Merge fe0c44827ae5e805ceb123224c650da4a451e945 into d8d5ea7cbc42b7800a3b030fb4341810074e7cb0

Backport 4.1: Fix resource leak in populate transform

ChangeLog.d/tls13-transform-resource-leak.txt

@@ -0,0 +1,4 @@
+Bugfix
+   * Fix a resource leak in TLS 1.3 transform setup when importing the
+     decryption traffic key fails after the encryption traffic key has already
+     been imported. Fixes #10917.

library/ssl_tls13_keys.c

@@ -1034,6 +1034,8 @@ int mbedtls_ssl_tls13_populate_transform(
                                      &transform->psa_key_dec)) != PSA_SUCCESS) {
             MBEDTLS_SSL_DEBUG_RET(
                 1, "psa_import_key", PSA_TO_MBEDTLS_ERR(status));
+            psa_destroy_key(transform->psa_key_enc);
+            transform->psa_key_enc = MBEDTLS_SVC_KEY_ID_INIT;
             return PSA_TO_MBEDTLS_ERR(status);
         }
     }

tests/suites/test_suite_ssl.data

@@ -2856,6 +2856,9 @@ SSL TLS 1.3 Record Encryption RFC 8448 Example #2
 depends_on:PSA_WANT_KEY_TYPE_AES:PSA_WANT_ALG_GCM:PSA_WANT_ALG_SHA_256
 ssl_tls13_record_protection:MBEDTLS_TLS1_3_AES_128_GCM_SHA256:MBEDTLS_SSL_IS_SERVER:1:1:"9f02283b6c9c07efc26bb9f2ac92e356":"cf782b88dd83549aadf1e984":"17422dda596ed5d9acd890e3c63f5051":"5b78923dee08579033e523d9":"000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f3031":"2e937e11ef4ac740e538ad36005fc4a46932fc3225d05f82aa1b36e30efaf97d90e6dffc602dcb501a59a8fcc49c4bf2e5f0a21c0047c2abf332540dd032e167c2955d"
 
+TLS 1.3 transform frees encryption key if decryption key import fails
+ssl_tls13_populate_transform_second_key_import_failure
+
 SSL TLS 1.3 Key schedule: Application secrets derivation helper
 # Vector from RFC 8448
 depends_on:PSA_WANT_ALG_SHA_256

tests/suites/test_suite_ssl.function

@@ -8,6 +8,7 @@
 #endif /* MBEDTLS_PK_HAVE_PRIVATE_HEADER */
 #include <ssl_tls13_keys.h>
 #include <ssl_tls13_invasive.h>
+#include <psa_crypto_slot_management.h>
 #include <test/ssl_helpers.h>
 #include <test/ssl_helpers_internal.h>
 
@@ -114,6 +115,36 @@ static void tls_abort_transcript(void *ctx, int level,
 }
 #endif
 
+#if defined(MBEDTLS_PSA_KEY_STORE_DYNAMIC)
+#if defined(MBEDTLS_TEST_HOOKS) && defined(MBEDTLS_SSL_CLI_C) && \
+    defined(MBEDTLS_PSA_CRYPTO_C)
+#define SSL_TEST_KEY_SLICE_1_LENGTH 4
+#define SSL_TEST_KEY_SLICE_2_LENGTH 10
+static size_t ssl_test_tiny_key_slice_length(size_t slice_idx)
+{
+    switch (slice_idx) {
+        case 1: return SSL_TEST_KEY_SLICE_1_LENGTH;
+        case 2: return SSL_TEST_KEY_SLICE_2_LENGTH;
+        default: return 1;
+    }
+}
+
+/* In the below definition SSL_TEST_KEY_SLICE_1_LENGTH has 4 slots and
+ * SSL_TEST_KEY_SLICE_2_LENGTH has 10 all other slices have 1.
+ * psa_key_slot_volatile_slice_count() returns the total number of slices.
+ * However we have already countes slices 1 and 2, so we mustr subtract 2 from
+ * this number to avoid double counting.
+ */
+
+#define SSL_TEST_MAX_VOLATILE_KEYS                         \
+    (SSL_TEST_KEY_SLICE_1_LENGTH +                         \
+     SSL_TEST_KEY_SLICE_2_LENGTH +                         \
+     psa_key_slot_volatile_slice_count() - 2)
+#endif /* MBEDTLS_TEST_HOOKS && MBEDTLS_SSL_CLI_C */
+#else /* MBEDTLS_PSA_KEY_STORE_DYNAMIC */
+#define SSL_TEST_MAX_VOLATILE_KEYS MBEDTLS_PSA_KEY_SLOT_COUNT
+#endif /* MBEDTLS_PSA_KEY_STORE_DYNAMIC */
+
 #if (!defined(MBEDTLS_SSL_PROTO_TLS1_2)) && \
     defined(MBEDTLS_SSL_EARLY_DATA) && defined(MBEDTLS_SSL_CLI_C) && \
     defined(MBEDTLS_SSL_SRV_C) && defined(MBEDTLS_DEBUG_C) && \
@@ -2489,6 +2520,85 @@ exit:
 }
 /* END_CASE */
 
