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aes.c: guard RSb and RTx properly

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If we enabled AES_DECRYPT_ALT and either AES_SETKEY_DEC_ALT or
AES_USE_HARDWARE_ONLY, this means RSb and RTx are not needed.
This commit extends how we guard RSb and RTx for the combinations of
these configurations.

Signed-off-by: Yanray Wang <yanray.wang@arm.com>
This commit is contained in:
Yanray Wang 2023-11-09 11:23:17 +08:00
parent d137da5a93
commit f03b49122c
1 changed files with 6 additions and 3 deletions
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9
library/aes.c
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@ -66,7 +66,12 @@
#include "mbedtls/platform.h"
#if (!defined(MBEDTLS_AES_DECRYPT_ALT) || !defined(MBEDTLS_AES_SETKEY_DEC_ALT)) && \
/*
* This is a convenience shorthand macro to check if we need reverse S-box and
* reverse tables. It's private and only defined in this file.
*/
#if (!defined(MBEDTLS_AES_DECRYPT_ALT) || \
(!defined(MBEDTLS_AES_SETKEY_DEC_ALT) && !defined(MBEDTLS_AES_USE_HARDWARE_ONLY))) && \
!defined(MBEDTLS_BLOCK_CIPHER_NO_DECRYPT)
#define MBEDTLS_AES_NEED_REVERSE_TABLES
#endif
@ -447,7 +452,6 @@ MBEDTLS_MAYBE_UNUSED static void aes_gen_tables(void)
#if defined(MBEDTLS_AES_NEED_REVERSE_TABLES)
x = RSb[i];
#if !defined(MBEDTLS_AES_USE_HARDWARE_ONLY)
RT0[i] = ((uint32_t) MUL(0x0E, x)) ^
((uint32_t) MUL(0x09, x) << 8) ^
((uint32_t) MUL(0x0D, x) << 16) ^
@ -458,7 +462,6 @@ MBEDTLS_MAYBE_UNUSED static void aes_gen_tables(void)
RT2[i] = ROTL8(RT1[i]);
RT3[i] = ROTL8(RT2[i]);
#endif /* !MBEDTLS_AES_FEWER_TABLES */
#endif /* !MBEDTLS_AES_USE_HARDWARE_ONLY */
#endif /* MBEDTLS_AES_NEED_REVERSE_TABLES */
}
}