[PATCH AUTOSEL 5.1 070/219] ipset: Fix memory accounting for hash types on resize

Sasha Levin
2019-07-15T14:08:01Z

From: Stefano Brivio <sbrivio@redhat.com>

[ Upstream commit 11921796f4799ca9c61c4b22cc54d84aa69f8a35 ]

If a fresh array block is allocated during resize, the current in-memory
set size should be increased by the size of the block, not replaced by it.

Before the fix, adding entries to a hash set type, leading to a table
resize, caused an inconsistent memory size to be reported. This becomes
more obvious when swapping sets with similar sizes:

# cat hash_ip_size.sh
#!/bin/sh
FAIL_RETRIES=10

tries=0
while [ ${tries} -lt ${FAIL_RETRIES} ]; do
ipset create t1 hash:ip
for i in `seq 1 4345`; do
ipset add t1 1.2.$((i / 255)).$((i % 255))
done
t1_init="$(ipset list t1|sed -n 's/Size in memory: \(.*\)/\1/p')"

ipset create t2 hash:ip
for i in `seq 1 4360`; do
ipset add t2 1.2.$((i / 255)).$((i % 255))
done
t2_init="$(ipset list t2|sed -n 's/Size in memory: \(.*\)/\1/p')"

ipset swap t1 t2
t1_swap="$(ipset list t1|sed -n 's/Size in memory: \(.*\)/\1/p')"
t2_swap="$(ipset list t2|sed -n 's/Size in memory: \(.*\)/\1/p')"

ipset destroy t1
ipset destroy t2
tries=$((tries + 1))

if [ ${t1_init} -lt 10000 ] || [ ${t2_init} -lt 10000 ]; then
echo "FAIL after ${tries} tries:"
echo "T1 size ${t1_init}, after swap ${t1_swap}"
echo "T2 size ${t2_init}, after swap ${t2_swap}"
exit 1
fi
done
echo "PASS"
# echo -n 'func hash_ip4_resize +p' > /sys/kernel/debug/dynamic_debug/control
# ./hash_ip_size.sh
[ 2035.018673] attempt to resize set t1 from 10 to 11, t 00000000fe6551fa
[ 2035.078583] set t1 resized from 10 (00000000fe6551fa) to 11 (00000000172a0163)
[ 2035.080353] Table destroy by resize 00000000fe6551fa
FAIL after 4 tries:
T1 size 9064, after swap 71128
T2 size 71128, after swap 9064

Reported-by: NOYB <JunkYardMail1@Frontier.com>
Fixes: 9e41f26a505c ("netfilter: ipset: Count non-static extension memory for userspace")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/netfilter/ipset/ip_set_hash_gen.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netfilter/ipset/ip_set_hash_gen.h b/net/netfilter/ipset/ip_set_hash_gen.h
index 2c9609929c71..455804456008 100644
--- a/net/netfilter/ipset/ip_set_hash_gen.h
+++ b/net/netfilter/ipset/ip_set_hash_gen.h
@@ -625,7 +625,7 @@ mtype_resize(struct ip_set *set, bool retried)
goto cleanup;
}
m->size = AHASH_INIT_SIZE;
- extsize = ext_size(AHASH_INIT_SIZE, dsize);
+ extsize += ext_size(AHASH_INIT_SIZE, dsize);
RCU_INIT_POINTER(hbucket(t, key), m);
} else if (m->pos >= m->size) {
struct hbucket *ht;
--
2.20.1