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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 E842CC2D0BE for ; Sat, 7 Dec 2019 17:38:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BDEDF2176D for ; Sat, 7 Dec 2019 17:38:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726599AbfLGRiM (ORCPT ); Sat, 7 Dec 2019 12:38:12 -0500 Received: from correo.us.es ([193.147.175.20]:57126 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726414AbfLGRiM (ORCPT ); Sat, 7 Dec 2019 12:38:12 -0500 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id 02CF6BAF0B for ; Sat, 7 Dec 2019 18:38:08 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id E6C19DA707 for ; Sat, 7 Dec 2019 18:38:07 +0100 (CET) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id D2014DA70F; Sat, 7 Dec 2019 18:38:07 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 8C9D1DA70B; Sat, 7 Dec 2019 18:38:05 +0100 (CET) Received: from 192.168.1.97 (192.168.1.97) by antivirus1-rhel7.int (F-Secure/fsigk_smtp/550/antivirus1-rhel7.int); Sat, 07 Dec 2019 18:38:05 +0100 (CET) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/antivirus1-rhel7.int) Received: from us.es (sys.soleta.eu [212.170.55.40]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: 1984lsi) by entrada.int (Postfix) with ESMTPSA id 20E9141E4800; Sat, 7 Dec 2019 18:38:05 +0100 (CET) Date: Sat, 7 Dec 2019 18:38:05 +0100 X-SMTPAUTHUS: auth mail.us.es From: Pablo Neira Ayuso To: Justin Forbes Cc: Laura Abbott , Marcelo Ricardo Leitner , Jozsef Kadlecsik , Florian Westphal , "David S. Miller" , netfilter-devel@vger.kernel.org, coreteam@netfilter.org, netdev@vger.kernel.org, LKML , Kees Cook Subject: Re: [PATCH] netfilter: nf_flow_table_offload: Correct memcpy size for flow_overload_mangle Message-ID: <20191207173805.jvunyfnijgefn3z5@salvia> References: <20191203160345.24743-1-labbott@redhat.com> <20191203170114.GB377782@localhost.localdomain> <9bc4b04b-a3cc-4e58-4c73-1d77b7ed05da@redhat.com> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="xqstvcc2mbtblrb2" Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) X-Virus-Scanned: ClamAV using ClamSMTP Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --xqstvcc2mbtblrb2 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Dec 06, 2019 at 04:58:30PM -0600, Justin Forbes wrote: > On Tue, Dec 3, 2019 at 2:50 PM Laura Abbott wrote: > > > > On 12/3/19 12:01 PM, Marcelo Ricardo Leitner wrote: > > > On Tue, Dec 03, 2019 at 11:03:45AM -0500, Laura Abbott wrote: > > >> The sizes for memcpy in flow_offload_mangle don't match > > >> the source variables, leading to overflow errors on some > > >> build configurations: > > >> > > >> In function 'memcpy', > > >> inlined from 'flow_offload_mangle' at net/netfilter/nf_flow_table_offload.c:112:2, > > >> inlined from 'flow_offload_port_dnat' at net/netfilter/nf_flow_table_offload.c:373:2, > > >> inlined from 'nf_flow_rule_route_ipv4' at net/netfilter/nf_flow_table_offload.c:424:3: > > >> ./include/linux/string.h:376:4: error: call to '__read_overflow2' declared with attribute error: detected read beyond size of object passed as 2nd parameter > > >> 376 | __read_overflow2(); > > >> | ^~~~~~~~~~~~~~~~~~ > > >> make[2]: *** [scripts/Makefile.build:266: net/netfilter/nf_flow_table_offload.o] Error 1 > > >> > > >> Fix this by using the corresponding type. > > >> > > >> Fixes: c29f74e0df7a ("netfilter: nf_flow_table: hardware offload support") > > >> Signed-off-by: Laura Abbott > > >> --- > > >> Seen on a Fedora powerpc little endian build with -O3 but it looks like > > >> it is correctly catching an error with doing a memcpy outside the source > > >> variable. > > > > > > Hi, > > > > > > It is right but the fix is not. In that call trace: > > > > > > flow_offload_port_dnat() { > > > ... > > > u32 