From patchwork Tue Apr 6 16:04:35 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ricardo Ribalda X-Patchwork-Id: 416204 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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 8CFCDC43460 for ; Tue, 6 Apr 2021 16:04:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 62A76613CB for ; Tue, 6 Apr 2021 16:04:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346174AbhDFQEr (ORCPT ); Tue, 6 Apr 2021 12:04:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36260 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239349AbhDFQEr (ORCPT ); Tue, 6 Apr 2021 12:04:47 -0400 Received: from mail-ed1-x534.google.com (mail-ed1-x534.google.com [IPv6:2a00:1450:4864:20::534]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 52F6AC06174A for ; Tue, 6 Apr 2021 09:04:39 -0700 (PDT) Received: by mail-ed1-x534.google.com with SMTP id dd20so10017155edb.12 for ; Tue, 06 Apr 2021 09:04:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=y9UWeHSBoySzTHkOgKQzF5RiGebYchxO96+3Wf+rxXc=; b=Xa3fFCTQCoUijqu6po9q3HjZRjXP27V6wL5ACYsFzPZbcSqjqqMU1RIM6ZZ7fDYhUg inNmTU5i2JKGLgCVpqGzf5vmZ/SiLojWM338IOj+7vCfJ+o2ibNViO+2xg+rTQaCXNW6 n7jmS0tPAe4YlLmXaDge4BF8Tkua+GP0ZnJGA= 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=y9UWeHSBoySzTHkOgKQzF5RiGebYchxO96+3Wf+rxXc=; b=jGWGePK66s3mkVYdFT/4IcwPEL/73hgOmzVLni5dTfTFXsOUXy4LnyZD5ZWtOek2Ai gyjORnK030HYEiZfdWDiE5DHq/ZignxNFs6zgTzP/4KbXw3KepYYIVl2KEFIZeO9jQk8 jutQCEaERO09m77KD6YqThqmZhovMKox33sCeEgyiq6LQl2VFsre/siDBSWMO3R7cnUq Mipj6fHPERl8DpndWzp8LahxR3KyREh3I7O3CkjH8psWajG+zMcydI/WX0Q/cslMID7h YTqvvZ6Rr/hOhTOUIt6rVOfAtAy9RZdipiAS397kprVh91Yx8c24rHbvZezZ961Ayw8x wYrA== X-Gm-Message-State: AOAM533Izi2RywiPK93EcoxC9uSyX8ydvY8Bk+Yw9yAVpw9+zPBov9N8 xMdU95TIKF1gaQNTyi/UUQWt5w== X-Google-Smtp-Source: ABdhPJyP6fqRB9nYYchphWa0F5/357LF8RkkaedmGdLVe2OQDDAEKML5Y1zJxywfpsUsfk80MJzHpA== X-Received: by 2002:a05:6402:c:: with SMTP id d12mr38059165edu.100.1617725078058; Tue, 06 Apr 2021 09:04:38 -0700 (PDT) Received: from alco.lan ([80.71.134.83]) by smtp.gmail.com with ESMTPSA id hz24sm6411140ejc.119.2021.04.06.09.04.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 Apr 2021 09:04:37 -0700 (PDT) From: Ricardo Ribalda To: Tomasz Figa , Marek Szyprowski , Mauro Carvalho Chehab , Daniel Vetter , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Christoph Hellwig , iommu@lists.linux-foundation.org Cc: Ricardo Ribalda , stable@vger.kernel.org Subject: [PATCH RESEND] lib/scatterlist: Fix NULL pointer deference Date: Tue, 6 Apr 2021 18:04:35 +0200 Message-Id: <20210406160435.206115-1-ribalda@chromium.org> X-Mailer: git-send-email 2.31.0.208.g409f899ff0-goog MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org When sg_alloc_table_from_pages is called with n_pages = 0, we write in a non-allocated page. Fix it by checking early the error condition. [ 7.666801] BUG: kernel NULL pointer dereference, address: 0000000000000010 [ 7.667487] #PF: supervisor read access in kernel mode [ 7.667970] #PF: error_code(0x0000) - not-present page [ 7.668448] PGD 0 P4D 0 [ 7.668690] Oops: 0000 [#1] SMP NOPTI [ 7.669037] CPU: 0 PID: 184 Comm: modprobe Not tainted 5.11.0+ #2 [ 7.669606] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 [ 7.670378] RIP: 0010:__sg_alloc_table_from_pages+0x2c5/0x4a0 [ 7.670924] Code: c9 01 48 c7 40 08 00 00 00 00 48 89 08 8b 47 0c 41 8d 44 00 ff 89 47 0c 48 81 fa 00 f0 ff ff 0f 87 d4 01 00 00 49 8b 16 89 d8 <4a> 8b 74 fd 00 4c 89 d1 44 29 f8 c1 e0 0c 44 29 d8 4c 39 d0 48 0f [ 7.672643] RSP: 0018:ffffba1e8028fb30 EFLAGS: 00010287 [ 7.673133] RAX: 0000000000000001 RBX: 0000000000000001 RCX: 0000000000000002 [ 7.673791] RDX: 0000000000000002 RSI: ffffffffada6d0ba RDI: ffff9afe01fff820 [ 7.674448] RBP: 0000000000000010 R08: 0000000000000001 R09: 0000000000000001 [ 7.675100] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 7.675754] R13: 00000000fffff000 R14: ffff9afe01fff800 R15: 0000000000000000 [ 7.676409] FS: 00007fb0f448f540(0000) GS:ffff9afe07a00000(0000) knlGS:0000000000000000 [ 7.677151] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 7.677681] CR2: 0000000000000010 CR3: 0000000002184001 CR4: 0000000000370ef0 [ 7.678342] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 7.679019] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 7.680349] Call Trace: [ 7.680605] ? device_add+0x146/0x810 [ 7.681021] sg_alloc_table_from_pages+0x11/0x30 [ 7.681511] vb2_dma_sg_alloc+0x162/0x280 [videobuf2_dma_sg] Cc: stable@vger.kernel.org Fixes: efc42bc98058 ("scatterlist: add sg_alloc_table_from_pages function") Signed-off-by: Ricardo Ribalda Reviewed-by: Christoph Hellwig --- lib/scatterlist.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/lib/scatterlist.c b/lib/scatterlist.c index a59778946404..1e83b6a3d930 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -435,6 +435,9 @@ struct scatterlist *__sg_alloc_table_from_pages(struct sg_table *sgt, unsigned int added_nents = 0; struct scatterlist *s = prv; + if (n_pages == 0) + return ERR_PTR(-EINVAL); + /* * The algorithm below requires max_segment to be aligned to PAGE_SIZE * otherwise it can overshoot.