From: Florian Westphal Date: Thu, 17 Apr 2025 15:14:28 +0000 (+0200) Subject: selftests: netfilter: add conntrack stress test X-Git-Tag: v6.16-rc1~132^2~161^2~5 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=d33f889fd80c91e0250874e910fc58918eb660db;p=linux-block.git selftests: netfilter: add conntrack stress test Add a new test case to check: - conntrack_max limit is effective - conntrack_max limit cannot be exceeded from within a netns - resizing the hash table while packets are inflight works - removal of all conntrack rules disables conntrack in netns - conntrack tool dump (conntrack -L) returns expected number of (unique) entries - procfs interface - if available - has same number of entries as conntrack -L dump Expected output with selftest framework: selftests: net/netfilter: conntrack_resize.sh PASS: got 1 connections: netns conntrack_max is pernet bound PASS: got 100 connections: netns conntrack_max is init_net bound PASS: dump in netns had same entry count (-C 1778, -L 1778, -p 1778, /proc 0) PASS: dump in netns had same entry count (-C 2000, -L 2000, -p 2000, /proc 0) PASS: test parallel conntrack dumps PASS: resize+flood PASS: got 0 connections: conntrack disabled PASS: got 1 connections: conntrack enabled ok 1 selftests: net/netfilter: conntrack_resize.sh Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- diff --git a/tools/testing/selftests/net/netfilter/Makefile b/tools/testing/selftests/net/netfilter/Makefile index ffe161fac8b5..3bdcbbdba925 100644 --- a/tools/testing/selftests/net/netfilter/Makefile +++ b/tools/testing/selftests/net/netfilter/Makefile @@ -12,6 +12,7 @@ TEST_PROGS += conntrack_dump_flush.sh TEST_PROGS += conntrack_icmp_related.sh TEST_PROGS += conntrack_ipip_mtu.sh TEST_PROGS += conntrack_tcp_unreplied.sh +TEST_PROGS += conntrack_resize.sh TEST_PROGS += conntrack_sctp_collision.sh TEST_PROGS += conntrack_vrf.sh TEST_PROGS += conntrack_reverse_clash.sh diff --git a/tools/testing/selftests/net/netfilter/config b/tools/testing/selftests/net/netfilter/config index 43d8b500d391..363646f4fefe 100644 --- a/tools/testing/selftests/net/netfilter/config +++ b/tools/testing/selftests/net/netfilter/config @@ -46,6 +46,7 @@ CONFIG_NETFILTER_XT_MATCH_STATE=m CONFIG_NETFILTER_XT_MATCH_STRING=m CONFIG_NETFILTER_XT_TARGET_REDIRECT=m CONFIG_NF_CONNTRACK=m +CONFIG_NF_CONNTRACK_PROCFS=y CONFIG_NF_CONNTRACK_EVENTS=y CONFIG_NF_CONNTRACK_FTP=m CONFIG_NF_CONNTRACK_MARK=y diff --git a/tools/testing/selftests/net/netfilter/conntrack_resize.sh b/tools/testing/selftests/net/netfilter/conntrack_resize.sh new file mode 100755 index 000000000000..aabc7c51181e --- /dev/null +++ b/tools/testing/selftests/net/netfilter/conntrack_resize.sh @@ -0,0 +1,406 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 + +source lib.sh + +checktool "conntrack --version" "run test without conntrack" +checktool "nft --version" "run test without nft tool" + +init_net_max=0 +ct_buckets=0 +tmpfile="" +ret=0 + +modprobe -q nf_conntrack +if ! sysctl -q net.netfilter.nf_conntrack_max >/dev/null;then + echo "SKIP: conntrack sysctls not available" + exit $KSFT_SKIP +fi + +init_net_max=$(sysctl -n net.netfilter.nf_conntrack_max) || exit 1 +ct_buckets=$(sysctl -n net.netfilter.nf_conntrack_buckets) || exit 1 + +cleanup() { + cleanup_all_ns + + rm -f "$tmpfile" + + # restore original sysctl setting + sysctl -q net.netfilter.nf_conntrack_max=$init_net_max + sysctl -q net.netfilter.nf_conntrack_buckets=$ct_buckets +} +trap cleanup EXIT + +check_max_alias() +{ + local expected="$1" + # old name, expected to alias to the first, i.e. changing one + # changes the other as well. + local lv=$(sysctl -n net.nf_conntrack_max) + + if [ $expected -ne "$lv" ];then + echo "nf_conntrack_max sysctls should have identical values" + exit 1 + fi +} + +insert_ctnetlink() { + local ns="$1" + local count="$2" + local i=0 + local bulk=16 + + while [ $i -lt $count ] ;do + ip netns exec "$ns" bash -c "for i in \$(seq 1 $bulk); do \ + if ! conntrack -I -s \$((\$RANDOM%256)).