From nobody Fri Dec 19 04:23:32 2025 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2AE86FA373E for ; Mon, 24 Oct 2022 11:45:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229966AbiJXLpC (ORCPT ); Mon, 24 Oct 2022 07:45:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43336 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229682AbiJXLnq (ORCPT ); Mon, 24 Oct 2022 07:43:46 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BCB40112E; Mon, 24 Oct 2022 04:40:48 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 7A4A0CE130F; Mon, 24 Oct 2022 11:39:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8ACE3C433D6; Mon, 24 Oct 2022 11:39:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666611558; bh=RN47miuc4QC2GlUe7aKV+8SGfPx1U5VJI+JT1YJIOLA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rLt2/YJmMw60J2SyL/fHPszEKUUSj30fdMH8jc23M88AZPS2gF05jXTl7NcfJTENg ij2p+BGWimB5fMp+4lXPhAoZFj8N4iHXkgS7ZB++vYzT1DvapqBfF66gdDMhTznApW lippoKp7pPFKzn860HubszMJq9A6d25vGvxisWxw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Dmitry Vyukov" , stable , syzbot+23f57c5ae902429285d7@syzkaller.appspotmail.com, Tadeusz Struk , PaX Team Subject: [PATCH 4.9 025/159] usb: mon: make mmapped memory read only Date: Mon, 24 Oct 2022 13:29:39 +0200 Message-Id: <20221024112950.324575967@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024112949.358278806@linuxfoundation.org> References: <20221024112949.358278806@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Tadeusz Struk commit a659daf63d16aa883be42f3f34ff84235c302198 upstream. Syzbot found an issue in usbmon module, where the user space client can corrupt the monitor's internal memory, causing the usbmon module to crash the kernel with segfault, UAF, etc. The reproducer mmaps the /dev/usbmon memory to user space, and overwrites it with arbitrary data, which causes all kinds of issues. Return an -EPERM error from mon_bin_mmap() if the flag VM_WRTIE is set. Also clear VM_MAYWRITE to make it impossible to change it to writable later. Cc: "Dmitry Vyukov" Cc: stable Fixes: 6f23ee1fefdc ("USB: add binary API to usbmon") Suggested-by: PaX Team # for the VM_MAYRITE portion Link: https://syzkaller.appspot.com/bug?id=3D2eb1f35d6525fa4a74d75b4244971e= 5b1411c95a Reported-by: syzbot+23f57c5ae902429285d7@syzkaller.appspotmail.com Signed-off-by: Tadeusz Struk Link: https://lore.kernel.org/r/20220919215957.205681-1-tadeusz.struk@linar= o.org Signed-off-by: Greg Kroah-Hartman --- drivers/usb/mon/mon_bin.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/drivers/usb/mon/mon_bin.c +++ b/drivers/usb/mon/mon_bin.c @@ -1265,6 +1265,11 @@ static int mon_bin_mmap(struct file *fil { /* don't do anything here: "fault" will set up page table entries */ vma->vm_ops =3D &mon_bin_vm_ops; + + if (vma->vm_flags & VM_WRITE) + return -EPERM; + + vma->vm_flags &=3D ~VM_MAYWRITE; vma->vm_flags |=3D VM_DONTEXPAND | VM_DONTDUMP; vma->vm_private_data =3D filp->private_data; mon_bin_vma_open(vma);