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Fix issues in Cryptocell 310 ccm_alt discovered by On Target Testing #8704

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Merged
merged 9 commits into from
Nov 27, 2018
Merged

Fix issues in Cryptocell 310 ccm_alt discovered by On Target Testing #8704

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8cc8481
Add unsupported functions for CCM*.
Nov 15, 2018
93e0f64
Use mbedtls_platform_zeroize
Nov 15, 2018
4e7e054
Fix memory overflow
Nov 15, 2018
1aaff0e
Return `MBEDTLS_ERR_CCM_AUTH_FAILED` where needed.
Nov 15, 2018
53c02d7
Zeroize output buffer, upon authentication faliure.
Nov 15, 2018
d487c80
Additional fix for ccm_alt from On Target Testings
Nov 15, 2018
1b34927
Style fixes
Nov 15, 2018
5ed3a64
Return MBEDTLS_ERR_CCM_BAD_INPUT on invalid key
Nov 18, 2018
5e0223f
Add the platform generic errors
Nov 25, 2018
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148 changes: 112 additions & 36 deletions features/cryptocell/FEATURE_CRYPTOCELL310/ccm_alt.c
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Original file line number Diff line number Diff line change
Expand Up @@ -22,13 +22,9 @@
#if defined(MBEDTLS_CCM_ALT)
#include <string.h>
#include "mbedtls/platform.h"
#include "mbedtls/platform_util.h"
#include "mbedtls/aes.h"

/* Implementation that should never be optimized out by the compiler */
static void mbedtls_zeroize( void *v, size_t n ) {
volatile unsigned char *p = (unsigned char*)v;
while( n-- ) *p++ = 0;
}
#include "crys_aesccm_error.h"

void mbedtls_ccm_init( mbedtls_ccm_context *ctx )
{
Expand All @@ -37,7 +33,7 @@ void mbedtls_ccm_init( mbedtls_ccm_context *ctx )

void mbedtls_ccm_free( mbedtls_ccm_context *ctx )
{
mbedtls_zeroize( ctx, sizeof( mbedtls_ccm_context ) );
mbedtls_platform_zeroize( ctx, sizeof( mbedtls_ccm_context ) );
}

int mbedtls_ccm_setkey( mbedtls_ccm_context *ctx,
Expand All @@ -46,18 +42,30 @@ int mbedtls_ccm_setkey( mbedtls_ccm_context *ctx,
unsigned int keybits )
{
if( ctx == NULL )
return ( MBEDTLS_ERR_CCM_BAD_INPUT );
return( MBEDTLS_ERR_CCM_BAD_INPUT );

if( cipher != MBEDTLS_CIPHER_ID_AES )
{
return( MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED );
}

if( cipher != MBEDTLS_CIPHER_ID_AES ||
keybits != 128 )
switch( keybits )
{
return ( MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED );
case 128:
{
memcpy( ctx->cipher_key , key, keybits / 8 );
ctx->key_size = CRYS_AES_Key128BitSize;
}
break;
case 192:
case 256:
return( MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED );
default:
return( MBEDTLS_ERR_CCM_BAD_INPUT );
}

memcpy( ctx->cipher_key , key, keybits / 8 );
ctx->keySize_ID = CRYS_AES_Key128BitSize;

return ( 0 );
return( 0 );

}

Expand All @@ -66,36 +74,55 @@ int mbedtls_ccm_setkey( mbedtls_ccm_context *ctx,
*/

int mbedtls_ccm_encrypt_and_tag( mbedtls_ccm_context *ctx, size_t length,
const unsigned char *iv, size_t iv_len,
const unsigned char *add, size_t add_len,
const unsigned char *input, unsigned char *output,
unsigned char *tag, size_t tag_len )
const unsigned char *iv, size_t iv_len,
const unsigned char *add, size_t add_len,
const unsigned char *input,
unsigned char *output,
unsigned char *tag, size_t tag_len )

{
CRYSError_t CrysRet = CRYS_OK;
CRYSError_t crys_ret = CRYS_OK;
CRYS_AESCCM_Mac_Res_t cc_mac_res = { 0 };
int ret = 0;
/*
* Check length requirements: SP800-38C A.1
* Additional requirement: a < 2^16 - 2^8 to simplify the code.
* 'length' checked later (when writing it to the first block)
*/
if( tag_len < 4 || tag_len > 16 || tag_len % 2 != 0 )
return ( MBEDTLS_ERR_CCM_BAD_INPUT );
return( MBEDTLS_ERR_CCM_BAD_INPUT );

if( tag_len > sizeof( cc_mac_res ) )
return( MBEDTLS_ERR_CCM_BAD_INPUT );