\$((\$RANDOM%256)).\$((\$RANDOM%256)).\$((\$RANDOM%255+1)) \ + -d \$((\$RANDOM%256)).\$((\$RANDOM%256)).\$((\$RANDOM%256)).\$((\$RANDOM%255+1)) \ + --protonum 17 --timeout 120 --status ASSURED,SEEN_REPLY --sport \$RANDOM --dport 53; then \ + return;\ + fi & \ + done ; wait" 2>/dev/null + + i=$((i+bulk)) + done +} + +check_ctcount() { + local ns="$1" + local count="$2" + local msg="$3" + + local now=$(ip netns exec "$ns" conntrack -C) + + if [ $now -ne "$count" ] ;then + echo "expected $count entries in $ns, not $now: $msg" + exit 1 + fi + + echo "PASS: got $count connections: $msg" +} + +ctresize() { + local duration="$1" + local now=$(date +%s) + local end=$((now + duration)) + + while [ $now -lt $end ]; do + sysctl -q net.netfilter.nf_conntrack_buckets=$RANDOM + now=$(date +%s) + done +} + +do_rsleep() { + local limit="$1" + local r=$RANDOM + + r=$((r%limit)) + sleep "$r" +} + +ct_flush_once() { + local ns="$1" + + ip netns exec "$ns" conntrack -F 2>/dev/null +} + +ctflush() { + local ns="$1" + local duration="$2" + local now=$(date +%s) + local end=$((now + duration)) + + do_rsleep "$duration" + + while [ $now -lt $end ]; do + ct_flush_once "$ns" + do_rsleep "$duration" + now=$(date +%s) + done +} + +ctflood() +{ + local ns="$1" + local duration="$2" + local msg="$3" + local now=$(date +%s) + local end=$((now + duration)) + local j=0 + local k=0 + + while [ $now -lt $end ]; do + j=$((j%256)) + k=$((k%256)) + + ip netns exec "$ns" bash -c \ + "j=$j k=$k; for i in \$(seq 1 254); do ping -q -c 1 127.\$k.\$j.\$i & done; wait" >/dev/null 2>&1 + + j=$((j+1)) + + if [ $j -eq 256 ];then + k=$((k+1)) + fi + + now=$(date +%s) + done + + wait +} + +# dump to /dev/null. We don't want dumps to cause infinite loops +# or use-after-free even when conntrack table is altered while dumps +# are in progress. +ct_nulldump() +{ + local ns="$1" + + ip netns exec "$ns" conntrack -L > /dev/null 2>&1 & + + # Don't require /proc support in conntrack + if [ -r /proc/self/net/nf_conntrack ] ; then + ip netns exec "$ns" bash -c "wc -l < /proc/self/net/nf_conntrack" > /dev/null & + fi + + wait +} + +check_taint() +{ + local tainted_then="$1" + local msg="$2" + + local tainted_now=0 + + if [ "$tainted_then" -ne 0 ];then + return + fi + + read tainted_now < /proc/sys/kernel/tainted + + if [ "$tainted_now" -eq 0 ];then + echo "PASS: $msg" + else + echo "TAINT: $msg" + dmesg + exit 1 + fi +} + +insert_flood() +{ + local n="$1" + local r=0 + + r=$((RANDOM%2000)) + + ctflood "$n" "$timeout" "floodresize" & + insert_ctnetlink "$n" "$r" & + ctflush "$n" "$timeout" & + ct_nulldump "$n" & + + wait +} + +test_floodresize_all() +{ + local timeout=20 + local n="" + local tainted_then="" + + read tainted_then < /proc/sys/kernel/tainted + + for n in "$nsclient1" "$nsclient2";do + insert_flood "$n" & + done + + # resize table constantly while flood/insert/dump/flushs + # are happening in parallel. + ctresize "$timeout" + + # wait for subshells to complete, everything is limited + # by $timeout. + wait + + check_taint "$tainted_then" "resize+flood" +} + +check_dump() +{ + local ns="$1" + local protoname="$2" + local c=0 + local proto=0 + local proc=0 + local unique="" + + c=$(ip netns exec "$ns" conntrack -C) + + # NOTE: assumes timeouts are large enough to not have + # expirations in all following tests. + l=$(ip netns exec "$ns" conntrack -L 2>/dev/null | tee "$tmpfile" | wc -l) + + if [ "$c" -ne "$l" ]; then + echo "FAIL: count inconsistency for $ns: $c != $l" + ret=1 + fi + + # check the dump we retrieved is free of duplicated entries. + unique=$(sort "$tmpfile" | uniq | wc -l) + if [ "$l" -ne "$unique" ]; then + echo "FAIL: count identical but listing contained redundant entries: $l != $unique" + ret=1 + fi + + # we