Fix compressed BLE file transfers

bitchat/Protocols/BinaryProtocol.swift

@@ -320,8 +320,8 @@ struct BinaryProtocol {
                     guard let rawSize = read16() else { return nil }
                     originalSize = Int(rawSize)
                 }
-                // Guard to keep decompression bounded (1 MiB ceiling aligns with previous behaviour)
-                guard originalSize >= 0 && originalSize <= 1_048_576 else { return nil }
+                // Guard to keep decompression bounded to sane BLE payload limits
+                guard originalSize >= 0 && originalSize <= FileTransferLimits.maxPayloadBytes else { return nil }
                 let compressedSize = payloadLength - lengthFieldBytes
                 guard compressedSize >= 0, let compressed = readData(compressedSize) else { return nil }
                 guard let decompressed = CompressionUtil.decompress(compressed, originalSize: originalSize),

bitchat/Services/BLEService.swift

@@ -26,7 +26,9 @@ struct NotificationStreamAssembler {
         var reset = false
         let maxFrameLength = TransportConfig.bleNotificationAssemblerHardCapBytes
 
-        while buffer.count >= BinaryProtocol.v1HeaderSize + BinaryProtocol.senderIDSize {
+        let minimumFramePrefix = BinaryProtocol.v1HeaderSize + BinaryProtocol.senderIDSize
+
+        while buffer.count >= minimumFramePrefix {
             guard let version = buffer.first else { break }
             guard version == 1 || version == 2 else {
                 dropped.append(buffer.removeFirst())
@@ -41,10 +43,13 @@ struct NotificationStreamAssembler {
             }
             guard buffer.count >= framePrefix else { break }
 
-            let flagsIndex = buffer.startIndex + 11
+            let flagsOffset = 1 + 1 + 1 + 8 // version + type + ttl + timestamp
+            let flagsIndex = buffer.startIndex + flagsOffset
+            guard flagsIndex < buffer.endIndex else { break }
             let flags = buffer[flagsIndex]
             let hasRecipient = (flags & BinaryProtocol.Flags.hasRecipient) != 0
             let hasSignature = (flags & BinaryProtocol.Flags.hasSignature) != 0
+            let isCompressed = (flags & BinaryProtocol.Flags.isCompressed) != 0
 
             let lengthOffset = 12
             let payloadLength: Int
@@ -63,6 +68,15 @@ struct NotificationStreamAssembler {
             var frameLength = framePrefix + payloadLength
             if hasRecipient { frameLength += BinaryProtocol.recipientIDSize }
             if hasSignature { frameLength += BinaryProtocol.signatureSize }
+            if isCompressed {
+                let rawLengthFieldBytes = (version == 2) ? 4 : 2
+                if payloadLength < rawLengthFieldBytes {
+                    SecureLogger.error("❌ Invalid compressed payload length (\(payloadLength))", category: .session)
+                    buffer.removeAll()
+                    reset = true
+                    break
+                }
+            }
 
             guard frameLength > 0, frameLength <= maxFrameLength else {
                 SecureLogger.error("❌ Notification frame length \(frameLength) invalid (cap=\(maxFrameLength)); resetting stream", category: .session)

