Merge branch 'bugfix/s2_gcm_hw' into 'master'

aes: Fixed tag sometime being wrong for HW GCM

See merge request espressif/esp-idf!8009

components/mbedtls/Kconfig

@@ -208,7 +208,7 @@ menu "mbedTLS"
     config MBEDTLS_HARDWARE_GCM
         bool "Enable partially hardware accelerated GCM"
         depends on IDF_TARGET_ESP32S2 && MBEDTLS_HARDWARE_AES
-        default n
+        default y
         help
             Enable partially hardware accelerated GCM. GHASH calculation is still done
             in software.

components/mbedtls/port/esp32s2/aes.c

@@ -345,7 +345,6 @@ static int esp_aes_process_dma_ext_ram(esp_aes_context *ctx, const unsigned char
     unsigned char *input_buf = NULL;
     unsigned char *output_buf = NULL;
     const unsigned char *dma_input;
-
     chunk_len = MIN(AES_MAX_CHUNK_WRITE_SIZE, len);
 
     if (realloc_input) {
@@ -1290,6 +1289,8 @@ void esp_aes_gcm_init( esp_gcm_context *ctx)
     }
 
     bzero(ctx, sizeof(esp_gcm_context));
+
+    ctx->gcm_state = ESP_AES_GCM_STATE_INIT;
 }
 
 /* Function to clear AES-GCM context */
@@ -1298,7 +1299,6 @@ void esp_aes_gcm_free( esp_gcm_context *ctx)
     if (ctx == NULL) {
         return;
     }
-
     bzero(ctx, sizeof(esp_gcm_context));
 }
 
@@ -1333,15 +1333,18 @@ int esp_aes_gcm_starts( esp_gcm_context *ctx,
         return -1;
     }
 
-
     /* Initialize AES-GCM context */
+    memset(ctx->ghash, 0, sizeof(ctx->ghash));
+    ctx->data_len = 0;
+
     ctx->iv = iv;
     ctx->iv_len = iv_len;
     ctx->aad = aad;
     ctx->aad_len = aad_len;
-    ctx->gcm_state = ESP_AES_GCM_STATE_INIT;
     ctx->mode = mode;
 
+    /* H and the lookup table are only generated once per ctx */
+    if (ctx->gcm_state == ESP_AES_GCM_STATE_INIT) {
         /* Lock the AES engine to calculate ghash key H in hardware */
         esp_aes_acquire_hardware();
         esp_aes_setkey_hardware( &ctx->aes_ctx, mode);
@@ -1354,7 +1357,11 @@ int esp_aes_gcm_starts( esp_gcm_context *ctx,
         memcpy(ctx->H, (uint8_t *)AES_H_BASE, AES_BLOCK_BYTES);
 
         esp_aes_release_hardware();
+
         gcm_gen_table(ctx);
+    }
+
+    ctx->gcm_state = ESP_AES_GCM_STATE_START;
 
     /* Once H is obtained we need to derive J0 (Initial Counter Block) */
     esp_gcm_derive_J0(ctx);
@@ -1367,7 +1374,6 @@ int esp_aes_gcm_starts( esp_gcm_context *ctx,
 
     esp_gcm_ghash(ctx, ctx->aad, ctx->aad_len, ctx->ghash);
 
-
     return ( 0 );
 }
 
@@ -1400,7 +1406,7 @@ int esp_aes_gcm_update( esp_gcm_context *ctx,
     /* If this is the first time esp_gcm_update is getting called
      * calculate GHASH on aad and preincrement the ICB
      */
-    if (ctx->gcm_state == ESP_AES_GCM_STATE_INIT) {
+    if (ctx->gcm_state == ESP_AES_GCM_STATE_START) {
         /* Jo needs to be incremented first time, later the CTR
          * operation will auto update it
          */
@@ -1410,20 +1416,23 @@ int esp_aes_gcm_update( esp_gcm_context *ctx,
         memcpy(nonce_counter, ctx->J0, AES_BLOCK_BYTES);
     }
 
