1 From e4a8cca460c381539a5403d9434a5977c453fe0b Mon Sep 17 00:00:00 2001
2 From: Pablo Neira Ayuso <pablo@netfilter.org>
3 Date: Mon, 11 Mar 2019 13:04:16 +0100
4 Subject: netfilter: nf_tables: use-after-free in dynamic operations
6 [ Upstream commit 3f3a390dbd59d236f62cff8e8b20355ef7069e3d ]
10 net/netfilter/nf_tables_api.c:2167 nf_tables_expr_destroy()
11 error: dereferencing freed memory 'expr->ops'
13 net/netfilter/nf_tables_api.c
14 2162 static void nf_tables_expr_destroy(const struct nft_ctx *ctx,
15 2163 struct nft_expr *expr)
17 2165 if (expr->ops->destroy)
18 2166 expr->ops->destroy(ctx, expr);
20 --> 2167 module_put(expr->ops->type->owner);
24 Smatch says there are three functions which free expr->ops.
26 Fixes: b8e204006340 ("netfilter: nft_compat: use .release_ops and remove list of extension")
27 Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
28 Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
29 Signed-off-by: Sasha Levin <sashal@kernel.org>
31 net/netfilter/nf_tables_api.c | 4 +++-
32 1 file changed, 3 insertions(+), 1 deletion(-)
34 diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
35 index dc3670f2860e..f20b904873c6 100644
36 --- a/net/netfilter/nf_tables_api.c
37 +++ b/net/netfilter/nf_tables_api.c
38 @@ -2119,9 +2119,11 @@ static int nf_tables_newexpr(const struct nft_ctx *ctx,
39 static void nf_tables_expr_destroy(const struct nft_ctx *ctx,
40 struct nft_expr *expr)
42 + const struct nft_expr_type *type = expr->ops->type;
44 if (expr->ops->destroy)
45 expr->ops->destroy(ctx, expr);
46 - module_put(expr->ops->type->owner);
47 + module_put(type->owner);
50 struct nft_expr *nft_expr_init(const struct nft_ctx *ctx,