From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Carpenter Date: Fri, 26 Jul 2013 08:47:08 +0000 Subject: Re: [patch] RDMA/cxgb3: stack info leak in iwch_craete_cq() Message-Id: <20130726084708.GA5636@mwanda> List-Id: References: <20130725170409.GB7026@elgon.mountain> <51F171D0.7050204@opengridcomputing.com> In-Reply-To: <51F171D0.7050204-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Steve Wise Cc: Steve Wise , Roland Dreier , Sean Hefty , Hal Rosenstock , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kernel-janitors-u79uwXL29TY76Z2rM5mHXA@public.gmane.org On Thu, Jul 25, 2013 at 01:43:28PM -0500, Steve Wise wrote: > On 7/25/2013 12:04 PM, Dan Carpenter wrote: > >The "uresp.reserved" field isn't initialized. It's at the end, of the > >struct here so we don't need to copy it to the user. > > > >Signed-off-by: Dan Carpenter > > > >diff --git a/drivers/infiniband/hw/cxgb3/iwch_provider.c b/drivers/infiniband/hw/cxgb3/iwch_provider.c > >index e87f220..b8e26f2 100644 > >--- a/drivers/infiniband/hw/cxgb3/iwch_provider.c > >+++ b/drivers/infiniband/hw/cxgb3/iwch_provider.c > >@@ -226,7 +226,7 @@ static struct ib_cq *iwch_create_cq(struct ib_device *ibdev, int entries, int ve > > mm->len = PAGE_ALIGN(((1UL << uresp.size_log2) + 1) * > > sizeof(struct t3_cqe)); > > uresp.memsize = mm->len; > >- resplen = sizeof uresp; > >+ resplen = sizeof uresp - sizeof uresp.reserved; > > } > > if (ib_copy_to_udata(udata, &uresp, resplen)) { > > kfree(mm); > > How did you find this? This is some incoming Smatch stuff. > > What if, in the future, the iwch_create_cq_resp struct is changed > and stuff added to the end? I'm not sure this optimization is worth > it? Yeah. I'm not sure either. I wouldn't do it outside infiniband code because I was copying other code from there. I can redo this. regards, dan carpenter