+    /* Perform intermediate GHASH on "encrypted" data during decryption */
+    if (ctx->mode == ESP_AES_DECRYPT) {
+        esp_gcm_ghash(ctx, input, length, ctx->ghash);
+    }
+
     /* Output = GCTR(J0, Input): Encrypt/Decrypt the input */
     esp_aes_crypt_ctr(&ctx->aes_ctx, length, &nc_off, nonce_counter, stream, input, output);
+
     /* ICB gets auto incremented after GCTR operation here so update the context */
     memcpy(ctx->J0, nonce_counter, AES_BLOCK_BYTES);
 
     /* Keep updating the length counter for final tag calculation */
     ctx->data_len += length;
 
-    /* Perform intermediate GHASH on "encrypted" data irrespective of mode */
-    if (ctx->mode == ESP_AES_DECRYPT) {
-        esp_gcm_ghash(ctx, input, length, ctx->ghash);
-    } else {
+    /* Perform intermediate GHASH on "encrypted" data during encryption*/
+    if (ctx->mode == ESP_AES_ENCRYPT) {
         esp_gcm_ghash(ctx, output, length, ctx->ghash);
-
     }
 
     return 0;

components/mbedtls/port/include/esp32s2/gcm.h

@@ -36,6 +36,7 @@ extern "C" {
 
 typedef enum {
     ESP_AES_GCM_STATE_INIT,
+    ESP_AES_GCM_STATE_START,
     ESP_AES_GCM_STATE_UPDATE,
     ESP_AES_GCM_STATE_FINISH
 } esp_aes_gcm_state;

components/mbedtls/test/test_aes.c

@@ -547,6 +547,50 @@ void aes_psram_ctr_test(uint32_t input_buf_caps, uint32_t output_buf_caps)
     free(decryptedtext);
 }
 
+void aes_psram_one_buf_ctr_test(void)
+{
+    mbedtls_aes_context ctx;
+    uint8_t nonce[16];
+    uint8_t key[16];
+    uint8_t stream_block[16];
+    size_t SZ = 6000;
+    size_t ALIGNMENT_SIZE_BYTES = 16;
+    memset(nonce, 0x2F, 16);
+    memset(key, 0x1E, 16);
+
+    // allocate internal memory
+    uint8_t *buf = heap_caps_malloc(SZ + ALIGNMENT_SIZE_BYTES, MALLOC_CAP_SPIRAM);
+
+    TEST_ASSERT_NOT_NULL(buf);
+
+    mbedtls_aes_init(&ctx);
+    mbedtls_aes_setkey_enc(&ctx, key, 128);
+    memset(buf, 0x26, SZ + ALIGNMENT_SIZE_BYTES);
+
+    size_t offset;
+
+    /* Shift buffers and test for all different misalignments */
+    for (int i = 0; i < ALIGNMENT_SIZE_BYTES; i++ ) {
+        // Encrypt with input buffer in external ram
+        offset = 0;
+        memset(buf, 0x26, SZ + ALIGNMENT_SIZE_BYTES);
+        memset(nonce, 0x2F, 16);
+        mbedtls_aes_crypt_ctr(&ctx, SZ, &offset, nonce, stream_block, buf + i, buf + i);
+        TEST_ASSERT_EQUAL_HEX8_ARRAY(expected_cipher_psram_end, buf + i + SZ - 32, 32);
+
+        // Decrypt
+        offset = 0;
+        memset(nonce, 0x2F, 16);
+        // Decrypt with input buffer in instruction memory, the crypto DMA can't access this
+        mbedtls_aes_crypt_ctr(&ctx, SZ, &offset, nonce, stream_block, buf + i, buf);
+
+        TEST_ASSERT_EACH_EQUAL_HEX8(0x26, buf + i, SZ - i);
+
+    }
+    free(buf);
+}
+
+
 const uint8_t long_input[] = {
     0xf7, 0xe6, 0x6b, 0x8d, 0x2e, 0xbf, 0x88, 0xd6,
     0xb0, 0x77, 0xdf, 0x72, 0xbf, 0xa8, 0x0, 0x55,
@@ -1116,6 +1160,7 @@ TEST_CASE("mbedtls AES PSRAM tests", "[aes]")
     aes_psram_ctr_test(MALLOC_CAP_INTERNAL, MALLOC_CAP_SPIRAM);
     aes_psram_ctr_test(MALLOC_CAP_SPIRAM, MALLOC_CAP_INTERNAL);
     aes_psram_ctr_test(MALLOC_CAP_SPIRAM, MALLOC_CAP_SPIRAM);
+    aes_psram_one_buf_ctr_test();
 }
 
