[PATCH 5.4 29/76] netfilter: ipset: fixes possible oops in mtype_resize

Greg Kroah-Hartman
2021-01-18T11:52:12Z

From: Vasily Averin <vvs@virtuozzo.com>

[ Upstream commit 2b33d6ffa9e38f344418976b06057e2fc2aa9e2a ]

currently mtype_resize() can cause oops

t = ip_set_alloc(htable_size(htable_bits));
if (!t) {
ret = -ENOMEM;
goto out;
}
t->hregion = ip_set_alloc(ahash_sizeof_regions(htable_bits));

Increased htable_bits can force htable_size() to return 0.
In own turn ip_set_alloc(0) returns not 0 but ZERO_SIZE_PTR,
so follwoing access to t->hregion should trigger an OOPS.

Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Acked-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/netfilter/ipset/ip_set_hash_gen.h | 22 +++++++++++++---------
1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/net/netfilter/ipset/ip_set_hash_gen.h b/net/netfilter/ipset/ip_set_hash_gen.h
index 1a58cfdb862d6..500de37858ac8 100644
--- a/net/netfilter/ipset/ip_set_hash_gen.h
+++ b/net/netfilter/ipset/ip_set_hash_gen.h
@@ -630,7 +630,7 @@ mtype_resize(struct ip_set *set, bool retried)
struct htype *h = set->data;
struct htable *t, *orig;
u8 htable_bits;
- size_t dsize = set->dsize;
+ size_t hsize, dsize = set->dsize;
#ifdef IP_SET_HASH_WITH_NETS
u8 flags;
struct mtype_elem *tmp;
@@ -654,14 +654,12 @@ mtype_resize(struct ip_set *set, bool retried)
retry:
ret = 0;
htable_bits++;
- if (!htable_bits) {
- /* In case we have plenty of memory :-) */
- pr_warn("Cannot increase the hashsize of set %s further\n",
- set->name);
- ret = -IPSET_ERR_HASH_FULL;
- goto out;
- }
- t = ip_set_alloc(htable_size(htable_bits));
+ if (!htable_bits)
+ goto hbwarn;
+ hsize = htable_size(htable_bits);
+ if (!hsize)
+ goto hbwarn;
+ t = ip_set_alloc(hsize);
if (!t) {
ret = -ENOMEM;
goto out;
@@ -803,6 +801,12 @@ cleanup:
if (ret == -EAGAIN)
goto retry;
goto out;
+
+hbwarn:
+ /* In case we have plenty of memory :-) */
+ pr_warn("Cannot increase the hashsize of set %s further\n", set->name);
+ ret = -IPSET_ERR_HASH_FULL;
+ goto out;
}

/* Get the current number of elements and ext_size in the set */
--
2.27.0