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tests: suit: tests for direct decryption
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Tests for decrypting without AES KW.

Signed-off-by: Artur Hadasz <[email protected]>
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@ahasztag @jukkar
ahasztag authored and jukkar committed Dec 10, 2024
1 parent 00b1a0d commit d420700
Showing 1 changed file with 113 additions and 19 deletions.
132 changes: 113 additions & 19 deletions tests/subsys/suit/decrypt_filter/src/main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,7 @@ psa_status_t suit_aes_key_unwrap_manual(psa_key_id_t kek_key_id, const uint8_t *
* nrfkms export_derived -k TEST_AES_KEY -c test --format native
* hexdump -e '16/1 "0x%02x, " "\n"' kms_output/derived_key_native_test_from_TEST_AES_KEY.bin
*/
static const uint8_t test_kek_key[] = {
static const uint8_t test_key_data[] = {
0xf8, 0xfa, 0x8e, 0x7b, 0xed, 0x32, 0xd0, 0xc7, 0x15, 0x1f, 0xd9, 0xab, 0x0d,
0x8d, 0xed, 0x95, 0x26, 0xa8, 0x6a, 0x15, 0x34, 0x16, 0x01, 0xcf, 0x9c, 0x6b,
0xba, 0x00, 0x6a, 0xab, 0xaa, 0x9a,
Expand Down Expand Up @@ -59,7 +59,7 @@ static const uint8_t aad[] = {
* Ciphertext and NONCE (IV) taken from the encrypted_asset-... file, which is in format
* |nonce (12 bytes)|ciphertext|tag (16 bytes)|
*
*/
*/
static const uint8_t wrapped_cek[] = {
0x7d, 0xd6, 0xf4, 0xd3, 0x52, 0x44, 0x5a, 0x3a, 0x67, 0xb8, 0xcc,
0x74, 0x5b, 0x4b, 0x6f, 0x70, 0x62, 0xc3, 0xf2, 0x7b, 0x6b, 0x14,
Expand All @@ -84,35 +84,73 @@ static const uint8_t iv_aes_kw[] = {
0x61, 0xb4, 0x70, 0x53, 0xa5, 0xe2, 0x05, 0x68, 0xfe, 0x77, 0x12, 0x89,
};

/**
* Encryption without wrapping CEK achieved by running:
*
* echo "This is a sample plaintext for testing the decryption filter" > plaintext.txt
* nrfkms encrypt -k TEST_AES_KEY -c test -f plaintext.txt --aad "sample aad" --format native
*
* Ciphertext and NONCE (IV) taken from the encrypted_data_using_TEST_AES_KEY-test.bin file,
* which is in format |nonce (12 bytes)|tag (16 bytes)|ciphertext|
*/

static const uint8_t ciphertext_direct[] = {
/* tag (16 bytes) */
0x4d, 0x21, 0x30, 0xb7, 0xce, 0x8a, 0xd6, 0x00, 0xe4, 0x04, 0xbb, 0x32,
0x72, 0x7a, 0xbb, 0x7c,
/* ciphertext */
0xf0, 0x72, 0xdb, 0x63, 0x03, 0xdd, 0x24, 0x69,
0xd4, 0xbf, 0xd7, 0xa0, 0xec, 0xfa, 0x66, 0x58, 0x95, 0x2b, 0xc1, 0xc2,
0x9d, 0x82, 0x02, 0x1a, 0xd7, 0x5b, 0xc0, 0x01, 0xce, 0x0b, 0x79, 0x53,
0xe7, 0xdb, 0x0d, 0x35, 0xab, 0xef, 0x81, 0xc8, 0x68, 0xc5, 0xa7, 0x22,
0x90, 0xea, 0xd0, 0x7f, 0x36, 0xed, 0x14, 0xbe, 0x30, 0xf2, 0x81, 0x56,
0x7e, 0x2e, 0x5f, 0xd8, 0x7c,
};


static const uint8_t iv_direct[] = {
0x60, 0x90, 0x6d, 0xb2, 0xfe, 0xc3, 0xc8, 0x5a, 0xf0, 0x28, 0xb1, 0xb6,
};

static uint8_t output_buffer[128] = {0};

static void *test_suite_setup(void)
static void init_encryption_key(const uint8_t *data, size_t size, psa_key_id_t *key_id,
psa_key_id_t alg, uint8_t *cbor_key_id)
{
static struct suit_decrypt_filter_tests_fixture fixture = {0};
psa_status_t status;

/* Configure the key attributes */
psa_key_attributes_t key_attributes = PSA_KEY_ATTRIBUTES_INIT;

psa_set_key_usage_flags(&key_attributes, PSA_KEY_USAGE_ENCRYPT | PSA_KEY_USAGE_DECRYPT);
psa_set_key_lifetime(&key_attributes, PSA_KEY_LIFETIME_VOLATILE);
psa_set_key_algorithm(&key_attributes, PSA_ALG_ECB_NO_PADDING);
psa_set_key_algorithm(&key_attributes, alg);
psa_set_key_type(&key_attributes, PSA_KEY_TYPE_AES);
psa_set_key_bits(&key_attributes, 256);

status = psa_crypto_init();
zassert_equal(status, PSA_SUCCESS, "Failed to init psa crypto");
status = psa_import_key(&key_attributes, data, size, key_id);

status = psa_import_key(&key_attributes, test_kek_key, sizeof(test_kek_key),
&fixture.key_id);

zassert_equal(status, PSA_SUCCESS, "Failed to import KEK");
zassert_equal(status, PSA_SUCCESS, "Failed to import key");

