4.20-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit b91d9036883793122cf6575ca4dfbfbdd201a83d ]
There is no code that decreases the reference count of stateful objects in error path of the nft_add_set_elem(). this causes a leak of reference count of stateful objects.
Test commands: $nft add table ip filter $nft add counter ip filter c1 $nft add map ip filter m1 { type ipv4_addr : counter ;} $nft add element ip filter m1 { 1 : c1 } $nft add element ip filter m1 { 1 : c1 } $nft delete element ip filter m1 { 1 } $nft delete counter ip filter c1
Result: Error: Could not process rule: Device or resource busy delete counter ip filter c1 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
At the second 'nft add element ip filter m1 { 1 : c1 }', the reference count of the 'c1' is increased then it tries to insert into the 'm1'. but the 'm1' already has same element so it returns -EEXIST. But it doesn't decrease the reference count of the 'c1' in the error path. Due to a leak of the reference count of the 'c1', the 'c1' can't be removed by 'nft delete counter ip filter c1'.
Fixes: 8aeff920dcc9 ("netfilter: nf_tables: add stateful object reference to set elements") Signed-off-by: Taehee Yoo ap420073@gmail.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/netfilter/nf_tables_api.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 6e548d7c9f67b..aba6ec4a14cec 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -4474,6 +4474,8 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set, err5: kfree(trans); err4: + if (obj) + obj->use--; kfree(elem.priv); err3: if (nla[NFTA_SET_ELEM_DATA] != NULL)