[PATCH 5.15 075/135] sock: redo the psock vs ULP protection check

Greg Kroah-Hartman
2022-06-27T11:41:42Z

From: Jakub Kicinski <kuba@kernel.org>

[ Upstream commit e34a07c0ae3906f97eb18df50902e2a01c1015b6 ]

Commit 8a59f9d1e3d4 ("sock: Introduce sk->sk_prot->psock_update_sk_prot()")
has moved the inet_csk_has_ulp(sk) check from sk_psock_init() to
the new tcp_bpf_update_proto() function. I'm guessing that this
was done to allow creating psocks for non-inet sockets.

Unfortunately the destruction path for psock includes the ULP
unwind, so we need to fail the sk_psock_init() itself.
Otherwise if ULP is already present we'll notice that later,
and call tcp_update_ulp() with the sk_proto of the ULP
itself, which will most likely result in the ULP looping
its callbacks.

Fixes: 8a59f9d1e3d4 ("sock: Introduce sk->sk_prot->psock_update_sk_prot()")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Tested-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/r/20220620191353.1184629-2-kuba@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/net/inet_sock.h | 5 +++++
net/core/skmsg.c | 5 +++++
net/ipv4/tcp_bpf.c | 3 ---
net/tls/tls_main.c | 2 ++
4 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index 9e1111f5915b..d81b7f85819e 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -252,6 +252,11 @@ struct inet_sock {
#define IP_CMSG_CHECKSUM BIT(7)
#define IP_CMSG_RECVFRAGSIZE BIT(8)

+static inline bool sk_is_inet(struct sock *sk)
+{
+ return sk->sk_family == AF_INET || sk->sk_family == AF_INET6;
+}
+
/**
* sk_to_full_sk - Access to a full socket
* @sk: pointer to a socket
diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index cc381165ea08..ede0af308f40 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -695,6 +695,11 @@ struct sk_psock *sk_psock_init(struct sock *sk, int node)

write_lock_bh(&sk->sk_callback_lock);

+ if (sk_is_inet(sk) && inet_csk_has_ulp(sk)) {
+ psock = ERR_PTR(-EINVAL);
+ goto out;
+ }
+
if (sk->sk_user_data) {
psock = ERR_PTR(-EBUSY);
goto out;
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
index 1cdcb4df0eb7..2c597a4e429a 100644
--- a/net/ipv4/tcp_bpf.c
+++ b/net/ipv4/tcp_bpf.c
@@ -612,9 +612,6 @@ int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore)
return 0;
}

- if (inet_csk_has_ulp(sk))
- return -EINVAL;
-
if (sk->sk_family == AF_INET6) {
if (tcp_bpf_assert_proto_ops(psock->sk_proto))
return -EINVAL;
diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c
index 9aac9c60d786..62b1c5e32bbd 100644
--- a/net/tls/tls_main.c
+++ b/net/tls/tls_main.c
@@ -790,6 +790,8 @@ static void tls_update(struct sock *sk, struct proto *p,
{
struct tls_context *ctx;

+ WARN_ON_ONCE(sk->sk_prot == p);
+
ctx = tls_get_ctx(sk);
if (likely(ctx)) {
ctx->sk_write_space = write_space;
--
2.35.1