From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f175.google.com (mail-pf1-f175.google.com [209.85.210.175]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EF5BB36215E for ; Fri, 8 May 2026 14:43:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.175 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778251436; cv=none; b=nfslGM2HTL3P232nwjQQfiMQtk5CqLMTG2r837olKVDvCfZfce7Qje1w5L6NaxWNxgfcyEuEIyz/6QbSL6swLS/fBQ9srtb4rRkO7QzE/zgz5ti1qSCCFNIovPilKrkY5pW35uLmzXiTiOGJ17f9YqR0zBhcNV4dg4HnpBODOFs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778251436; c=relaxed/simple; bh=EyXG+VwrAF+um4XflE0usQdCTWRvEq/i5fmd3Ev8uzE=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=eZtYqUmKMnLOZYebJZHCcLHYaHpUsE9jFBudanWrx8lKOuV0pbpKaDM7t/1ebNJmDPumDgKXWUfUsc0gd6m3mBIaEVaYwBJqaesNN+I21ClcIulglWcvSv4Dt1byQ7iAGuBASTDQvii+UZZldUzg+kc57SHoR7/QphGyrkHMhDI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=Dg8HjAmb; arc=none smtp.client-ip=209.85.210.175 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Dg8HjAmb" Received: by mail-pf1-f175.google.com with SMTP id d2e1a72fcca58-82748257f5fso2013749b3a.1 for ; Fri, 08 May 2026 07:43:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1778251434; x=1778856234; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=a2w1uSP/0twE+5ljaP1rCYoWbGtAjbga1hTtB1LlN6c=; b=Dg8HjAmbjrTgvDXVnmvLLG25cAknvGCWOVEvIZpItXfQt+6YIWNUAP0jI1hNIXzX23 IA4TJzQ9LQRSEcfKZQIgE5RsNd1iV5LBMtBCvx33MWIZmuxOShb7FYvNfAex3lt/+7DL SU4GoxlxwCb5srsbctjt5kYfB1AQLKL1FZWLtJ6z753owcHsQbG1RdpylocU6eofoIB/ 8d5Ig1EvZsJ7B1HsYqNkdXiPPh4+yKll97a0sMeTCDIfsYcN3fJ802iFti7Vu38lMOht VhHJ4+SYpyy5OjpMHI9xZNxZYljgSb3dXY/JncuRaL7kK+OoRPWCiJn0pzveQXJuUn21 bBYw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1778251434; x=1778856234; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=a2w1uSP/0twE+5ljaP1rCYoWbGtAjbga1hTtB1LlN6c=; b=jAkkkLBjEkP1WQuE5xVeolF6tkiD1LNQdz/RNRn/bF2Xytlj3g8uugQQ+7ypAN+O24 O/gGCLKIvrfxhwj2x3XBw052TYYeXAwLUvvqIokXmqefHibzk9gDEZSnDrcyChPUaEz4 LIYTrYzv22C0jrcUwh6enCRGwvTZ909PrhMrXKr9N2ZwIb9SxFxHvYeZmTIK6MZZ6K8F 0aj3C4s9L0Kept0mB4dPGqp+AupmPMSIKhI0I29rTlKEZsXYuaCNRqD6hrwVinYj4gf0 QCTW/bBF75mjVxaYysUbcn+d+VD9AMm5IVIDK7aSzCtscv0o55oOWwFFA4cJanHJeAtd TKlg== X-Forwarded-Encrypted: i=1; AFNElJ/9CfgiWmXjZYQTyBBHmrw7Ro4L96tOsYwLrO1/On7kw3ju0RaOvifh3lLpRw/VuNaOhcU=@vger.kernel.org X-Gm-Message-State: AOJu0YxuLwvydCpjuAGwuPyulPMMLdcNEjqkaKRkznGu1lKKFdJ3XnX+ jMQf7xnariS6Qw6QY/XFFxikXzi1I54l3zxQEJsI3TxwxQX7TApUrmoX X-Gm-Gg: Acq92OGjwn7Z3oMPOACSY/EsgVjD8nY29RNi+BRjeTX7Knlk4kBiyzN3eQOGsJ1rca4 omXWk8P7PNkKoU1itq+tvUHVCnJADFNtPECJyqPGwwsz8isO6CqpsVTPSIWOQdofIAd3aomSSM6 prDEybukit+6NuvwUE8f3t/pamj8iO1TtbVb05eR3Up2SuzFWRj/JYXa+dDRwqRmJ6QkIK7EYBq