either inserted icmp or only udp, hence, --proto should return same entry count as without filter. + proto=$(ip netns exec "$ns" conntrack -L --proto $protoname 2>/dev/null | wc -l) + if [ "$l" -ne "$proto" ]; then + echo "FAIL: dump inconsistency for $ns: $l != $proto" + ret=1 + fi + + if [ -r /proc/self/net/nf_conntrack ] ; then + proc=$(ip netns exec "$ns" bash -c "wc -l < /proc/self/net/nf_conntrack") + + if [ "$l" -ne "$proc" ]; then + echo "FAIL: proc inconsistency for $ns: $l != $proc" + ret=1 + fi + + proc=$(ip netns exec "$ns" bash -c "sort < /proc/self/net/nf_conntrack | uniq | wc -l") + + if [ "$l" -ne "$proc" ]; then + echo "FAIL: proc inconsistency after uniq filter for $ns: $l != $proc" + ret=1 + fi + fi + + echo "PASS: dump in netns had same entry count (-C $c, -L $l, -p $proto, /proc $proc)" +} + +test_dump_all() +{ + local timeout=3 + local tainted_then="" + + read tainted_then < /proc/sys/kernel/tainted + + ct_flush_once "$nsclient1" + ct_flush_once "$nsclient2" + + ctflood "$nsclient1" $timeout "dumpall" & + insert_ctnetlink "$nsclient2" 2000 + + wait + + check_dump "$nsclient1" "icmp" + check_dump "$nsclient2" "udp" + + check_taint "$tainted_then" "test parallel conntrack dumps" +} + +check_sysctl_immutable() +{ + local ns="$1" + local name="$2" + local failhard="$3" + local o=0 + local n=0 + + o=$(ip netns exec "$ns" sysctl -n "$name" 2>/dev/null) + n=$((o+1)) + + # return value isn't reliable, need to read it back + ip netns exec "$ns" sysctl -q "$name"=$n 2>/dev/null >/dev/null + + n=$(ip netns exec "$ns" sysctl -n "$name" 2>/dev/null) + + [ -z "$n" ] && return 1 + + if [ $o -ne $n ]; then + if [ $failhard -gt 0 ] ;then + echo "FAIL: net.$name should not be changeable from namespace (now $n)" + ret=1 + fi + return 0 + fi + + return 1 +} + +test_conntrack_max_limit() +{ + sysctl -q net.netfilter.nf_conntrack_max=100 + insert_ctnetlink "$nsclient1" 101 + + # check netns is clamped by init_net, i.e., either netns follows + # init_net value, or a higher pernet limit (compared to init_net) is ignored. + check_ctcount "$nsclient1" 100 "netns conntrack_max is init_net bound" + + sysctl -q net.netfilter.nf_conntrack_max=$init_net_max +} + +test_conntrack_disable() +{ + local timeout=2 + + # disable conntrack pickups + ip netns exec "$nsclient1" nft flush table ip test_ct + + ct_flush_once "$nsclient1" + ct_flush_once "$nsclient2" + + ctflood "$nsclient1" "$timeout" "conntrack disable" + ip netns exec "$nsclient2" ping -q -c 1 127.0.0.1 >/dev/null 2>&1 + + # Disabled, should not have picked up any connection. + check_ctcount "$nsclient1" 0 "conntrack disabled" + + # This one is still active, expect 1 connection. + check_ctcount "$nsclient2" 1 "conntrack enabled" +} + +init_net_max=$(sysctl -n net.netfilter.nf_conntrack_max) + +check_max_alias $init_net_max + +sysctl -q net.netfilter.nf_conntrack_max="262000" +check_max_alias 262000 + +setup_ns nsclient1 nsclient2 + +# check this only works from init_net +for n in netfilter.nf_conntrack_buckets netfilter.nf_conntrack_expect_max net.nf_conntrack_max;do + check_sysctl_immutable "$nsclient1" "net.$n" 1 +done + +# won't work on older kernels. If it works, check that the netns obeys the limit +if check_sysctl_immutable "$nsclient1" net.netfilter.nf_conntrack_max 0;then + # subtest: if pernet is changeable, check that reducing it in pernet + # limits the pernet entries. Inverse, pernet clamped by a lower init_net + # setting, is already checked by "test_conntrack_max_limit" test. + + ip netns exec "$nsclient1" sysctl -q net.netfilter.nf_conntrack_max=1 + insert_ctnetlink "$nsclient1" 2 + check_ctcount "$nsclient1" 1 "netns conntrack_max is pernet bound" + ip netns exec "$nsclient1" sysctl -q net.netfilter.nf_conntrack_max=$init_net_max +fi + +for n in "$nsclient1" "$nsclient2";do +# enable conntrack in both namespaces +ip netns exec "$n" nft -f - <