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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT 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 14CF4C04AB5 for ; Mon, 3 Jun 2019 18:15:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E238E26EEF for ; Mon, 3 Jun 2019 18:15:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726638AbfFCSP1 (ORCPT ); Mon, 3 Jun 2019 14:15:27 -0400 Received: from charlotte.tuxdriver.com ([70.61.120.58]:37485 "EHLO smtp.tuxdriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726190AbfFCSP1 (ORCPT ); Mon, 3 Jun 2019 14:15:27 -0400 Received: from cpe-2606-a000-111b-405a-0-0-0-162e.dyn6.twc.com ([2606:a000:111b:405a::162e] helo=localhost) by smtp.tuxdriver.com with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.63) (envelope-from ) id 1hXrUN-0002zD-Na; Mon, 03 Jun 2019 14:15:23 -0400 Date: Mon, 3 Jun 2019 14:14:52 -0400 From: Neil Horman To: Marcelo Ricardo Leitner Cc: linux-sctp@vger.kernel.org, syzbot+f7e9153b037eac9b1df8@syzkaller.appspotmail.com, "David S. Miller" , netdev@vger.kernel.org Subject: Re: [PATCH] Fix memory leak in sctp_process_init Message-ID: <20190603181452.GA14795@hmswarspite.think-freely.org> References: <20190603142112.20229-1-nhorman@tuxdriver.com> <20190603143113.GH3713@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190603143113.GH3713@localhost.localdomain> User-Agent: Mutt/1.11.3 (2019-02-01) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Jun 03, 2019 at 11:31:13AM -0300, Marcelo Ricardo Leitner wrote: > On Mon, Jun 03, 2019 at 10:21:12AM -0400, Neil Horman wrote: > > syzbot found the following leak in sctp_process_init > > BUG: memory leak > > unreferenced object 0xffff88810ef68400 (size 1024): > > comm "syz-executor273", pid 7046, jiffies 4294945598 (age 28.770s) > > hex dump (first 32 bytes): > > 1d de 28 8d de 0b 1b e3 b5 c2 f9 68 fd 1a 97 25 ..(........h...% > > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > > backtrace: > > [<00000000a02cebbd>] kmemleak_alloc_recursive include/linux/kmemleak.h:55 > > [inline] > > [<00000000a02cebbd>] slab_post_alloc_hook mm/slab.h:439 [inline] > > [<00000000a02cebbd>] slab_alloc mm/slab.c:3326 [inline] > > [<00000000a02cebbd>] __do_kmalloc mm/slab.c:3658 [inline] > > [<00000000a02cebbd>] __kmalloc_track_caller+0x15d/0x2c0 mm/slab.c:3675 > > [<000000009e6245e6>] kmemdup+0x27/0x60 mm/util.c:119 > > [<00000000dfdc5d2d>] kmemdup include/linux/string.h:432 [inline] > > [<00000000dfdc5d2d>] sctp_process_init+0xa7e/0xc20 > > net/sctp/sm_make_chunk.c:2437 > > [<00000000b58b62f8>] sctp_cmd_process_init net/sctp/sm_sideeffect.c:682 > > [inline] > > [<00000000b58b62f8>] sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1384 > > [inline] > > [<00000000b58b62f8>] sctp_side_effects net/sctp/sm_sideeffect.c:1194 > > [inline] > > [<00000000b58b62f8>] sctp_do_sm+0xbdc/0x1d60 net/sctp/sm_sideeffect.c:1165 > > [<0000000044e11f96>] sctp_assoc_bh_rcv+0x13c/0x200 > > net/sctp/associola.c:1074 > > [<00000000ec43804d>] sctp_inq_push+0x7f/0xb0 net/sctp/inqueue.c:95 > > [<00000000726aa954>] sctp_backlog_rcv+0x5e/0x2a0 net/sctp/input.c:354 > > [<00000000d9e249a8>] sk_backlog_rcv include/net/sock.h:950 [inline] > > [<00000000d9e249a8>] __release_sock+0xab/0x110 net/core/sock.c:2418 > > [<00000000acae44fa>] release_sock+0x37/0xd0 net/core/sock.c:2934 > > [<00000000963cc9ae>] sctp_sendmsg+0x2c0/0x990 net/sctp/socket.c:2122 > > [<00000000a7fc7565>] inet_sendmsg+0x64/0x120 net/ipv4/af_inet.c:802 > > [<00000000b732cbd3>] sock_sendmsg_nosec net/socket.c:652 [inline] > > [<00000000b732cbd3>] sock_sendmsg+0x54/0x70 net/socket.c:671 > > [<00000000274c57ab>] ___sys_sendmsg+0x393/0x3c0 net/socket.c:2292 > > [<000000008252aedb>] __sys_sendmsg+0x80/0xf0 net/socket.c:2330 > > [<00000000f7bf23d1>] __do_sys_sendmsg net/socket.c:2339 [inline] > > [<00000000f7bf23d1>] __se_sys_sendmsg net/socket.c:2337 [inline] > > [<00000000f7bf23d1>] __x64_sys_sendmsg+0x23/0x30 net/socket.c:2337 > > [<00000000a8b4131f>] do_syscall_64+0x76/0x1a0 arch/x86/entry/common.c:3 > > > > The problem was that the peer.cookie value points to an skb allocated > > area on the first pass through this function, at which point it is > > overwritten with a heap allocated value, but in certain cases, where a > > COOKIE_ECHO chunk is included in the packet, a second pass through > > sctp_process_init is made, where the cookie value is re-allocated, > > leaking the first allocation. > > > > Fix is to always allocate the cookie value, and free it when we are done > > using it. > > > > Signed-off-by: Neil Horman > > Reported-by: syzbot+f7e9153b037eac9b1df8@syzkaller.appspotmail.com > > CC: Marcelo Ricardo Leitner > > CC: "David S. Miller" > > CC: netdev@vger.kernel.org > > --- > > net/sctp/associola.c | 1 + > > net/sctp/sm_make_chunk.c | 12 +++--------- > > net/sctp/sm_sideeffect.c | 5 +++++ > > 3 files changed, 9 insertions(+), 9 deletions(-) > > > > diff --git a/net/sctp/associola.c b/net/sctp/associola.c > > index d2c7d0d2abc1..718b9917844e 100644 > > --- a/net/sctp/associola.c > > +++ b/net/sctp/associola.c > > @@ -393,6 +393,7 @@ void sctp_association_free(struct sctp_association *asoc) > > kfree(asoc->peer.peer_random); > > kfree(asoc->peer.peer_chunks); > > kfree(asoc->peer.peer_hmacs); > > + kfree(asoc->peer.cookie); > > This one slipped back.. > Ah, thanks, I forgot to clean that up. > > > > /* Release the transport structures. */ > > list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) { > > diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c > > index 72e74503f9fc..ff365f22a3c1 100644 > > --- a/net/sctp/sm_make_chunk.c > > +++ b/net/sctp/sm_make_chunk.c > > @@ -2431,14 +2431,6 @@ int sctp_process_init(struct sctp_association *asoc, struct sctp_chunk *chunk, > > /* Peer Rwnd : Current calculated value of the peer's rwnd. */ > > asoc->peer.rwnd = asoc->peer.i.a_rwnd; > > > > - /* Copy cookie in case we need to resend COOKIE-ECHO. */ > > - cookie = asoc->peer.cookie; > > - if (cookie) { > > - asoc->peer.cookie = kmemdup(cookie, asoc->peer.cookie_len, gfp); > > - if (!asoc->peer.cookie) > > - goto clean_up; > > - } > > cookie will be left unused after this. May as well remove it too. > Yup, will do. V2 soon > Marcelo > > > - > > /* RFC 2960 7.2.1 The initial value of ssthresh MAY be arbitrarily > > * high (for example, implementations MAY use the size of the receiver > > * advertised window). > > @@ -2607,7 +2599,9 @@ static int sctp_process_param(struct sctp_association *asoc, > > case SCTP_PARAM_STATE_COOKIE: > > asoc->peer.cookie_len = > > ntohs(param.p->length) - sizeof(struct sctp_paramhdr); > > - asoc->peer.cookie = param.cookie->body; > > + asoc->peer.cookie = kmemdup(param.cookie->body, asoc->peer.cookie_len, gfp); > > + if (!asoc->peer.cookie) > > + retval = 0; > > break; > > > > case SCTP_PARAM_HEARTBEAT_INFO: > > diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c > > index 4aa03588f87b..27ddf2d8f001 100644 > > --- a/net/sctp/sm_sideeffect.c > > +++ b/net/sctp/sm_sideeffect.c > > @@ -898,6 +898,11 @@ static void sctp_cmd_new_state(struct sctp_cmd_seq *cmds, > > asoc->rto_initial; > > } > > > > + if (sctp_state(asoc, ESTABLISHED)) { > > + kfree(asoc->peer.cookie); > > + asoc->peer.cookie = NULL; > > + } > > + > > if (sctp_state(asoc, ESTABLISHED) || > > sctp_state(asoc, CLOSED) || > > sctp_state(asoc, SHUTDOWN_RECEIVED)) { > > -- > > 2.20.1 > > >