From: Roland Dreier Date: Sat, 20 Oct 2007 03:01:43 +0000 (-0700) Subject: IB/uverbs: Fix checking of userspace object ownership X-Git-Tag: v2.6.24-rc1~27^2~2 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=cbfb50e6e2e9c580848c0f51d37c24cdfb1cb704;p=linux-2.6-omap-h63xx.git 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 Signed-off-by: Roland Dreier --- diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c index 01d70084aeb..495c803fb11 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;