Rbl9pTQZwwLWqEVUP/RysYCm8DOYyBxVAE59fy6W8oD0foVSZla5lkBbsUrphbMSMHIb8riTcF+ uAhgFPQ5fnpvYHz/1cizckV/BV0uT1i0l6HXY+Hh3oXaNHi+j/2f7DpB6Yxp7y7+t1joCU1iCQP c91uYNdMCbfyPpaKqrTNDLDHXbOF3FFR1AqhGqc9QzbBUYcEZd+H+WjrVucwOWvNsiGXm/Irgpt wMH1Kkzvna1B5QGmbvRK38mIvzSrrLuhXinA== X-Received: by 2002:a05:6a00:2304:b0:837:8a0c:8f70 with SMTP id d2e1a72fcca58-83bb8691c49mr6557122b3a.28.1778251434012; Fri, 08 May 2026 07:43:54 -0700 (PDT) Received: from hyj0824TXAir ([110.65.147.186]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-83967dbdda0sm12856887b3a.44.2026.05.08.07.43.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 08 May 2026 07:43:53 -0700 (PDT) From: Linpu Yu To: kerneljasonxing@gmail.com, magnus.karlsson@intel.com, maciej.fijalkowski@intel.com, netdev@vger.kernel.org, bpf@vger.kernel.org Cc: sdf@fomichev.me, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, ast@kernel.org, daniel@iogearbox.net, hawk@kernel.org, john.fastabend@gmail.com, bjorn@kernel.org, linux-kernel@vger.kernel.org, tanyuan98@outlook.com, yifanwucs@gmail.com Subject: [PATCH bpf v4] xskmap: reject TX-only AF_XDP sockets Date: Fri, 8 May 2026 22:43:43 +0800 Message-ID: <20260508144344.694-1-linpu5433@gmail.com> X-Mailer: git-send-email 2.54.0 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit XSKMAP entries are used as redirect targets for incoming XDP frames. A TX-only AF_XDP socket lacks an Rx ring and cannot handle redirected traffic, but xsk_map_update_elem() currently allows such sockets to be inserted into the map. Redirecting packets to such a socket on the veth generic-XDP path causes a kernel crash in xsk_generic_rcv(). This became possible after xsk_is_setup_for_bpf_map() was removed from the XSKMAP update path, which allowed bound TX-only sockets to be inserted into the map. Reject TX-only sockets during XSKMAP updates to avoid the crash. They remain fully operational for pure Tx purposes outside XSKMAP. Fixes: 968be23ceaca ("xsk: Fix possible segfault at xskmap entry insertion") Reported-by: Juefei Pu Reported-by: Yuan Tan Reported-by: Xin Liu Signed-off-by: Yifan Wu Signed-off-by: Linpu Yu --- Changes in v4: - retarget the patch from bpf-next to bpf - resend after no feedback net/xdp/xskmap.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/xdp/xskmap.c b/net/xdp/xskmap.c index afa457506274..3bff346308d0 100644 --- a/net/xdp/xskmap.c +++ b/net/xdp/xskmap.c @@ -184,6 +184,10 @@ static long xsk_map_update_elem(struct bpf_map *map, void *key, void *value, } xs = (struct xdp_sock *)sock->sk; + if (!READ_ONCE(xs->rx)) { + sockfd_put(sock); + return -ENOBUFS; + } map_entry = &m->xsk_map[i]; node = xsk_map_node_alloc(m, map_entry); -- 2.54.0