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authorPablo Neira Ayuso <pablo@netfilter.org>2022-06-21 14:01:41 +0200
committerPablo Neira Ayuso <pablo@netfilter.org>2022-06-27 19:03:37 +0200
commit05907f10e235680cc7fb196810e4ad3215d5e648 (patch)
tree86ed120de0ef116f27b9aa350df0996f93c84c5e /net
parentcb8092d70a6f5f01ec1490fce4d35efed3ed996c (diff)
netfilter: nft_dynset: restore set element counter when failing to update
This patch fixes a race condition. nft_rhash_update() might fail for two reasons: - Element already exists in the hashtable. - Another packet won race to insert an entry in the hashtable. In both cases, new() has already bumped the counter via atomic_add_unless(), therefore, decrement the set element counter. Fixes: 22fe54d5fefc ("netfilter: nf_tables: add support for dynamic set updates") Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
-rw-r--r--net/netfilter/nft_set_hash.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/net/netfilter/nft_set_hash.c b/net/netfilter/nft_set_hash.c
index df40314de21f..76de6c8d9865 100644
--- a/net/netfilter/nft_set_hash.c
+++ b/net/netfilter/nft_set_hash.c
@@ -143,6 +143,7 @@ static bool nft_rhash_update(struct nft_set *set, const u32 *key,
/* Another cpu may race to insert the element with the same key */
if (prev) {
nft_set_elem_destroy(set, he, true);
+ atomic_dec(&set->nelems);
he = prev;
}
@@ -152,6 +153,7 @@ out:
err2:
nft_set_elem_destroy(set, he, true);
+ atomic_dec(&set->nelems);
err1:
return false;
}