mask = ~htonl(0xffff); > > > __be16 port; > > > ... > > > flow_offload_mangle(entry, flow_offload_l4proto(flow), offset, > > > (u8 *)&port, (u8 *)&mask); > > > } > > > > > > port should have a 32b storage as well, and aligned with the mask. > > > > > >> --- > > >> net/netfilter/nf_flow_table_offload.c | 4 ++-- > > >> 1 file changed, 2 insertions(+), 2 deletions(-) > > >> > > >> diff --git a/net/netfilter/nf_flow_table_offload.c b/net/netfilter/nf_flow_table_offload.c > > >> index c54c9a6cc981..526f894d0bdb 100644 > > >> --- a/net/netfilter/nf_flow_table_offload.c > > >> +++ b/net/netfilter/nf_flow_table_offload.c > > >> @@ -108,8 +108,8 @@ static void flow_offload_mangle(struct flow_action_entry *entry, > > >> entry->id = FLOW_ACTION_MANGLE; > > >> entry->mangle.htype = htype; > > >> entry->mangle.offset = offset; > > >> - memcpy(&entry->mangle.mask, mask, sizeof(u32)); > > >> - memcpy(&entry->mangle.val, value, sizeof(u32)); > > > ^^^^^ ^^^ which is &port in the call above > > >> + memcpy(&entry->mangle.mask, mask, sizeof(u8)); > > >> + memcpy(&entry->mangle.val, value, sizeof(u8)); > > > > > > This fix would cause it to copy only the first byte, which is not the > > > intention. > > > > > > > Thanks for the review. I took another look at fixing this and I > > think it might be better for the maintainer or someone who is more > > familiar with the code to fix this. I ended up down a rabbit > > hole trying to get the types to work and I wasn't confident about > > the casting. > > Any update on this? It is definitely a problem on PPC LE. I'm attaching a tentative patch to address this problem. Thanks. --xqstvcc2mbtblrb2 Content-Type: text/x-diff; charset=us-ascii Content-Disposition: attachment; filename="x.patch" diff --git a/net/netfilter/nf_flow_table_offload.c b/net/netfilter/nf_flow_table_offload.c index 30205d57226d..cfa5602f54f5 100644 --- a/net/netfilter/nf_flow_table_offload.c +++ b/net/netfilter/nf_flow_table_offload.c @@ -336,23 +336,22 @@ static void flow_offload_port_snat(struct net *net, struct nf_flow_rule *flow_rule) { struct flow_action_entry *entry = flow_action_entry_next(flow_rule); - u32 mask = ~htonl(0xffff0000); - __be16 port; + u32 mask = ~htonl(0xffff0000), port; u32 offset; switch (dir) { case FLOW_OFFLOAD_DIR_ORIGINAL: - port = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_port; + port = ntohs(flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_port); offset = 0; /* offsetof(struct tcphdr, source); */ break; case FLOW_OFFLOAD_DIR_REPLY: - port = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_port; + port = ntohs(flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_port); offset = 0; /* offsetof(struct tcphdr, dest); */ break; default: return; } - + port = htonl(port << 16); flow_offload_mangle(entry, flow_offload_l4proto(flow), offset, (u8 *)&port, (u8 *)&mask); } @@ -363,23 +362,22 @@ static void flow_offload_port_dnat(struct net *net, struct nf_flow_rule *flow_rule) { struct flow_action_entry *entry = flow_action_entry_next(flow_rule); - u32 mask = ~htonl(0xffff); - __be16 port; + u32 mask = ~htonl(0xffff), port; u32 offset; switch (dir) { case FLOW_OFFLOAD_DIR_ORIGINAL: - port = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_port; + port = ntohs(flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_port); offset = 0; /* offsetof(struct tcphdr, source); */ break; case FLOW_OFFLOAD_DIR_REPLY: - port = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_port; + port = ntohs(flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_port); offset = 0; /* offsetof(struct tcphdr, dest); */ break; default: return; } - + port = htonl(port); flow_offload_mangle(entry, flow_offload_l4proto(flow), offset, (u8 *)&port, (u8 *)&mask); } --xqstvcc2mbtblrb2--