platform/x86/intel/tpmi: Prevent overflow for cap_offset

cap_offset is a u16 field, so multiplying with TPMI_CAP_OFFSET_UNIT
(which is equal to 1024) to covert to bytes will cause overflow. This
will be a problem once more TPMI features are added.

This field is not used except for calculating pfs->vsec_offset. So, leave
cap_offset field unchanged and multiply with TPMI_CAP_OFFSET_UNIT while
calculating pfs->vsec_offset.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Link: https://lore.kernel.org/r/20230622195717.3125088-1-srinivas.pandruvada@linux.intel.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

diff --git a/drivers/platform/x86/intel/tpmi.c b/drivers/platform/x86/intel/tpmi.c
index 9c606ee..d1fd6e6 100644 (file)
--- a/drivers/platform/x86/intel/tpmi.c
+++ b/drivers/platform/x86/intel/tpmi.c
@@ -356,9 +356,7 @@ static int intel_vsec_tpmi_init(struct auxiliary_device *auxdev)
                if (!pfs_start)
                        pfs_start = res_start;
 
-               pfs->pfs_header.cap_offset *= TPMI_CAP_OFFSET_UNIT;
-
-               pfs->vsec_offset = pfs_start + pfs->pfs_header.cap_offset;
+               pfs->vsec_offset = pfs_start + pfs->pfs_header.cap_offset * TPMI_CAP_OFFSET_UNIT;
 
                /*
                 * Process TPMI_INFO to get PCI device to CPU package ID.