blob: c97c3e3e2f832c97f6cb5b67dfd310968a35498c [file] [log] [blame]
From e3af5aefdf2462379e1c65c4a82d8e6e1f3085c1 Mon Sep 17 00:00:00 2001
From: Vladis Dronov <>
Date: Mon, 13 Jan 2020 14:00:09 +0100
Subject: [PATCH] ptp: free ptp device pin descriptors properly
commit 75718584cb3c64e6269109d4d54f888ac5a5fd15 upstream.
There is a bug in ptp_clock_unregister(), where ptp_cleanup_pin_groups()
first frees ptp->pin_{,dev_}attr, but then posix_clock_unregister() needs
them to destroy a related sysfs device.
These functions can not be just swapped, as posix_clock_unregister() frees
ptp which is needed in the ptp_cleanup_pin_groups(). Fix this by calling
ptp_cleanup_pin_groups() in ptp_clock_release(), right before ptp is freed.
This makes this patch fix an UAF bug in a patch which fixes an UAF bug.
Reported-by: Antti Laakso <>
Fixes: a33121e5487b ("ptp: fix the race between the release of ptp_clock and cdev")
Signed-off-by: Vladis Dronov <>
Acked-by: Richard Cochran <>
Signed-off-by: David S. Miller <>
Signed-off-by: Paul Gortmaker <>
diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
index a622cd38cf3b..1a9af1138f84 100644
--- a/drivers/ptp/ptp_clock.c
+++ b/drivers/ptp/ptp_clock.c
@@ -169,6 +169,7 @@ static void ptp_clock_release(struct device *dev)
struct ptp_clock *ptp = container_of(dev, struct ptp_clock, dev);
+ ptp_cleanup_pin_groups(ptp);
ida_simple_remove(&ptp_clocks_map, ptp->index);
@@ -301,9 +302,8 @@ int ptp_clock_unregister(struct ptp_clock *ptp)
if (ptp->pps_source)
- ptp_cleanup_pin_groups(ptp);
return 0;