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rmnet: fix PacketLen missing QMAP_UL_CHECKSUM size in QMAP header for V2/V3/V4 #61

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Merged
hangzqcom merged 1 commit into from
Jun 19, 2026
+44 −2
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rmnet: fix PacketLen missing QMAP_UL_CHECKSUM size in QMAP header for V2/V3/V4 #61

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46 changes: 44 additions & 2 deletions src/windows/ndis/MPUsb.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4502,7 +4502,28 @@ VOID MPUSB_TLPTxPacket
Qmap->PadCD |= (paddingBytes);
Qmap->MuxId = pAdapter->MuxId;
sendBytes += paddingBytes;
Qmap->PacketLen = RtlUshortByteSwap(sendBytes);
/* When QMAPEnabledV4/V2/V3 is active, the QMAP_UL_CHECKSUM structure
* (8 bytes) is placed between the QMAP header and the IP payload. The
* PacketLen field must cover all bytes that follow the QMAP header, so it
* must include sizeof(QMAP_UL_CHECKSUM). Without this fix, PacketLen is
* undersized by sizeof(QMAP_UL_CHECKSUM); IPA advances its frame-boundary
* pointer sizeof(QMAP_UL_CHECKSUM) bytes early, misreads trailing IP
* payload as the next QMAP header, and raises exception=4
* (status.pkt_len < qmap.pkt_len). */
if ((pAdapter->QMAPEnabledV4 == TRUE)
#ifdef QCUSB_MUX_PROTOCOL
#if defined(QCMP_QMAP_V2_SUPPORT)

@hangzqcom hangzqcom Jun 19, 2026

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if a new QMAP version with UL checksum gets added later, it's easy to miss this block and silently get wrong PacketLen again. consider extracting the condition into a helper macro

For example, add this on top of the file,
#if defined(QCUSB_MUX_PROTOCOL) && defined(QCMP_QMAP_V2_SUPPORT)
#define QMAP_UL_CHECKSUM_ENABLED(pAdapter)
((pAdapter)->QMAPEnabledV4 || (pAdapter)->QMAPEnabledV2 || (pAdapter)->QMAPEnabledV3)
#else
#define QMAP_UL_CHECKSUM_ENABLED(pAdapter)
((pAdapter)->QMAPEnabledV4)
#endif

And then use it here,
if (QMAP_UL_CHECKSUM_ENABLED(pAdapter))
Qmap->PacketLen = RtlUshortByteSwap((USHORT)(sendBytes + sizeof(QMAP_UL_CHECKSUM)));
else
Qmap->PacketLen = RtlUshortByteSwap((USHORT)sendBytes);

This eliminates the #ifdef nesting inside the if condition, removes the duplication, and makes future QMAP version additions a single-point change.

|| (pAdapter->QMAPEnabledV2 == TRUE) || (pAdapter->QMAPEnabledV3 == TRUE)
#endif
#endif
)
{
Qmap->PacketLen = RtlUshortByteSwap((USHORT)(sendBytes + sizeof(QMAP_UL_CHECKSUM)));
}
else
{
Qmap->PacketLen = RtlUshortByteSwap((USHORT)sendBytes);
}
if (pAdapter->QMAPEnabledV4 == TRUE)
{
PQMAP_UL_CHECKSUM pULCheckSum = (PQMAP_UL_CHECKSUM)((PUCHAR)Qmap + sizeof(QMAP_STRUCT));
Expand Down Expand Up @@ -5798,7 +5819,28 @@ VOID MPUSB_TLPTxPacketEx
Qmap->PadCD |= (paddingBytes);
Qmap->MuxId = pAdapter->MuxId;
sendBytes += paddingBytes;
Qmap->PacketLen = RtlUshortByteSwap(sendBytes);
/* When QMAPEnabledV4/V2/V3 is active, the QMAP_UL_CHECKSUM structure
* (8 bytes) is placed between the QMAP header and the IP payload. The
* PacketLen field must cover all bytes that follow the QMAP header, so it
* must include sizeof(QMAP_UL_CHECKSUM). Without this fix, PacketLen is
* undersized by sizeof(QMAP_UL_CHECKSUM); IPA advances its frame-boundary
* pointer sizeof(QMAP_UL_CHECKSUM) bytes early, misreads trailing IP
* payload as the next QMAP header, and raises exception=4
* (status.pkt_len < qmap.pkt_len). */
if ((pAdapter->QMAPEnabledV4 == TRUE)
#ifdef QCUSB_MUX_PROTOCOL
#if defined(QCMP_QMAP_V2_SUPPORT)

@hangzqcom hangzqcom Jun 19, 2026

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same as above

|| (pAdapter->QMAPEnabledV2 == TRUE) || (pAdapter->QMAPEnabledV3 == TRUE)
#endif
#endif
)
{
Qmap->PacketLen = RtlUshortByteSwap((USHORT)(sendBytes + sizeof(QMAP_UL_CHECKSUM)));
}
else
{
Qmap->PacketLen = RtlUshortByteSwap((USHORT)sendBytes);
}
if (pAdapter->QMAPEnabledV4 == TRUE)
{
PQMAP_UL_CHECKSUM pULCheckSum = (PQMAP_UL_CHECKSUM)((PUCHAR)Qmap + sizeof(QMAP_STRUCT));
Expand Down
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