From b12fece4c64857e5fab4290bf01b2e0317a88456 Mon Sep 17 00:00:00 2001
From: Pietro Borrello <borrello@diag.uniroma1.it>
Date: Mon, 16 Jan 2023 11:11:24 +0000
Subject: [PATCH] HID: check empty report_list in hid_validate_values()
Git-commit: b12fece4c64857e5fab4290bf01b2e0317a88456
Patch-mainline: v6.2-rc5
References: git-fixes, bsc#1206784
Add a check for empty report_list in hid_validate_values().
The missing check causes a type confusion when issuing a list_entry()
on an empty report_list.
The problem is caused by the assumption that the device must
have valid report_list. While this will be true for all normal HID
devices, a suitably malicious device can violate the assumption.
Fixes: 1b15d2e5b807 ("HID: core: fix validation of report id 0")
Signed-off-by: Pietro Borrello <borrello@diag.uniroma1.it>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/hid/hid-core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index bd47628da6be..3e1803592bd4 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -993,8 +993,8 @@ struct hid_report *hid_validate_values(struct hid_device *hid,
* Validating on id 0 means we should examine the first
* report in the list.
*/
- report = list_entry(
- hid->report_enum[type].report_list.next,
+ report = list_first_entry_or_null(
+ &hid->report_enum[type].report_list,
struct hid_report, list);
} else {
report = hid->report_enum[type].report_id_hash[id];
--
2.35.3