Patch Detail
get:
Show a patch.
patch:
Update a patch.
put:
Update a patch.
GET /api/patches/817513/?format=api
{ "id": 817513, "url": "http://patchwork.ozlabs.org/api/patches/817513/?format=api", "web_url": "http://patchwork.ozlabs.org/project/netdev/patch/11b04a711e0c263d3d7626961cd211464360d314.1506086081.git.g.nault@alphalink.fr/", "project": { "id": 7, "url": "http://patchwork.ozlabs.org/api/projects/7/?format=api", "name": "Linux network development", "link_name": "netdev", "list_id": "netdev.vger.kernel.org", "list_email": "netdev@vger.kernel.org", "web_url": null, "scm_url": null, "webscm_url": null, "list_archive_url": "", "list_archive_url_format": "", "commit_url_format": "" }, "msgid": "<11b04a711e0c263d3d7626961cd211464360d314.1506086081.git.g.nault@alphalink.fr>", "list_archive_url": null, "date": "2017-09-22T13:39:24", "name": "[net,2/2] l2tp: fix race between l2tp_session_delete() and l2tp_tunnel_closeall()", "commit_ref": null, "pull_url": null, "state": "accepted", "archived": true, "hash": "2fe3bce4a142926e2a4041a0ab0ba4eb615525fc", "submitter": { "id": 22975, "url": "http://patchwork.ozlabs.org/api/people/22975/?format=api", "name": "Guillaume Nault", "email": "g.nault@alphalink.fr" }, "delegate": { "id": 34, "url": "http://patchwork.ozlabs.org/api/users/34/?format=api", "username": "davem", "first_name": "David", "last_name": "Miller", "email": "davem@davemloft.net" }, "mbox": "http://patchwork.ozlabs.org/project/netdev/patch/11b04a711e0c263d3d7626961cd211464360d314.1506086081.git.g.nault@alphalink.fr/mbox/", "series": [ { "id": 4627, "url": "http://patchwork.ozlabs.org/api/series/4627/?format=api", "web_url": "http://patchwork.ozlabs.org/project/netdev/list/?series=4627", "date": "2017-09-22T13:39:22", "name": "l2tp: fix some races in session deletion", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/4627/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/817513/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/817513/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "<netdev-owner@vger.kernel.org>", "X-Original-To": "patchwork-incoming@ozlabs.org", "Delivered-To": "patchwork-incoming@ozlabs.org", "Authentication-Results": "ozlabs.org;\n\tspf=none (mailfrom) smtp.mailfrom=vger.kernel.org\n\t(client-ip=209.132.180.67; helo=vger.kernel.org;\n\tenvelope-from=netdev-owner@vger.kernel.org;\n\treceiver=<UNKNOWN>)", "Received": [ "from vger.kernel.org (vger.kernel.org [209.132.180.67])\n\tby ozlabs.org (Postfix) with ESMTP id 3xzF2h69qDz9s06\n\tfor <patchwork-incoming@ozlabs.org>;\n\tFri, 22 Sep 2017 23:39:40 +1000 (AEST)", "(majordomo@vger.kernel.org) by vger.kernel.org via listexpand\n\tid S1752376AbdIVNje (ORCPT <rfc822;patchwork-incoming@ozlabs.org>);\n\tFri, 22 Sep 2017 09:39:34 -0400", "from zimbra.alphalink.fr ([217.15.80.77]:52471 \"EHLO\n\tzimbra.alphalink.fr\" rhost-flags-OK-OK-OK-OK) by vger.kernel.org\n\twith ESMTP id S1752340AbdIVNjc (ORCPT\n\t<rfc822;netdev@vger.kernel.org>); Fri, 22 Sep 2017 09:39:32 -0400", "from localhost (localhost [127.0.0.1])\n\tby mail-2-cbv2.admin.alphalink.fr (Postfix) with ESMTP id\n\tA27432B5206F; Fri, 22 Sep 2017 15:39:31 +0200 (CEST)", "from zimbra.alphalink.fr ([127.0.0.1])\n\tby localhost (mail-2-cbv2.admin.alphalink.fr [127.0.0.1])\n\t(amavisd-new, port 10032)\n\twith ESMTP id IY2cYXijsnPW; Fri, 22 Sep 2017 15:39:24 +0200 (CEST)", "from localhost (localhost [127.0.0.1])\n\tby mail-2-cbv2.admin.alphalink.fr (Postfix) with ESMTP id\n\tD5D462B5212C; Fri, 22 Sep 2017 15:39:24 +0200 (CEST)", "from zimbra.alphalink.fr ([127.0.0.1])\n\tby localhost (mail-2-cbv2.admin.alphalink.fr [127.0.0.1])\n\t(amavisd-new, port 10026)\n\twith ESMTP id 7mNNWR1AH840; Fri, 22 Sep 2017 15:39:24 +0200 (CEST)", "from c-dev-0.admin.alphalink.fr (94-84-15-217.reverse.alphalink.fr\n\t[217.15.84.94])\n\tby