/* Also implies q is within bounds */
if( iv_len < 7 || iv_len > 13 )
return ( MBEDTLS_ERR_CCM_BAD_INPUT );
return( MBEDTLS_ERR_CCM_BAD_INPUT );

#if SIZE_MAX > UINT_MAX
if( length > 0xFFFFFFFF || add_len > 0xFFFFFFFF )
return ( MBEDTLS_ERR_CCM_BAD_INPUT );
return( MBEDTLS_ERR_CCM_BAD_INPUT );
#endif

CrysRet = CRYS_AESCCM( SASI_AES_ENCRYPT, ctx->cipher_key, ctx->keySize_ID,(uint8_t*)iv, iv_len,
(uint8_t*)add, add_len, (uint8_t*)input, length, output, tag_len, tag );
if( CrysRet != CRYS_OK )
return ( MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED );
crys_ret = CRYS_AESCCM( SASI_AES_ENCRYPT, ctx->cipher_key, ctx->key_size,
(uint8_t*)iv, iv_len, (uint8_t*)add, add_len,
(uint8_t*)input, length, output, tag_len,
cc_mac_res );
if( crys_ret == CRYS_AESCCM_ILLEGAL_PARAMETER_SIZE_ERROR )
{
ret = MBEDTLS_ERR_CCM_BAD_INPUT;
goto exit;
}
else if( crys_ret != CRYS_OK )
{
ret = MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED;
goto exit;
}

memcpy( tag, cc_mac_res, tag_len );

return ( 0 );
exit:
return( ret );

}

Expand All @@ -109,31 +136,80 @@ int mbedtls_ccm_auth_decrypt( mbedtls_ccm_context *ctx, size_t length,
const unsigned char *tag, size_t tag_len )

{
CRYSError_t CrysRet = CRYS_OK;
CRYSError_t crys_ret = CRYS_OK;
int ret = 0;
/*
* Check length requirements: SP800-38C A.1
* Additional requirement: a < 2^16 - 2^8 to simplify the code.
* 'length' checked later (when writing it to the first block)
*/
if( tag_len < 4 || tag_len > 16 || tag_len % 2 != 0 )
return ( MBEDTLS_ERR_CCM_BAD_INPUT );
return( MBEDTLS_ERR_CCM_BAD_INPUT );

/* Also implies q is within bounds */
if( iv_len < 7 || iv_len > 13 )
return ( MBEDTLS_ERR_CCM_BAD_INPUT );
return( MBEDTLS_ERR_CCM_BAD_INPUT );

#if SIZE_MAX > UINT_MAX
if( length > 0xFFFFFFFF || add_len > 0xFFFFFFFF )
return ( MBEDTLS_ERR_CCM_BAD_INPUT );
return( MBEDTLS_ERR_CCM_BAD_INPUT );
#endif

CrysRet = CRYS_AESCCM( SASI_AES_DECRYPT, ctx->cipher_key, ctx->keySize_ID,(uint8_t*)iv, iv_len,
(uint8_t*)add, add_len, (uint8_t*)input, length, output, tag_len, (uint8_t*)tag );
if ( CrysRet != CRYS_OK )
return ( MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED );
crys_ret = CRYS_AESCCM( SASI_AES_DECRYPT, ctx->cipher_key, ctx->key_size,
(uint8_t*)iv, iv_len, (uint8_t*)add, add_len,
(uint8_t*)input, length, output, tag_len,
(uint8_t*)tag );
if( crys_ret == CRYS_AESCCM_ILLEGAL_PARAMETER_SIZE_ERROR )
{
/*
* When CRYS_AESCCM_ILLEGAL_PARAMETER_SIZE_ERROR is returned,
* no operation has occured, and no need to zeroize output.
* In addition, it could be that the message length is too big,
* returning this error code, and we don't want to overflow
* the output buffer.
*/
return( MBEDTLS_ERR_CCM_BAD_INPUT );
}
else if( crys_ret == CRYS_FATAL_ERROR )
{
/*
* Unfortunately, Crys AESCCM returns CRYS_FATAL_ERROR when
* MAC isn't as expected.
*/
ret = MBEDTLS_ERR_CCM_AUTH_FAILED;
goto exit;
}
else if( crys_ret != CRYS_OK )
{
ret = MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED;
goto exit;
}

return ( 0 );
exit:
if( ret != 0 )
mbedtls_platform_zeroize( output, length );
return( ret );

}

int mbedtls_ccm_star_encrypt_and_tag( mbedtls_ccm_context *ctx, size_t length,
const unsigned char *iv, size_t iv_len,
const unsigned char *add, size_t add_len,
const unsigned char *input,
unsigned char *output,
unsigned char *tag, size_t tag_len )
{
return( MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED );
}

int mbedtls_ccm_star_auth_decrypt( mbedtls_ccm_context *ctx, size_t length,
const unsigned char *iv, size_t iv_len,
const unsigned char *add, size_t add_len,
const unsigned char *input,
unsigned char *output,
const unsigned char *tag, size_t tag_len )
{
return( MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED );
}

#endif
97 changes: 2 additions & 95 deletions features/cryptocell/FEATURE_CRYPTOCELL310/ccm_alt.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -24,104 +24,11 @@
#if defined(MBEDTLS_CCM_ALT)
#include "crys_aesccm.h"

#ifdef __cplusplus
extern "C" {
#endif

typedef struct {
CRYS_AESCCM_Key_t cipher_key; /*!< cipher key used */
CRYS_AESCCM_KeySize_t keySize_ID;
CRYS_AESCCM_Key_t cipher_key; /*!< cipher key used */
CRYS_AESCCM_KeySize_t key_size;
}
mbedtls_ccm_context;

/**
* \brief Initialize CCM context (just makes references valid)
* Makes the context ready for mbedtls_ccm_setkey() or
* mbedtls_ccm_free().
*
* \param ctx CCM context to initialize
*/
void mbedtls_ccm_init( mbedtls_ccm_context *ctx );

/**
* \brief CCM initialization (encryption and decryption)
*
* \param ctx CCM context to be initialized
* \param cipher cipher to use (a 128-bit block cipher)
* \param key encryption key
* \param keybits key size in bits (must be acceptable by the cipher)
*
* \return 0 if successful, or a cipher specific error code
*/
int mbedtls_ccm_setkey( mbedtls_ccm_context *ctx,
mbedtls_cipher_id_t cipher,
const unsigned char *key,
unsigned int keybits );

/**
* \brief Free a CCM context and underlying cipher sub-context
*
* \param ctx CCM context to free
*/
void mbedtls_ccm_free( mbedtls_ccm_context *ctx );

/**
* \brief CCM buffer encryption
*
* \param ctx CCM context
* \param length length of the input data in bytes
* \param iv nonce (initialization vector)
* \param iv_len length of IV in bytes
* must be 2, 3, 4, 5, 6, 7 or 8
* \param add additional data
* \param add_len length of additional data in bytes
* must be less than 2^16 - 2^8
* \param input buffer holding the input data
* \param output buffer for holding the output data
* must be at least 'length' bytes wide
* \param tag buffer for holding the tag
* \param tag_len length of the tag to generate in bytes
* must be 4, 6, 8, 10, 14 or 16
*
* \note The tag is written to a separate buffer. To get the tag
* concatenated with the output as in the CCM spec, use
* tag = output + length and make sure the output buffer is
* at least length + tag_len wide.
*
* \return 0 if successful
*/
int mbedtls_ccm_encrypt_and_tag( mbedtls_ccm_context *ctx, size_t length,
const unsigned char *iv, size_t iv_len,
const unsigned char *add, size_t add_len,
const unsigned char *input, unsigned char *output,
unsigned char *tag, size_t tag_len );

/**
* \brief CCM buffer authenticated decryption
*
* \param ctx CCM context
* \param length length of the input data
* \param iv initialization vector
* \param iv_len length of IV
* \param add additional data
* \param add_len length of additional data
* \param input buffer holding the input data
* \param output buffer for holding the output data
* \param tag buffer holding the tag
* \param tag_len length of the tag
*
* \return 0 if successful and authenticated,
* MBEDTLS_ERR_CCM_AUTH_FAILED if tag does not match
*/
int mbedtls_ccm_auth_decrypt( mbedtls_ccm_context *ctx, size_t length,
const unsigned char *iv, size_t iv_len,
const unsigned char *add, size_t add_len,
const unsigned char *input, unsigned char *output,
const unsigned char *tag, size_t tag_len );

#ifdef __cplusplus
}
#endif

#endif /* MBEDTLS_CCM_ALT */
#endif /* __CCM_ALT__ */