[PATCH char-misc] mei: vsc: Fix packet CRC computed over pointer size

From: Alexander Usyskin

Date: Tue Oct 06 2026 - 03:38:33 EST


From: Wentao Guan <guanwentao@xxxxxxxxxxxxx>

vsc_tp_xfer() computes the packet CRC over sizeof(pkt) + olen bytes,
but pkt is a pointer, so sizeof(pkt) evaluates to the pointer size
instead of the size of struct vsc_tp_packet_hdr. The value correctly
match the 8-byte header on 64-bit builds.

Use sizeof(pkt->hdr), consistent with the header size used everywhere
else in the driver, e.g. in VSC_TP_PACKET_SIZE().

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 566f5ca97680 ("mei: Add transport driver for IVSC device")
Reviewed-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
Signed-off-by: Wentao Guan <guanwentao@xxxxxxxxxxxxx>
Signed-off-by: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>
---
drivers/misc/mei/vsc-tp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/misc/mei/vsc-tp.c b/drivers/misc/mei/vsc-tp.c
index 432bc59f11f9..ce877cb95757 100644
--- a/drivers/misc/mei/vsc-tp.c
+++ b/drivers/misc/mei/vsc-tp.c
@@ -293,7 +293,7 @@ int vsc_tp_xfer(struct vsc_tp *tp, u8 cmd, const void *obuf, size_t olen,
pkt->hdr.seq = cpu_to_le32(++tp->seq);
memcpy(pkt->buf, obuf, olen);

- crc = ~crc32(~0, (u8 *)pkt, sizeof(pkt) + olen);
+ crc = ~crc32(~0, (u8 *)pkt, sizeof(pkt->hdr) + olen);
memcpy(pkt->buf + olen, &crc, sizeof(crc));

ret = vsc_tp_wakeup_request(tp);

---
base-commit: cee9395acd8043be0644b25c34bfa86623f2b935
change-id: 20261006-vcs_fix_crc-d2bc03a64163

Best regards,
--
Alexander Usyskin <alexander.usyskin@xxxxxxxxx>