mail-2-cbv2.admin.alphalink.fr (Postfix) with ESMTP id\n\tAD5CA2B52057; Fri, 22 Sep 2017 15:39:24 +0200 (CEST)", "by c-dev-0.admin.alphalink.fr (Postfix, from userid 1000)\n\tid 92A3660179; Fri, 22 Sep 2017 15:39:24 +0200 (CEST)" ], "X-Virus-Scanned": "amavisd-new at mail-2-cbv2.admin.alphalink.fr", "Date": "Fri, 22 Sep 2017 15:39:24 +0200", "From": "Guillaume Nault <g.nault@alphalink.fr>", "To": "netdev@vger.kernel.org", "Cc": "James Chapman <jchapman@katalix.com>, Tom Parkin <tparkin@katalix.com>,\n\tSabrina Dubroca <sd@queasysnail.net>", "Subject": "[PATCH net 2/2] l2tp: fix race between l2tp_session_delete() and\n\tl2tp_tunnel_closeall()", "Message-ID": "<11b04a711e0c263d3d7626961cd211464360d314.1506086081.git.g.nault@alphalink.fr>", "References": "<cover.1506086081.git.g.nault@alphalink.fr>", "MIME-Version": "1.0", "Content-Type": "text/plain; charset=us-ascii", "Content-Disposition": "inline", "In-Reply-To": "<cover.1506086081.git.g.nault@alphalink.fr>", "X-Mutt-Fcc": "=Sent", "User-Agent": "NeoMutt/20170609 (1.8.3)", "Sender": "netdev-owner@vger.kernel.org", "Precedence": "bulk", "List-ID": "<netdev.vger.kernel.org>", "X-Mailing-List": "netdev@vger.kernel.org" }, "content": "There are several ways to remove L2TP sessions:\n\n * deleting a session explicitly using the netlink interface (with\n L2TP_CMD_SESSION_DELETE),\n * deleting the session's parent tunnel (either by closing the\n tunnel's file descriptor or using the netlink interface),\n * closing the PPPOL2TP file descriptor of a PPP pseudo-wire.\n\nIn some cases, when these methods are used concurrently on the same\nsession, the session can be removed twice, leading to use-after-free\nbugs.\n\nThis patch adds a 'dead' flag, used by l2tp_session_delete() and\nl2tp_tunnel_closeall() to prevent them from stepping on each other's\ntoes.\n\nThe session deletion path used when closing a PPPOL2TP file descriptor\ndoesn't need to be adapted. It already has to ensure that a session\nremains valid for the lifetime of its PPPOL2TP file descriptor.\nSo it takes an extra reference on the session in the ->session_close()\ncallback (pppol2tp_session_close()), which is eventually dropped\nin the ->sk_destruct() callback of the PPPOL2TP socket\n(pppol2tp_session_destruct()).\nStill, __l2tp_session_unhash() and l2tp_session_queue_purge() can be\ncalled twice and even concurrently for a given session, but thanks to\nproper locking and re-initialisation of list fields, this is not an\nissue.\n\nSigned-off-by: Guillaume Nault <g.nault@alphalink.fr>\n---\n net/l2tp/l2tp_core.c | 6 ++++++\n net/l2tp/l2tp_core.h | 1 +\n 2 files changed, 7 insertions(+)", "diff": "diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c\nindex ee485df73ccd..d8c2a89a76e1 100644\n--- a/net/l2tp/l2tp_core.c\n+++ b/net/l2tp/l2tp_core.c\n@@ -1314,6 +1314,9 @@ void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)\n \n \t\t\thlist_del_init(&session->hlist);\n \n+\t\t\tif (test_and_set_bit(0, &session->dead))\n+\t\t\t\tgoto again;\n+\n \t\t\tif (session->ref != NULL)\n \t\t\t\t(*session->ref)(session);\n \n@@ -1750,6 +1753,9 @@ EXPORT_SYMBOL_GPL(__l2tp_session_unhash);\n */\n int l2tp_session_delete(struct l2tp_session *session)\n {\n+\tif (test_and_set_bit(0, &session->dead))\n+\t\treturn 0;\n+\n \tif (session->ref)\n \t\t(*session->ref)(session);\n \t__l2tp_session_unhash(session);\ndiff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h\nindex a305e0c5925a..70a12df40a5f 100644\n--- a/net/l2tp/l2tp_core.h\n+++ b/net/l2tp/l2tp_core.h\n@@ -76,6 +76,7 @@ struct l2tp_session_cfg {\n struct l2tp_session {\n \tint\t\t\tmagic;\t\t/* should be\n \t\t\t\t\t\t * L2TP_SESSION_MAGIC */\n+\tlong\t\t\tdead;\n \n \tstruct l2tp_tunnel\t*tunnel;\t/* back pointer to tunnel\n \t\t\t\t\t\t * context */\n", "prefixes": [ "net", "2/2" ] }