Merge branch '7-list-ssh-keys-endpoint' into 'master'

Add endpoint for listing ssh keys

Closes #7

See merge request !4

src/api/ssh_keys_get.c

+/**
+ * Read the authorized_keys file of the initrd, and put its lines in a json
+ * array.
+ * @return json array of authorized_keys
+ */
+json_t * readAuthorizedKeysToJson()
+{
+    json_t * keys = json_object();
+
+    // Open file.
+    FILE * authorized_keys = fopen(AUTHORIZED_KEYS_PATH, "r");
+    // Check if that succeeded.
+    if (authorized_keys == NULL)
+    {
+        return NULL;
+    }
+
+    // Read file line by line.
+    int index = 1;
+    char * field;
+    char * line = NULL;
+    size_t line_length = 0;
+    ssize_t read;
+    while ((read = getline(&line, &line_length, authorized_keys)) != -1)
+    {
+        asprintf(&field, "%d", index);
+        // Remove trailing newline.
+        line[strcspn(line, "\n")] = 0;
+        json_object_set(keys, field, json_string(line));
+        ++index;
+    }
+
+    // Close file and clean up.
+    fclose(authorized_keys);
+    if (line)
+    {
+        free(line);
+    }
+
+    return keys;
+}
+
+/**
+ * Callback function that lists the current ssh keys authorised for access
+ * to the initrd.
+ *
+ * Example output:
+ * {"ssh-keys":{"1":"ssh-rsa AAAAB3... example@example.com",
+ * "2":"ssh-rsa AAAAB3...","5":"command=\"/usr/bin/cryptops-client\" ssh-rsa
+ *  AAAAB3... cryptops-test@greenhost"}}
+ *
+ * The indices correspond to line numbers of the authorized_keys file.
+ * Missing indices (like 3 and 4 in the example) arise from empty lines in the
+ * file; those are creted when keys are deleted.
+ *
+ * @param[in]   request   incoming HTTP request
+ * @param[out]  response  HTTP response to the request
+ * @param[in]   user_data extra data to pass between main thread and callbacks
+ * @return                internal status code
+ */
+int callback_ssh_keys_get(const struct _u_request * request,
+    struct _u_response * response, void * user_data)
+{
+    // Read lines of authorized_keys file into json array.
+    json_t * keys = readAuthorizedKeysToJson();
+    if (keys == NULL)
+    {
+        printf("Could not open authorized_keys file\n");
+        return send_simple_response(response, 500, "error",
+            "error reading authorized_keys");
+    }
+
+    // Create json response.
+    json_t * json_body = NULL;
+    json_body = json_object();
+    json_object_set_new(json_body, "ssh-keys", keys);
+
+    // Send response.
+    ulfius_set_json_body_response(response, 200, json_body);
+    json_decref(json_body);
+    return U_CALLBACK_CONTINUE;
+}

src/cryptops-api.c

@@ -8,6 +8,7 @@
 #include <api/default.c>
 #include <api/encryption_add.c>
 #include <api/encryption_unlock.c>
+#include <api/ssh_keys_get.c>
 
 int main(int argc, char ** argv)
 {
@@ -31,6 +32,8 @@ int main(int argc, char ** argv)
         0, &callback_encryption_add, NULL);
     ulfius_add_endpoint_by_val(&instance, "POST", PREFIX, "/encryption/unlock",
         0, &callback_encryption_unlock, NULL);
+    ulfius_add_endpoint_by_val(&instance, "GET" , PREFIX, "/ssh/keys",
+        0, &callback_ssh_keys_get, NULL);
 
     // Add default endpoint.
     ulfius_set_default_endpoint(&instance, &callback_default, NULL);

src/includes/settings.h

@@ -8,3 +8,5 @@
 #define UNENCRYPTED_MOUNTPOINT "/tmp/mnt-plain"
 #define ENCRYPTED_MOUNTPOINT "/tmp/mnt-encrypted"
 #define TMP_LOCATION "/tmp/" MAPPED_DEVICE_NAME
+#define AUTHORIZED_KEYS_DIR "/root/.ssh"
+#define AUTHORIZED_KEYS_PATH AUTHORIZED_KEYS_DIR "/authorized_keys"