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From:   Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
To:     hdegoede@redhat.com, markgross@kernel.org
Cc:     platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org,
        Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Subject: [PATCH] platform/x86/intel/tpmi: Prevent overflow for cap_offset
Date:   Thu, 22 Jun 2023 12:57:17 -0700
Message-Id: <20230622195717.3125088-1-srinivas.pandruvada@linux.intel.com>
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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>
---
Rebased on top of
https://kernel.googlesource.com/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86
review-hans 

 drivers/platform/x86/intel/tpmi.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/platform/x86/intel/tpmi.c b/drivers/platform/x86/intel/tpmi.c
index 9c606ee2030c..d1fd6e69401c 100644
--- 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.
-- 
2.38.1