From 665315df9c3486cb213fc44d83cc8bcd47fe0d26 Mon Sep 17 00:00:00 2001 From: Junxi Qian Date: Wed, 8 Apr 2026 16:10:06 +0800 Subject: [PATCH] nfc: llcp: add missing return after LLCP_CLOSED checks 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 Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20260408081006.3723-1-qjx1298677004@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/nfc/llcp_core.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/nfc/llcp_core.c b/net/nfc/llcp_core.c index 504245aeb4e2..e04634f22b49 100644 --- a/net/nfc/llcp_core.c +++ b/net/nfc/llcp_core.c @@ -1098,6 +1098,7 @@ static void nfc_llcp_recv_hdlc(struct nfc_llcp_local *local, if (sk->sk_state == LLCP_CLOSED) { release_sock(sk); nfc_llcp_sock_put(llcp_sock); + return; } /* Pass the payload upstream */ @@ -1189,6 +1190,7 @@ static void nfc_llcp_recv_disc(struct nfc_llcp_local *local, if (sk->sk_state == LLCP_CLOSED) { release_sock(sk); nfc_llcp_sock_put(llcp_sock); + return; } if (sk->sk_state == LLCP_CONNECTED) {