u-boot: fit: add support to decrypt fit with aes
This commit add to u-boot the support to decrypt
fit image encrypted with aes. The FIT image contains
the key name and the IV name. Then u-boot look for
the key and IV in his device tree and decrypt images
before moving to the next stage.
Signed-off-by: Philippe Reynes <philippe.reynes@softathome.com>
diff --git a/common/image-cipher.c b/common/image-cipher.c
index ab8b45b..cee3b03 100644
--- a/common/image-cipher.c
+++ b/common/image-cipher.c
@@ -24,6 +24,7 @@
.calculate_type = EVP_aes_128_cbc,
#endif
.encrypt = image_aes_encrypt,
+ .decrypt = image_aes_decrypt,
.add_cipher_data = image_aes_add_cipher_data
},
{
@@ -34,6 +35,7 @@
.calculate_type = EVP_aes_192_cbc,
#endif
.encrypt = image_aes_encrypt,
+ .decrypt = image_aes_decrypt,
.add_cipher_data = image_aes_add_cipher_data
},
{
@@ -44,6 +46,7 @@
.calculate_type = EVP_aes_256_cbc,
#endif
.encrypt = image_aes_encrypt,
+ .decrypt = image_aes_decrypt,
.add_cipher_data = image_aes_add_cipher_data
}
};
@@ -61,3 +64,104 @@
return NULL;
}
+
+static int fit_image_setup_decrypt(struct image_cipher_info *info,
+ const void *fit, int image_noffset,
+ int cipher_noffset)
+{
+ const void *fdt = gd_fdt_blob();
+ const char *node_name;
+ char node_path[128];
+ int noffset;
+ char *algo_name;
+ int ret;
+
+ node_name = fit_get_name(fit, image_noffset, NULL);
+ if (!node_name) {
+ printf("Can't get node name\n");
+ return -1;
+ }
+
+ if (fit_image_cipher_get_algo(fit, cipher_noffset, &algo_name)) {
+ printf("Can't get algo name for cipher '%s' in image '%s'\n",
+ node_name, node_name);
+ return -1;
+ }
+
+ info->keyname = fdt_getprop(fit, cipher_noffset, "key-name-hint", NULL);
+ if (!info->keyname) {
+ printf("Can't get key name\n");
+ return -1;
+ }
+
+ info->ivname = fdt_getprop(fit, cipher_noffset, "iv-name-hint", NULL);
+ if (!info->ivname) {
+ printf("Can't get IV name\n");
+ return -1;
+ }
+
+ info->fit = fit;
+ info->node_noffset = image_noffset;
+ info->name = algo_name;
+ info->cipher = image_get_cipher_algo(algo_name);
+ if (!info->cipher) {
+ printf("Can't get cipher\n");
+ return -1;
+ }
+
+ ret = fit_image_get_data_size_unciphered(fit, image_noffset,
+ &info->size_unciphered);
+ if (ret) {
+ printf("Can't get size of unciphered data\n");
+ return -1;
+ }
+
+ /*
+ * Search the cipher node in the u-boot fdt
+ * the path should be: /cipher/key-<algo>-<key>-<iv>
+ */
+ snprintf(node_path, sizeof(node_path), "/%s/key-%s-%s-%s",
+ FIT_CIPHER_NODENAME, algo_name, info->keyname, info->ivname);
+
+ noffset = fdt_path_offset(fdt, node_path);
+ if (noffset < 0) {
+ printf("Can't found cipher node offset\n");
+ return -1;
+ }
+
+ /* read key */
+ info->key = fdt_getprop(fdt, noffset, "key", NULL);
+ if (!info->key) {
+ printf("Can't get key in cipher node '%s'\n", node_path);
+ return -1;
+ }
+
+ /* read iv */
+ info->iv = fdt_getprop(fdt, noffset, "iv", NULL);
+ if (!info->iv) {
+ printf("Can't get IV in cipher node '%s'\n", node_path);
+ return -1;
+ }
+
+ return 0;
+}
+
+int fit_image_decrypt_data(const void *fit,
+ int image_noffset, int cipher_noffset,
+ const void *data_ciphered, size_t size_ciphered,
+ void **data_unciphered, size_t *size_unciphered)
+{
+ struct image_cipher_info info;
+ int ret;
+
+ ret = fit_image_setup_decrypt(&info, fit, image_noffset,
+ cipher_noffset);
+ if (ret < 0)
+ goto out;
+
+ ret = info.cipher->decrypt(&info, data_ciphered, size_ciphered,
+ data_unciphered, size_unciphered);
+
+ out:
+ return ret;
+}
diff --git a/common/image-fit.c b/common/image-fit.c
index 6b50ceb..f3bb00c 100644
--- a/common/image-fit.c
+++ b/common/image-fit.c
@@ -948,6 +948,31 @@
}
/**
+ * Get 'data-size-unciphered' property from a given image node.
+ *
+ * @fit: pointer to the FIT image header
+ * @noffset: component image node offset
+ * @data_size: holds the data-size property
+ *
+ * returns:
+ * 0, on success
+ * -ENOENT if the property could not be found
+ */
+int fit_image_get_data_size_unciphered(const void *fit, int noffset,
+ size_t *data_size)
+{
+ const fdt32_t *val;
+
+ val = fdt_getprop(fit, noffset, "data-size-unciphered", NULL);
+ if (!val)
+ return -ENOENT;
+
+ *data_size = (size_t)fdt32_to_cpu(*val);
+
+ return 0;
+}
+
+/**
* fit_image_get_data_and_size - get data and its size including
* both embedded and external data
* @fit: pointer to the FIT format image header
@@ -1381,6 +1406,32 @@
return 1;
}
+#ifdef CONFIG_FIT_CIPHER
+static int fit_image_uncipher(const void *fit, int image_noffset,
+ void **data, size_t *size)
+{
+ int cipher_noffset, ret;
+ void *dst;
+ size_t size_dst;
+
+ cipher_noffset = fdt_subnode_offset(fit, image_noffset,
+ FIT_CIPHER_NODENAME);
+ if (cipher_noffset < 0)
+ return 0;
+
+ ret = fit_image_decrypt_data(fit, image_noffset, cipher_noffset,
+ *data, *size, &dst, &size_dst);
+ if (ret)
+ goto out;
+
+ *data = dst;
+ *size = size_dst;
+
+ out:
+ return ret;
+}
+#endif /* CONFIG_FIT_CIPHER */
+
/**
* fit_image_check_os - check whether image node is of a given os type
* @fit: pointer to the FIT format image header
@@ -1981,6 +2032,18 @@
return -ENOENT;
}
+#ifdef CONFIG_FIT_CIPHER
+ /* Decrypt data before uncompress/move */
+ if (IMAGE_ENABLE_DECRYPT) {
+ puts(" Decrypting Data ... ");
+ if (fit_image_uncipher(fit, noffset, &buf, &size)) {
+ puts("Error\n");
+ return -EACCES;
+ }
+ puts("OK\n");
+ }
+#endif
+
#if !defined(USE_HOSTCC) && defined(CONFIG_FIT_IMAGE_POST_PROCESS)
/* perform any post-processing on the image data */
board_fit_image_post_process(&buf, &size);