refactor(bootloader_support): Unify bootloader_sha layer

2025-03-20 17:06:41 +05:30
parent ce7ec7f19f
commit a02dec09ca
14 changed files with 93 additions and 536 deletions
@@ -0,0 +1,202 @@
+/*
+ * SPDX-FileCopyrightText: 2025 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <assert.h>
+#include <stdbool.h>
+#include <string.h>
+#include <sys/param.h>
+
+#include "bootloader_sha.h"
+#include "soc/soc_caps.h"
+#include "rom/sha.h"
+#include "sdkconfig.h"
+
+#if NON_OS_BUILD || CONFIG_APP_BUILD_TYPE_RAM
+#if !CONFIG_IDF_TARGET_ESP32
+static SHA_CTX ctx;
+
+bootloader_sha256_handle_t bootloader_sha256_start()
+{
+    // Enable SHA hardware
+    ets_sha_enable();
+    ets_sha_init(&ctx, SHA2_256);
+    return &ctx; // Meaningless non-NULL value
+}
+
+void bootloader_sha256_data(bootloader_sha256_handle_t handle, const void *data, size_t data_len)
+{
+    assert(handle != NULL);
+
+#if !SOC_SECURE_BOOT_V2_ECC
+    /* For secure boot, the key field consists of 1 byte of curve identifier and 64 bytes of ECDSA public key.
+     * While verifying the signature block, we need to calculate the SHA of this key field which is of 65 bytes.
+     * ets_sha_update handles it cleanly so we can safely remove the check:
+     */
+    assert(data_len % 4 == 0);
+#endif /* SOC_SECURE_BOOT_V2_ECC */
+
+    ets_sha_update(&ctx, data, data_len, false);
+}
+
+void bootloader_sha256_finish(bootloader_sha256_handle_t handle, uint8_t *digest)
+{
+    assert(handle != NULL);
+
+    if (digest == NULL) {
+        bzero(&ctx, sizeof(ctx));
+        return;
+    }
+    ets_sha_finish(&ctx, digest);
+}
+#else /* !CONFIG_IDF_TARGET_ESP32 */
+
+#include "soc/dport_reg.h"
+#include "soc/hwcrypto_periph.h"
+
+static uint32_t words_hashed;
+
+// Words per SHA256 block
+static const size_t BLOCK_WORDS = (64 / sizeof(uint32_t));
+// Words in final SHA256 digest
+static const size_t DIGEST_WORDS = (32 / sizeof(uint32_t));
+
+bootloader_sha256_handle_t bootloader_sha256_start(void)
+{
+    // Enable SHA hardware
+    ets_sha_enable();
+    words_hashed = 0;
+    return (bootloader_sha256_handle_t)&words_hashed; // Meaningless non-NULL value
+}
+
+void bootloader_sha256_data(bootloader_sha256_handle_t handle, const void *data, size_t data_len)
+{
+    assert(handle != NULL);
+    assert(data_len % 4 == 0);
+
+    const uint32_t *w = (const uint32_t *)data;
+    size_t word_len = data_len / 4;
+    uint32_t *sha_text_reg = (uint32_t *)(SHA_TEXT_BASE);
+
+    while (word_len > 0) {
+        size_t block_count = words_hashed % BLOCK_WORDS;
+        size_t copy_words = (BLOCK_WORDS - block_count);
+
+        copy_words = MIN(word_len, copy_words);
+
+        // Wait for SHA engine idle
+        while (_DPORT_REG_READ(SHA_256_BUSY_REG) != 0) { }
+
+        // Copy to memory block
+        for (size_t i = 0; i < copy_words; i++) {
+            sha_text_reg[block_count + i] = __builtin_bswap32(w[i]);
+        }
+        asm volatile ("memw");
+
+        // Update counters
+        words_hashed += copy_words;
+        block_count += copy_words;
+        word_len -= copy_words;
+        w += copy_words;
+
+        // If we loaded a full block, run the SHA engine
+        if (block_count == BLOCK_WORDS) {
+            if (words_hashed == BLOCK_WORDS) {
+                _DPORT_REG_WRITE(SHA_256_START_REG, 1);
+            } else {
+                _DPORT_REG_WRITE(SHA_256_CONTINUE_REG, 1);
+            }
+            block_count = 0;
+        }
+    }
+}
+
+void bootloader_sha256_finish(bootloader_sha256_handle_t handle, uint8_t *digest)
+{
+    assert(handle != NULL);
+
+    if (digest == NULL) {
+        return; // We'd free resources here, but there are none to free
+    }
+
+    uint32_t data_words = words_hashed;
+
+    // Pad to a 55 byte long block loaded in the engine
+    // (leaving 1 byte 0x80 plus variable padding plus 8 bytes of length,
+    // to fill a 64 byte block.)
