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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 F11FFC3A59F for ; Thu, 29 Aug 2019 18:32:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CAB4D2166E for ; Thu, 29 Aug 2019 18:32:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567103561; bh=5y9dvtzLtnMSqUk9d8sNDkmgONsLAP0F782sRfpeUOY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=h2qVzg7qv/15w31fXFXoYK/iWxKqCys7CYDmQExAGdLGiHa+gL1FRJkmOCwNKjh7k wrOZWbnQJIRAczh3DWpi60Q33Oe50MsnRnOpnia3nh1PJirYCgZMQBNQjAPsq2MA3+ 9radkq5WMpHXWl67fIRZBzVd8nvnlBLBH4AYicBs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729604AbfH2Scl (ORCPT ); Thu, 29 Aug 2019 14:32:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:55674 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728657AbfH2SN7 (ORCPT ); Thu, 29 Aug 2019 14:13:59 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0D4F821874; Thu, 29 Aug 2019 18:13:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567102437; bh=5y9dvtzLtnMSqUk9d8sNDkmgONsLAP0F782sRfpeUOY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ru7PmfHqWAi1lwEjRb3KUNkUXUDpLzqPKT/BX+BwsVAksaBnD5LGm/DU5HDDT1imk CcQrI37cEdZj03MDI6iNH9wstr8ga/GvykyqEETh6RAvYrgjs7aeTQUH+Z+cIYjRNL meq18KxDy75HPB24vM+E0ag0znmBgCTsAArl5QdI= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: David Howells , syzbot+78e71c5bab4f76a6a719@syzkaller.appspotmail.com, Sasha Levin , linux-afs@lists.infradead.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 5.2 26/76] rxrpc: Fix read-after-free in rxrpc_queue_local() Date: Thu, 29 Aug 2019 14:12:21 -0400 Message-Id: <20190829181311.7562-26-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190829181311.7562-1-sashal@kernel.org> References: <20190829181311.7562-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: David Howells [ Upstream commit 06d9532fa6b34f12a6d75711162d47c17c1add72 ] rxrpc_queue_local() attempts to queue the local endpoint it is given and then, if successful, prints a trace line. The trace line includes the current usage count - but we're not allowed to look at the local endpoint at this point as we passed our ref on it to the workqueue. Fix this by reading the usage count before queuing the work item. Also fix the reading of local->debug_id for trace lines, which must be done with the same consideration as reading the usage count. Fixes: 09d2bf595db4 ("rxrpc: Add a tracepoint to track rxrpc_local refcounting") Reported-by: syzbot+78e71c5bab4f76a6a719@syzkaller.appspotmail.com Signed-off-by: David Howells Signed-off-by: Sasha Levin --- include/trace/events/rxrpc.h | 6 +++--- net/rxrpc/local_object.c | 19 ++++++++++--------- 2 files changed, 13 insertions(+), 12 deletions(-) diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h index cc1d060cbf133..fa06b528c73c5 100644 --- a/include/trace/events/rxrpc.h +++ b/include/trace/events/rxrpc.h @@ -498,10 +498,10 @@ rxrpc_tx_points; #define E_(a, b) { a, b } TRACE_EVENT(rxrpc_local, - TP_PROTO(struct rxrpc_local *local, enum rxrpc_local_trace op, + TP_PROTO(unsigned int local_debug_id, enum rxrpc_local_trace op, int usage, const void *where), - TP_ARGS(local, op, usage, where), + TP_ARGS(local_debug_id, op, usage, where), TP_STRUCT__entry( __field(unsigned int, local ) @@ -511,7 +511,7 @@ TRACE_EVENT(rxrpc_local, ), TP_fast_assign( - __entry->local = local->debug_id; + __entry->local = local_debug_id; __entry->op = op; __entry->usage = usage; __entry->where = where; diff --git a/net/rxrpc/local_object.c b/net/rxrpc/local_object.c index 918bffca3ddb6..68e9342fd4335 100644 --- a/net/rxrpc/local_object.c +++ b/net/rxrpc/local_object.c @@ -93,7 +93,7 @@ static struct rxrpc_local *rxrpc_alloc_local(struct rxrpc_net *rxnet, local->debug_id = atomic_inc_return(&rxrpc_debug_id); memcpy(&local->srx, srx, sizeof(*srx)); local->srx.srx_service = 0; - trace_rxrpc_local(local, rxrpc_local_new, 1, NULL); + trace_rxrpc_local(local->debug_id, rxrpc_local_new, 1, NULL); } _leave(" = %p", local); @@ -321,7 +321,7 @@ struct rxrpc_local *rxrpc_get_local(struct rxrpc_local *local) int n; n = atomic_inc_return(&local->usage); - trace_rxrpc_local(local, rxrpc_local_got, n, here); + trace_rxrpc_local(local->debug_id, rxrpc_local_got, n, here); return local; } @@ -335,7 +335,8 @@ struct rxrpc_local *rxrpc_get_local_maybe(struct rxrpc_local *local) if (local) { int n = atomic_fetch_add_unless(&local->usage, 1, 0); if (n > 0) - trace_rxrpc_local(local, rxrpc_local_got, n + 1, here); + trace_rxrpc_local(local->debug_id, rxrpc_local_got, + n + 1, here); else local = NULL; } @@ -343,16 +344,16 @@ struct rxrpc_local *rxrpc_get_local_maybe(struct rxrpc_local *local) } /* - * Queue a local endpoint unless it has become unreferenced and pass the - * caller's reference to the work item. + * Queue a local endpoint and pass the caller's reference to the work item. */ void rxrpc_queue_local(struct rxrpc_local *local) { const void *here = __builtin_return_address(0); + unsigned int debug_id = local->debug_id; + int n = atomic_read(&local->usage); if (rxrpc_queue_work(&local->processor)) - trace_rxrpc_local(local, rxrpc_local_queued, - atomic_read(&local->usage), here); + trace_rxrpc_local(debug_id, rxrpc_local_queued, n, here); else rxrpc_put_local(local); } @@ -367,7 +368,7 @@ void rxrpc_put_local(struct rxrpc_local *local) if (local) { n = atomic_dec_return(&local->usage); - trace_rxrpc_local(local, rxrpc_local_put, n, here); + trace_rxrpc_local(local->debug_id, rxrpc_local_put, n, here); if (n == 0) call_rcu(&local->rcu, rxrpc_local_rcu); @@ -454,7 +455,7 @@ static void rxrpc_local_processor(struct work_struct *work) container_of(work, struct rxrpc_local, processor); bool again; - trace_rxrpc_local(local, rxrpc_local_processing, + trace_rxrpc_local(local->debug_id, rxrpc_local_processing, atomic_read(&local->usage), NULL); do { -- 2.20.1