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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Dalegaard <dalegaard@gmail.com>,
        Liping Zhang <zlpnobody@gmail.com>,
        Pablo Neira Ayuso <pablo@netfilter.org>,
        Amit Pundir <amit.pundir@linaro.org>
Subject: [PATCH 4.4 72/86] netfilter: nf_tables: fix oops when inserting an element into a verdict map
Date:   Thu, 29 Nov 2018 15:12:37 +0100
Message-Id: <20181129140115.788351734@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Liping Zhang <zlpnobody@gmail.com>

commit 58c78e104d937c1f560fb10ed9bb2dcde0db4fcf upstream.

Dalegaard says:
 The following ruleset, when loaded with 'nft -f bad.txt'
 ----snip----
 flush ruleset
 table ip inlinenat {
   map sourcemap {
     type ipv4_addr : verdict;
   }

   chain postrouting {
     ip saddr vmap @sourcemap accept
   }
 }
 add chain inlinenat test
 add element inlinenat sourcemap { 100.123.10.2 : jump test }
 ----snip----

 results in a kernel oops:
 BUG: unable to handle kernel paging request at 0000000000001344
 IP: [<ffffffffa07bf704>] nf_tables_check_loops+0x114/0x1f0 [nf_tables]
 [...]
 Call Trace:
  [<ffffffffa07c2aae>] ? nft_data_init+0x13e/0x1a0 [nf_tables]
  [<ffffffffa07c1950>] nft_validate_register_store+0x60/0xb0 [nf_tables]
  [<ffffffffa07c74b5>] nft_add_set_elem+0x545/0x5e0 [nf_tables]
  [<ffffffffa07bfdd0>] ? nft_table_lookup+0x30/0x60 [nf_tables]
  [<ffffffff8132c630>] ? nla_strcmp+0x40/0x50
  [<ffffffffa07c766e>] nf_tables_newsetelem+0x11e/0x210 [nf_tables]
  [<ffffffff8132c400>] ? nla_validate+0x60/0x80
  [<ffffffffa030d9b4>] nfnetlink_rcv+0x354/0x5a7 [nfnetlink]

Because we forget to fill the net pointer in bind_ctx, so dereferencing
it may cause kernel crash.

Reported-by: Dalegaard <dalegaard@gmail.com>
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/netfilter/nf_tables_api.c |    1 +
 1 file changed, 1 insertion(+)

--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -3452,6 +3452,7 @@ static int nft_add_set_elem(struct nft_c
 		dreg = nft_type_to_reg(set->dtype);
 		list_for_each_entry(binding, &set->bindings, list) {
 			struct nft_ctx bind_ctx = {
+				.net	= ctx->net,
 				.afi	= ctx->afi,
 				.table	= ctx->table,
 				.chain	= (struct nft_chain *)binding->chain,