From a8ebc7bceb104fa5e1ef1ce116d3fd85f2081af2 Mon Sep 17 00:00:00 2001 From: Roland Dreier Date: Sun, 28 Oct 2007 10:14:32 -0700 Subject: [PATCH] IB/uverbs: Fix checking of userspace object ownership Upstream as cbfb50e6e2e9c580848c0f51d37c24cdfb1cb704 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. Signed-off-by: Roland Dreier Signed-off-by: Greg Kroah-Hartman --- drivers/infiniband/core/uverbs_cmd.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c index 01d70084aebe..495c803fb11d 100644 --- a/drivers/infiniband/core/uverbs_cmd.c +++ b/drivers/infiniband/core/uverbs_cmd.c @@ -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) - kref_get(&uobj->ref); + if (uobj) { + if (uobj->context == context) + kref_get(&uobj->ref); + else + uobj = NULL; + } spin_unlock(&ib_uverbs_idr_lock); return uobj; -- 2.39.5