1 files changed, 28 insertions, 14 deletions

diff --git a/modules/ext/cryptogzip.js b/modules/ext/cryptogzip.js
index cc275df..25b6ca4 100644
--- a/modules/ext/cryptogzip.js
+++ b/modules/ext/cryptogzip.js
@@ -190,8 +190,31 @@ class CryptoGzipModule {
         for (let i = 0; i < bytes.length; i++) s += String.fromCharCode(bytes[i]);
         return btoa(s);
     }
+    // Validate before atob(): atob() throws a raw DOMException (InvalidCharacterError / "characters
+    // outside of the Latin1 range") for arbitrary input, which escaped as an unhandledrejection when
+    // called from the node/JS console (RPT-20261102-203616-e2641bff). Everything atob() would reject
+    // is rejected here first, as a plain Error the command wrappers can print.
+    _base64InvalidReason(s) {
+        if (typeof s !== 'string') return 'expected a string, got ' + (s === null ? 'null' : typeof s);
+        const t = s.replace(/[\t\n\f\r ]/g, '');   // atob() ignores exactly these ASCII whitespace chars
+        if (t.length === 0) return null;           // atob('') === '' — keep the empty case working
+        if (!/^[A-Za-z0-9+/]*={0,2}$/.test(t)) {
+            const bad = t.match(/[^A-Za-z0-9+/=]/);
+            if (bad) return 'illegal character ' + JSON.stringify(bad[0]) + ' — expected A-Z a-z 0-9 + / =';
+            return 'misplaced or excessive "=" padding';
+        }
+        const rem = t.length % 4;
+        if (rem === 1) return 'length ' + t.length + ' is not a valid base64 length';
+        // Padding may be omitted (atob accepts that too), but when present the length must be a
+        // multiple of 4 — otherwise atob() throws "not correctly encoded".
+        if (t.indexOf('=') !== -1 && rem !== 0) return 'length ' + t.length + ' has incomplete "=" padding';
+        return null;
+    }
+    _isBase64(s) { return this._base64InvalidReason(s) === null; }
     _base64ToBytes(b64) {
-        const s = atob(b64);
+        const reason = this._base64InvalidReason(b64);
+        if (reason) throw new Error('not valid base64 input (' + reason + ')');
+        const s = atob(b64.replace(/[\t\n\f\r ]/g, ''));
         const u8 = new Uint8Array(s.length);
         for (let i = 0; i < s.length; i++) u8[i] = s.charCodeAt(i);
         return u8;
@@ -582,19 +605,10 @@ class CryptoGzipModule {
     }
 
     // ============================================================
-    // Base64 Helpers
-    // ============================================================
-
-    _bytesToBase64(bytes) {
-        const bin = Array.from(bytes, (b) => String.fromCharCode(b)).join('');
-        return btoa(bin);
-    }
-
-    _base64ToBytes(b64) {
-        const bin = atob(b64);
-        return Uint8Array.from(bin, (c) => c.charCodeAt(0));
-    }
-
+    // Base64 Helpers — defined once, above, next to the gzip code.
+    // (A second, later copy of _bytesToBase64/_base64ToBytes used to
+    // live here and silently shadow the first; it carried the unguarded
+    // atob() call. Do not re-add a duplicate.)
     // ============================================================
 
     registerCommands() {