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 1BCBBC433EF for ; Wed, 24 Nov 2021 13:11:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345053AbhKXNOw (ORCPT ); Wed, 24 Nov 2021 08:14:52 -0500 Received: from mail.kernel.org ([198.145.29.99]:52018 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347167AbhKXNML (ORCPT ); Wed, 24 Nov 2021 08:12:11 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id F308B61A85; Wed, 24 Nov 2021 12:42:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1637757738; bh=Hw4ioX8VStx2ymBPiv3NQlNyTTnqyXkxgYUBC6NSLPw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hJ4UdB4cYgMXPOxNV7kdzMes9n8NkBvWquJ7a1Ho8DfbJIeC79iys/iI22TJhDdIV HyKX96vnOFKlGpQ/xMRJ+I+o1Qa0lZ8Pvm024UHtpPqeK3zH9Zw2yViKp5gFTN51bS B8nsoHzjs4TnJxZ2kb5Wx+eNlolmOwJqh27RFP4M= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , syzbot , "David S. Miller" , Sasha Levin Subject: [PATCH 4.19 227/323] llc: fix out-of-bound array index in llc_sk_dev_hash() Date: Wed, 24 Nov 2021 12:56:57 +0100 Message-Id: <20211124115726.584860718@linuxfoundation.org> X-Mailer: git-send-email 2.34.0 In-Reply-To: <20211124115718.822024889@linuxfoundation.org> References: <20211124115718.822024889@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: Eric Dumazet [ Upstream commit 8ac9dfd58b138f7e82098a4e0a0d46858b12215b ] Both ifindex and LLC_SK_DEV_HASH_ENTRIES are signed. This means that (ifindex % LLC_SK_DEV_HASH_ENTRIES) is negative if @ifindex is negative. We could simply make LLC_SK_DEV_HASH_ENTRIES unsigned. In this patch I chose to use hash_32() to get more entropy from @ifindex, like llc_sk_laddr_hashfn(). UBSAN: array-index-out-of-bounds in ./include/net/llc.h:75:26 index -43 is out of range for type 'hlist_head [64]' CPU: 1 PID: 20999 Comm: syz-executor.3 Not tainted 5.15.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 ubsan_epilogue+0xb/0x5a lib/ubsan.c:151 __ubsan_handle_out_of_bounds.cold+0x62/0x6c lib/ubsan.c:291 llc_sk_dev_hash include/net/llc.h:75 [inline] llc_sap_add_socket+0x49c/0x520 net/llc/llc_conn.c:697 llc_ui_bind+0x680/0xd70 net/llc/af_llc.c:404 __sys_bind+0x1e9/0x250 net/socket.c:1693 __do_sys_bind net/socket.c:1704 [inline] __se_sys_bind net/socket.c:1702 [inline] __x64_sys_bind+0x6f/0xb0 net/socket.c:1702 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fa503407ae9 Fixes: 6d2e3ea28446 ("llc: use a device based hash table to speed up multicast delivery") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- include/net/llc.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/include/net/llc.h b/include/net/llc.h index df282d9b40170..9c10b121b49b0 100644 --- a/include/net/llc.h +++ b/include/net/llc.h @@ -72,7 +72,9 @@ struct llc_sap { static inline struct hlist_head *llc_sk_dev_hash(struct llc_sap *sap, int ifindex) { - return &sap->sk_dev_hash[ifindex % LLC_SK_DEV_HASH_ENTRIES]; + u32 bucket = hash_32(ifindex, LLC_SK_DEV_HASH_BITS); + + return &sap->sk_dev_hash[bucket]; } static inline -- 2.33.0