[PATCH RESEND] w1: Use kfree_sensitive to clear sensitive information
From: Deepak R Varma
Date: Wed Mar 01 2023 - 15:28:01 EST
Replace combination of 'memset(0) + kfree()' by kfree_sensitive() as it
prevents compiler from optimizing away from zeroing out memory at the
end of a scope. kfree_sensitive() is also safe in case the memory
pointer turns out to be null, which simply gets ignored.
Issue identified using kfree_sensitive.cocci coccinelle semantic patch.
Signed-off-by: Deepak R Varma <drv@xxxxxxxxx>
---
Note:
- proposed change is compile tested only.
- Resending the patch for review and feedback. Initially sent on Dec 23 2022.
drivers/w1/w1.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
index 9d199fed9628..0241fc6ca65a 100644
--- a/drivers/w1/w1.c
+++ b/drivers/w1/w1.c
@@ -73,8 +73,7 @@ static void w1_master_release(struct device *dev)
struct w1_master *md = dev_to_w1_master(dev);
dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name);
- memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
- kfree(md);
+ kfree_sensitive(md);
}
static void w1_slave_release(struct device *dev)
@@ -805,9 +804,10 @@ int w1_unref_slave(struct w1_slave *sl)
w1_family_notify(BUS_NOTIFY_DEL_DEVICE, sl);
device_unregister(&sl->dev);
#ifdef DEBUG
- memset(sl, 0, sizeof(*sl));
- #endif
+ kfree_sensitive(sl);
+ #else
kfree(sl);
+ #endif
}
atomic_dec(&dev->refcnt);
mutex_unlock(&dev->list_mutex);
--
2.34.1