+/* BEGIN_CASE depends_on:MBEDTLS_SSL_PROTO_TLS1_3:MBEDTLS_SSL_CLI_C:SSL_TEST_MAX_VOLATILE_KEYS:MBEDTLS_PSA_CRYPTO_C */
+void ssl_tls13_populate_transform_second_key_import_failure(void)
+{
+    mbedtls_ssl_key_set traffic_keys;
+    mbedtls_ssl_transform transform;
+    mbedtls_svc_key_id_t *keys = NULL;
+    psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT;
+    mbedtls_psa_stats_t stats_before, stats_after;
+    psa_status_t status = PSA_SUCCESS;
+    size_t i = 0;
+
+    memset(&traffic_keys, 0, sizeof(traffic_keys));
+    mbedtls_ssl_transform_init(&transform);
+
+#if defined(MBEDTLS_PSA_KEY_STORE_DYNAMIC) && defined(MBEDTLS_TEST_HOOKS)
+    mbedtls_test_hook_psa_volatile_key_slice_length =
+        ssl_test_tiny_key_slice_length;
+#endif
+
+    PSA_INIT();
+    TEST_CALLOC(keys, SSL_TEST_MAX_VOLATILE_KEYS + 1);
+
+    psa_set_key_usage_flags(&attributes, PSA_KEY_USAGE_EXPORT);
+    psa_set_key_type(&attributes, PSA_KEY_TYPE_RAW_DATA);
+
+    /* Allow one more attempt than the maximum number of volatile keys so
+     * that the loop ends because the key store is full. */
+    while (i <= SSL_TEST_MAX_VOLATILE_KEYS) {
+        status = psa_import_key(&attributes,
+                                (const uint8_t *) &i, sizeof(i),
+                                &keys[i]);
+        if (status == PSA_ERROR_INSUFFICIENT_MEMORY) {
+            break;
+        }
+        PSA_ASSERT(status);
+        i++;
+    }
+    TEST_EQUAL(status, PSA_ERROR_INSUFFICIENT_MEMORY);
+    TEST_ASSERT(i > 0);
+
+    /* Leave exactly one slot free: the encryption key import consumes it,
+     * then the decryption key import fails. */
+    PSA_ASSERT(psa_destroy_key(keys[--i]));
+    keys[i] = MBEDTLS_SVC_KEY_ID_INIT;
+    mbedtls_psa_get_stats(&stats_before);
+
+    traffic_keys.key_len = 16;
+    traffic_keys.iv_len = 12;
+    TEST_ASSERT(mbedtls_ssl_tls13_populate_transform(
+                    &transform, MBEDTLS_SSL_IS_CLIENT,
+                    MBEDTLS_TLS1_3_AES_128_GCM_SHA256,
+                    &traffic_keys, NULL) != 0);
+
+    /* The first import must be rolled back when the second one fails. */
+    TEST_ASSERT(mbedtls_svc_key_id_is_null(transform.psa_key_enc));
+
+    /* Also check the key store itself: the failed operation must neither
+     * consume a slot nor leave the only free slot unusable. */
+    mbedtls_psa_get_stats(&stats_after);
+    TEST_EQUAL(stats_after.volatile_slots, stats_before.volatile_slots);
+    TEST_EQUAL(stats_after.empty_slots, stats_before.empty_slots);
+    PSA_ASSERT(psa_import_key(&attributes,
+                              (const uint8_t *) &i, sizeof(i),
+                              &keys[i]));
+    i++;
+
+exit:
+    mbedtls_ssl_transform_free(&transform);
+    while (i > 0) {
+        psa_destroy_key(keys[--i]);
+    }
+    mbedtls_free(keys);
+    PSA_DONE();
+#if defined(MBEDTLS_PSA_KEY_STORE_DYNAMIC) && defined(MBEDTLS_TEST_HOOKS)
+    mbedtls_test_hook_psa_volatile_key_slice_length = NULL;
+#endif
+}
+/* END_CASE */
+
 /* BEGIN_CASE depends_on:MBEDTLS_SSL_PROTO_TLS1_3 */
 void ssl_tls13_key_evolution(int hash_alg,
                              data_t *secret,