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 Received: from lists.zx2c4.com (lists.zx2c4.com [165.227.139.114]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 57721C77B75 for ; Tue, 23 May 2023 17:08:09 +0000 (UTC) Received: by lists.zx2c4.com (ZX2C4 Mail Server) with ESMTP id bb07bd66; Tue, 23 May 2023 17:05:41 +0000 (UTC) Received: from mail-wm1-x335.google.com (mail-wm1-x335.google.com [2a00:1450:4864:20::335]) by lists.zx2c4.com (ZX2C4 Mail Server) with ESMTPS id cb69d1ef (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO) for ; Tue, 23 May 2023 17:05:39 +0000 (UTC) Received: by mail-wm1-x335.google.com with SMTP id 5b1f17b1804b1-3f5dbd8f677so2725e9.1 for ; Tue, 23 May 2023 10:05:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1684861539; x=1687453539; 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=rIR5dBTy4LAOVVbHQuz2WZ9012ZJ29GqkZ6Duz5IJ1o=; b=0ph8Fiwykgc2GiwRw+3NbsZHDpATEbqZdsCFqEUKNhnPhmdDYoJ4qb8MZ7WI1hfU5m WV/7wqMXZsumFezN//QAqQsPeyI6LpF0C2suuwfgHDEJyttsA+OfdEVIz6kR6QUncdG6 ZZYBnUNg1apIvfMHVFg/sFZHmt+SgZMlE0kXBcXmq3M9TA/Ay7nmsxKumWKZa3JUvYRr NEnmT4H5+eqw/tKZ56n0lJ5mL1En05RX9pKHC568xPvDkVfbOoROgnPrSO5PRe2DM9UO C/bGtXt9qkZJhM4wEhkqkUr42S1FFtoS9oWiwH3Geq5KVx9oy5OcBr1ljnVtcJNWProg 1WVg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1684861539; x=1687453539; 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=rIR5dBTy4LAOVVbHQuz2WZ9012ZJ29GqkZ6Duz5IJ1o=; b=GwENcc7FtdWo1e6JbpqiVK1rHWqiZRB/9WqnUb7h/qrsRViNUlBMF9Tr5Joju9Fvei fstUnpwgRhJz+CVLFLEhA8RBYzx0ylJ1prnQSAZza+bYKzg3WOoKtAyMgaJLw4rDrq/l zvcRow8x2y/q5l+SKt73xtL6lwQEE3pTZpbKZSzvtVtKngy6Aq10gQ61IxAsMSU71fiR 9OFEwwTDOosZN765VP92oj7ivTNdVhw9z5z06aa2H37KYzh26/nBCJP3bdHNCV3B2by7 Z9L/A7XCQ0jETuGmL33jqD3BQzKzbldJt2Q5Y27+jIQrD9Of0LAcCYOAjrfyID/U53wf bNYg== X-Gm-Message-State: AC+VfDwISnG8MA7X9Z6zdKGRDxGm4rRF4fvvfhHay8VpYM6j3DVAiBM6 hqKjpMJMYUiBsFq2JDSinxIxc5bpovCicXogMmjTMA== X-Google-Smtp-Source: ACHHUZ4JrYStaHVNsIxq+qlNQuKOS/DwLStXtaCqL3kzj1eOBBKVWiuPzynxEqHX5UHiWs6n9l9i8AGRpPPNyk+1xPs= X-Received: by 2002:a05:600c:3b8c:b0:3f4:2736:b5eb with SMTP id n12-20020a05600c3b8c00b003f42736b5ebmr5437wms.1.1684861538921; Tue, 23 May 2023 10:05:38 -0700 (PDT) MIME-Version: 1.0 References: <000000000000c0b11d05fa917fe3@google.com> <20230523090512.19ca60b6@kernel.org> <20230523094108.0c624d47@kernel.org> <20230523094736.3a9f6f8c@kernel.org> In-Reply-To: From: Eric Dumazet Date: Tue, 23 May 2023 19:05:27 +0200 Message-ID: Subject: Re: [syzbot] [wireguard?] KASAN: slab-use-after-free Write in enqueue_timer To: "Jason A. Donenfeld" Cc: Jakub Kicinski , syzbot , netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com, davem@davemloft.net, linux-kernel@vger.kernel.org, pabeni@redhat.com, wireguard@lists.zx2c4.com, jann@thejh.net Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-BeenThere: wireguard@lists.zx2c4.com X-Mailman-Version: 2.1.30rc1 Precedence: list List-Id: Development discussion of WireGuard List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: wireguard-bounces@lists.zx2c4.com Sender: "WireGuard" On Tue, May 23, 2023 at 7:01=E2=80=AFPM Jason A. Donenfeld wrote: > > On Tue, May 23, 2023 at 09:47:36AM -0700, Jakub Kicinski wrote: > > On Tue, 23 May 2023 18:42:53 +0200 Jason A. Donenfeld wrote: > > > > It should, no idea why it isn't. Looking thru the code now I don't = see > > > > any obvious gaps where timer object is on a list but not active :S > > > > There's no way to get a vmcore from syzbot, right? :) > > > > > > > > Also I thought the shutdown leads to a warning when someone tries t= o > > > > schedule the dead timer but in fact add_timer() just exits cleanly. > > > > So the shutdown won't help us find the culprit :( > > > > > > Worth noting that it could also be caused by adding to a dead timer > > > anywhere in priv_data of another netdev, not just the sole timer_list > > > in net_device. > > > > Oh, I thought you zero'ed in on the watchdog based on offsets. > > Still, object debug should track all timers in the slab and complain > > on the free path. > > No, I mentioned watchdog because it's the only timer_list in struct > net_device. > > Offset analysis is an interesting idea though. Look at this: > > > The buggy address belongs to the object at ffff88801ecc0000 > > which belongs to the cache kmalloc-cg-8k of size 8192 > > The buggy address is located 5376 bytes inside of > > freed 8192-byte region [ffff88801ecc0000, ffff88801ecc2000) > > IDA says that for syzkaller's vmlinux, net_device has a size of 0xc80 > and wg_device has a size of 0x880. 0xc80+0x880=3D5376. Coincidence that > the address offset is just after what wg uses? Note that the syzkaller report mentioned: alloc_netdev_mqs+0x89/0xf30 net/core/dev.c:10626 usbnet_probe+0x196/0x2770 drivers/net/usb/usbnet.c:1698 usb_probe_interface+0x5c4/0xb00 drivers/usb/core/driver.c:396 really_probe+0x294/0xc30 drivers/base/dd.c:658 __driver_probe_device+0x1a2/0x3d0 drivers/base/dd.c:800 driver_probe_device+0x50/0x420 drivers/base/dd.c:830 __device_attach_driver+0x2d3/0x520 drivers/base/dd.c:958 So maybe an usbnet driver has a timer_list in its priv_data.