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Fix AES multiblock issues for NXP DCP #10307

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Fix AES multiblock issues for NXP DCP #10307

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7 changes: 5 additions & 2 deletions wolfcrypt/src/port/nxp/dcp_port.c
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Original file line number Diff line number Diff line change
Expand Up @@ -255,7 +255,7 @@ int DCPAesCbcEncrypt(Aes* aes, byte* out, const byte* in, word32 sz)
if (ret)
ret = WC_HW_E;
else
XMEMCPY(aes->reg, out, WC_AES_BLOCK_SIZE);
XMEMCPY(aes->reg, out + sz - WC_AES_BLOCK_SIZE, WC_AES_BLOCK_SIZE);
dcp_unlock();
return ret;
}
Expand All @@ -265,12 +265,15 @@ int DCPAesCbcDecrypt(Aes* aes, byte* out, const byte* in, word32 sz)
int ret;
if (sz % 16)
return BAD_FUNC_ARG;
/* Snapshot last ciphertext block before decrypt; in-place decryption
* (in == out) overwrites the input with plaintext. */
XMEMCPY(aes->tmp, in + sz - WC_AES_BLOCK_SIZE, WC_AES_BLOCK_SIZE);
dcp_lock();
ret = DCP_AES_DecryptCbc(DCP, &aes->handle, in, out, sz, (const byte *)aes->reg);
if (ret)
ret = WC_HW_E;
else
XMEMCPY(aes->reg, in, WC_AES_BLOCK_SIZE);
XMEMCPY(aes->reg, aes->tmp, WC_AES_BLOCK_SIZE);
dcp_unlock();
return ret;
}
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147 changes: 147 additions & 0 deletions wolfcrypt/test/test.c
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Original file line number Diff line number Diff line change
Expand Up @@ -16860,6 +16860,153 @@ WOLFSSL_TEST_SUBROUTINE wc_test_ret_t aes_cbc_test(void)
}
#endif /* HAVE_AES_DECRYPT */

/* Multi-block streaming: exercises the IV-handoff path with sz > 16
* so that out[0] and out[sz-16] differ. Hardware backends that stash
* the wrong ciphertext block into aes->reg between calls (e.g. the
* first block instead of the last) will fail the second KAT. */
{
WOLFSSL_SMALL_STACK_STATIC const byte msg4[] = {
0x6b,0xc1,0xbe,0xe2,0x2e,0x40,0x9f,0x96,
0xe9,0x3d,0x7e,0x11,0x73,0x93,0x17,0x2a,
0xae,0x2d,0x8a,0x57,0x1e,0x03,0xac,0x9c,
0x9e,0xb7,0x6f,0xac,0x45,0xaf,0x8e,0x51,
0x30,0xc8,0x1c,0x46,0xa3,0x5c,0xe4,0x11,
0xe5,0xfb,0xc1,0x19,0x1a,0x0a,0x52,0xef,
0xf6,0x9f,0x24,0x45,0xdf,0x4f,0x9b,0x17,
0xad,0x2b,0x41,0x7b,0xe6,0x6c,0x37,0x10
};
WOLFSSL_SMALL_STACK_STATIC const byte verify4[] = {
0x76,0x49,0xab,0xac,0x81,0x19,0xb2,0x46,
0xce,0xe9,0x8e,0x9b,0x12,0xe9,0x19,0x7d,
0x50,0x86,0xcb,0x9b,0x50,0x72,0x19,0xee,
0x95,0xdb,0x11,0x3a,0x91,0x76,0x78,0xb2,
0x73,0xbe,0xd6,0xb8,0xe3,0xc1,0x74,0x3b,
0x71,0x16,0xe6,0x9e,0x22,0x22,0x95,0x16,
0x3f,0xf1,0xca,0xa1,0x68,0x1f,0xac,0x09,
0x12,0x0e,0xca,0x30,0x75,0x86,0xe1,0xa7
};

ret = wc_AesSetKey(enc, key2, sizeof(key2), iv2, AES_ENCRYPTION);
if (ret != 0)
ERROR_OUT(WC_TEST_RET_ENC_EC(ret), out);

XMEMSET(cipher, 0, sizeof(cipher));
ret = wc_AesCbcEncrypt(enc, cipher, msg4, WC_AES_BLOCK_SIZE * 2);
#if defined(WOLFSSL_ASYNC_CRYPT)
ret = wc_AsyncWait(ret, &enc->asyncDev, WC_ASYNC_FLAG_NONE);
#endif
if (ret != 0)
ERROR_OUT(WC_TEST_RET_ENC_EC(ret), out);

ret = wc_AesCbcEncrypt(enc, cipher + WC_AES_BLOCK_SIZE * 2,
msg4 + WC_AES_BLOCK_SIZE * 2,
WC_AES_BLOCK_SIZE * 2);
#if defined(WOLFSSL_ASYNC_CRYPT)
ret = wc_AsyncWait(ret, &enc->asyncDev, WC_ASYNC_FLAG_NONE);
#endif
if (ret != 0)
ERROR_OUT(WC_TEST_RET_ENC_EC(ret), out);

if (XMEMCMP(cipher, verify4, sizeof(verify4))) {
WOLFSSL_MSG("wc_AesCbcEncrypt streaming failed cipher compare");
ERROR_OUT(WC_TEST_RET_ENC_NC, out);
}

