[PATCH 6.6 067/166] nfc: llcp: add missing return after LLCP_CLOSED checks

Greg Kroah-Hartman
2026-04-24T13:36:22Z

From: Junxi Qian <qjx1298677004@gmail.com>

commit 2b5dd4632966c39da6ba74dbc8689b309065e82c upstream.

In nfc_llcp_recv_hdlc() and nfc_llcp_recv_disc(), when the socket
state is LLCP_CLOSED, the code correctly calls release_sock() and
nfc_llcp_sock_put() but fails to return. Execution falls through to
the remainder of the function, which calls release_sock() and
nfc_llcp_sock_put() again. This results in a double release_sock()
and a refcount underflow via double nfc_llcp_sock_put(), leading to
a use-after-free.

Add the missing return statements after the LLCP_CLOSED branches
in both functions to prevent the fall-through.

Fixes: d646960f7986 ("NFC: Initial LLCP support")
Signed-off-by: Junxi Qian <qjx1298677004@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260408081006.3723-1-qjx1298677004@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/nfc/llcp_core.c | 2 ++
1 file changed, 2 insertions(+)

--- a/net/nfc/llcp_core.c
+++ b/net/nfc/llcp_core.c
@@ -1089,6 +1089,7 @@ static void nfc_llcp_recv_hdlc(struct nf
if (sk->sk_state == LLCP_CLOSED) {
release_sock(sk);
nfc_llcp_sock_put(llcp_sock);
+ return;
}

/* Pass the payload upstream */
@@ -1180,6 +1181,7 @@ static void nfc_llcp_recv_disc(struct nf
if (sk->sk_state == LLCP_CLOSED) {
release_sock(sk);
nfc_llcp_sock_put(llcp_sock);
+ return;
}

if (sk->sk_state == LLCP_CONNECTED) {