This is a note to let you know that I've just added the patch titled
mei: protect mei_cl_mtu from null dereference
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From bcbc0b2e275f0a797de11a10eff495b4571863fc Mon Sep 17 00:00:00 2001
From: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>
Date: Thu, 29 Oct 2020 11:54:42 +0200
Subject: mei: protect mei_cl_mtu from null dereference
A receive callback is queued while the client is still connected
but can still be called after the client was disconnected. Upon
disconnect cl->me_cl is set to NULL, hence we need to check
that ME client is not-NULL in mei_cl_mtu to avoid
null dereference.
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>
Signed-off-by: Tomas Winkler <tomas.winkler@xxxxxxxxx>
Link: https://lore.kernel.org/r/20201029095444.957924-2-tomas.winkler@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/misc/mei/client.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/misc/mei/client.h b/drivers/misc/mei/client.h
index 64143d4ec758..9e08a9843bba 100644
--- a/drivers/misc/mei/client.h
+++ b/drivers/misc/mei/client.h
@@ -182,11 +182,11 @@ static inline u8 mei_cl_me_id(const struct mei_cl *cl)
*
* @cl: host client
*
- * Return: mtu
+ * Return: mtu or 0 if client is not connected
*/
static inline size_t mei_cl_mtu(const struct mei_cl *cl)
{
- return cl->me_cl->props.max_msg_length;
+ return cl->me_cl ? cl->me_cl->props.max_msg_length : 0;
}
/**
--
2.29.2