bitchatTests/NotificationStreamAssemblerTests.swift

@@ -95,4 +95,67 @@ struct NotificationStreamAssemblerTests {
         let decoded = try #require(BinaryProtocol.decode(result.frames[0]), "Failed to decode frame after drop")
         #expect(decoded.timestamp == packet.timestamp)
     }
+
+    func testAssemblesCompressedLargeFrame() throws {
+        var assembler = NotificationStreamAssembler()
+
+        let largeContent = Data(repeating: 0x41, count: 2_500_000)
+        let filePacket = BitchatFilePacket(
+            fileName: "large.bin",
+            fileSize: UInt64(largeContent.count),
+            mimeType: "application/octet-stream",
+            content: largeContent
+        )
+        guard let tlvPayload = filePacket.encode() else {
+            return XCTFail("Failed to encode file packet")
+        }
+
+        let senderID = Data(repeating: 0xAA, count: BinaryProtocol.senderIDSize)
+        let packet = BitchatPacket(
+            type: MessageType.fileTransfer.rawValue,
+            senderID: senderID,
+            recipientID: nil,
+            timestamp: 0x010203040506,
+            payload: tlvPayload,
+            signature: nil,
+            ttl: 3,
+            version: 2
+        )
+
+        guard let frame = packet.toBinaryData(padding: false) else {
+            return XCTFail("Failed to encode packet frame")
+        }
+
+        let flagsOffset = 1 + 1 + 1 + 8
+        XCTAssertLessThan(flagsOffset, frame.count)
+        let flags = frame[frame.startIndex + flagsOffset]
+        XCTAssertNotEqual(flags & BinaryProtocol.Flags.isCompressed, 0, "Frame should be compressed for large payloads")
+
+        let splitIndex = min(4096, frame.count / 2)
+        var result = assembler.append(frame.prefix(splitIndex))
+        XCTAssertTrue(result.frames.isEmpty)
+
+        result = assembler.append(frame.suffix(from: splitIndex))
+        XCTAssertEqual(result.frames.count, 1)
+        XCTAssertTrue(result.droppedPrefixes.isEmpty)
+        XCTAssertFalse(result.reset)
+
+        guard let assembled = result.frames.first else {
+            return XCTFail("Missing assembled frame")
+        }
+        XCTAssertEqual(assembled.count, frame.count)
+
+        guard let decodedPacket = BinaryProtocol.decode(assembled) else {
+            return XCTFail("Failed to decode compressed frame")
+        }
+        XCTAssertEqual(decodedPacket.payload.count, tlvPayload.count)
+
+        guard let decodedFile = BitchatFilePacket.decode(decodedPacket.payload) else {
+            return XCTFail("Failed to decode TLV payload")
+        }
+        XCTAssertEqual(decodedFile.fileName, filePacket.fileName)
+        XCTAssertEqual(decodedFile.mimeType, filePacket.mimeType)
+        XCTAssertEqual(decodedFile.content.count, largeContent.count)
+        XCTAssertEqual(decodedFile.content.prefix(32), largeContent.prefix(32))
+    }
 }

bitchatTests/Protocols/BitchatFilePacketTests.swift

@@ -0,0 +1,47 @@
+import XCTest
+@testable import bitchat
+
+final class BitchatFilePacketTests: XCTestCase {
+
+    func testRoundTripPreservesFields() throws {
+        let content = Data((0..<4096).map { UInt8($0 % 251) })
+        let packet = BitchatFilePacket(
+            fileName: "sample.jpg",
+            fileSize: UInt64(content.count),
+            mimeType: "image/jpeg",
+            content: content
+        )
+
+        guard let encoded = packet.encode() else {
+            return XCTFail("Failed to encode file packet")
+        }
+        guard let decoded = BitchatFilePacket.decode(encoded) else {
+            return XCTFail("Failed to decode file packet")
+        }
+
+        XCTAssertEqual(decoded.fileName, packet.fileName)
+        XCTAssertEqual(decoded.fileSize, packet.fileSize)
+        XCTAssertEqual(decoded.mimeType, packet.mimeType)
+        XCTAssertEqual(decoded.content, packet.content)
+    }
+
+    func testDecodeFallsBackToContentSizeWhenFileSizeMissing() throws {
+        let content = Data(repeating: 0x7F, count: 1024)
+        let packet = BitchatFilePacket(
+            fileName: nil,
+            fileSize: nil,
+            mimeType: nil,
+            content: content
+        )
+
+        guard let encoded = packet.encode() else {
+            return XCTFail("Failed to encode file packet")
+        }
+        guard let decoded = BitchatFilePacket.decode(encoded) else {
+            return XCTFail("Failed to decode file packet")
+        }
+
+        XCTAssertEqual(decoded.fileSize, UInt64(content.count))
+        XCTAssertEqual(decoded.content, content)
+    }
+}