ota: store component hash as binary array

Component hash is received from the server as a hex string. Convert it to a
binary array when decoding the manifest so that it's ready to compare to a
locally generated hash.

Signed-off-by: Mike Szczys <[email protected]>

CHANGELOG.md

@@ -15,6 +15,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   include `block_buffer_len` for the actual length of data and
   `negotiated_block_size` to indicate the maximum block size (may be
   used along with 'block_idx' to calculate a byte offset).
+- `golioth_ota_component->hash` is now stored as an array of bytes
+  instead of as a hex string.
 
 ### Removed:
 

include/golioth/ota.h

@@ -22,8 +22,10 @@ extern "C"
 /// https://docs.golioth.io/reference/protocols/coap/ota
 /// @{
 
-/// Size of a SHA256 of Artifact Binary in bytes
-#define GOLIOTH_OTA_COMPONENT_HASH_LEN 64
+/// Size of a SHA256 of Artifact hex string in bytes
+#define GOLIOTH_OTA_COMPONENT_HEX_HASH_LEN 64
+/// Size of a SHA256 of Artifact bin array in bytes
+#define GOLIOTH_OTA_COMPONENT_BIN_HASH_LEN 32
 /// Maximum size of Binary Detected Type in bytes
 #define GOLIOTH_OTA_MAX_COMPONENT_BOOTLOADER_NAME_LEN 7
 /// Maximum size of Relative URI to download binary (+ 7 bytes for Path)
@@ -78,7 +80,7 @@ struct golioth_ota_component
     /// Size of the artifact, in bytes
     int32_t size;
     /// Artifact Hash
-    char hash[GOLIOTH_OTA_COMPONENT_HASH_LEN + 1];
+    uint8_t hash[GOLIOTH_OTA_COMPONENT_BIN_HASH_LEN];
     /// Artifact uri (e.g. "/.u/c/[email protected]")
     char uri[GOLIOTH_OTA_MAX_COMPONENT_URI_LEN + 1];
     /// Artifact bootloader ("mcuboot" or "default"")

src/ota.c

@@ -12,6 +12,7 @@
 #include "coap_blockwise.h"
 #include "coap_client.h"
 #include <golioth/golioth_debug.h>
+#include <golioth/golioth_sys.h>
 #include "golioth_util.h"
 #include <golioth/zcbor_utils.h>
 
@@ -216,9 +217,10 @@ static int components_decode(zcbor_state_t *zsd, void *value)
             component->version,
             sizeof(component->version) - 1,
         };
+        char hash_string[GOLIOTH_OTA_COMPONENT_HEX_HASH_LEN + 1];
         struct component_tstr_value hash = {
-            component->hash,
-            sizeof(component->hash) - 1,
+            hash_string,
+            sizeof(hash_string) - 1,
         };
         struct component_tstr_value uri = {
             component->uri,
@@ -248,6 +250,7 @@ static int components_decode(zcbor_state_t *zsd, void *value)
             return err;
         }
 
+        hex2bin(hash_string, strlen(hash_string), component->hash, sizeof(component->hash));
         component->size = component_size;
 
         manifest->num_components++;

tests/hil/tests/ota/test.c

@@ -32,10 +32,23 @@ struct golioth_client *client;
 
 static void log_component_members(const struct golioth_ota_component *component)
 {
+    char hash_string[GOLIOTH_OTA_COMPONENT_HEX_HASH_LEN + 1];
+    for (int i = 0; i < sizeof(component->hash); i++)
+    {
+        int write_idx = i * 2;
+        if (write_idx > (GOLIOTH_OTA_COMPONENT_HEX_HASH_LEN - 2))
+        {
+            GLTH_LOGE(TAG, "Error converting component hash to string");
+            return;
+        }
+
+        sprintf(hash_string + write_idx, "%02x", component->hash[i]);
+    }
+
     GLTH_LOGI(TAG, "component.package: %s", component->package);
     GLTH_LOGI(TAG, "component.version: %s", component->version);
     GLTH_LOGI(TAG, "component.size: %u", (unsigned int) component->size);
-    GLTH_LOGI(TAG, "component.hash: %s", component->hash);
+    GLTH_LOGI(TAG, "component.hash: %s", hash_string);
     GLTH_LOGI(TAG, "component.uri: %s", component->uri);
     GLTH_LOGI(TAG, "component.bootloader: %s", component->bootloader);
 }