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GCM in the cipher layer, step 1

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- no support for additional data
- no support for tag
This commit is contained in:
Manuel Pégourié-Gonnard 2013-08-30 18:34:08 +02:00
parent b5e85885de
commit 07f8fa5a69
7 changed files with 225 additions and 7 deletions
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70
library/cipher.c
View file

@ -34,6 +34,10 @@
#include "polarssl/cipher.h"
#include "polarssl/cipher_wrap.h"
#if defined(POLARSSL_GCM_C)
#include "polarssl/gcm.h"
#endif
#include <stdlib.h>
#if defined(POLARSSL_ARC4_C) || defined(POLARSSL_CIPHER_NULL_CIPHER)
@ -285,7 +289,14 @@ const cipher_info_t *cipher_info_from_string( const char *cipher_name )
if( !strcasecmp( "AES-256-CTR", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_AES_256_CTR );
#endif /* defined(POLARSSL_CIPHER_MODE_CTR) */
#if defined(POLARSSL_GCM_C)
if( !strcasecmp( "AES-128-GCM", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_AES_128_GCM );
if( !strcasecmp( "AES-256-GCM", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_AES_256_GCM );
#endif
#endif /* POLARSSL_AES_C */
#if defined(POLARSSL_ARC4_C)
if( !strcasecmp( "ARC4-128", cipher_name ) )
@ -392,6 +403,16 @@ int cipher_reset( cipher_context_t *ctx, const unsigned char *iv )
ctx->unprocessed_len = 0;
#if defined(POLARSSL_GCM_C)
if( POLARSSL_MODE_GCM == ctx->cipher_info->mode )
{
// TODO: allow other IV length
// TODO: allow additional data
return gcm_starts( ctx->cipher_ctx, ctx->operation,
iv, 12, (unsigned char *) "", 0 );
}
#endif
memcpy( ctx->iv, iv, cipher_get_iv_size( ctx ) );
return 0;
@ -416,7 +437,8 @@ int cipher_update( cipher_context_t *ctx, const unsigned char *input, size_t ile
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
}
if( ctx->cipher_info->mode == POLARSSL_MODE_CBC )
if( ctx->cipher_info->mode == POLARSSL_MODE_CBC ||
ctx->cipher_info->mode == POLARSSL_MODE_GCM )
{
/*
* If there is not enough data for a full block, cache it.
@ -443,6 +465,18 @@ int cipher_update( cipher_context_t *ctx, const unsigned char *input, size_t ile
memcpy( &( ctx->unprocessed_data[ctx->unprocessed_len] ), input,
copy_len );
#if defined(POLARSSL_GCM_C)
if( ctx->cipher_info->mode == POLARSSL_MODE_GCM )
{
if( 0 != ( ret = gcm_update( ctx->cipher_ctx,
cipher_get_block_size( ctx ),
ctx->unprocessed_data, output ) ) )
{
return ret;
}
}
else
#endif
if( 0 != ( ret = ctx->cipher_info->base->cbc_func( ctx->cipher_ctx,
ctx->operation, cipher_get_block_size( ctx ), ctx->iv,
ctx->unprocessed_data, output ) ) )
@ -479,11 +513,23 @@ int cipher_update( cipher_context_t *ctx, const unsigned char *input, size_t ile
*/
if( ilen )
{
#if defined(POLARSSL_GCM_C)
if( ctx->cipher_info->mode == POLARSSL_MODE_GCM )
{
if( 0 != ( ret = gcm_update( ctx->cipher_ctx,
ilen, input, output ) ) )
{
return ret;
}
}
else
#endif
if( 0 != ( ret = ctx->cipher_info->base->cbc_func( ctx->cipher_ctx,
ctx->operation, ilen, ctx->iv, input, output ) ) )
{
return ret;
}
*olen += ilen;
}
@ -712,6 +758,28 @@ int cipher_finish( cipher_context_t *ctx, unsigned char *output, size_t *olen)
return 0;
}
#if defined(POLARSSL_GCM_C)
if( POLARSSL_MODE_GCM == ctx->cipher_info->mode )
{
size_t tag_len = 0; // TODO
unsigned char tag[16];
if( 0 != ( ret = gcm_update( ctx->cipher_ctx,
ctx->unprocessed_len, ctx->unprocessed_data,
output ) ) )
{
return( ret );
}
*olen += ctx->unprocessed_len;
if( 0 != ( ret = gcm_finish( ctx->cipher_ctx, tag, tag_len ) ) )
return( ret );
return( 0 );
}
#endif
if( POLARSSL_MODE_CBC == ctx->cipher_info->mode )
{
if( POLARSSL_ENCRYPT == ctx->operation )

35
library/cipher_wrap.c
View file

@ -53,6 +53,10 @@
#include "polarssl/blowfish.h"
#endif
#if defined(POLARSSL_GCM_C)
#include "polarssl/gcm.h"
#endif
#if defined(POLARSSL_MEMORY_C)
#include "polarssl/memory.h"
#else
@ -235,6 +239,33 @@ const cipher_info_t aes_256_ctr_info = {
#endif /* POLARSSL_CIPHER_MODE_CTR */
#if defined(POLARSSL_GCM_C)
static void *gcm_ctx_alloc( void )
{
return polarssl_malloc( sizeof( gcm_context ) );
}
static void gcm_ctx_free( void *ctx )
{
polarssl_free( ctx );
}
static int gcm_setkey_wrap( void *ctx, const unsigned char *key, unsigned int key_length )
{
return gcm_init( (gcm_context *) ctx, key, key_length );
}
const cipher_base_t gcm_aes_info = {
POLARSSL_CIPHER_ID_AES,
NULL,
NULL,
NULL,
NULL,
gcm_setkey_wrap,
gcm_setkey_wrap,
gcm_ctx_alloc,
gcm_ctx_free,
};
const cipher_info_t aes_128_gcm_info = {
POLARSSL_CIPHER_AES_128_GCM,
POLARSSL_MODE_GCM,
@ -242,7 +273,7 @@ const cipher_info_t aes_128_gcm_info = {
"AES-128-GCM",
16,
16,
&aes_info
&gcm_aes_info
};
const cipher_info_t aes_256_gcm_info = {
@ -252,7 +283,7 @@ const cipher_info_t aes_256_gcm_info = {
"AES-256-GCM",
16,
16,
&aes_info
&gcm_aes_info
};
#endif /* POLARSSL_GCM_C */

4
library/gcm.c
View file

@ -293,11 +293,11 @@ int gcm_finish( gcm_context *ctx,
uint64_t orig_len = ctx->len * 8;
uint64_t orig_add_len = ctx->add_len * 8;
memcpy( tag, ctx->base_ectr, tag_len );
if( tag_len > 16 )
return( POLARSSL_ERR_GCM_BAD_INPUT );
memcpy( tag, ctx->base_ectr, tag_len );
if( orig_len || orig_add_len )
{
memset( work_buf, 0x00, 16 );