+    int block_bytes = (words_hashed % BLOCK_WORDS) * 4;
+    int pad_bytes = 55 - block_bytes;
+    if (pad_bytes < 0) {
+        pad_bytes += 64;
+    }
+    static const uint8_t padding[64] = { 0x80, 0, };
+
+    pad_bytes += 5; // 1 byte for 0x80 plus first 4 bytes of the 64-bit length
+    assert(pad_bytes % 4 == 0); // should be, as (block_bytes % 4 == 0)
+
+    bootloader_sha256_data(handle, padding, pad_bytes);
+
+    assert(words_hashed % BLOCK_WORDS == 60 / 4); // 32-bits left in block
+
+    // Calculate 32-bit length for final 32 bits of data
+    uint32_t bit_count = __builtin_bswap32( data_words * 32 );
+    bootloader_sha256_data(handle, &bit_count, sizeof(bit_count));
+
+    assert(words_hashed % BLOCK_WORDS == 0);
+
+    while (_DPORT_REG_READ(SHA_256_BUSY_REG) == 1) { }
+    _DPORT_REG_WRITE(SHA_256_LOAD_REG, 1);
+    while (_DPORT_REG_READ(SHA_256_BUSY_REG) == 1) { }
+
+    uint32_t *digest_words = (uint32_t *)digest;
+    uint32_t *sha_text_reg = (uint32_t *)(SHA_TEXT_BASE);
+    for (size_t i = 0; i < DIGEST_WORDS; i++) {
+        digest_words[i] = __builtin_bswap32(sha_text_reg[i]);
+    }
+    asm volatile ("memw");
+}
+#endif /* CONFIG_IDF_TARGET_ESP32 */
+#else /* NON_OS_BUILD || CONFIG_APP_BUILD_TYPE_RAM */
+
+#include "bootloader_flash_priv.h"
+#include <mbedtls/sha256.h>
+
+bootloader_sha256_handle_t bootloader_sha256_start(void)
+{
+    mbedtls_sha256_context *ctx = (mbedtls_sha256_context *)malloc(sizeof(mbedtls_sha256_context));
+    if (!ctx) {
+        return NULL;
+    }
+    mbedtls_sha256_init(ctx);
+    int ret = mbedtls_sha256_starts(ctx, false);
+    if (ret != 0) {
+        return NULL;
+    }
+    return ctx;
+}
+
+void bootloader_sha256_data(bootloader_sha256_handle_t handle, const void *data, size_t data_len)
+{
+    assert(handle != NULL);
+    mbedtls_sha256_context *ctx = (mbedtls_sha256_context *)handle;
+    int ret = mbedtls_sha256_update(ctx, data, data_len);
+    assert(ret == 0);
+    (void)ret;
+}
+
+void bootloader_sha256_finish(bootloader_sha256_handle_t handle, uint8_t *digest)
+{
+    assert(handle != NULL);
+    mbedtls_sha256_context *ctx = (mbedtls_sha256_context *)handle;
+    if (digest != NULL) {
+        int ret = mbedtls_sha256_finish(ctx, digest);
+        assert(ret == 0);
+        (void)ret;
+    }
+    mbedtls_sha256_free(ctx);
+    free(handle);
+    handle = NULL;
+}
+#endif /* !(NON_OS_BUILD || CONFIG_APP_BUILD_TYPE_RAM) */