 /* Tests how crypto DMA handles data from iCache */
@@ -1131,3 +1176,69 @@ TEST_CASE("mbedtls AES GCM self-tests", "[aes]")
     TEST_ASSERT_FALSE_MESSAGE(mbedtls_gcm_self_test(1), "AES GCM self-test should pass.");
 }
 
+
+TEST_CASE("mbedtls AES GCM crypt-and-tag", "[aes]")
+{
+    const unsigned CALL_SZ = 32 * 1024;
+    mbedtls_gcm_context ctx;
+    unsigned char tag_buf[16];
+    mbedtls_cipher_id_t cipher = MBEDTLS_CIPHER_ID_AES;
+    uint8_t iv[16];
+    uint8_t key[16];
+
+    memset(iv, 0xEE, 16);
+    memset(key, 0x44, 16);
+
+    // allocate internal memory
+    uint8_t *buf = heap_caps_malloc(CALL_SZ, MALLOC_CAP_8BIT | MALLOC_CAP_INTERNAL);
+    TEST_ASSERT_NOT_NULL(buf);
+    uint8_t aad[16];
+    memset(aad, 0x22, 16);
+
+    mbedtls_gcm_init(&ctx);
+    mbedtls_gcm_setkey( &ctx, cipher, key, 128);
+
+    memset(buf, 0xAA, CALL_SZ);
+    mbedtls_gcm_crypt_and_tag(&ctx, MBEDTLS_AES_ENCRYPT, CALL_SZ, iv, sizeof(iv), aad, sizeof(aad), buf, buf, 16, tag_buf);
+
+
+    /* Sanity check: make sure the last ciphertext block matches
+       what we expect to see.
+
+       Last block and tag produced via this Python:
+
+        import os, binascii
+        from cryptography.hazmat.primitives.ciphers.aead import AESGCM
+
+        key = b'\x44' * 16
+        iv = b'\xEE' * 16
+        data = b'\xAA' * 100
+        aad = b'\x22 * 16
+
+        aesgcm = AESGCM(key)
+
+        ct = aesgcm.encrypt(iv, data, aad)
+    */
+    const uint8_t expected_last_block[] = {
+        0x7d, 0x3d, 0x16, 0x84, 0xd0, 0xb4, 0x38, 0x30,
+        0xd1, 0x24, 0x6f, 0x7e, 0x9a, 0x9c, 0x81, 0x58,
+    };
+
+    const uint8_t expected_tag[] = {
+        0x7e, 0x16, 0x04, 0x07, 0x4b, 0x7e, 0x6b, 0xf7,
+        0x5d, 0xce, 0x9e, 0x7d, 0x3f, 0x85, 0xc5, 0xa5,
+    };
+
+    TEST_ASSERT_EQUAL_HEX8_ARRAY(expected_last_block, buf + CALL_SZ - 16, 16);
+    TEST_ASSERT_EQUAL_HEX8_ARRAY(expected_tag, tag_buf, 16);
+
+
+    memset(iv, 0xEE, 16);
+
+    TEST_ASSERT_EQUAL(mbedtls_gcm_auth_decrypt(&ctx, CALL_SZ, iv, sizeof(iv), aad, sizeof(aad), expected_tag, sizeof(expected_tag), buf, buf), 0);
+    TEST_ASSERT_EACH_EQUAL_HEX8(0xAA, buf, CALL_SZ);
+
+
+    free(buf);
+}
+

tools/ci/config/target-test.yml

@@ -495,7 +495,7 @@ UT_034:
 
 UT_035:
   extends: .unit_test_s2_template
-  parallel: 29
+  parallel: 30
   tags:
     - ESP32S2_IDF
     - UT_T1_1