/* In-place multi-block streaming encrypt: input and output
* overlap. The next-call IV is read from the output buffer,
* which always holds ciphertext post-call, so this must work
* for any correct backend regardless of aliasing. */
ret = wc_AesSetKey(enc, key2, sizeof(key2), iv2, AES_ENCRYPTION);
if (ret != 0)
ERROR_OUT(WC_TEST_RET_ENC_EC(ret), out);

XMEMCPY(cipher, msg4, sizeof(msg4));

ret = wc_AesCbcEncrypt(enc, cipher, cipher, WC_AES_BLOCK_SIZE * 2);
#if defined(WOLFSSL_ASYNC_CRYPT)
ret = wc_AsyncWait(ret, &enc->asyncDev, WC_ASYNC_FLAG_NONE);
#endif
if (ret != 0)
ERROR_OUT(WC_TEST_RET_ENC_EC(ret), out);

ret = wc_AesCbcEncrypt(enc, cipher + WC_AES_BLOCK_SIZE * 2,
cipher + WC_AES_BLOCK_SIZE * 2,
WC_AES_BLOCK_SIZE * 2);
#if defined(WOLFSSL_ASYNC_CRYPT)
ret = wc_AsyncWait(ret, &enc->asyncDev, WC_ASYNC_FLAG_NONE);
#endif
if (ret != 0)
ERROR_OUT(WC_TEST_RET_ENC_EC(ret), out);

if (XMEMCMP(cipher, verify4, sizeof(verify4))) {
WOLFSSL_MSG("wc_AesCbcEncrypt in-place streaming failed"
" cipher compare");
ERROR_OUT(WC_TEST_RET_ENC_NC, out);
}

#ifdef HAVE_AES_DECRYPT
ret = wc_AesSetKey(dec, key2, sizeof(key2), iv2, AES_DECRYPTION);
if (ret != 0)
ERROR_OUT(WC_TEST_RET_ENC_EC(ret), out);

XMEMSET(plain, 0, sizeof(plain));
ret = wc_AesCbcDecrypt(dec, plain, verify4, WC_AES_BLOCK_SIZE * 2);
#if defined(WOLFSSL_ASYNC_CRYPT)
ret = wc_AsyncWait(ret, &dec->asyncDev, WC_ASYNC_FLAG_NONE);
#endif
if (ret != 0)
ERROR_OUT(WC_TEST_RET_ENC_EC(ret), out);

ret = wc_AesCbcDecrypt(dec, plain + WC_AES_BLOCK_SIZE * 2,
verify4 + WC_AES_BLOCK_SIZE * 2,
WC_AES_BLOCK_SIZE * 2);
#if defined(WOLFSSL_ASYNC_CRYPT)
ret = wc_AsyncWait(ret, &dec->asyncDev, WC_ASYNC_FLAG_NONE);
#endif
if (ret != 0)
ERROR_OUT(WC_TEST_RET_ENC_EC(ret), out);

if (XMEMCMP(plain, msg4, sizeof(msg4))) {
WOLFSSL_MSG("wc_AesCbcDecrypt streaming failed plain compare");
ERROR_OUT(WC_TEST_RET_ENC_NC, out);
}

/* In-place multi-block streaming decrypt: input and output
* overlap, so backends must snapshot the last ciphertext block
* BEFORE decrypting (it is clobbered by the plaintext write).
* Backends that read the IV for the next call from the output
* buffer after decrypt will stash plaintext and garble the
* first block of the next call. */
ret = wc_AesSetKey(dec, key2, sizeof(key2), iv2, AES_DECRYPTION);
if (ret != 0)
ERROR_OUT(WC_TEST_RET_ENC_EC(ret), out);

XMEMCPY(plain, verify4, sizeof(verify4));

ret = wc_AesCbcDecrypt(dec, plain, plain, WC_AES_BLOCK_SIZE * 2);
#if defined(WOLFSSL_ASYNC_CRYPT)
ret = wc_AsyncWait(ret, &dec->asyncDev, WC_ASYNC_FLAG_NONE);
#endif
if (ret != 0)
ERROR_OUT(WC_TEST_RET_ENC_EC(ret), out);

ret = wc_AesCbcDecrypt(dec, plain + WC_AES_BLOCK_SIZE * 2,
plain + WC_AES_BLOCK_SIZE * 2,
WC_AES_BLOCK_SIZE * 2);
#if defined(WOLFSSL_ASYNC_CRYPT)
ret = wc_AsyncWait(ret, &dec->asyncDev, WC_ASYNC_FLAG_NONE);
#endif
if (ret != 0)
ERROR_OUT(WC_TEST_RET_ENC_EC(ret), out);

if (XMEMCMP(plain, msg4, sizeof(msg4))) {
WOLFSSL_MSG("wc_AesCbcDecrypt in-place streaming failed"
" plain compare");
ERROR_OUT(WC_TEST_RET_ENC_NC, out);
}
#endif /* HAVE_AES_DECRYPT */
}

aes_cbc_oneshot_test();
}
#endif /* WOLFSSL_AES_128 && !HAVE_RENESAS_SYNC */
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