From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Cc: davem@davemloft.net, netdev@vger.kernel.org
Subject: [PATCH 4/5] netfilter: nf_tables: use-after-free in dynamic operations
Date: Mon, 11 Mar 2019 23:50:34 +0100 [thread overview]
Message-ID: <20190311225035.21250-5-pablo@netfilter.org> (raw)
In-Reply-To: <20190311225035.21250-1-pablo@netfilter.org>
Smatch reports:
net/netfilter/nf_tables_api.c:2167 nf_tables_expr_destroy()
error: dereferencing freed memory 'expr->ops'
net/netfilter/nf_tables_api.c
2162 static void nf_tables_expr_destroy(const struct nft_ctx *ctx,
2163 struct nft_expr *expr)
2164 {
2165 if (expr->ops->destroy)
2166 expr->ops->destroy(ctx, expr);
^^^^
--> 2167 module_put(expr->ops->type->owner);
^^^^^^^^^
2168 }
Smatch says there are three functions which free expr->ops.
Fixes: b8e204006340 ("netfilter: nft_compat: use .release_ops and remove list of extension")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
net/netfilter/nf_tables_api.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index ca09ef037ca5..9d8f51dfc593 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -2162,9 +2162,11 @@ static int nf_tables_newexpr(const struct nft_ctx *ctx,
static void nf_tables_expr_destroy(const struct nft_ctx *ctx,
struct nft_expr *expr)
{
+ const struct nft_expr_type *type = expr->ops->type;
+
if (expr->ops->destroy)
expr->ops->destroy(ctx, expr);
- module_put(expr->ops->type->owner);
+ module_put(type->owner);
}
struct nft_expr *nft_expr_init(const struct nft_ctx *ctx,
--
2.11.0
next prev parent reply other threads:[~2019-03-11 22:50 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-11 22:50 [PATCH 0/5] Netfilter fixes for net Pablo Neira Ayuso
2019-03-11 22:50 ` [PATCH 1/5] netfilter: nat: don't register device notifier twice Pablo Neira Ayuso
2019-03-11 22:50 ` [PATCH 2/5] netfilter: nf_tables: fix set double-free in abort path Pablo Neira Ayuso
2019-03-11 22:50 ` [PATCH 3/5] netfilter: nf_tables: bogus EBUSY when deleting set after flush Pablo Neira Ayuso
2019-03-11 22:50 ` Pablo Neira Ayuso [this message]
2019-03-11 22:50 ` [PATCH 5/5] netfilter: nf_tables: return immediately on empty commit Pablo Neira Ayuso
2019-03-11 23:14 ` [PATCH 0/5] Netfilter fixes for net David Miller
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