/* Encode KEK key ID as CBOR unsigned int */
kek_key_id_cbor[1] = ((fixture.key_id >> 24) & 0xFF);
kek_key_id_cbor[2] = ((fixture.key_id >> 16) & 0xFF);
kek_key_id_cbor[3] = ((fixture.key_id >> 8) & 0xFF);
kek_key_id_cbor[4] = ((fixture.key_id >> 0) & 0xFF);
cbor_key_id[1] = ((*key_id >> 24) & 0xFF);
cbor_key_id[2] = ((*key_id >> 16) & 0xFF);
cbor_key_id[3] = ((*key_id >> 8) & 0xFF);
cbor_key_id[4] = ((*key_id >> 0) & 0xFF);

}

static void *test_suite_setup(void)
{
static struct suit_decrypt_filter_tests_fixture fixture = {0};
psa_status_t status;

status = psa_crypto_init();
zassert_equal(status, PSA_SUCCESS, "Failed to init psa crypto");

/* Init the KEK key */
init_encryption_key(test_key_data, sizeof(test_key_data), &fixture.key_id,
PSA_ALG_ECB_NO_PADDING, kek_key_id_cbor);

return &fixture;
}
Expand All @@ -127,14 +165,15 @@ static void test_suite_teardown(void *f)
}
}

static void test_before(void* f)
static void test_before(void *f)
{
(void) f;
memset(output_buffer, 0, sizeof(output_buffer));
}


ZTEST_SUITE(suit_decrypt_filter_tests, NULL, test_suite_setup, test_before, NULL, test_suite_teardown);
ZTEST_SUITE(suit_decrypt_filter_tests, NULL, test_suite_setup, test_before, NULL,
test_suite_teardown);

ZTEST_F(suit_decrypt_filter_tests, test_aes_unwrap_smoke)
{
Expand All @@ -147,7 +186,7 @@ ZTEST_F(suit_decrypt_filter_tests, test_aes_unwrap_smoke)
zassert_equal(status, PSA_SUCCESS, "Failed to unwrap CEK");
}

ZTEST_F(suit_decrypt_filter_tests, test_filter_smoke)
ZTEST_F(suit_decrypt_filter_tests, test_filter_smoke_aes_kw)
{
struct stream_sink dec_sink;
struct stream_sink ram_sink;
Expand Down Expand Up @@ -189,5 +228,60 @@ ZTEST_F(suit_decrypt_filter_tests, test_filter_smoke)

zassert_equal(err, SUIT_PLAT_SUCCESS, "Failed to release decrypt filter");

zassert_equal(memcmp(output_buffer, plaintext, strlen(plaintext)), 0, "Decrypted plaintext does not match");
zassert_equal(memcmp(output_buffer, plaintext, strlen(plaintext)), 0,
"Decrypted plaintext does not match");
}

ZTEST_F(suit_decrypt_filter_tests, test_filter_smoke_direct)
{
struct stream_sink dec_sink;
struct stream_sink ram_sink;
uint8_t cek_key_id_cbor[] = {
0x1A, 0x00, 0x00, 0x00, 0x00,
};

psa_key_id_t cek_key_id;

init_encryption_key(test_key_data, sizeof(test_key_data), &cek_key_id,
PSA_ALG_GCM, cek_key_id_cbor);

struct suit_encryption_info enc_info = {
.enc_alg_id = suit_cose_aes256_gcm,
.IV = {
.value = iv_direct,
.len = sizeof(iv_direct),
},
.aad = {
.value = aad,
.len = strlen(aad),
},
.kw_alg_id = suit_cose_direct,
.kw_key.aes = {.key_id = {.value = cek_key_id_cbor,
.len = sizeof(cek_key_id_cbor)},}
};

suit_plat_err_t err = suit_ram_sink_get(&ram_sink, output_buffer, sizeof(output_buffer));

zassert_equal(err, SUIT_PLAT_SUCCESS, "Unable to create RAM sink");

err = suit_decrypt_filter_get(&dec_sink, &enc_info, &ram_sink);

zassert_equal(err, SUIT_PLAT_SUCCESS, "Failed to create decrypt filter");

err = suit_memptr_streamer_stream(ciphertext_direct, sizeof(ciphertext_direct), &dec_sink);

zassert_equal(err, SUIT_PLAT_SUCCESS, "Failed to decrypt ciphertext");

err = dec_sink.flush(dec_sink.ctx);

zassert_equal(err, SUIT_PLAT_SUCCESS, "Failed to flush decrypt filter");

err = dec_sink.release(dec_sink.ctx);

zassert_equal(err, SUIT_PLAT_SUCCESS, "Failed to release decrypt filter");

zassert_equal(memcmp(output_buffer, plaintext, strlen(plaintext)), 0,
"Decrypted plaintext does not match");

psa_destroy_key(cek_key_id);
}

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