From: Armin Wolf <W_Armin@gmx.de>
Date: Thu, 26 Jan 2023 20:40:18 +0100
Subject: [PATCH] platform/x86: dell-ddv: Return error if buffer is empty
References: bsc#1012628
Patch-mainline: 6.2.7
Git-commit: 36d44825faf42903a0b92dd49a9620e2cbdcbe18

[ Upstream commit 36d44825faf42903a0b92dd49a9620e2cbdcbe18 ]

In several cases, the DDV WMI interface can return buffers
with a length of zero. Return -ENODATA in such a case for
proper error handling. Also replace some -EIO errors with
more specialized ones.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://lore.kernel.org/r/20230126194021.381092-3-W_Armin@gmx.de
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Stable-dep-of: 0331b1b0ba65 ("platform/x86: dell-ddv: Fix temperature scaling")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/platform/x86/dell/dell-wmi-ddv.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/platform/x86/dell/dell-wmi-ddv.c b/drivers/platform/x86/dell/dell-wmi-ddv.c
index 9cb6ae42..f99c4cb6 100644
--- a/drivers/platform/x86/dell/dell-wmi-ddv.c
+++ b/drivers/platform/x86/dell/dell-wmi-ddv.c
@@ -11,6 +11,7 @@
 #include <linux/debugfs.h>
 #include <linux/device.h>
 #include <linux/dev_printk.h>
+#include <linux/errno.h>
 #include <linux/kernel.h>
 #include <linux/kstrtox.h>
 #include <linux/math.h>
@@ -125,21 +126,27 @@ static int dell_wmi_ddv_query_buffer(struct wmi_device *wdev, enum dell_ddv_meth
 	if (ret < 0)
 		return ret;
 
-	if (obj->package.count != 2)
-		goto err_free;
+	if (obj->package.count != 2 ||
+	    obj->package.elements[0].type != ACPI_TYPE_INTEGER ||
+	    obj->package.elements[1].type != ACPI_TYPE_BUFFER) {
+		ret = -ENOMSG;
 
-	if (obj->package.elements[0].type != ACPI_TYPE_INTEGER)
 		goto err_free;
+	}
 
 	buffer_size = obj->package.elements[0].integer.value;
 
-	if (obj->package.elements[1].type != ACPI_TYPE_BUFFER)
+	if (!buffer_size) {
+		ret = -ENODATA;
+
 		goto err_free;
+	}
 
 	if (buffer_size > obj->package.elements[1].buffer.length) {
 		dev_warn(&wdev->dev,
 			 FW_WARN "WMI buffer size (%llu) exceeds ACPI buffer size (%d)\n",
 			 buffer_size, obj->package.elements[1].buffer.length);
+		ret = -EMSGSIZE;
 
 		goto err_free;
 	}
@@ -151,7 +158,7 @@ static int dell_wmi_ddv_query_buffer(struct wmi_device *wdev, enum dell_ddv_meth
 err_free:
 	kfree(obj);
 
-	return -EIO;
+	return ret;
 }
 
 static int dell_wmi_ddv_query_string(struct wmi_device *wdev, enum dell_ddv_method method,
-- 
2.35.3