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authorJozsef Kadlecsik <kadlec@netfilter.org>2022-11-02 10:40:47 +0100
committerPablo Neira Ayuso <pablo@netfilter.org>2022-11-02 19:22:23 +0100
commit510841da1fcc16f702440ab58ef0b4d82a9056b7 (patch)
tree0ae9ae1a55f8b0b01e3783c9caa4b306ddf7f396 /net
parentcbc1dd5b659f5a2c3cba88b197b7443679bb35a0 (diff)
netfilter: ipset: enforce documented limit to prevent allocating huge memory
Daniel Xu reported that the hash:net,iface type of the ipset subsystem does not limit adding the same network with different interfaces to a set, which can lead to huge memory usage or allocation failure. The quick reproducer is $ ipset create ACL.IN.ALL_PERMIT hash:net,iface hashsize 1048576 timeout 0 $ for i in $(seq 0 100); do /sbin/ipset add ACL.IN.ALL_PERMIT 0.0.0.0/0,kaf_$i timeout 0 -exist; done The backtrace when vmalloc fails: [Tue Oct 25 00:13:08 2022] ipset: vmalloc error: size 1073741848, exceeds total pages <...> [Tue Oct 25 00:13:08 2022] Call Trace: [Tue Oct 25 00:13:08 2022] <TASK> [Tue Oct 25 00:13:08 2022] dump_stack_lvl+0x48/0x60 [Tue Oct 25 00:13:08 2022] warn_alloc+0x155/0x180 [Tue Oct 25 00:13:08 2022] __vmalloc_node_range+0x72a/0x760 [Tue Oct 25 00:13:08 2022] ? hash_netiface4_add+0x7c0/0xb20 [Tue Oct 25 00:13:08 2022] ? __kmalloc_large_node+0x4a/0x90 [Tue Oct 25 00:13:08 2022] kvmalloc_node+0xa6/0xd0 [Tue Oct 25 00:13:08 2022] ? hash_netiface4_resize+0x99/0x710 <...> The fix is to enforce the limit documented in the ipset(8) manpage: > The internal restriction of the hash:net,iface set type is that the same > network prefix cannot be stored with more than 64 different interfaces > in a single set. Fixes: ccf0a4b7fc68 ("netfilter: ipset: Add bucketsize parameter to all hash types") Reported-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
-rw-r--r--net/netfilter/ipset/ip_set_hash_gen.h30
1 files changed, 6 insertions, 24 deletions
diff --git a/net/netfilter/ipset/ip_set_hash_gen.h b/net/netfilter/ipset/ip_set_hash_gen.h
index 6e391308431d..3adc291d9ce1 100644
--- a/net/netfilter/ipset/ip_set_hash_gen.h
+++ b/net/netfilter/ipset/ip_set_hash_gen.h
@@ -42,31 +42,8 @@
#define AHASH_MAX_SIZE (6 * AHASH_INIT_SIZE)
/* Max muber of elements in the array block when tuned */
#define AHASH_MAX_TUNED 64
-
#define AHASH_MAX(h) ((h)->bucketsize)
-/* Max number of elements can be tuned */
-#ifdef IP_SET_HASH_WITH_MULTI
-static u8
-tune_bucketsize(u8 curr, u32 multi)
-{
- u32 n;
-
- if (multi < curr)
- return curr;
-
- n = curr + AHASH_INIT_SIZE;
- /* Currently, at listing one hash bucket must fit into a message.
- * Therefore we have a hard limit here.
- */
- return n > curr && n <= AHASH_MAX_TUNED ? n : curr;
-}
-#define TUNE_BUCKETSIZE(h, multi) \
- ((h)->bucketsize = tune_bucketsize((h)->bucketsize, multi))
-#else
-#define TUNE_BUCKETSIZE(h, multi)
-#endif
-
/* A hash bucket */
struct hbucket {
struct rcu_head rcu; /* for call_rcu */
@@ -936,7 +913,12 @@ mtype_add(struct ip_set *set, void *value, const struct ip_set_ext *ext,
goto set_full;
/* Create a new slot */
if (n->pos >= n->size) {
- TUNE_BUCKETSIZE(h, multi);
+#ifdef IP_SET_HASH_WITH_MULTI
+ if (h->bucketsize >= AHASH_MAX_TUNED)
+ goto set_full;
+ else if (h->bucketsize < multi)
+ h->bucketsize += AHASH_INIT_SIZE;
+#endif
if (n->size >= AHASH_MAX(h)) {
/* Trigger rehashing */
mtype_data_next(&h->next, d);