[PATCH 5.15 126/244] netfilter: nf_tables: possible module reference underflow in error path

Greg Kroah-Hartman
2022-08-23T10:10:01Z

From: Pablo Neira Ayuso <pablo@netfilter.org>

commit c485c35ff6783ccd12c160fcac6a0e504e83e0bf upstream.

dst->ops is set on when nft_expr_clone() fails, but module refcount has
not been bumped yet, therefore nft_expr_destroy() leads to module
reference underflow.

Fixes: 8cfd9b0f8515 ("netfilter: nftables: generalize set expressions support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/netfilter/nf_tables_api.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -5479,7 +5479,7 @@ int nft_set_elem_expr_clone(const struct

err = nft_expr_clone(expr, set->exprs[i]);
if (err < 0) {
- nft_expr_destroy(ctx, expr);
+ kfree(expr);
goto err_expr;
}
expr_array[i] = expr;