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Diffstat (limited to 'tests/suites/test_suite_ssl_decrypt.function')
| -rw-r--r-- | tests/suites/test_suite_ssl_decrypt.function | 312 |
1 files changed, 312 insertions, 0 deletions
diff --git a/tests/suites/test_suite_ssl_decrypt.function b/tests/suites/test_suite_ssl_decrypt.function new file mode 100644 index 00000000000..35f0adb5374 --- /dev/null +++ b/tests/suites/test_suite_ssl_decrypt.function @@ -0,0 +1,312 @@ +/* BEGIN_HEADER */ +/* Testing of mbedtls_ssl_decrypt_buf() specifically, focusing on negative + * testing (using malformed inputs). */ + +#include <mbedtls/ssl.h> +#include <ssl_misc.h> +#include <test/ssl_helpers.h> + +/* END_HEADER */ + +/* BEGIN_DEPENDENCIES + * depends_on:MBEDTLS_SSL_TLS_C + * END_DEPENDENCIES + */ + +/* BEGIN_CASE depends_on:MBEDTLS_SSL_PROTO_TLS1_2:MBEDTLS_CIPHER_NULL_CIPHER */ +void ssl_decrypt_null(int hash_id) +{ + mbedtls_ssl_transform transform_in, transform_out; + mbedtls_ssl_transform_init(&transform_in); + mbedtls_ssl_transform_init(&transform_out); + const mbedtls_ssl_protocol_version version = MBEDTLS_SSL_VERSION_TLS1_2; + const mbedtls_cipher_type_t cipher_type = MBEDTLS_CIPHER_NULL; + mbedtls_record rec_good = { + .ctr = { 0 }, + .type = MBEDTLS_SSL_MSG_APPLICATION_DATA, + .ver = { 0, 0 }, /* Will be set by a function call below */ + .buf = NULL, + .buf_len = 0, + .data_offset = 0, + .data_len = 0, +#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) + .cid_len = 0, + .cid = { 0 }, +#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ + }; + mbedtls_ssl_write_version(rec_good.ver, + MBEDTLS_SSL_TRANSPORT_STREAM, + version); + const char sample_plaintext[3] = "ABC"; + mbedtls_ssl_context ssl; + mbedtls_ssl_init(&ssl); + uint8_t *buf = NULL; + + MD_OR_USE_PSA_INIT(); + + TEST_EQUAL(mbedtls_test_ssl_build_transforms(&transform_in, &transform_out, + cipher_type, hash_id, 0, 0, + version, + 0, 0), 0); + + const size_t plaintext_length = sizeof(sample_plaintext); + rec_good.buf_len = plaintext_length + transform_in.maclen; + rec_good.data_len = plaintext_length; + TEST_CALLOC(rec_good.buf, rec_good.buf_len); + memcpy(rec_good.buf, sample_plaintext, plaintext_length); + TEST_EQUAL(mbedtls_test_ssl_prepare_record_mac(&rec_good, + &transform_out), 0); + + /* Good case */ + mbedtls_record rec = rec_good; + TEST_EQUAL(mbedtls_ssl_decrypt_buf(&ssl, &transform_in, &rec), 0); + + /* Change any one byte of the plaintext or MAC. The MAC will be wrong. */ + TEST_CALLOC(buf, rec.buf_len); + for (size_t i = 0; i < rec.buf_len; i++) { + mbedtls_test_set_step(i); + rec = rec_good; + rec.buf = buf; + memcpy(buf, rec_good.buf, rec.buf_len); + buf[i] ^= 1; + TEST_EQUAL(mbedtls_ssl_decrypt_buf(&ssl, &transform_in, &rec), + MBEDTLS_ERR_SSL_INVALID_MAC); + } + mbedtls_free(buf); + buf = NULL; + + /* Shorter input buffer. Either the MAC will be wrong, or there isn't + * enough room for a MAC. */ + for (size_t n = 1; n < rec.buf_len; n++) { + mbedtls_test_set_step(n); + rec = rec_good; + TEST_CALLOC(buf, n); + rec.buf = buf; + rec.buf_len = n; + rec.data_len = n; + memcpy(buf, rec_good.buf, n); + TEST_EQUAL(mbedtls_ssl_decrypt_buf(&ssl, &transform_in, &rec), + MBEDTLS_ERR_SSL_INVALID_MAC); + mbedtls_free(buf); + buf = NULL; + } + + /* For robustness, check a 0-length buffer (non-null, then null). + * This should not reach mbedtls_ssl_decrypt_buf() as used in the library, + * so the exact error doesn't matter, but we don't want a crash. */ + { + const uint8_t buf1[1] = { 'a' }; + rec = rec_good; + /* We won't write to buf1[0] since it's out of range, so we can cast + * the const away. */ + rec.buf = (uint8_t *) buf1; + rec.buf_len = 0; + TEST_EQUAL(mbedtls_ssl_decrypt_buf(&ssl, &transform_in, &rec), + MBEDTLS_ERR_SSL_INTERNAL_ERROR); + } + rec = rec_good; + rec.buf = NULL; + rec.buf_len = 0; + TEST_EQUAL(mbedtls_ssl_decrypt_buf(&ssl, &transform_in, &rec), + MBEDTLS_ERR_SSL_INTERNAL_ERROR); + +exit: + mbedtls_ssl_transform_free(&transform_in); + mbedtls_ssl_transform_free(&transform_out); + mbedtls_free(rec_good.buf); + mbedtls_ssl_free(&ssl); + mbedtls_free(buf); + MD_OR_USE_PSA_DONE(); +} +/* END_CASE */ + +/* BEGIN_CASE depends_on:MBEDTLS_SSL_HAVE_CBC:MBEDTLS_SSL_HAVE_AES:MBEDTLS_SSL_PROTO_TLS1_2 */ +void ssl_decrypt_non_etm_cbc(int cipher_type, int hash_id, int trunc_hmac, + int length_selector) +{ + /* + * Test record decryption for CBC without EtM, focused on the verification + * of padding and MAC. + * + * Actually depends on TLS 1.2 and either AES, ARIA or Camellia, but since + * the test framework doesn't support alternation in dependency statements, + * just depend on AES. + * + * The length_selector argument is interpreted as follows: + * - if it's -1, the plaintext length is 0 and minimal padding is applied + * - if it's -2, the plaintext length is 0 and maximal padding is applied + * - otherwise it must be in [0, 255] and is padding_length from RFC 5246: + * it's the length of the rest of the padding, that is, excluding the + * byte that encodes the length. The minimal non-zero plaintext length + * that gives this padding_length is automatically selected. + */ + mbedtls_ssl_context ssl; /* ONLY for debugging */ + mbedtls_ssl_transform t0, t1; + mbedtls_record rec, rec_save; + unsigned char *buf = NULL, *buf_save = NULL; + size_t buflen, olen = 0; + size_t plaintext_len, block_size, i; + unsigned char padlen; /* excluding the padding_length byte */ + int exp_ret; + int ret; + const unsigned char pad_max_len = 255; /* Per the standard */ + + mbedtls_ssl_init(&ssl); + mbedtls_ssl_transform_init(&t0); + mbedtls_ssl_transform_init(&t1); + MD_OR_USE_PSA_INIT(); + + /* Set up transforms with dummy keys */ + ret = mbedtls_test_ssl_build_transforms(&t0, &t1, cipher_type, hash_id, + 0, trunc_hmac, + MBEDTLS_SSL_VERSION_TLS1_2, + 0, 0); + + TEST_ASSERT(ret == 0); + + /* Determine padding/plaintext length */ + TEST_ASSERT(length_selector >= -2 && length_selector <= 255); + block_size = t0.ivlen; + if (length_selector < 0) { + plaintext_len = 0; + + /* Minimal padding + * The +1 is for the padding_length byte, not counted in padlen. */ + padlen = block_size - (t0.maclen + 1) % block_size; + + /* Maximal padding? */ + if (length_selector == -2) { + padlen += block_size * ((pad_max_len - padlen) / block_size); + } + } else { + padlen = length_selector; + + /* Minimal non-zero plaintext_length giving desired padding. + * The +1 is for the padding_length byte, not counted in padlen. */ + plaintext_len = block_size - (padlen + t0.maclen + 1) % block_size; + } + + /* Prepare a buffer for record data */ + buflen = block_size + + plaintext_len + + t0.maclen + + padlen + 1; + TEST_CALLOC(buf, buflen); + TEST_CALLOC(buf_save, buflen); + + /* Prepare a dummy record header */ + memset(rec.ctr, 0, sizeof(rec.ctr)); + rec.type = MBEDTLS_SSL_MSG_APPLICATION_DATA; + mbedtls_ssl_write_version(rec.ver, MBEDTLS_SSL_TRANSPORT_STREAM, + MBEDTLS_SSL_VERSION_TLS1_2); +#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) + rec.cid_len = 0; +#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ + + /* Prepare dummy record content */ + rec.buf = buf; + rec.buf_len = buflen; + rec.data_offset = block_size; + rec.data_len = plaintext_len; + memset(rec.buf + rec.data_offset, 42, rec.data_len); + + /* Set dummy IV */ + memset(t0.iv_enc, 0x55, t0.ivlen); + memcpy(rec.buf, t0.iv_enc, t0.ivlen); + + /* + * Prepare a pre-encryption record (with MAC and padding), and save it. + */ + TEST_EQUAL(0, mbedtls_test_ssl_prepare_record_mac(&rec, &t0)); + + /* Pad */ + memset(rec.buf + rec.data_offset + rec.data_len, padlen, padlen + 1); + rec.data_len += padlen + 1; + + /* Save correct pre-encryption record */ + rec_save = rec; + rec_save.buf = buf_save; + memcpy(buf_save, buf, buflen); + + /* + * Encrypt and decrypt the correct record, expecting success + */ + TEST_EQUAL(0, mbedtls_test_psa_cipher_encrypt_helper( + &t0, t0.iv_enc, t0.ivlen, rec.buf + rec.data_offset, + rec.data_len, rec.buf + rec.data_offset, &olen)); + rec.data_offset -= t0.ivlen; + rec.data_len += t0.ivlen; + + TEST_EQUAL(0, mbedtls_ssl_decrypt_buf(&ssl, &t1, &rec)); + + /* + * Modify each byte of the pre-encryption record before encrypting and + * decrypting it, expecting failure every time. + */ + for (i = block_size; i < buflen; i++) { + mbedtls_test_set_step(i); + + /* Restore correct pre-encryption record */ + rec = rec_save; + rec.buf = buf; + memcpy(buf, buf_save, buflen); + + /* Corrupt one byte of the data (could be plaintext, MAC or padding) */ + rec.buf[i] ^= 0x01; + + /* Encrypt */ + TEST_EQUAL(0, mbedtls_test_psa_cipher_encrypt_helper( + &t0, t0.iv_enc, t0.ivlen, rec.buf + rec.data_offset, + rec.data_len, rec.buf + rec.data_offset, &olen)); + rec.data_offset -= t0.ivlen; + rec.data_len += t0.ivlen; + + /* Decrypt and expect failure */ + TEST_EQUAL(MBEDTLS_ERR_SSL_INVALID_MAC, + mbedtls_ssl_decrypt_buf(&ssl, &t1, &rec)); + } + + /* + * Use larger values of the padding bytes - with small buffers, this tests + * the case where the announced padlen would be larger than the buffer + * (and before that, than the buffer minus the size of the MAC), to make + * sure our padding checking code does not perform any out-of-bounds reads + * in this case. (With larger buffers, ie when the plaintext is long or + * maximal length padding is used, this is less relevant but still doesn't + * hurt to test.) + * + * (Start the loop with correct padding, just to double-check that record + * saving did work, and that we're overwriting the correct bytes.) + */ + for (i = padlen; i <= pad_max_len; i++) { + mbedtls_test_set_step(i); + + /* Restore correct pre-encryption record */ + rec = rec_save; + rec.buf = buf; + memcpy(buf, buf_save, buflen); + + /* Set padding bytes to new value */ + memset(buf + buflen - padlen - 1, i, padlen + 1); + + /* Encrypt */ + TEST_EQUAL(0, mbedtls_test_psa_cipher_encrypt_helper( + &t0, t0.iv_enc, t0.ivlen, rec.buf + rec.data_offset, + rec.data_len, rec.buf + rec.data_offset, &olen)); + rec.data_offset -= t0.ivlen; + rec.data_len += t0.ivlen; + + /* Decrypt and expect failure except the first time */ + exp_ret = (i == padlen) ? 0 : MBEDTLS_ERR_SSL_INVALID_MAC; + TEST_EQUAL(exp_ret, mbedtls_ssl_decrypt_buf(&ssl, &t1, &rec)); + } + +exit: + mbedtls_ssl_free(&ssl); + mbedtls_ssl_transform_free(&t0); + mbedtls_ssl_transform_free(&t1); + mbedtls_free(buf); + mbedtls_free(buf_save); + MD_OR_USE_PSA_DONE(); +} +/* END_CASE */ |