[rh7,3/3] ms/netfilter: nft_compat: use-after-free when deleting targets

Submitted by Konstantin Khorenko on Nov. 25, 2019, 7:58 a.m.

Details

Message ID 20191125075827.1216-3-khorenko@virtuozzo.com
State New
Series "Series without cover letter"
Headers show

Commit Message

Konstantin Khorenko Nov. 25, 2019, 7:58 a.m.
From: Pablo Neira Ayuso <pablo@netfilter.org>

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>

Backported in the scope of https://jira.sw.ru/browse/PSBM-99656

(cherry picked from commit 753c111f655e38bbd52fc01321266633f022ebe2)
Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>
---
 net/netfilter/nft_compat.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

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diff --git a/net/netfilter/nft_compat.c b/net/netfilter/nft_compat.c
index be17f603b90d..4a875378c40d 100644
--- a/net/netfilter/nft_compat.c
+++ b/net/netfilter/nft_compat.c
@@ -265,6 +265,7 @@  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;
@@ -275,7 +276,7 @@  nft_target_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
 		par.target->destroy(&par);
 
 	nft_xt_put(container_of(expr->ops, struct nft_xt, ops));
-	module_put(target->me);
+	module_put(me);
 }
 
 static int nft_target_dump(struct sk_buff *skb, const struct nft_expr *expr)