From patchwork Wed Feb 3 08:47:56 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 12063779 X-Patchwork-Delegate: kuba@kernel.org 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=-16.3 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, URIBL_BLOCKED autolearn=ham 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 5766EC433E9 for ; Wed, 3 Feb 2021 08:49:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0EE3F64F6C for ; Wed, 3 Feb 2021 08:49:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232947AbhBCIte (ORCPT ); Wed, 3 Feb 2021 03:49:34 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:59065 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232863AbhBCIta (ORCPT ); Wed, 3 Feb 2021 03:49:30 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612342083; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=UV1mOlb0sZPvzlG9rQctRNEJYv8z9raqJ6JgD1LMKwk=; b=EUtcSBbut5NvtwMg5geaLQWREpKpToAxVH+BO3yrZl32oPigCNRGEXtb9agaOLfKZtu9je iUAXwH2uezdJ0HLNjGNj1qX5L4BEwGNiv02yTNx8voWg4vmYeI1F+SmnCwqdHf2mJWCAWw fGcRn4A9oxed4lCSKZ3DsW7q8nYyGm4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-357-5xy14DUgOiuhr2TvWxlV9g-1; Wed, 03 Feb 2021 03:47:59 -0500 X-MC-Unique: 5xy14DUgOiuhr2TvWxlV9g-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 580E99CC03; Wed, 3 Feb 2021 08:47:58 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-115-23.rdu2.redhat.com [10.10.115.23]) by smtp.corp.redhat.com (Postfix) with ESMTP id F348871C85; Wed, 3 Feb 2021 08:47:56 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH net] rxrpc: Fix clearance of Tx/Rx ring when releasing a call From: David Howells To: netdev@vger.kernel.org Cc: syzbot+174de899852504e4a74a@syzkaller.appspotmail.com, syzbot+3d1c772efafd3c38d007@syzkaller.appspotmail.com, Hillf Danton , dhowells@redhat.com, linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org Date: Wed, 03 Feb 2021 08:47:56 +0000 Message-ID: <161234207610.653119.5287360098400436976.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.23 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org At the end of rxrpc_release_call(), rxrpc_cleanup_ring() is called to clear the Rx/Tx skbuff ring, but this doesn't lock the ring whilst it's accessing it. Unfortunately, rxrpc_resend() might be trying to retransmit a packet concurrently with this - and whilst it does lock the ring, this isn't protection against rxrpc_cleanup_call(). Fix this by removing the call to rxrpc_cleanup_ring() from rxrpc_release_call(). rxrpc_cleanup_ring() will be called again anyway from rxrpc_cleanup_call(). The earlier call is just an optimisation to recycle skbuffs more quickly. Alternative solutions include rxrpc_release_call() could try to cancel the work item or wait for it to complete or rxrpc_cleanup_ring() could lock when accessing the ring (which would require a bh lock). This can produce a report like the following: BUG: KASAN: use-after-free in rxrpc_send_data_packet+0x19b4/0x1e70 net/rxrpc/output.c:372 Read of size 4 at addr ffff888011606e04 by task kworker/0:0/5 ... Workqueue: krxrpcd rxrpc_process_call Call Trace: ... kasan_report.cold+0x79/0xd5 mm/kasan/report.c:413 rxrpc_send_data_packet+0x19b4/0x1e70 net/rxrpc/output.c:372 rxrpc_resend net/rxrpc/call_event.c:266 [inline] rxrpc_process_call+0x1634/0x1f60 net/rxrpc/call_event.c:412 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275 ... Allocated by task 2318: ... sock_alloc_send_pskb+0x793/0x920 net/core/sock.c:2348 rxrpc_send_data+0xb51/0x2bf0 net/rxrpc/sendmsg.c:358 rxrpc_do_sendmsg+0xc03/0x1350 net/rxrpc/sendmsg.c:744 rxrpc_sendmsg+0x420/0x630 net/rxrpc/af_rxrpc.c:560 ... Freed by task 2318: ... kfree_skb+0x140/0x3f0 net/core/skbuff.c:704 rxrpc_free_skb+0x11d/0x150 net/rxrpc/skbuff.c:78 rxrpc_cleanup_ring net/rxrpc/call_object.c:485 [inline] rxrpc_release_call+0x5dd/0x860 net/rxrpc/call_object.c:552 rxrpc_release_calls_on_socket+0x21c/0x300 net/rxrpc/call_object.c:579 rxrpc_release_sock net/rxrpc/af_rxrpc.c:885 [inline] rxrpc_release+0x263/0x5a0 net/rxrpc/af_rxrpc.c:916 __sock_release+0xcd/0x280 net/socket.c:597 ... The buggy address belongs to the object at ffff888011606dc0 which belongs to the cache skbuff_head_cache of size 232 Fixes: 248f219cb8bc ("rxrpc: Rewrite the data and ack handling code") Reported-by: syzbot+174de899852504e4a74a@syzkaller.appspotmail.com Reported-by: syzbot+3d1c772efafd3c38d007@syzkaller.appspotmail.com Signed-off-by: David Howells cc: Hillf Danton --- net/rxrpc/call_object.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/net/rxrpc/call_object.c b/net/rxrpc/call_object.c index c845594b663f..4eb91d958a48 100644 --- a/net/rxrpc/call_object.c +++ b/net/rxrpc/call_object.c @@ -548,8 +548,6 @@ void rxrpc_release_call(struct rxrpc_sock *rx, struct rxrpc_call *call) rxrpc_disconnect_call(call); if (call->security) call->security->free_call_crypto(call); - - rxrpc_cleanup_ring(call); _leave(""); }