log a masked structural diagnostic when a Codex restore throws, and strip bucket padding in the browser-slot and root-key paths

@@ -3,6 +3,8 @@33 import android.content.Context44 import android.net.Uri55 import androidx.core.content.FileProvider6+import android.util.Log7+import com.peachpasswords.BuildConfig68 import androidx.lifecycle.ViewModel79 import androidx.lifecycle.viewModelScope810 import androidx.camera.core.ImageProxy@@ -182,12 +184,23 @@182184         viewModelScope.launch {183185             when (val r = vault.restoreFromCodex(payload.vaultBlob, password)) {184186                 is UnlockResult.Success -> { _restore.value = RestoreState.Restored; onDone() }185-                is UnlockResult.WrongPassword -> _restore.value = RestoreState.Error(186-                    codexRestoreErrorMessage(CodexErrorCode.RESTORE_FAILED, "WRONG_PASSPHRASE"),187-                )188-                is UnlockResult.Error -> _restore.value = RestoreState.Error(189-                    codexRestoreErrorMessage(CodexErrorCode.RESTORE_FAILED, r.reason),190-                )187+                is UnlockResult.WrongPassword -> {188+                    // The three outcomes below look nearly identical on screen but189+                    // mean completely different things (bad password vs. a slot190+                    // shape neither reader understands). Codex screens are191+                    // FLAG_SECURE, so a screenshot can't be used to tell them192+                    // apart — this line is the only way to see which one happened.193+                    if (BuildConfig.DEBUG) Log.w("PeachCodex", "restore rejected: WRONG_PASSPHRASE")194+                    _restore.value = RestoreState.Error(195+                        codexRestoreErrorMessage(CodexErrorCode.RESTORE_FAILED, "WRONG_PASSPHRASE"),196+                    )197+                }198+                is UnlockResult.Error -> {199+                    if (BuildConfig.DEBUG) Log.w("PeachCodex", "restore failed: ${r.reason}")200+                    _restore.value = RestoreState.Error(201+                        codexRestoreErrorMessage(CodexErrorCode.RESTORE_FAILED, r.reason),202+                    )203+                }191204             }192205         }193206     }

@@ -71,9 +71,17 @@7171             } catch (_: Exception) {7272                 return null7373             }74-            // The browser pads its plaintext to a size bucket with trailing75-            // SPACES; Android pads with NUL, so VaultCodec's own trim misses it.76-            val plain = payloadJson.toString(Charsets.UTF_8).trim()74+            // The browser pads its plaintext up to a size bucket with ZERO75+            // BYTES (`padToNearestBucket` in peachPayload.ts — "zero-filled in76+            // the padding region"), to stop file size leaking vault size.77+            //78+            // This said "trailing SPACES" and used a plain trim(), which only79+            // strips whitespace — and NUL is not whitespace to Kotlin. So the80+            // padding survived and JSON parsing died the moment the real81+            // payload ended, reporting an offset equal to the payload's own82+            // length. It looked like a corrupt Codex; the vault was fine and83+            // the password was right.84+            val plain = payloadJson.toString(Charsets.UTF_8).trimBucketPadding()7785             val payload = VaultCodec.decode(plain.toByteArray(Charsets.UTF_8))7886 7987             val rootKey = unwrapRootKey(browser, key)@@ -104,7 +112,7 @@104112                 derivedKey,105113                 VaultCrypto.AAD_ROOT_KEY,106114             )107-            unhex(hexBytes.toString(Charsets.UTF_8))115+            unhex(hexBytes.toString(Charsets.UTF_8).trimBucketPadding())108116         }.getOrNull()109117     }110118 @@ -137,3 +145,10 @@137145 138146     private fun b64(b: ByteArray): String = Base64.getEncoder().encodeToString(b)139147 }148+149+/**150+ * Strip the browser's size-bucket padding: zero bytes, plus any surrounding151+ * whitespace. `String.trim()` alone is not enough — `Char.isWhitespace()` is152+ * false for NUL, so the padding sails straight into the JSON parser.153+ */154+private fun String.trimBucketPadding(): String = trim { it == '\u0000' || it.isWhitespace() }

@@ -8,6 +8,8 @@88 import java.security.SecureRandom99 import java.text.Normalizer1010 import kotlinx.serialization.json.Json11+import android.util.Log12+import com.peachpasswords.BuildConfig1113 import kotlinx.serialization.json.JsonElement1214 import kotlinx.serialization.json.JsonNull1315 import kotlinx.serialization.json.JsonObject@@ -144,9 +146,45 @@144146             store.stampLocalMutation()145147             unlockLocked(password)146148         } catch (e: Exception) {149+            // A raw kotlinx parse error ("Unexpected JSON token at offset N")150+            // reaching the user says nothing about WHICH json failed — the151+            // wrapper, or the payload decrypted out of it. Codex screens are152+            // FLAG_SECURE so this can't be screenshotted either. Debug builds153+            // log the structure around the failure; alphanumerics are masked so154+            // no ciphertext or vault content lands in a log.155+            if (BuildConfig.DEBUG) Log.w("PeachCodex", codexFailureShape(vaultBlobBase64, e))147156             UnlockResult.Error(e.message ?: "restore_failed")148157         }149158     }159+160+    /** Debug-only: structure of a failed Codex restore, with content masked. */161+    private fun codexFailureShape(vaultBlobBase64: String, e: Exception): String = runCatching {162+        val wrapperJson = String(Base64.getUrlDecoder().decode(vaultBlobBase64), Charsets.UTF_8)163+        val offset = Regex("offset (\\d+)").find(e.message.orEmpty())?.groupValues?.get(1)?.toIntOrNull()164+        val window = offset?.let {165+            val from = (it - 40).coerceAtLeast(0)166+            val to = (it + 40).coerceAtMost(wrapperJson.length)167+            wrapperJson.substring(from, to).replace(Regex("[A-Za-z0-9+/=_-]"), "x")168+        }169+        val wrapper = runCatching { CodexJson.parseToJsonElement(wrapperJson) as? JsonObject }.getOrNull()170+        val slot = wrapper?.get("a")171+        buildString {172+            append("codex restore failed: ").append(e::class.simpleName).append(": ").append(e.message)173+            append(" | blobBase64=").append(vaultBlobBase64.length)174+            append(" wrapperChars=").append(wrapperJson.length)175+            append(" wrapperParses=").append(wrapper != null)176+            append(" keys=").append(wrapper?.keys)177+            append(" slotAKind=").append(178+                when {179+                    slot == null -> "absent"180+                    slot is JsonPrimitive && slot.isString -> "string"181+                    slot is JsonObject -> "object:" + slot.keys182+                    else -> slot::class.simpleName183+                },184+            )185+            if (window != null) append(" masked@").append(offset).append("=").append(window)186+        }187+    }.getOrElse { "codex restore failed: ${e.message} (shape unavailable: $it)" }150188 151189     suspend fun createVault(password: String): CreateVaultResult = mutex.withLock {152190         return try {