ALLOC( output, tag->len );
TEST_EQUAL( 0, mbedtls_gcm_finish( ctx, NULL, 0, output, tag->len ) );
TEST_EQUAL( 0, mbedtls_gcm_finish( ctx, NULL, 0, &olen, output, tag->len ) );
TEST_EQUAL( 0, olen );
ASSERT_COMPARE( output, tag->len, tag->x, tag->len );
exit:
@ -125,7 +127,9 @@ static void check_empty_cipher_with_ad( mbedtls_gcm_context *ctx,
}
ASSERT_ALLOC( output_tag, tag->len );
TEST_EQUAL( 0, mbedtls_gcm_finish( ctx, NULL, 0, output_tag, tag->len ) );
TEST_EQUAL( 0, mbedtls_gcm_finish( ctx, NULL, 0, &olen,
output_tag, tag->len ) );
TEST_EQUAL( 0, olen );
ASSERT_COMPARE( output_tag, tag->len, tag->x, tag->len );
exit:
@ -138,11 +142,13 @@ static void check_no_cipher_no_ad( mbedtls_gcm_context *ctx,
const data_t *tag )
{
uint8_t *output = NULL;
size_t olen = 0;
TEST_EQUAL( 0, mbedtls_gcm_starts( ctx, mode,
iv->x, iv->len ) );
ASSERT_ALLOC( output, tag->len );
TEST_EQUAL( 0, mbedtls_gcm_finish( ctx, NULL, 0, output, tag->len ) );
TEST_EQUAL( 0, mbedtls_gcm_finish( ctx, NULL, 0, &olen, output, tag->len ) );
TEST_EQUAL( 0, olen );
ASSERT_COMPARE( output, tag->len, tag->x, tag->len );
exit: