Swap out CRC calculation in AES in favour of a simple hash
XOR the key bytes upon setting and re-check hash during each use.
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/configs/baremetal.h b/configs/baremetal.h
index 71bf463..4656642 100644
--- a/configs/baremetal.h
+++ b/configs/baremetal.h
@@ -137,7 +137,6 @@
#define MBEDTLS_OID_C
#define MBEDTLS_PLATFORM_C
-#define MBEDTLS_CRC_C
#define MBEDTLS_VALIDATE_AES_KEYS_INTEGRITY
/* I/O buffer configuration */
diff --git a/include/mbedtls/aes.h b/include/mbedtls/aes.h
index 5fb020f..b410b5a 100644
--- a/include/mbedtls/aes.h
+++ b/include/mbedtls/aes.h
@@ -91,7 +91,7 @@
uint32_t frk[8]; /*!< Fake AES round keys. */
#endif
#if defined(MBEDTLS_VALIDATE_AES_KEYS_INTEGRITY)
- uint16_t crc; /*!< CRC-16 of the set key */
+ uint32_t hash; /*!< hash of the set key */
#endif
#if defined(MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH) && !defined(MBEDTLS_PADLOCK_C)
uint32_t buf[44]; /*!< Unaligned data buffer */
diff --git a/include/mbedtls/check_config.h b/include/mbedtls/check_config.h
index 974bf7b..7239557 100644
--- a/include/mbedtls/check_config.h
+++ b/include/mbedtls/check_config.h
@@ -986,10 +986,6 @@
#error "MBEDTLS_HAVE_INT32/MBEDTLS_HAVE_INT64 and MBEDTLS_HAVE_ASM cannot be defined simultaneously"
#endif /* (MBEDTLS_HAVE_INT32 || MBEDTLS_HAVE_INT64) && MBEDTLS_HAVE_ASM */
-#if defined(MBEDTLS_VALIDATE_AES_KEYS_INTEGRITY) && ( !defined(MBEDTLS_CRC_C) )
-#error "MBEDTLS_VALIDATE_AES_KEYS_INTEGRITY defined, but not MBEDTLS_CRC_C"
-#endif
-
/*
* Avoid warning from -pedantic. This is a convenient place for this
* workaround since this is included by every single file before the
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index db38e81..c4d98e4 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -2742,12 +2742,11 @@
/**
* \def MBEDTLS_VALIDATE_AES_KEYS_INTEGRITY
*
- * Enable validation of AES keys by checking their CRC
+ * Enable validation of AES keys by checking their hash
* during every encryption/decryption.
*
* Module: library/aes.c
*
- * Requires: MBEDTLS_CRC_C
*/
//#define MBEDTLS_VALIDATE_AES_KEYS_INTEGRITY
diff --git a/library/aes.c b/library/aes.c
index d6a6b00..8005172 100644
--- a/library/aes.c
+++ b/library/aes.c
@@ -45,10 +45,6 @@
#include "mbedtls/aesni.h"
#endif
-#if defined(MBEDTLS_CRC_C) && defined(MBEDTLS_VALIDATE_AES_KEYS_INTEGRITY)
-#include "mbedtls/crc.h"
-#endif
-
#if defined(MBEDTLS_SELF_TEST)
#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
@@ -89,6 +85,19 @@
}
#endif
+#if defined(MBEDTLS_VALIDATE_AES_KEYS_INTEGRITY)
+static uint32_t mbedtls_hash( const void *data, size_t data_len_bytes )
+{
+ uint32_t result = 0;
+ size_t i;
+ /* data_len_bytes - only multiples of 4 are considered, rest is truncated */
+ for( i = 0; i < data_len_bytes >> 2; i++ )
+ {
+ result ^= ( (uint32_t*) data )[i];
+ }
+ return result;
+}
+#endif
/*
* Data structure for AES round data
*/
@@ -835,7 +844,7 @@
) )
{
#if defined(MBEDTLS_VALIDATE_AES_KEYS_INTEGRITY)
- ctx->crc = mbedtls_crc_update( 0, ctx->rk, keybits >> 3 );
+ ctx->hash = mbedtls_hash( ctx->rk, keybits >> 3 );
#endif
return 0;
}
@@ -933,7 +942,7 @@
else if( ( i == 0 ) && ( j == 4 ) )
{
#if defined(MBEDTLS_VALIDATE_AES_KEYS_INTEGRITY)
- ctx->crc = mbedtls_crc_update( 0, ctx->rk, keybits >> 3 );
+ ctx->hash = mbedtls_hash( ctx->rk, keybits >> 3 );
#endif
return( ret );
}
@@ -1099,7 +1108,7 @@
#if defined(MBEDTLS_VALIDATE_AES_KEYS_INTEGRITY)
unsigned key_bytes = 0;
- uint16_t check_crc = 0;
+ uint32_t check_hash = 0;
switch( ctx->nr )
{
case 10: key_bytes = 16; break;
@@ -1109,7 +1118,7 @@
#endif /* !MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH */
default : return( MBEDTLS_ERR_AES_INVALID_KEY_LENGTH );
}
- check_crc = mbedtls_crc_update( 0, ctx->rk, key_bytes );
+ check_hash = mbedtls_hash( ctx->rk, key_bytes );
#endif
aes_data_real.rk_ptr = ctx->rk;
@@ -1209,13 +1218,13 @@
/* Double negation is used to silence an "extraneous parentheses" warning */
if( ! ( flow_control != tindex + dummy_rounds + 8 )
#if defined(MBEDTLS_VALIDATE_AES_KEYS_INTEGRITY)
- && check_crc == ctx->crc
+ && check_hash == ctx->hash
#endif
)
{
#if defined(MBEDTLS_VALIDATE_AES_KEYS_INTEGRITY)
mbedtls_platform_random_delay();
- if( mbedtls_crc_update( 0, ctx->rk, key_bytes ) == ctx->crc )
+ if( mbedtls_hash( ctx->rk, key_bytes ) == ctx->hash )
#endif
{
return 0;
@@ -1406,7 +1415,7 @@
#if defined(MBEDTLS_VALIDATE_AES_KEYS_INTEGRITY)
unsigned key_bytes = 0;
- uint16_t check_crc = 0;
+ uint32_t check_hash = 0;
switch( ctx->nr )
{
case 10: key_bytes = 16; break;
@@ -1416,7 +1425,7 @@
#endif /* !MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH */
default : return( MBEDTLS_ERR_AES_INVALID_KEY_LENGTH );
}
- check_crc = mbedtls_crc_update( 0, ctx->rk, key_bytes );
+ check_hash = mbedtls_hash( ctx->rk, key_bytes );
#endif
aes_data_real.rk_ptr = ctx->rk;
@@ -1516,13 +1525,13 @@
/* Double negation is used to silence an "extraneous parentheses" warning */
if( ! ( flow_control != tindex + dummy_rounds + 8 )
#if defined(MBEDTLS_VALIDATE_AES_KEYS_INTEGRITY)
- && check_crc == ctx->crc
+ && check_hash == ctx->hash
#endif
)
{
#if defined(MBEDTLS_VALIDATE_AES_KEYS_INTEGRITY)
mbedtls_platform_random_delay();
- if( mbedtls_crc_update( 0, ctx->rk, key_bytes ) == ctx->crc )
+ if( mbedtls_hash( ctx->rk, key_bytes ) == ctx->hash )
#endif
{
return 0;
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 1a00ca0..de5ed65 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -67,7 +67,7 @@
endif(MSVC)
add_test_suite(aes aes.ecb)
-add_test_suite(aes aes.ecb.crc)
+add_test_suite(aes aes.ecb.hash)
add_test_suite(aes aes.cbc)
add_test_suite(aes aes.cfb)
add_test_suite(aes aes.ofb)
diff --git a/tests/suites/test_suite_aes.ecb.crc.data b/tests/suites/test_suite_aes.ecb.crc.data
deleted file mode 100644
index cd42620..0000000
--- a/tests/suites/test_suite_aes.ecb.crc.data
+++ /dev/null
@@ -1,46 +0,0 @@
-AES-128-ECB Encrypt NIST KAT #1 good CRC
-aes_encrypt_ecb_crc:"00000000000000000000000000000000":"f34481ec3cc627bacd5dc3fb08f273e6":"0336763e966d92595a567cc9ce537f5e":0:0:1
-
-AES-128-ECB Encrypt NIST KAT #1 bad CRC
-aes_encrypt_ecb_crc:"00000000000000000000000000000000":"f34481ec3cc627bacd5dc3fb08f273e6":"00000000000000000000000000000000":42:MBEDTLS_ERR_PLATFORM_FAULT_DETECTED:0
-
-AES-128-ECB Decrypt NIST KAT #1 good CRC
-depends_on:!MBEDTLS_AES_ONLY_ENCRYPT
-aes_decrypt_ecb_crc:"00000000000000000000000000000000":"db4f1aa530967d6732ce4715eb0ee24b":"ff000000000000000000000000000000":614:0:1
-
-AES-128-ECB Decrypt NIST KAT #1 bad CRC
-depends_on:!MBEDTLS_AES_ONLY_ENCRYPT
-aes_decrypt_ecb_crc:"00000000000000000000000000000000":"db4f1aa530967d6732ce4715eb0ee24b":"00000000000000000000000000000000":42:MBEDTLS_ERR_PLATFORM_FAULT_DETECTED:0
-
-AES-192-ECB Encrypt NIST KAT #1 good CRC
-depends_on:!MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH
-aes_encrypt_ecb_crc:"000000000000000000000000000000000000000000000000":"fffffffffffffffffffff80000000000":"156f07767a85a4312321f63968338a01":0:0:1
-
-AES-192-ECB Encrypt NIST KAT #1 bad CRC
-depends_on:!MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH
-aes_encrypt_ecb_crc:"000000000000000000000000000000000000000000000000":"fffffffffffffffffffff80000000000":"00000000000000000000000000000000":42:MBEDTLS_ERR_PLATFORM_FAULT_DETECTED:0
-
-AES-192-ECB Decrypt NIST KAT #1 good CRC
-depends_on:!MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH:!MBEDTLS_AES_ONLY_ENCRYPT
-aes_decrypt_ecb_crc:"fffffffffffffffffffffffffffffffff000000000000000":"bb2852c891c5947d2ed44032c421b85f":"00000000000000000000000000000000":31004:0:1
-
-AES-192-ECB Decrypt NIST KAT #1 bad CRC
-depends_on:!MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH:!MBEDTLS_AES_ONLY_ENCRYPT
-aes_decrypt_ecb_crc:"fffffffffffffffffffffffffffffffff000000000000000":"bb2852c891c5947d2ed44032c421b85f":"00000000000000000000000000000000":42:MBEDTLS_ERR_PLATFORM_FAULT_DETECTED:0
-
-AES-256-ECB Encrypt NIST KAT #1 good CRC
-depends_on:!MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH
-aes_encrypt_ecb_crc:"c1cc358b449909a19436cfbb3f852ef8bcb5ed12ac7058325f56e6099aab1a1c":"00000000000000000000000000000000":"352065272169abf9856843927d0674fd":61384:0:1
-
-AES-256-ECB Encrypt NIST KAT #1 bad CRC
-depends_on:!MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH
-aes_encrypt_ecb_crc:"c1cc358b449909a19436cfbb3f852ef8bcb5ed12ac7058325f56e6099aab1a1c":"00000000000000000000000000000000":"00000000000000000000000000000000":42:MBEDTLS_ERR_PLATFORM_FAULT_DETECTED:0
-
-AES-256-ECB Decrypt NIST KAT #1 good CRC
-depends_on:!MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH:!MBEDTLS_AES_ONLY_ENCRYPT
-aes_decrypt_ecb_crc:"fffffffffffffffffffffffffffffffffffffffffffffff00000000000000000":"edf61ae362e882ddc0167474a7a77f3a":"00000000000000000000000000000000":32504:0:1
-
-AES-256-ECB Decrypt NIST KAT #1 bad CRC
-depends_on:!MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH:!MBEDTLS_AES_ONLY_ENCRYPT
-aes_decrypt_ecb_crc:"fffffffffffffffffffffffffffffffffffffffffffffff00000000000000000":"edf61ae362e882ddc0167474a7a77f3a":"00000000000000000000000000000000":42:MBEDTLS_ERR_PLATFORM_FAULT_DETECTED:0
-
diff --git a/tests/suites/test_suite_aes.ecb.hash.data b/tests/suites/test_suite_aes.ecb.hash.data
new file mode 100644
index 0000000..da8bbc9
--- /dev/null
+++ b/tests/suites/test_suite_aes.ecb.hash.data
@@ -0,0 +1,46 @@
+AES-128-ECB Encrypt NIST KAT #1 good hash
+aes_encrypt_ecb_hash:"00000000000000000000000000000000":"f34481ec3cc627bacd5dc3fb08f273e6":"0336763e966d92595a567cc9ce537f5e":0:0:1
+
+AES-128-ECB Encrypt NIST KAT #1 bad hash
+aes_encrypt_ecb_hash:"00000000000000000000000000000000":"f34481ec3cc627bacd5dc3fb08f273e6":"00000000000000000000000000000000":42:MBEDTLS_ERR_PLATFORM_FAULT_DETECTED:0
+
+AES-128-ECB Decrypt NIST KAT #1 good hash
+depends_on:!MBEDTLS_AES_ONLY_ENCRYPT
+aes_decrypt_ecb_hash:"00000000000000000000000000000000":"db4f1aa530967d6732ce4715eb0ee24b":"ff000000000000000000000000000000":2616204230:0:1
+
+AES-128-ECB Decrypt NIST KAT #1 bad hash
+depends_on:!MBEDTLS_AES_ONLY_ENCRYPT
+aes_decrypt_ecb_hash:"00000000000000000000000000000000":"db4f1aa530967d6732ce4715eb0ee24b":"00000000000000000000000000000000":42:MBEDTLS_ERR_PLATFORM_FAULT_DETECTED:0
+
+AES-192-ECB Encrypt NIST KAT #1 good hash
+depends_on:!MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH
+aes_encrypt_ecb_hash:"000000000000000000000000000000000000000000000000":"fffffffffffffffffffff80000000000":"156f07767a85a4312321f63968338a01":0:0:1
+
+AES-192-ECB Encrypt NIST KAT #1 bad hash
+depends_on:!MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH
+aes_encrypt_ecb_hash:"000000000000000000000000000000000000000000000000":"fffffffffffffffffffff80000000000":"00000000000000000000000000000000":42:MBEDTLS_ERR_PLATFORM_FAULT_DETECTED:0
+
+AES-192-ECB Decrypt NIST KAT #1 good hash
+depends_on:!MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH:!MBEDTLS_AES_ONLY_ENCRYPT
+aes_decrypt_ecb_hash:"fffffffffffffffffffffffffffffffff000000000000000":"bb2852c891c5947d2ed44032c421b85f":"00000000000000000000000000000000":197398770:0:1
+
+AES-192-ECB Decrypt NIST KAT #1 bad hash
+depends_on:!MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH:!MBEDTLS_AES_ONLY_ENCRYPT
+aes_decrypt_ecb_hash:"fffffffffffffffffffffffffffffffff000000000000000":"bb2852c891c5947d2ed44032c421b85f":"00000000000000000000000000000000":42:MBEDTLS_ERR_PLATFORM_FAULT_DETECTED:0
+
+AES-256-ECB Encrypt NIST KAT #1 good hash
+depends_on:!MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH
+aes_encrypt_ecb_hash:"c1cc358b449909a19436cfbb3f852ef8bcb5ed12ac7058325f56e6099aab1a1c":"00000000000000000000000000000000":"352065272169abf9856843927d0674fd":1553260283:0:1
+
+AES-256-ECB Encrypt NIST KAT #1 bad hash
+depends_on:!MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH
+aes_encrypt_ecb_hash:"c1cc358b449909a19436cfbb3f852ef8bcb5ed12ac7058325f56e6099aab1a1c":"00000000000000000000000000000000":"00000000000000000000000000000000":42:MBEDTLS_ERR_PLATFORM_FAULT_DETECTED:0
+
+AES-256-ECB Decrypt NIST KAT #1 good hash
+depends_on:!MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH:!MBEDTLS_AES_ONLY_ENCRYPT
+aes_decrypt_ecb_hash:"fffffffffffffffffffffffffffffffffffffffffffffff00000000000000000":"edf61ae362e882ddc0167474a7a77f3a":"00000000000000000000000000000000":1875230928:0:1
+
+AES-256-ECB Decrypt NIST KAT #1 bad hash
+depends_on:!MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH:!MBEDTLS_AES_ONLY_ENCRYPT
+aes_decrypt_ecb_hash:"fffffffffffffffffffffffffffffffffffffffffffffff00000000000000000":"edf61ae362e882ddc0167474a7a77f3a":"00000000000000000000000000000000":42:MBEDTLS_ERR_PLATFORM_FAULT_DETECTED:0
+
diff --git a/tests/suites/test_suite_aes.function b/tests/suites/test_suite_aes.function
index 2a2f9cb..dd5b243 100644
--- a/tests/suites/test_suite_aes.function
+++ b/tests/suites/test_suite_aes.function
@@ -371,8 +371,8 @@
/* END_CASE */
/* BEGIN_CASE depends_on:MBEDTLS_VALIDATE_AES_KEYS_INTEGRITY:MBEDTLS_AES_SCA_COUNTERMEASURES:!MBEDTLS_AES_SETKEY_ENC_ALT:!MBEDTLS_AESNI_C */
-void aes_encrypt_ecb_crc( data_t * key_str, data_t * src_str,
- data_t * hex_dst_string, unsigned int crc, int crypt_result, int check_crc )
+void aes_encrypt_ecb_hash( data_t * key_str, data_t * src_str,
+ data_t * hex_dst_string, unsigned int hash, int crypt_result, int check_hash )
{
unsigned char output[100];
mbedtls_aes_context ctx;
@@ -383,10 +383,10 @@
TEST_ASSERT( mbedtls_aes_setkey_enc( &ctx, key_str->x, key_str->len * 8 ) == 0 );
- if( check_crc )
- TEST_ASSERT( ctx.crc == crc );
+ if( check_hash )
+ TEST_ASSERT( ctx.hash == hash );
else
- ctx.crc = crc;
+ ctx.hash = hash;
TEST_ASSERT( mbedtls_aes_crypt_ecb( &ctx, MBEDTLS_AES_ENCRYPT, src_str->x, output ) == crypt_result );
@@ -398,8 +398,8 @@
/* END_CASE */
/* BEGIN_CASE depends_on:MBEDTLS_VALIDATE_AES_KEYS_INTEGRITY:MBEDTLS_AES_SCA_COUNTERMEASURES:!MBEDTLS_AES_SETKEY_ENC_ALT:!MBEDTLS_AESNI_C */
-void aes_decrypt_ecb_crc( data_t * key_str, data_t * src_str,
- data_t * hex_dst_string, unsigned int crc, int crypt_result, int check_crc )
+void aes_decrypt_ecb_hash( data_t * key_str, data_t * src_str,
+ data_t * hex_dst_string, unsigned int hash, int crypt_result, int check_hash )
{
unsigned char output[100];
mbedtls_aes_context ctx;
@@ -410,10 +410,10 @@
TEST_ASSERT( mbedtls_aes_setkey_dec( &ctx, key_str->x, key_str->len * 8 ) == 0 );
- if( check_crc )
- TEST_ASSERT( ctx.crc == crc );
+ if( check_hash )
+ TEST_ASSERT( ctx.hash == hash );
else
- ctx.crc = crc;
+ ctx.hash = hash;
TEST_ASSERT( mbedtls_aes_crypt_ecb( &ctx, MBEDTLS_AES_DECRYPT, src_str->x, output ) == crypt_result );