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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 C93CAC3526B for ; Thu, 17 Dec 2020 01:13:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9202523405 for ; Thu, 17 Dec 2020 01:13:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389087AbgLQBNL (ORCPT ); Wed, 16 Dec 2020 20:13:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55064 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389016AbgLQBNK (ORCPT ); Wed, 16 Dec 2020 20:13:10 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 434B8C0617B0; Wed, 16 Dec 2020 17:12:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:In-Reply-To:References; bh=F8PQcYi3gvouvVHva2A57eJGUWi5JG5zYlkbXK0yVMo=; b=EBkrCGqMq/3cf0a2Z0P7yAhM0r LoFNNB7S/agSex5YbwWgpt+4NKxHgCTaBgsbCX4qXSlEqt1CQoxSYpTdElUe0nHP5bkE5G2k2Xx/J tnYxQiyJNSUPLBjmsGqHwmi3xMHtoIPHKY4Z4Lu4JkSlcPCBMo7rqlKBoa2GSnfs6k42gQkvVpc2+ cVzc+Dgm1gR7QNN6F40mulJCOfSnmztxSgNBXp/HfG0r5EKd/4VcEXpb7tQPkbksvdu619QepoDAI LxkOxtdfiKUya/YARcUxc7FSzsGfPqLjBvsWRxA5+TIDKM9wAxOJtNlK0dkRooPshWOcfeQutC1Gm 6+O/QoPw==; Received: from [2601:1c0:6280:3f0::64ea] (helo=smtpauth.infradead.org) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kphqF-0003ck-7i; Thu, 17 Dec 2020 01:12:27 +0000 From: Randy Dunlap To: linux-kernel@vger.kernel.org Cc: Randy Dunlap , syzbot+1e911ad71dd4ea72e04a@syzkaller.appspotmail.com, Jiri Kosina , Benjamin Tissoires , linux-input@vger.kernel.org Subject: [PATCH] HID: core: detect and skip invalid inputs to snto32() Date: Wed, 16 Dec 2020 17:12:21 -0800 Message-Id: <20201217011221.25678-1-rdunlap@infradead.org> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org Prevent invalid (0, 0) inputs to hid-core's snto32() function. Maybe it is just the dummy device here that is causing this, but there are hundreds of calls to snto32(0, 0). Having n (bits count) of 0 is causing the current UBSAN trap with a shift value of 0xffffffff (-1, or n - 1 in this function). Either of the value to shift being 0 or the bits count being 0 can be handled by just returning 0 to the caller, avoiding the following complex shift + OR operations: return value & (1 << (n - 1)) ? value | (~0U << n) : value; Fixes: dde5845a529f ("[PATCH] Generic HID layer - code split") Signed-off-by: Randy Dunlap Reported-by: syzbot+1e911ad71dd4ea72e04a@syzkaller.appspotmail.com Cc: Jiri Kosina Cc: Benjamin Tissoires Cc: linux-input@vger.kernel.org --- drivers/hid/hid-core.c | 3 +++ 1 file changed, 3 insertions(+) --- lnx-510.orig/drivers/hid/hid-core.c +++ lnx-510/drivers/hid/hid-core.c @@ -1307,6 +1307,9 @@ EXPORT_SYMBOL_GPL(hid_open_report); static s32 snto32(__u32 value, unsigned n) { + if (!value || !n) + return 0; + switch (n) { case 8: return ((__s8)value); case 16: return ((__s16)value);