commit 0e5e1a9fc6f8757ee3339ed716f4a38a4b1729e1
author David Vincze <david.vincze@arm.com> Fri Jul 26 11:04:47 2024 +0200
committer Dávid Vincze <david.vincze@arm.com> Wed Jul 31 16:55:55 2024 +0200
tree 82394dd1fd8b4d11d8e101de8a2b778c6689ef52
parent ef598b13b5537ae61610646f0c8425c4b9244ee9

Reapply "boot: Add MCUBOOT_HW_KEY support for image encryption"

This reverts commit c06f7bb36782e0220b30c3d0640219d1368735d3.

Signed-off-by: David Vincze <david.vincze@arm.com>
Change-Id: Ic2ab2c4d3981dec3cd3c25a50b5a989000375372

boot/bootutil/include/bootutil/enc_key.h

diff --git a/boot/bootutil/include/bootutil/enc_key.h b/boot/bootutil/include/bootutil/enc_key.h
index 8db6e72..297381f 100644
--- a/boot/bootutil/include/bootutil/enc_key.h
+++ b/boot/bootutil/include/bootutil/enc_key.h
@@ -32,6 +32,7 @@
 #include <flash_map_backend/flash_map_backend.h>
 #include "bootutil/crypto/aes_ctr.h"
 #include "bootutil/image.h"
+#include "bootutil/sign_key.h"
 #include "bootutil/enc_key_public.h"
 
 #ifdef __cplusplus
@@ -45,7 +46,17 @@
     bootutil_aes_ctr_context aes_ctr;
 };
 
-extern const struct bootutil_key bootutil_enc_key;
+/**
+ * Retrieve the private key for image encryption.
+ *
+ * @param[out]  private_key  structure to store the private key and
+ *                           its length.
+ *
+ * @return                   0 on success; nonzero on failure.
+ *
+ */
+int boot_enc_retrieve_private_key(struct bootutil_key **private_key);
+
 struct boot_status;
 
 /* Decrypt random, symmetric encryption key */

boot/bootutil/src/encrypted.c

diff --git a/boot/bootutil/src/encrypted.c b/boot/bootutil/src/encrypted.c
index f3516ac..ea73b17 100644
--- a/boot/bootutil/src/encrypted.c
+++ b/boot/bootutil/src/encrypted.c
@@ -67,13 +67,13 @@
 
 #if defined(MCUBOOT_ENCRYPT_KW)
 static int
-key_unwrap(const uint8_t *wrapped, uint8_t *enckey)
+key_unwrap(const uint8_t *wrapped, uint8_t *enckey, struct bootutil_key *bootutil_enc_key)
 {
     bootutil_aes_kw_context aes_kw;
     int rc;
 
     bootutil_aes_kw_init(&aes_kw);
-    rc = bootutil_aes_kw_set_unwrap_key(&aes_kw, bootutil_enc_key.key, *bootutil_enc_key.len);
+    rc = bootutil_aes_kw_set_unwrap_key(&aes_kw, bootutil_enc_key->key, *bootutil_enc_key->len);
     if (rc != 0) {
         goto done;
     }
@@ -441,13 +441,23 @@
     uint8_t counter[BOOTUTIL_CRYPTO_AES_CTR_BLOCK_SIZE];
     uint16_t len;
 #endif
+    struct bootutil_key *bootutil_enc_key = NULL;
     int rc = -1;
 
+    rc = boot_enc_retrieve_private_key(&bootutil_enc_key);
+    if (rc) {
+        return rc;
+    }
+
+    if (bootutil_enc_key == NULL) {
+        return rc;
+    }
+
 #if defined(MCUBOOT_ENCRYPT_RSA)
 
     bootutil_rsa_init(&rsa);
-    cp = (uint8_t *)bootutil_enc_key.key;
-    cpend = cp + *bootutil_enc_key.len;
+    cp = (uint8_t *)bootutil_enc_key->key;
+    cpend = cp + *bootutil_enc_key->len;
 
     /* The enckey is encrypted through RSA so for decryption we need the private key */
     rc = bootutil_rsa_parse_private_key(&rsa, &cp, cpend);
@@ -466,15 +476,15 @@
 
 #if defined(MCUBOOT_ENCRYPT_KW)
 
-    assert(*bootutil_enc_key.len == BOOT_ENC_KEY_SIZE);
-    rc = key_unwrap(buf, enckey);
+    assert(*bootutil_enc_key->len == BOOT_ENC_KEY_SIZE);
+    rc = key_unwrap(buf, enckey, bootutil_enc_key);
 
 #endif /* defined(MCUBOOT_ENCRYPT_KW) */
 
 #if defined(MCUBOOT_ENCRYPT_EC256)
 
-    cp = (uint8_t *)bootutil_enc_key.key;
-    cpend = cp + *bootutil_enc_key.len;
+    cp = (uint8_t *)bootutil_enc_key->key;
+    cpend = cp + *bootutil_enc_key->len;
 
     /*
      * Load the stored EC256 decryption private key
@@ -500,8 +510,8 @@
 
 #if defined(MCUBOOT_ENCRYPT_X25519)
 
-    cp = (uint8_t *)bootutil_enc_key.key;
-    cpend = cp + *bootutil_enc_key.len;
+    cp = (uint8_t *)bootutil_enc_key->key;
+    cpend = cp + *bootutil_enc_key->len;
 
     /*
      * Load the stored X25519 decryption private key