added "DB dump" tool, WIP

dump-db/inc/decrypt.js

@@ -0,0 +1,79 @@
+import crypto from "crypto";
+
+function decryptString(dataKey, cipherText) {
+    const buffer = decrypt(dataKey, cipherText);
+
+    if (buffer === null) {
+        return null;
+    }
+
+    const str = buffer.toString('utf-8');
+
+    if (str === 'false') {
+        throw new Error("Could not decrypt string.");
+    }
+
+    return str;
+}
+
+function decrypt(key, cipherText, ivLength = 13) {
+    if (cipherText === null) {
+        return null;
+    }
+
+    if (!key) {
+        return "[protected]";
+    }
+
+    try {
+        const cipherTextBufferWithIv = Buffer.from(cipherText.toString(), 'base64');
+        const iv = cipherTextBufferWithIv.slice(0, ivLength);
+
+        const cipherTextBuffer = cipherTextBufferWithIv.slice(ivLength);
+
+        const decipher = crypto.createDecipheriv('aes-128-cbc', pad(key), pad(iv));
+
+        const decryptedBytes = Buffer.concat([decipher.update(cipherTextBuffer), decipher.final()]);
+
+        const digest = decryptedBytes.slice(0, 4);
+        const payload = decryptedBytes.slice(4);
+
+        const computedDigest = shaArray(payload).slice(0, 4);
+
+        if (!arraysIdentical(digest, computedDigest)) {
+            return false;
+        }
+
+        return payload;
+    }
+    catch (e) {
+        // recovery from https://github.com/zadam/trilium/issues/510
+        if (e.message && e.message.includes("WRONG_FINAL_BLOCK_LENGTH")) {
+            log.info("Caught WRONG_FINAL_BLOCK_LENGTH, returning cipherText instead");
+
+            return cipherText;
+        }
+        else {
+            throw e;
+        }
+    }
+}
+
+function arraysIdentical(a, b) {
+    let i = a.length;
+    if (i !== b.length) return false;
+    while (i--) {
+        if (a[i] !== b[i]) return false;
+    }
+    return true;
+}
+
+function shaArray(content) {
+    // we use this as simple checksum and don't rely on its security so SHA-1 is good enough
+    return crypto.createHash('sha1').update(content).digest();
+}
+
+module.exports = {
+    decrypt,
+    decryptString
+};