From: Daniel Borkmann <daniel@iogearbox.net>
To: Magnus Karlsson <magnus.karlsson@gmail.com>,
Fletcher Dunn <fletcherd@valvesoftware.com>
Cc: Alexei Starovoitov <ast@kernel.org>,
Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
Yonghong Song <yhs@fb.com>, Andrii Nakryiko <andriin@fb.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"bpf@vger.kernel.org" <bpf@vger.kernel.org>,
Brandon Gilmore <bgilmore@valvesoftware.com>,
Steven Noonan <steven@valvesoftware.com>
Subject: Re: [PATCH bpf-next] xsk: Init all ring members in xsk_umem__create and xsk_socket__create
Date: Sat, 28 Mar 2020 18:14:25 +0100 [thread overview]
Message-ID: <ae371400-e37f-bbac-691e-cc50235f1ee0@iogearbox.net> (raw)
In-Reply-To: <CAJ8uoz2M0Xj_maD3jZeZedrUXGNJqvbV_DyC2A8Yh9R6z7gfsg@mail.gmail.com>
On 3/28/20 10:18 AM, Magnus Karlsson wrote:
> On Fri, Mar 27, 2020 at 4:40 AM Fletcher Dunn
> <fletcherd@valvesoftware.com> wrote:
>>
>> Fix a sharp edge in xsk_umem__create and xsk_socket__create. Almost all of
>> the members of the ring buffer structs are initialized, but the "cached_xxx"
>> variables are not all initialized. The caller is required to zero them.
>> This is needlessly dangerous. The results if you don't do it can be very bad.
>> For example, they can cause xsk_prod_nb_free and xsk_cons_nb_avail to return
>> values greater than the size of the queue. xsk_ring_cons__peek can return an
>> index that does not refer to an item that has been queued.
>>
>> I have confirmed that without this change, my program misbehaves unless I
>> memset the ring buffers to zero before calling the function. Afterwards,
>> my program works without (or with) the memset.
>
> Thank you Flecther for catching this. Appreciated.
>
> /Magnus
>
> Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Applied, thanks!
prev parent reply other threads:[~2020-03-28 17:14 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-27 3:24 [PATCH bpf-next] xsk: Init all ring members in xsk_umem__create and xsk_socket__create Fletcher Dunn
2020-03-28 9:18 ` Magnus Karlsson
2020-03-28 17:14 ` Daniel Borkmann [this message]
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