Skip to content

nxp hashcrypt: preserve AES OFB/CFB streaming state across calls #11262

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
night1rider wants to merge 1 commit into
base: master
Choose a base branch
from
Open

nxp hashcrypt: preserve AES OFB/CFB streaming state across calls #11262

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
109 changes: 75 additions & 34 deletions wolfcrypt/src/port/nxp/hashcrypt_port.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -283,73 +283,114 @@ int wc_AesCbcDecrypt(Aes* aes, byte* out, const byte* in, word32 sz)
#endif /* HAVE_AES_CBC */

#ifdef WOLFSSL_AES_OFB
int wc_AesOfbEncrypt(Aes* aes, byte* out, const byte* in, word32 sz)
/* OFB is symmetric (encrypt and decrypt run the same keystream). Generate the
* keystream one block at a time with the SDK's ECB primitive and keep the
* feedback register plus any unused keystream bytes in the Aes context, so a
* message split across calls continues the stream instead of restarting from
* the original IV. */
static int _hashcrypt_aes_ofb(Aes* aes, byte* out, const byte* in, word32 sz)
{
int ret;
byte* tmp;

if (aes == NULL || out == NULL || in == NULL)
return BAD_FUNC_ARG;

if (sz == 0)
return 0;

ret = _hashcrypt_set_key(aes);
if (ret)
return ret;

if (HASHCRYPT_AES_CryptOfb(
HASHCRYPT, &aes_handle, in, out, sz, (const uint8_t *)aes->reg)
!= kStatus_Success)
return WC_HW_E;
while (sz > 0) {
if (aes->left == 0) {
/* keystream block O = E(reg); OFB feeds O back as the next reg */
if (HASHCRYPT_AES_EncryptEcb(HASHCRYPT, &aes_handle,
(const uint8_t *)aes->reg, (uint8_t *)aes->tmp,
WC_AES_BLOCK_SIZE) != kStatus_Success)
return WC_HW_E;
XMEMCPY(aes->reg, aes->tmp, WC_AES_BLOCK_SIZE);
aes->left = WC_AES_BLOCK_SIZE;
}
tmp = (byte*)aes->tmp + WC_AES_BLOCK_SIZE - aes->left;
while (aes->left > 0 && sz > 0) {
*(out++) = *(in++) ^ *(tmp++);
aes->left--;
sz--;
}
}

return 0;
}

int wc_AesOfbEncrypt(Aes* aes, byte* out, const byte* in, word32 sz)
{
return _hashcrypt_aes_ofb(aes, out, in, sz);
}

#ifdef HAVE_AES_DECRYPT
int wc_AesOfbDecrypt(Aes* aes, byte* out, const byte* in, word32 sz)
{
int ret;

ret = _hashcrypt_set_key(aes);
if (ret)
return ret;

if (HASHCRYPT_AES_CryptOfb(
HASHCRYPT, &aes_handle, in, out, sz, (const uint8_t *)aes->reg)
!= kStatus_Success)
return WC_HW_E;

return 0;
return _hashcrypt_aes_ofb(aes, out, in, sz);
}
#endif
#endif /* WOLFSSL_AES_OFB */

#ifdef WOLFSSL_AES_CFB
int wc_AesCfbEncrypt(Aes* aes, byte* out, const byte* in, word32 sz)
/* CFB-128, byte capable. The keystream block is E(reg); each ciphertext byte is
* fed back into reg at the matching offset, so once a full block has passed reg
* holds the next feedback block. State (reg, tmp keystream, left) persists in
* the Aes context so one message may be processed across several calls. */
static int _hashcrypt_aes_cfb(Aes* aes, byte* out, const byte* in, word32 sz,
int decrypt)
{
int ret;
word32 idx;
byte c;

if (aes == NULL || out == NULL || in == NULL)
return BAD_FUNC_ARG;

if (sz == 0)
return 0;

ret = _hashcrypt_set_key(aes);
if (ret)
return ret;

if (HASHCRYPT_AES_EncryptCfb(
HASHCRYPT, &aes_handle, in, out, sz, (const uint8_t *)aes->reg)
!= kStatus_Success)
return WC_HW_E;
while (sz > 0) {
if (aes->left == 0) {
if (HASHCRYPT_AES_EncryptEcb(HASHCRYPT, &aes_handle,
(const uint8_t *)aes->reg, (uint8_t *)aes->tmp,
WC_AES_BLOCK_SIZE) != kStatus_Success)
return WC_HW_E;
aes->left = WC_AES_BLOCK_SIZE;
}
idx = WC_AES_BLOCK_SIZE - aes->left;
/* ciphertext = plaintext XOR keystream (and vice-versa for decrypt) */
c = (byte)(*in ^ ((byte*)aes->tmp)[idx]);
/* feedback register always takes the ciphertext byte */
((byte*)aes->reg)[idx] = decrypt ? *in : c;
*out = c;
in++;
out++;
sz--;
aes->left--;
}

return 0;
}

int wc_AesCfbEncrypt(Aes* aes, byte* out, const byte* in, word32 sz)
{
return _hashcrypt_aes_cfb(aes, out, in, sz, 0);
}

