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fix(usb): accept the padding iOS 27 adds after USBMUX replies - #43
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An iPhone on iOS 27 can send four extra bytes after some USBMUX replies: the version reply declares 20 bytes and arrives as 24, and TCP replies, with or without data, can carry the same trailer. Iap2UsbMuxHost read those bytes as the start of the next header, got a length of 6 and ended the wired session with "Invalid USBMUX frame length 6". Framing now goes through UsbMuxFrameBuffer. Exactly four bytes are skipped, only after the version reply, a valid TCP reply from the iPhone or a diagnostic reply, and only when a valid header follows; incomplete data waits for more instead of being dropped, and any other bad length still fails. Skips and rejections are reported through a new onDiagnostic hook, which CarPlayController writes to its debug log. The fix and its tests come from DiPlay (shihabal3amri/DiPlay, commits 3d0411d5 and f7af3286, for its issue #100), which shares this code with xcertplay; both are GPL-3.0. UsbMuxIssue100RegressionTest replays the USB transfers captured in that issue through the real Iap2UsbSession read and the Iap2UsbMuxHost handshake, so shared gains a Robolectric test dependency.
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Eight pull requests (shilapi#43 to shilapi#50) and one issue (shilapi#51) went to shilapi/xcertplay, each built on upstream 1.4.0 with one change. docs/UPSTREAM.md lists them with the commits of this branch they come from, and what was left out and why.
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An iPhone on iOS 27 can send four extra bytes after some USBMUX replies: the
version reply declares 20 bytes and arrives as 24, and TCP replies, with or
without data, can carry the same trailer. Iap2UsbMuxHost read those bytes as
the start of the next header, got a length of 6 and ended the wired session
with "Invalid USBMUX frame length 6".
Framing now goes through UsbMuxFrameBuffer. Exactly four bytes are skipped,
only after the version reply, a valid TCP reply from the iPhone or a
diagnostic reply, and only when a valid header follows; incomplete data waits
for more instead of being dropped, and any other bad length still fails.
Skips and rejections are reported through a new onDiagnostic hook, which
CarPlayController writes to its debug log.
The fix and its tests come from DiPlay (shihabal3amri/DiPlay, commits
3d0411d5 and f7af3286, for its issue #100), which shares this code with
xcertplay; both are GPL-3.0. UsbMuxIssue100RegressionTest replays the USB
transfers captured in that issue through the real Iap2UsbSession read and the
Iap2UsbMuxHost handshake, so shared gains a Robolectric test dependency.