[PATCH 4.19 60/63] netfilter: nft_socket: fix erroneous socket assignment

From: Greg Kroah-Hartman
Date: Sun Sep 29 2019 - 10:00:18 EST


From: Fernando Fernandez Mancera <ffmancera@xxxxxxxxxx>

[ Upstream commit 039b1f4f24ecc8493b6bb9d70b4b78750d1b35c2 ]

The socket assignment is wrong, see skb_orphan():
When skb->destructor callback is not set, but skb->sk is set, this hits BUG().

Link: https://bugzilla.redhat.com/show_bug.cgi?id=1651813
Fixes: 554ced0a6e29 ("netfilter: nf_tables: add support for native socket matching")
Signed-off-by: Fernando Fernandez Mancera <ffmancera@xxxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/netfilter/nft_socket.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/netfilter/nft_socket.c b/net/netfilter/nft_socket.c
index d7f3776dfd719..637ce3e8c575c 100644
--- a/net/netfilter/nft_socket.c
+++ b/net/netfilter/nft_socket.c
@@ -47,9 +47,6 @@ static void nft_socket_eval(const struct nft_expr *expr,
return;
}

- /* So that subsequent socket matching not to require other lookups. */
- skb->sk = sk;
-
switch(priv->key) {
case NFT_SOCKET_TRANSPARENT:
nft_reg_store8(dest, inet_sk_transparent(sk));
@@ -66,6 +63,9 @@ static void nft_socket_eval(const struct nft_expr *expr,
WARN_ON(1);
regs->verdict.code = NFT_BREAK;
}
+
+ if (sk != skb->sk)
+ sock_gen_put(sk);
}

static const struct nla_policy nft_socket_policy[NFTA_SOCKET_MAX + 1] = {
--
2.20.1