From ad9f151e560b016b6ad3280b48e42fa11e1a5440 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Fri, 4 Jun 2021 03:07:28 +0200 Subject: netfilter: nf_tables: initialize set before expression setup nft_set_elem_expr_alloc() needs an initialized set if expression sets on the NFT_EXPR_GC flag. Move set fields initialization before expression setup. [4512935.019450] ================================================================== [4512935.019456] BUG: KASAN: null-ptr-deref in nft_set_elem_expr_alloc+0x84/0xd0 [nf_tables] [4512935.019487] Read of size 8 at addr 0000000000000070 by task nft/23532 [4512935.019494] CPU: 1 PID: 23532 Comm: nft Not tainted 5.12.0-rc4+ #48 [...] [4512935.019502] Call Trace: [4512935.019505] dump_stack+0x89/0xb4 [4512935.019512] ? nft_set_elem_expr_alloc+0x84/0xd0 [nf_tables] [4512935.019536] ? nft_set_elem_expr_alloc+0x84/0xd0 [nf_tables] [4512935.019560] kasan_report.cold.12+0x5f/0xd8 [4512935.019566] ? nft_set_elem_expr_alloc+0x84/0xd0 [nf_tables] [4512935.019590] nft_set_elem_expr_alloc+0x84/0xd0 [nf_tables] [4512935.019615] nf_tables_newset+0xc7f/0x1460 [nf_tables] Reported-by: syzbot+ce96ca2b1d0b37c6422d@syzkaller.appspotmail.com Fixes: 65038428b2c6 ("netfilter: nf_tables: allow to specify stateful expression in set definition") Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_tables_api.c | 85 ++++++++++++++++++++++--------------------- 1 file changed, 43 insertions(+), 42 deletions(-) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 72bc759179ef..bf4d6ec9fc55 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -4364,13 +4364,45 @@ static int nf_tables_newset(struct sk_buff *skb, const struct nfnl_info *info, err = nf_tables_set_alloc_name(&ctx, set, name); kfree(name); if (err < 0) - goto err_set_alloc_name; + goto err_set_name; + + udata = NULL; + if (udlen) { + udata = set->data + size; + nla_memcpy(udata, nla[NFTA_SET_USERDATA], udlen); + } + + INIT_LIST_HEAD(&set->bindings); + INIT_LIST_HEAD(&set->catchall_list); + set->table = table; + write_pnet(&set->net, net); + set->ops = ops; + set->ktype = ktype; + set->klen = desc.klen; + set->dtype = dtype; + set->objtype = objtype; + set->dlen = desc.dlen; + set->flags = flags; + set->size = desc.size; + set->policy = policy; + set->udlen = udlen; + set->udata = udata; + set->timeout = timeout; + set->gc_int = gc_int; + + set->field_count = desc.field_count; + for (i = 0; i < desc.field_count; i++) + set->field_len[i] = desc.field_len[i]; + + err = ops->init(set, &desc, nla); + if (err < 0) + goto err_set_init; if (nla[NFTA_SET_EXPR]) { expr = nft_set_elem_expr_alloc(&ctx, set, nla[NFTA_SET_EXPR]); if (IS_ERR(expr)) { err = PTR_ERR(expr); - goto err_set_alloc_name; + goto err_set_expr_alloc; } set->exprs[0] = expr; set->num_exprs++; @@ -4381,75 +4413,44 @@ static int nf_tables_newset(struct sk_buff *skb, const struct nfnl_info *info, if (!