netfilter: nft_compat: use-after-free when deleting targets

commit 753c111f655e38bbd52fc01321266633f022ebe2 upstream.

Fetch pointer to module before target object is released.

Fixes: 29e3880109e3 ("netfilter: nf_tables: fix use-after-free when deleting compat expressions")
Fixes: 0ca743a55991 ("netfilter: nf_tables: add compatibility layer for x_tables")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/netfilter/nft_compat.c b/net/netfilter/nft_compat.c
index 26ed2e4d2335001f74a8c8892100219aa513d519..0d2b40981c6c194a110ddcf5c160b404f88949ce 100644 (file)
--- a/net/netfilter/nft_compat.c
+++ b/net/netfilter/nft_compat.c
@@ -221,6 +221,7 @@ nft_target_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
 {
        struct xt_target *target = expr->ops->data;
        void *info = nft_expr_priv(expr);
+       struct module *me = target->me;
        struct xt_tgdtor_param par;
 
        par.net = ctx->net;
@@ -231,7 +232,7 @@ nft_target_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
                par.target->destroy(&par);
 
        if (nft_xt_put(container_of(expr->ops, struct nft_xt, ops)))
-               module_put(target->me);
+               module_put(me);
 }
 
 static int