linux-kernel - [PATCH] driver core: fix null pointer deref in device_find

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 20 Jan 2022 16:02:46 +0100
From:   Soenke Huster <soenke.huster@...oes.de>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     Soenke Huster <soenke.huster@...oes.de>,
        linux-kernel@...r.kernel.org
Subject: [PATCH] driver core: fix null pointer deref in device_find_child

Similar to device_for_each_child, device_find_child should not ooops
if parent->p is NULL. While fuzzing the Bluetooth subsystem, I got a null
pointer dereference in next_device, which is prevented by this change.

Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=215497
Signed-off-by: Soenke Huster <soenke.huster@...oes.de>
---
I found this while fuzzing the bluetooth subsystem and reported this bug
in bugzilla. As I feel more like a kernelnewbie, I am not sure whether
this needs to be patched in driver core, or is just an issue of the
bluetooth subsystem itself. If the latter is the case: sorry for the
spam!

A similar fix was applied in 014c90dbb9b6 ("driver core: prevent
device_for_each_child from oopsing") for device_for_each_child, which is
mentioned in the docstring of device_find_child as similar function.

 drivers/base/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 7bb957b11861..654d904631f9 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -3780,7 +3780,7 @@ struct device *device_find_child(struct device *parent, void *data,
 	struct klist_iter i;
 	struct device *child;
 
-	if (!parent)
+	if (!parent || !parent->p)
 		return NULL;
 
 	klist_iter_init(&parent->p->klist_children, &i);
-- 
2.34.1