(flags & NFT_SET_EXPR)) { err = -EINVAL; - goto err_set_alloc_name; + goto err_set_expr_alloc; } i = 0; nla_for_each_nested(tmp, nla[NFTA_SET_EXPRESSIONS], left) { if (i == NFT_SET_EXPR_MAX) { err = -E2BIG; - goto err_set_init; + goto err_set_expr_alloc; } if (nla_type(tmp) != NFTA_LIST_ELEM) { err = -EINVAL; - goto err_set_init; + goto err_set_expr_alloc; } expr = nft_set_elem_expr_alloc(&ctx, set, tmp); if (IS_ERR(expr)) { err = PTR_ERR(expr); - goto err_set_init; + goto err_set_expr_alloc; } set->exprs[i++] = expr; set->num_exprs++; } } - udata = NULL; - if (udlen) { - udata = set->data + size; - nla_memcpy(udata, nla[NFTA_SET_USERDATA], udlen); - } - - INIT_LIST_HEAD(&set->bindings); - INIT_LIST_HEAD(&set->catchall_list); - set->table = table; - write_pnet(&set->net, net); - set->ops = ops; - set->ktype = ktype; - set->klen = desc.klen; - set->dtype = dtype; - set->objtype = objtype; - set->dlen = desc.dlen; - set->flags = flags; - set->size = desc.size; - set->policy = policy; - set->udlen = udlen; - set->udata = udata; - set->timeout = timeout; - set->gc_int = gc_int; set->handle = nf_tables_alloc_handle(table); - set->field_count = desc.field_count; - for (i = 0; i < desc.field_count; i++) - set->field_len[i] = desc.field_len[i]; - - err = ops->init(set, &desc, nla); - if (err < 0) - goto err_set_init; - err = nft_trans_set_add(&ctx, NFT_MSG_NEWSET, set); if (err < 0) - goto err_set_trans; + goto err_set_expr_alloc; list_add_tail_rcu(&set->list, &table->sets); table->use++; return 0; -err_set_trans: - ops->destroy(set); -err_set_init: +err_set_expr_alloc: for (i = 0; i < set->num_exprs; i++) nft_expr_destroy(&ctx, set->exprs[i]); -err_set_alloc_name: + + ops->destroy(set); +err_set_init: kfree(set->name); err_set_name: kvfree(set); -- cgit v1.2.3 From 82944421243e5988898f54266687586ba07d889e Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Tue, 8 Jun 2021 13:48:17 +0200 Subject: selftests: netfilter: add fib test case There is a bug report on netfilter.org bugzilla pointing to fib expression dropping ipv6 DAD packets. Add a test case that demonstrates this problem. Next patch excludes icmpv6 packets coming from any to linklocal. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- tools/testing/selftests/netfilter/Makefile | 2 +- tools/testing/selftests/netfilter/nft_fib.sh | 221 +++++++++++++++++++++++++++ 2 files changed, 222 insertions(+), 1 deletion(-) create mode 100755 tools/testing/selftests/netfilter/nft_fib.sh diff --git a/tools/testing/selftests/netfilter/Makefile b/tools/testing/selftests/netfilter/Makefile index 3171069a6b46..cd6430b39982 100644 --- a/tools/testing/selftests/netfilter/Makefile +++ b/tools/testing/selftests/netfilter/Makefile @@ -1,7 +1,7 @@ # SPDX-License-Identifier: GPL-2.0 # Makefile for netfilter selftests -TEST_PROGS := nft_trans_stress.sh nft_nat.sh bridge_brouter.sh \ +TEST_PROGS := nft_trans_stress.sh nft_fib.sh nft_nat.sh bridge_brouter.sh \ conntrack_icmp_related.sh nft_flowtable.sh ipvs.sh \ nft_concat_range.sh nft_conntrack_helper.sh \ nft_queue.sh nft_meta.sh nf_nat_edemux.sh \ diff --git a/tools/testing/selftests/netfilter/nft_fib.sh b/tools/testing/selftests/netfilter/nft_fib.sh new file mode 100755 index 000000000000..6caf6ac8c285 --- /dev/null +++ b/tools/testing/selftests/netfilter/nft_fib.sh @@ -0,0 +1,221 @@ +#!