From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f50.google.com (mail-wm1-f50.google.com [209.85.128.50]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4F11940C09 for ; Tue, 19 Dec 2023 23:25:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="dOwqhfMd" Received: by mail-wm1-f50.google.com with SMTP id 5b1f17b1804b1-40d12b56a38so42639395e9.2 for ; Tue, 19 Dec 2023 15:25:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1703028301; x=1703633101; darn=vger.kernel.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=8jJtlAviAEqHUpEmCol6f8oT3KPiB6Zv+60pl+WH7WI=; b=dOwqhfMdQOytMtZlgIuP6QAkWd0QTM3YgDYtUWtsW5l5OItR2INN6EF4pqfBE7wQnI pj6dhAG0Ge7rHvx15eis+ppXNc+NZZkfCmCkFGw6N/XngxVx2YYyb7j4rcIsd3okCJtA tZrFq8Q556HhzdOU1ldh2gCKI/HJYFmQtSMxG6CbgZ6gkYUQaItau3VSRokDfO4OfTv5 9vn1PZwSfUVW/pzlLGdSCyHSvROiKEh9BKRAtRAo6b7wgKadh9BC5w9ou+4c2RS1zJrm D8elByty0Ht17/O0F9xnguO9iCODCvH34CvXA33dYoFofuUlNJdrfeHcTJ2nss23woQL TVdA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1703028301; x=1703633101; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=8jJtlAviAEqHUpEmCol6f8oT3KPiB6Zv+60pl+WH7WI=; b=fFicfZAZZHZJyqQcLjoBxNvfzHE0UxBqQiz76pc+m6xUDwsaB+2UXndDqVPXgOQ3nd HJ5GeTilpCBXq96oMKhL1C6uQPpsKft6m5sXOPaVLD1aEh6BckMX3iQ/Y00qR4kX4Mxp hvU8dtaHrKuAmV6WCmj0LUayhpFcvBr5oQwob2FmsJLIEEMOlSuYX2xaJa1RnJbIo7VQ ZtnASIGqseGsJshG3C/0grEkAtJOtYHui33yqwW3X5+Kl1RSE/QHcHBk81Kw0ck39u2y E+6BRiGdSL3l0AjAbUx5SFQJ/E3m7ChvRFobXNhmfJjck8ZhaSFR7719WsOJ9dnxVDeF E9fg== X-Gm-Message-State: AOJu0Yw2RUgeE7d1P8H9zMiNJg5EiR8JatykFJMhll/m+r5KtyA9lNxt Z1pcdiCw3w73gvWUAoVTEUT8mzGKH/KaRl4OcUtwHg== X-Google-Smtp-Source: AGHT+IGjyS8owAoubjnIHkRSsr3sANlRTRlkbfa7qjlypkLg+bw8Xx0wFu4y2R2AfChr/ivDqYOL0QFZ7rhMQeNaPq8= X-Received: by 2002:a05:600c:ac6:b0:40c:310b:b694 with SMTP id c6-20020a05600c0ac600b0040c310bb694mr4396321wmr.333.1703028301270; Tue, 19 Dec 2023 15:25:01 -0800 (PST) Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20231219210357.4029713-1-dw@davidwei.uk> <20231219210357.4029713-3-dw@davidwei.uk> In-Reply-To: <20231219210357.4029713-3-dw@davidwei.uk> From: Mina Almasry Date: Tue, 19 Dec 2023 15:24:49 -0800 Message-ID: Subject: Re: [RFC PATCH v3 02/20] tcp: don't allow non-devmem originated ppiov To: David Wei Cc: io-uring@vger.kernel.org, netdev@vger.kernel.org, Jens Axboe , Pavel Begunkov , Jakub Kicinski , Paolo Abeni , "David S. Miller" , Eric Dumazet , Jesper Dangaard Brouer , David Ahern Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, Dec 19, 2023 at 1:04=E2=80=AFPM David Wei wrote: > > From: Pavel Begunkov > > NOT FOR UPSTREAM > > There will be more users of struct page_pool_iov, and ppiovs from one > subsystem must not be used by another. That should never happen for any > sane application, but we need to enforce it in case of bufs and/or > malicious users. > > Signed-off-by: Pavel Begunkov > Signed-off-by: David Wei > --- > net/ipv4/tcp.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c > index 33a8bb63fbf5..9c6b18eebb5b 100644 > --- a/net/ipv4/tcp.c > +++ b/net/ipv4/tcp.c > @@ -2384,6 +2384,13 @@ static int tcp_recvmsg_devmem(const struct sock *s= k, const struct sk_buff *skb, > } > > ppiov =3D skb_frag_page_pool_iov(frag); > + > + /* Disallow non devmem owned buffers */ > + if (ppiov->pp->p.memory_provider !=3D PP_MP_DMABU= F_DEVMEM) { > + err =3D -ENODEV; > + goto out; > + } > + Instead of this, I maybe recommend modifying the skb->dmabuf flag? My mental model is that flag means all the frags in the skb are specifically dmabuf, not general ppiovs or net_iovs. Is it possible to add skb->io_uring or something? If that bloats the skb headers, then maybe we need another place to put this flag. Maybe the [page_pool|net]_iov should declare whether it's dmabuf or otherwise, and we can check frag[0] and assume all frags are the same as frag0. But IMO the page pool internals should not leak into the implementation of generic tcp stack functions. > end =3D start + skb_frag_size(frag); > copy =3D end - offset; > > -- > 2.39.3 > --=20 Thanks, Mina