From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1F2F7C433E0 for ; Mon, 25 May 2020 08:04:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ED44C207DA for ; Mon, 25 May 2020 08:04:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Zes3Uz9l" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387838AbgEYIEZ (ORCPT ); Mon, 25 May 2020 04:04:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42332 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387807AbgEYIEZ (ORCPT ); Mon, 25 May 2020 04:04:25 -0400 Received: from mail-pg1-x541.google.com (mail-pg1-x541.google.com [IPv6:2607:f8b0:4864:20::541]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0201AC061A0E; Mon, 25 May 2020 01:04:25 -0700 (PDT) Received: by mail-pg1-x541.google.com with SMTP id f21so5373560pgg.12; Mon, 25 May 2020 01:04:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=OMcD6XNHpVb4lacePOdo/rE18+iLuc+4mEImQrhoTNs=; b=Zes3Uz9lypw63iz50yk+D+/L836Fzh/13qv8blPLh6AMjg+/vJ0wjdVaD01QpnrIPZ mEKSAPE2qXhLBeRNQD7fOkdQ1AIUcP2cmrXiN/EGLosPyEoNHpGQCA8XU849gqjZUoO1 mhaFyal9X5gUUo3FIUSFnix/eQElBBQqwcM6KjbRgcgkzGfsxMkc6nBnN/ouqGnV6Miq fnaun6KSUAPkLv0FlFk/RKE+E8rkOg/sMuziVzFHs9nkKar7/fQn2l4WD/x1ksPd0hon GpRw/0iVcfkTDiyXc44Gx2Bu4CvfaIjQU6e3M2TGUbIsfDK9/ZL153i0h5uPmYui92SG I82w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=OMcD6XNHpVb4lacePOdo/rE18+iLuc+4mEImQrhoTNs=; b=U98TrnSVI5WBvRI4McrNfLAuOEBPGNr1D93XzS99dH8AtHnyDoKdPoCqQb/Fzbjn/R 0b7X3UxjunoiDjrq+ht+2ZXKimCYB5dE7g/5UwR/s0+nG9y4F6HVkhuMNjyxNEeOxX9O RQv7IIkZbLb7fFLyOByvhmI+sR9mUsNa2THwmgJerQF1YNMiZCVmaRahzhGltuPN7oq8 iz47L4Ug40ldlSq5hcWVNM7NQxsOg8ON2a7UnS9ucFC3stVDSicr9SDBnkCzQejP5ekW hlfmolDj4WnjIGp54fHKVC6eUQsSsjc+MHWtp/5hd0EhrscASwrooSjaBRiUMwhgGjbZ UVhA== X-Gm-Message-State: AOAM533KzENDfqJVNXNjTrm4d9gI1XpKngMBxo+9GRk0opkcidj1xu4n 93Xeq7XZkZ0Vpi0mqC1MyG4= X-Google-Smtp-Source: ABdhPJx7kAsmj8qo8AgkJFRnVqYtFp7l0+6zcxTgxGfPKoB/qiFUZjr+Vp+QMDLdyIqfnDUroAWEhQ== X-Received: by 2002:a62:a518:: with SMTP id v24mr14926568pfm.295.1590393864494; Mon, 25 May 2020 01:04:24 -0700 (PDT) Received: from btopel-mobl.ger.intel.com ([192.55.54.40]) by smtp.gmail.com with ESMTPSA id k29sm11453316pgf.77.2020.05.25.01.04.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 25 May 2020 01:04:23 -0700 (PDT) From: =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= To: magnus.karlsson@intel.com, jonathan.lemon@gmail.com, ast@kernel.org, daniel@iogearbox.net, netdev@vger.kernel.org, bpf@vger.kernel.org Cc: =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= , maximmi@mellanox.com, =?UTF-8?q?Minh=20B=C3=B9i=20Quang?= Subject: [PATCH bpf] xsk: add overflow check for u64 division, stored into u32 Date: Mon, 25 May 2020 10:03:59 +0200 Message-Id: <20200525080400.13195-1-bjorn.topel@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org From: Björn Töpel The npgs member of struct xdp_umem is an u32 entity, and stores the number of pages the UMEM consumes. The calculation of npgs npgs = size / PAGE_SIZE can overflow. To avoid overflow scenarios, the division is now first stored in a u64, and the result is verified to fit into 32b. An alternative would be storing the npgs as a u64, however, this wastes memory and is an unrealisticly large packet area. Link: https://lore.kernel.org/bpf/CACtPs=GGvV-_Yj6rbpzTVnopgi5nhMoCcTkSkYrJHGQHJWFZMQ@mail.gmail.com/ Fixes: c0c77d8fb787 ("xsk: add user memory registration support sockopt") Reported-by: "Minh Bùi Quang" Signed-off-by: Björn Töpel --- net/xdp/xdp_umem.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c index ed7a6060f73c..3889bd9aec46 100644 --- a/net/xdp/xdp_umem.c +++ b/net/xdp/xdp_umem.c @@ -341,8 +341,8 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr) { bool unaligned_chunks = mr->flags & XDP_UMEM_UNALIGNED_CHUNK_FLAG; u32 chunk_size = mr->chunk_size, headroom = mr->headroom; + u64 npgs, addr = mr->addr, size = mr->len; unsigned int chunks, chunks_per_page; - u64 addr = mr->addr, size = mr->len; int err; if (chunk_size < XDP_UMEM_MIN_CHUNK_SIZE || chunk_size > PAGE_SIZE) { @@ -372,6 +372,10 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr) if ((addr + size) < addr) return -EINVAL; + npgs = div_u64(size, PAGE_SIZE); + if (npgs > U32_MAX) + return -EINVAL; + chunks = (unsigned int)div_u64(size, chunk_size); if (chunks == 0) return -EINVAL; @@ -391,7 +395,7 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr) umem->size = size; umem->headroom = headroom; umem->chunk_size_nohr = chunk_size - headroom; - umem->npgs = size / PAGE_SIZE; + umem->npgs = (u32)npgs; umem->pgs = NULL; umem->user = NULL; umem->flags = mr->flags; base-commit: d04322a0da1e86aedaa322ce933cfb8c0191d1eb -- 2.25.1