/bin/bash +# +# This tests the fib expression. +# +# Kselftest framework requirement - SKIP code is 4. +ksft_skip=4 +ret=0 + +sfx=$(mktemp -u "XXXXXXXX") +ns1="ns1-$sfx" +ns2="ns2-$sfx" +nsrouter="nsrouter-$sfx" +timeout=4 + +log_netns=$(sysctl -n net.netfilter.nf_log_all_netns) + +cleanup() +{ + ip netns del ${ns1} + ip netns del ${ns2} + ip netns del ${nsrouter} + + [ $log_netns -eq 0 ] && sysctl -q net.netfilter.nf_log_all_netns=$log_netns +} + +nft --version > /dev/null 2>&1 +if [ $? -ne 0 ];then + echo "SKIP: Could not run test without nft tool" + exit $ksft_skip +fi + +ip -Version > /dev/null 2>&1 +if [ $? -ne 0 ];then + echo "SKIP: Could not run test without ip tool" + exit $ksft_skip +fi + +ip netns add ${nsrouter} +if [ $? -ne 0 ];then + echo "SKIP: Could not create net namespace" + exit $ksft_skip +fi + +trap cleanup EXIT + +dmesg | grep -q ' nft_rpfilter: ' +if [ $? -eq 0 ]; then + dmesg -c | grep ' nft_rpfilter: ' + echo "WARN: a previous test run has failed" 1>&2 +fi + +sysctl -q net.netfilter.nf_log_all_netns=1 +ip netns add ${ns1} +ip netns add ${ns2} + +load_ruleset() { + local netns=$1 + +ip netns exec ${netns} nft -f /dev/stdin <&2 + ip netns exec ${ns} nft list table inet filter + return 1 + fi + + if [ $want -gt 0 ]; then + echo "PASS: fib expression did drop packets for $address" + fi + + return 0 +} + +load_ruleset ${nsrouter} +load_ruleset ${ns1} +load_ruleset ${ns2} + +ip link add veth0 netns ${nsrouter} type veth peer name eth0 netns ${ns1} > /dev/null 2>&1 +if [ $? -ne 0 ];then + echo "SKIP: No virtual ethernet pair device support in kernel" + exit $ksft_skip +fi +ip link add veth1 netns ${nsrouter} type veth peer name eth0 netns ${ns2} + +ip -net ${nsrouter} link set lo up +ip -net ${nsrouter} link set veth0 up +ip -net ${nsrouter} addr add 10.0.1.1/24 dev veth0 +ip -net ${nsrouter} addr add dead:1::1/64 dev veth0 + +ip -net ${nsrouter} link set veth1 up +ip -net ${nsrouter} addr add 10.0.2.1/24 dev veth1 +ip -net ${nsrouter} addr add dead:2::1/64 dev veth1 + +ip -net ${ns1} link set lo up +ip -net ${ns1} link set eth0 up + +ip -net ${ns2} link set lo up +ip -net ${ns2} link set eth0 up + +ip -net ${ns1} addr add 10.0.1.99/24 dev eth0 +ip -net ${ns1} addr add dead:1::99/64 dev eth0 +ip -net ${ns1} route add default via 10.0.1.1 +ip -net ${ns1} route add default via dead:1::1 + +ip -net ${ns2} addr add 10.0.2.99/24 dev eth0 +ip -net ${ns2} addr add dead:2::99/64 dev eth0 +ip -net ${ns2} route add default via 10.0.2.1 +ip -net ${ns2} route add default via dead:2::1 + +test_ping() { + local daddr4=$1 + local daddr6=$2 + + ip netns exec ${ns1} ping -c 1 -q $daddr4 > /dev/null + ret=$? + if [ $ret -ne 0 ];then + check_drops + echo "FAIL: ${ns1} cannot reach $daddr4, ret $ret" 1>&2 + return 1 + fi + + ip netns exec ${ns1} ping -c 3 -q $daddr6 > /dev/null + ret=$? + if [ $ret -ne 0 ];then + check_drops + echo "FAIL: ${ns1} cannot reach $daddr6, ret $ret" 1>&2 + return 1 + fi + + return 0 +} + +ip netns exec ${nsrouter} sysctl net.ipv6.conf.all.forwarding=1 > /dev/null +ip netns exec ${nsrouter} sysctl net.ipv4.conf.veth0.forwarding=1 > /dev/null +ip netns exec ${nsrouter} sysctl net.ipv4.conf.veth1.forwarding=1 > /dev/null + +sleep 3 + +test_ping 10.0.2.1 dead:2::1 || exit 1 +check_drops || exit 1 + +test_ping 10.0.2.99 dead:2::99 || exit 1 +check_drops || exit 1 + +echo "PASS: fib expression did not cause unwanted