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,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 3BB9CC43331 for ; Mon, 1 Mar 2021 20:33:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 00E5964E5F for ; Mon, 1 Mar 2021 20:33:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243433AbhCAUc5 (ORCPT ); Mon, 1 Mar 2021 15:32:57 -0500 Received: from mail.kernel.org ([198.145.29.99]:36106 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236783AbhCARHG (ORCPT ); Mon, 1 Mar 2021 12:07:06 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0010564F79; Mon, 1 Mar 2021 16:40:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1614616837; bh=s//kz97nON8nvzw4MNeeNZmq/9waPmgrwHCSQPCHk1w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=q3O0JBEpC3k/J+eyXLidP87PC+6x9vJaUsMB8ywTC/Z13+SnuCnTsPwFdTiQcUisg 9Du1hNI4yhrXRta4JeWTQHQ832KiBsDjlRl0Ztv69GkL/pcVZey6e5nRKnOit9bgQv eKGEoUkE63wBlEMEr1EMcULs/3G3A1Ifh/1Q2QWk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Randy Dunlap , syzbot+1e911ad71dd4ea72e04a@syzkaller.appspotmail.com, Jiri Kosina , Benjamin Tissoires , linux-input@vger.kernel.org, Jiri Kosina , Sasha Levin Subject: [PATCH 4.19 112/247] HID: core: detect and skip invalid inputs to snto32() Date: Mon, 1 Mar 2021 17:12:12 +0100 Message-Id: <20210301161037.154110947@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210301161031.684018251@linuxfoundation.org> References: <20210301161031.684018251@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Randy Dunlap [ Upstream commit a0312af1f94d13800e63a7d0a66e563582e39aec ] 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 Signed-off-by: Jiri Kosina Signed-off-by: Sasha Levin --- drivers/hid/hid-core.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index bde5cef3290f5..9b66eb1d42c2d 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -1128,6 +1128,9 @@ 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); -- 2.27.0