#ifdef HAVE_AES_DECRYPT
int wc_AesCfbDecrypt(Aes* aes, byte* out, const byte* in, word32 sz)
{
int ret;

ret = _hashcrypt_set_key(aes);
if (ret)
return ret;

if (HASHCRYPT_AES_DecryptCfb(
HASHCRYPT, &aes_handle, in, out, sz, (const uint8_t *)aes->reg)
!= kStatus_Success)
return WC_HW_E;

return 0;
return _hashcrypt_aes_cfb(aes, out, in, sz, 1);
}
#endif
#endif /* WOLFSSL_AES_CFB */
Expand Down
12 changes: 0 additions & 12 deletions wolfcrypt/test/test.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -13828,11 +13828,9 @@ static wc_test_ret_t aes_ofb_256_test(Aes* enc, Aes* dec, byte* cipher,
plain1 + WC_AES_BLOCK_SIZE, WC_AES_BLOCK_SIZE);
if (ret != 0)
return WC_TEST_RET_ENC_EC(ret);
#ifndef WOLFSSL_NXP_HASHCRYPT_AES
if (XMEMCMP(cipher + WC_AES_BLOCK_SIZE, cipher1 + WC_AES_BLOCK_SIZE,
WC_AES_BLOCK_SIZE))
return WC_TEST_RET_ENC_NC;
#endif /* !WOLFSSL_NXP_HASHCRYPT_AES */

#ifdef HAVE_AES_DECRYPT
ret = wc_AesOfbDecrypt(dec, plain, cipher1, WC_AES_BLOCK_SIZE);
Expand All @@ -13845,11 +13843,9 @@ static wc_test_ret_t aes_ofb_256_test(Aes* enc, Aes* dec, byte* cipher,
cipher1 + WC_AES_BLOCK_SIZE, WC_AES_BLOCK_SIZE);
if (ret != 0)
return WC_TEST_RET_ENC_EC(ret);
#ifndef WOLFSSL_NXP_HASHCRYPT_AES
if (XMEMCMP(plain + WC_AES_BLOCK_SIZE, plain1 + WC_AES_BLOCK_SIZE,
WC_AES_BLOCK_SIZE))
return WC_TEST_RET_ENC_NC;
#endif /* !WOLFSSL_NXP_HASHCRYPT_AES */
#endif /* HAVE_AES_DECRYPT */

/* Multiple blocks at once */
Expand Down Expand Up @@ -13922,10 +13918,8 @@ static wc_test_ret_t aes_ofb_256_test(Aes* enc, Aes* dec, byte* cipher,
ret = wc_AesOfbEncrypt(enc, cipher + 3, plain1 + 3, WC_AES_BLOCK_SIZE);
if (ret != 0)
return WC_TEST_RET_ENC_EC(ret);
#ifndef WOLFSSL_NXP_HASHCRYPT_AES
if (XMEMCMP(cipher + 3, cipher1 + 3, WC_AES_BLOCK_SIZE))
return WC_TEST_RET_ENC_NC;
#endif /* !WOLFSSL_NXP_HASHCRYPT_AES */

#ifdef HAVE_AES_DECRYPT
ret = wc_AesOfbDecrypt(dec, plain, cipher1, 6);
Expand All @@ -13937,10 +13931,8 @@ static wc_test_ret_t aes_ofb_256_test(Aes* enc, Aes* dec, byte* cipher,
ret = wc_AesOfbDecrypt(dec, plain + 6, cipher1 + 6, WC_AES_BLOCK_SIZE);
if (ret != 0)
return WC_TEST_RET_ENC_EC(ret);
#ifndef WOLFSSL_NXP_HASHCRYPT_AES
if (XMEMCMP(plain + 6, plain1 + 6, WC_AES_BLOCK_SIZE))
return WC_TEST_RET_ENC_NC;
#endif /* !WOLFSSL_NXP_HASHCRYPT_AES */
#endif /* HAVE_AES_DECRYPT */

return 0;
Expand Down Expand Up @@ -14302,7 +14294,6 @@ WOLFSSL_TEST_SUBROUTINE wc_test_ret_t aesofb_test(void)
ERROR_OUT(WC_TEST_RET_ENC_NC, out);

/* test restarting encryption process */
#ifndef WOLFSSL_NXP_HASHCRYPT_AES
ret = wc_AesCfbEncrypt(enc, cipher + (WC_AES_BLOCK_SIZE * 2),
msg1 + (WC_AES_BLOCK_SIZE * 2), WC_AES_BLOCK_SIZE);
if (ret != 0)
Expand All @@ -14320,7 +14311,6 @@ WOLFSSL_TEST_SUBROUTINE wc_test_ret_t aesofb_test(void)
if (XMEMCMP(plain, msg1, WC_AES_BLOCK_SIZE * 3))
ERROR_OUT(WC_TEST_RET_ENC_NC, out);
#endif /* HAVE_AES_DECRYPT */
#endif /* !WOLFSSL_NXP_HASHCRYPT_AES */
#endif /* WOLFSSL_AES_128 */

#ifdef WOLFSSL_AES_192
Expand Down Expand Up @@ -14386,7 +14376,6 @@ WOLFSSL_TEST_SUBROUTINE wc_test_ret_t aesofb_test(void)
ERROR_OUT(WC_TEST_RET_ENC_EC(ret), out);
#endif

#ifndef WOLFSSL_NXP_HASHCRYPT_AES
/* test with data left overs, magic lengths are checking near edges */
XMEMSET(cipher, 0, sizeof(cipher));
ret = wc_AesCfbEncrypt(enc, cipher, msg3, 4);
Expand Down Expand Up @@ -14438,7 +14427,6 @@ WOLFSSL_TEST_SUBROUTINE wc_test_ret_t aesofb_test(void)
if (XMEMCMP(plain, msg3, WC_AES_BLOCK_SIZE * 4))
ERROR_OUT(WC_TEST_RET_ENC_NC, out);
#endif /* HAVE_AES_DECRYPT */
#endif /* !WOLFSSL_NXP_HASHCRYPT_AES */
#endif /* WOLFSSL_AES_256 */

out:
Expand Down
Loading