Patch "sock: redo the psock vs ULP protection check" has been added to the 5.18-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    sock: redo the psock vs ULP protection check

to the 5.18-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     sock-redo-the-psock-vs-ulp-protection-check.patch
and it can be found in the queue-5.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 6e8ec4a6b17bd232c32b934a21ef9e4de7ea5b4e
Author: Jakub Kicinski <kuba@xxxxxxxxxx>
Date:   Mon Jun 20 12:13:53 2022 -0700

    sock: redo the psock vs ULP protection check
    
    [ 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@xxxxxxxxxx>
    Reviewed-by: John Fastabend <john.fastabend@xxxxxxxxx>
    Reviewed-by: Jakub Sitnicki <jakub@xxxxxxxxxxxxxx>
    Tested-by: Jakub Sitnicki <jakub@xxxxxxxxxxxxxx>
    Link: https://lore.kernel.org/r/20220620191353.1184629-2-kuba@xxxxxxxxxx
    Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index 234d70ae5f4c..48e4c59d85e2 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 7b2b0e7ffee4..5c9697840ef7 100644
--- a/net/tls/tls_main.c
+++ b/net/tls/tls_main.c
@@ -873,6 +873,8 @@ 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;