Commit cbfb50e6 authored Oct 19, 2007 by Roland Dreier

IB/uverbs: Fix checking of userspace object ownership


    
Commit 9ead190b ("IB/uverbs: Don't serialize with ib_uverbs_idr_mutex")
rewrote how userspace objects are looked up in the uverbs module's
idrs, and introduced a severe bug in the process: there is no checking
that an operation is being performed by the right process any more.
Fix this by adding the missing check of uobj->context in __idr_get_uobj().

Apparently everyone is being very careful to only touch their own
objects, because this bug was introduced in June 2006 in 2.6.18, and
has gone undetected until now.

Cc: stable <stable@kernel.org>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

parent 83904132

drivers/infiniband/core/uverbs_cmd.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -147,8 +147,12 @@ static struct ib_uobject __idr_get_uobj(struct idr idr, int id,

		spin_lock(&ib_uverbs_idr_lock);
		uobj = idr_find(idr, id);
		if (uobj)
		if (uobj) {
		if (uobj->context == context)
		kref_get(&uobj->ref);
		else
		uobj = NULL;
		}
		spin_unlock(&ib_uverbs_idr_lock);

		return uobj;