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Add support for chunked plaintext/cyphertext input.

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Signed-off-by: Mateusz Starzyk <mateusz.starzyk@mobica.com>
This commit is contained in:
Mateusz Starzyk 2021-07-07 13:41:30 +02:00
parent 2ad7d8e1ff
commit 6a15bcf61b
1 changed files with 52 additions and 44 deletions
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96
library/ccm.c
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@ -333,59 +333,67 @@ int mbedtls_ccm_update( mbedtls_ccm_context *ctx,
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char i;
size_t len_left, olen;
const unsigned char *src;
unsigned char *dst;
size_t use_len, offset, olen;
if( output_size < input_len )
return( MBEDTLS_ERR_CCM_BAD_INPUT );
CCM_VALIDATE_RET( output_length != NULL );
*output_len = input_len;
/*
* Authenticate and {en,de}crypt the message.
*
* The only difference between encryption and decryption is
* the respective order of authentication and {en,de}cryption.
*/
len_left = input_len;
src = input;
dst = output;
while( len_left > 0 )
if( ctx->processed == 0 )
{
size_t use_len = len_left > 16 ? 16 : len_left;
if( ctx->mode == CCM_ENCRYPT )
{
memset( ctx->b, 0, 16 );
memcpy( ctx->b, src, use_len );
UPDATE_CBC_MAC;
}
mbedtls_ccm_crypt( ctx, 0, use_len, src, dst );
if( ctx->mode == CCM_DECRYPT )
{
memset( ctx->b, 0, 16 );
memcpy( ctx->b, dst, use_len );
UPDATE_CBC_MAC;
}
dst += use_len;
src += use_len;
len_left -= use_len;
/*
* Increment counter.
* No need to check for overflow thanks to the length check above.
*/
for( i = 0; i < ctx->q; i++ )
if( ++(ctx->ctr)[15-i] != 0 )
break;
memset( ctx->b, 0, 16 );
}
return (0);
while ( input_len > 0 )
{
offset = ctx->processed % 16;
use_len = 16 - offset;
if( use_len > input_len )
use_len = input_len;
ctx->processed += use_len;
memcpy( ctx->b + offset, input, use_len );
if( use_len + offset == 16 || ctx->processed == ctx->plaintext_len )
{
if( ctx->mode == CCM_ENCRYPT )
{
UPDATE_CBC_MAC;
ret = mbedtls_ccm_crypt( ctx, 0, use_len, ctx->b, output );
if( ret != 0 )
return ret;
memset( ctx->b, 0, 16 );
}
if( ctx->mode == CCM_DECRYPT )
{
ret = mbedtls_ccm_crypt( ctx, 0, use_len, ctx->b, output );
if( ret != 0 )
return ret;
memset( ctx->b, 0, 16 );
memcpy( ctx->b, output, use_len );
UPDATE_CBC_MAC;
memset( ctx->b, 0, 16 );
}
input_len -= use_len;
input += use_len;
output += use_len;
/*
* Increment counter.
* No need to check for overflow thanks to the length check above.
*/
for( i = 0; i < ctx->q; i++ )
if( ++(ctx->ctr)[15-i] != 0 )
break;
}
}
return 0;
}
int mbedtls_ccm_finish( mbedtls_ccm_context *ctx,