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aes.c: provide finer guard for RSb

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Variable RSb is only used for either computing reverse tables
in aes_gen_tables or AES-decryption function. This commit provides
more guards for when RSb is defined and used.

Signed-off-by: Yanray Wang <yanray.wang@arm.com>
This commit is contained in:
Yanray Wang 2023-07-07 17:28:24 +08:00
parent 422a77f716
commit 427424768a
1 changed files with 12 additions and 3 deletions
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15
library/aes.c
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@ -391,9 +391,14 @@ static uint32_t FT3[256];
/* /*
* Reverse S-box & tables * Reverse S-box & tables
*/ */
#if !defined(MBEDTLS_AES_SETKEY_ENC_ALT) || !defined(MBEDTLS_AES_DECRYPT_ALT)
#if !defined(MBEDTLS_AES_SETKEY_ENC_ALT) && !defined(MBEDTLS_AES_SETKEY_DEC_ALT)
static unsigned char RSb[256]; static unsigned char RSb[256];
#endif /* !MBEDTLS_AES_SETKEY_ENC_ALT || !MBEDTLS_AES_DECRYPT_ALT */ #else /* !MBEDTLS_AES_SETKEY_ENC_ALT && !MBEDTLS_AES_SETKEY_DEC_ALT */
#if !defined(MBEDTLS_AES_DECRYPT_ALT)
static unsigned char RSb[256];
#endif /* !MBEDTLS_AES_DECRYPT_ALT */
#endif /* !MBEDTLS_AES_SETKEY_ENC_ALT && !MBEDTLS_AES_SETKEY_DEC_ALT */
#if !defined(MBEDTLS_AES_DECRYPT_ALT) || !defined(MBEDTLS_AES_SETKEY_DEC_ALT) #if !defined(MBEDTLS_AES_DECRYPT_ALT) || !defined(MBEDTLS_AES_SETKEY_DEC_ALT)
static uint32_t RT0[256]; static uint32_t RT0[256];
@ -447,7 +452,9 @@ static void aes_gen_tables(void)
* generate the forward and reverse S-boxes * generate the forward and reverse S-boxes
*/ */
FSb[0x00] = 0x63; FSb[0x00] = 0x63;
#if !defined(MBEDTLS_AES_DECRYPT_ALT) || !defined(MBEDTLS_AES_SETKEY_DEC_ALT)
RSb[0x63] = 0x00; RSb[0x63] = 0x00;
#endif
for (i = 1; i < 256; i++) { for (i = 1; i < 256; i++) {
x = pow[255 - log[i]]; x = pow[255 - log[i]];
@ -459,7 +466,9 @@ static void aes_gen_tables(void)
x ^= y ^ 0x63; x ^= y ^ 0x63;
FSb[i] = x; FSb[i] = x;
#if !defined(MBEDTLS_AES_DECRYPT_ALT) || !defined(MBEDTLS_AES_SETKEY_DEC_ALT)
RSb[x] = (unsigned char) i; RSb[x] = (unsigned char) i;
#endif
} }
/* /*
@ -481,9 +490,9 @@ static void aes_gen_tables(void)
FT3[i] = ROTL8(FT2[i]); FT3[i] = ROTL8(FT2[i]);
#endif /* !MBEDTLS_AES_FEWER_TABLES */ #endif /* !MBEDTLS_AES_FEWER_TABLES */
#if !defined(MBEDTLS_AES_DECRYPT_ALT) || !defined(MBEDTLS_AES_SETKEY_DEC_ALT)
x = RSb[i]; x = RSb[i];
#if !defined(MBEDTLS_AES_DECRYPT_ALT) || !defined(MBEDTLS_AES_SETKEY_DEC_ALT)
RT0[i] = ((uint32_t) MUL(0x0E, x)) ^ RT0[i] = ((uint32_t) MUL(0x0E, x)) ^
((uint32_t) MUL(0x09, x) << 8) ^ ((uint32_t) MUL(0x09, x) << 8) ^
((uint32_t) MUL(0x0D, x) << 16) ^ ((uint32_t) MUL(0x0D, x) << 16) ^