packet drops" + +ip netns exec ${nsrouter} nft flush table inet filter + +ip -net ${ns1} route del default +ip -net ${ns1} -6 route del default + +ip -net ${ns1} addr del 10.0.1.99/24 dev eth0 +ip -net ${ns1} addr del dead:1::99/64 dev eth0 + +ip -net ${ns1} addr add 10.0.2.99/24 dev eth0 +ip -net ${ns1} addr add dead:2::99/64 dev eth0 + +ip -net ${ns1} route add default via 10.0.2.1 +ip -net ${ns1} -6 route add default via dead:2::1 + +ip -net ${nsrouter} addr add dead:2::1/64 dev veth0 + +# switch to ruleset that doesn't log, this time +# its expected that this does drop the packets. +load_ruleset_count ${nsrouter} + +# ns1 has a default route, but nsrouter does not. +# must not check return value, ping to 1.1.1.1 will +# fail. +check_fib_counter 0 ${nsrouter} 1.1.1.1 || exit 1 +check_fib_counter 0 ${nsrouter} 1c3::c01d || exit 1 + +ip netns exec ${ns1} ping -c 1 -W 1 -q 1.1.1.1 > /dev/null +check_fib_counter 1 ${nsrouter} 1.1.1.1 || exit 1 + +sleep 2 +ip netns exec ${ns1} ping -c 3 -q 1c3::c01d > /dev/null +check_fib_counter 3 ${nsrouter} 1c3::c01d || exit 1 + +exit 0 -- cgit v1.2.3 From 12f36e9bf678a81d030ca1b693dcda62b55af7c5 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Tue, 8 Jun 2021 13:48:18 +0200 Subject: netfilter: nft_fib_ipv6: skip ipv6 packets from any to link-local The ip6tables rpfilter match has an extra check to skip packets with "::" source address. Extend this to ipv6 fib expression. Else ipv6 duplicate address detection packets will fail rpf route check -- lookup returns -ENETUNREACH. While at it, extend the prerouting check to also cover the ingress hook. Closes: https://bugzilla.netfilter.org/show_bug.cgi?id=1543 Fixes: f6d0cbcf09c5 ("netfilter: nf_tables: add fib expression") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/ipv6/netfilter/nft_fib_ipv6.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) diff --git a/net/ipv6/netfilter/nft_fib_ipv6.c b/net/ipv6/netfilter/nft_fib_ipv6.c index e204163c7036..92f3235fa287 100644 --- a/net/ipv6/netfilter/nft_fib_ipv6.c +++ b/net/ipv6/netfilter/nft_fib_ipv6.c @@ -135,6 +135,17 @@ void nft_fib6_eval_type(const struct nft_expr *expr, struct nft_regs *regs, } EXPORT_SYMBOL_GPL(nft_fib6_eval_type); +static bool nft_fib_v6_skip_icmpv6(const struct sk_buff *skb, u8 next, const struct ipv6hdr *iph) +{ + if (likely(next != IPPROTO_ICMPV6)) + return false; + + if (ipv6_addr_type(&iph->saddr) != IPV6_ADDR_ANY) + return false; + + return ipv6_addr_type(&iph->daddr) & IPV6_ADDR_LINKLOCAL; +} + void nft_fib6_eval(const struct nft_expr *expr, struct nft_regs *regs, const struct nft_pktinfo *pkt) { @@ -163,10 +174,13 @@ void nft_fib6_eval(const struct nft_expr *expr, struct nft_regs *regs, lookup_flags = nft_fib6_flowi_init(&fl6, priv, pkt, oif, iph); - if (nft_hook(pkt) == NF_INET_PRE_ROUTING && - nft_fib_is_loopback(pkt->skb, nft_in(pkt))) { - nft_fib_store_result(dest, priv, nft_in(pkt)); - return; + if (nft_hook(pkt) == NF_INET_PRE_ROUTING || + nft_hook(pkt) == NF_INET_INGRESS) { + if (nft_fib_is_loopback(pkt->skb, nft_in(pkt)) || + nft_fib_v6_skip_icmpv6(pkt->skb, pkt->tprot, iph)) { + nft_fib_store_result(dest, priv, nft_in(pkt)); + return; + } } *dest = 0; -- cgit v1.2.3