linux-kernel - [PATCH linux-next v2 1/3] platform/x86/intel/tpmi: Fix double free in tpmi_create

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Date:   Thu,  9 Mar 2023 12:01:05 +0800
From:   Dongliang Mu <dzm91@...t.edu.cn>
To:     Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        Hans de Goede <hdegoede@...hat.com>,
        Mark Gross <markgross@...nel.org>
Cc:     Dongliang Mu <dzm91@...t.edu.cn>,
        platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH linux-next v2 1/3] platform/x86/intel/tpmi: Fix double free in tpmi_create_device()

The previous commit 6a192c0cbf38 ("platform/x86/intel/tpmi: Fix
double free reported by Smatch") incorrectly handle the deallocation of
res variable. As shown in the comment, intel_vsec_add_aux handles all
the deallocation of res and feature_vsec_dev. Therefore, kfree(res) can
still cause double free if intel_vsec_add_aux returns error.

Fix this by adjusting the error handling part in tpmi_create_device,
following the function intel_vsec_add_dev.

Fixes: 6a192c0cbf38 ("platform/x86/intel/tpmi: Fix double free reported by Smatch")
Signed-off-by: Dongliang Mu <dzm91@...t.edu.cn>
---
 drivers/platform/x86/intel/tpmi.c | 17 ++++-------------
 1 file changed, 4 insertions(+), 13 deletions(-)

diff --git a/drivers/platform/x86/intel/tpmi.c b/drivers/platform/x86/intel/tpmi.c
index c999732b0f1e..882fe5e4763f 100644
--- a/drivers/platform/x86/intel/tpmi.c
+++ b/drivers/platform/x86/intel/tpmi.c
@@ -215,8 +215,8 @@ static int tpmi_create_device(struct intel_tpmi_info *tpmi_info,
 
 	feature_vsec_dev = kzalloc(sizeof(*feature_vsec_dev), GFP_KERNEL);
 	if (!feature_vsec_dev) {
-		ret = -ENOMEM;
-		goto free_res;
+		kfree(res);
+		return -ENOMEM;
 	}
 
 	snprintf(feature_id_name, sizeof(feature_id_name), "tpmi-%s", name);
@@ -242,17 +242,8 @@ static int tpmi_create_device(struct intel_tpmi_info *tpmi_info,
 	 * feature_vsec_dev memory is also freed as part of device
 	 * delete.
 	 */
-	ret = intel_vsec_add_aux(vsec_dev->pcidev, &vsec_dev->auxdev.dev,
-				 feature_vsec_dev, feature_id_name);
-	if (ret)
-		goto free_res;
-
-	return 0;
-
-free_res:
-	kfree(res);
-
-	return ret;
+	return intel_vsec_add_aux(vsec_dev->pcidev, &vsec_dev->auxdev.dev,
+				  feature_vsec_dev, feature_id_name);
 }
 
 static int tpmi_create_devices(struct intel_tpmi_info *tpmi_info)
-- 
2.39.2