From patchwork Thu Dec 6 04:40:48 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stanislav Fomichev X-Patchwork-Id: 1008608 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=google.com header.i=@google.com header.b="SrR/KdVA"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 439NGz1fXmz9s3Z for ; Thu, 6 Dec 2018 15:41:47 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728951AbeLFElp (ORCPT ); Wed, 5 Dec 2018 23:41:45 -0500 Received: from mail-pg1-f202.google.com ([209.85.215.202]:55274 "EHLO mail-pg1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728144AbeLFElo (ORCPT ); Wed, 5 Dec 2018 23:41:44 -0500 Received: by mail-pg1-f202.google.com with SMTP id p4so12549543pgj.21 for ; Wed, 05 Dec 2018 20:41:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=EWBWFW17Lr/UhmSk/UKyBs74HwJ6mMGJj+/HRR4JM+I=; b=SrR/KdVAwY6hNNXh6dTmvqM8LBsJ8A0hd/XFZ72+hEgGssaYlkHwXQpO3J7MeoWW2t w4NvF7pswAnbuyVAuSHoCL11YtM3wcoY3qF/XWULmPmUG64FoaMkIY563CcdUeuhmExV xXN288FTSR+QSQCS8JC3YDevnToZdaGXKcDlNTMnbRM+9VsyAzN+KZ0rZBtIM2EYr3IC ByUVLuPDZG9ykd9Jpi5vl3ZPbsIeTD2xOOB/lrB84P+leCEaFHCRxSnIe9g3qeORy742 LJgxNgiv9nthb7KBcpgo/YcFVxdtnw8OtuIjaHd2rmP13H21Xh6OXh2Q/SjddBWXh6di RGMg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=EWBWFW17Lr/UhmSk/UKyBs74HwJ6mMGJj+/HRR4JM+I=; b=fnfq4b3OZpJu22oRinU2QD2FQP3rWls6BVx68/eikqXbztqmLgtZGxy9dIUNXhBAhv A2f1gNVH4wna8BjaaJcum5L4Rqf8UVitefumPTmBXzeII8O6qu4jiy9ioy3d0rmPoRQl SwoDA5XplrwPF8W+Be0ZibN3jEy8RVTjg1czYK6xwNgsLvtGEaD0G+1pk1b1ibkpu6tF BzLtV1TPVbKZd9U347wwI74xORjNaUV5UfUYC/lZv0CVZPX4UsN7e4Ja+7J/e714o5nR xALS++GrkOFD4d8Dn+3ZjSyJ9B7HDoYxH0GnUHwiwevYcG6QiAcLru8SHOAogOW36ObJ Oq4A== X-Gm-Message-State: AA+aEWapn+X1mkbojbBcNMIxjJWDjLM6PyxlxsRoOCfFCcwpHjx8F0pr OD4qTet52Lhgc9bCB5/f9I5vd7T/PKw+Ksd78kVvB/vE9MczVRjPIyh5KukxrSAsT0HvY79qfq2 u5XtF6IYoxdlMA7GT3bKZUDPi7BAPuxL9q45ITQVWff7T0luF4h/WKg== X-Google-Smtp-Source: AFSGD/XkPlG6TrMhXN2hPYKIjU8SfhuvdGgtE+DiYN4ypZrzZ4zC/Lf9LOdSpV8Xh+kCE09amrnByis= X-Received: by 2002:a62:564b:: with SMTP id k72mr12549951pfb.30.1544071303539; Wed, 05 Dec 2018 20:41:43 -0800 (PST) Date: Wed, 5 Dec 2018 20:40:48 -0800 In-Reply-To: Message-Id: <33711939695bf620703d60064c6242a8e4f4b64a.1544071106.git.sdf@google.com> Mime-Version: 1.0 References: X-Mailer: git-send-email 2.20.0.rc1.387.gf8505762e3-goog Subject: [PATCH bpf 2/2] net/flow_dissector: correctly cap nhoff and thoff in case of BPF From: Stanislav Fomichev To: netdev@vger.kernel.org, ast@kernel.org Cc: davem@davemloft.net, daniel@iogearbox.net, simon.horman@netronome.com, liu.song.a23@gmail.com, Stanislav Fomichev Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org We want to make sure that the following condition holds: 0 <= nhoff <= thoff <= skb->len BPF program can set out-of-bounds nhoff and thoff, which is dangerous, see recent commit d0c081b49137 ("flow_dissector: properly cap thoff field")'. Signed-off-by: Stanislav Fomichev Acked-by: Song Liu --- net/core/flow_dissector.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index ff5556d80570..af68207ee56c 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -791,9 +791,12 @@ bool __skb_flow_dissect(const struct sk_buff *skb, /* Restore state */ memcpy(cb, &cb_saved, sizeof(cb_saved)); + flow_keys.nhoff = clamp_t(u16, flow_keys.nhoff, 0, skb->len); + flow_keys.thoff = clamp_t(u16, flow_keys.thoff, + flow_keys.nhoff, skb->len); + __skb_flow_bpf_to_target(&flow_keys, flow_dissector, target_container); - key_control->thoff = min_t(u16, key_control->thoff, skb->len); rcu_read_unlock(); return result == BPF_OK; }