From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-dl1-f41.google.com (mail-dl1-f41.google.com [74.125.82.41]) (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 91415336EFF for ; Fri, 9 Jan 2026 10:04:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.82.41 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767953094; cv=none; b=VjPv8XIF++SHmypQ/6mUUKlglY0bq+2F2MPbBMlH7tdpPSit/szCYcLfEVDArfEy9eIPhynZ6LGHnH4/p3vDjR6FCe+d8kKff9UsJtNaL3cGAEJ9MSfp2JutB08W1LTc2QiAze8mTmED8gcCzKSrZ8xRAhJ3LAHju9Ljmo4va4k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767953094; c=relaxed/simple; bh=5jrWyB4XCBVBz8ho+oQz/OHpCGaaHiVH2B1jpdtutqY=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=dLNjqz7vWqXmBMHMdbBz/LEvPE3C4mi60ZojJ6tDnIVmktvnHbhA7NpSQpSfK+TIY7cxChxCBm7HhgbJhEXLN35fKHDfDLU5LKneR67qv7p9z5wNCNs/+ILkKK90wgAL/jtpCoQLFV82UH5qgrxczEWw+Bzb0UiTJvq3LCDWw1o= 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=ErAySkM8; arc=none smtp.client-ip=74.125.82.41 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="ErAySkM8" Received: by mail-dl1-f41.google.com with SMTP id a92af1059eb24-11f3a10dcbbso3352410c88.1 for ; Fri, 09 Jan 2026 02:04:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1767953092; x=1768557892; 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=Ug9UXruECokBl2MPfxQMo1D+f+1ql2Retnj+DiiH+DY=; b=ErAySkM8BKnthtcpMjJ0dL565BjnYt4vwBhSp2uQSYlhpk/u4gOvM5bR8MXwsrriD0 imStvU5oHJh9G/+68LCuu0jjPTPEpyOwOJPtu7+PW19F/mcSmmBcZ2OPfsMQTLxReIeL DYNtSua3MT+rq0pcgnX/ifj++XTCRq+TmmqJL7uiyPwZqDIw2i4iUij1ZK7q5FUFO0wr Prtu/Efl8a2+BUW2tIKXMx+4qtw/RgdEj+H17xpsCdgn7G5NTkN/2b+LMFaAR4RJYMRQ MGOzvsRabqQ2UEDyt/znFdXx/LnrRkwmpmzO0S9npozLw0shuaMSPCnNq+3fpeiDUoqd Kifw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1767953092; x=1768557892; 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=Ug9UXruECokBl2MPfxQMo1D+f+1ql2Retnj+DiiH+DY=; b=JBYSk9VP8uQWT5DzR067mmfRIXnof5YTQ+ZiB6ntr146hJSGcmG1FQsgPkU4ycGGtO UNgKjRhmRVaWBCCJjgnRSlmZpbfqYIlQ+mKPfjpJzIESdXt+7BO9oM86akQv3yS3gdyv pCA7t6Z4mwWPkjx7m6W4LltPGgoj0PpuyKjax7nBQxZdlKY1FDQhSvCWfQ9YWv7DKKNX 8IYBfLItZ0BFG40SpPdw9Sb/D9r/Tol/S1wW7EnQPQsAkyTJCZq69HaLQyF1ZMjCAu+D zEzkLhbqWYiDkOoHwuY2QzvgTrP6dfYVErDHNxR9ht/EfORX7RNAIkAqda/sEx8TBhc4 1yjg== X-Gm-Message-State: AOJu0YyhFCo7J/zIuFAGqZaa8WTX4MCmovKeg5jmtqDOpPPjbGJdTNPm cnUsLoGk9fkCrsALpuNSzZAGrwzQa3XHcQY0VfilwIk9rEKJgrXbX8Fe05Hs/W6E+TdL0A8= X-Gm-Gg: AY/fxX4M8A9QtF/ys6B3KygFEobKFibAC99EtyhtnxVyTrFABV7zVO7ckOjTUMRuhhE pEdIR68hLxXxIPamNHpFSv78G5RB6N5NNWS5lMJxnRAeEEGH0K6dM1EeFhdVWqC6+CLgMaq4bx9 iPwUtPMzaK6P9IxDSVY14w3NFbphlMvxa7Ed15H1E40nDdkIIGRHKEKUq8Zh3yCBPD1Bnj7p9ld QADyqK1xTncpHs/PK6QmW+OzfPCzsNrtVOtIIbLtFKGjID0rEHWA/tWERhyWD3hmpppei2ibq5r AFRWrEv/FFDQV0gxUnCKfSNsHC7c9riWdjjJmlbLQ66MAMllQ9IErF4+dVcq6BjvrJlskm9CAxa zC+DmA22R0oM/CUCOysK2ukA/AVIlAYrhdgsbjJszvk0mq9bXG/MrX1AKAfHdru5ZsGrHEmEsih ctIR3OD26v9zpRdH0= X-Google-Smtp-Source: AGHT+IEuXoXtHTnUokSTkV/047cQ2XVT2pT27RHEC/fHpKbJH7+a13ZDPg9quvun7MxRLm7ESuhhCQ== X-Received: by 2002:a05:7022:48d:b0:11b:ceee:a49f with SMTP id a92af1059eb24-121f8afbcd2mr7993025c88.8.1767953091595; Fri, 09 Jan 2026 02:04:51 -0800 (PST) Received: from DESKTOP-BKIPFGN ([209.141.36.37]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-121f243f6c7sm12742527c88.7.2026.01.09.02.04.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Jan 2026 02:04:50 -0800 (PST) From: Kery Qi To: bpf@vger.kernel.org Cc: linux-kernel@vger.kernel.org, bjorn@kernel.org, hawk@kernel.org, pabeni@redhat.com, magnus.karlsson@intel.com, daniel@iogearbox.net, maciej.fijalkowski@intel.com, kuba@kernel.org, edumazet@google.com, horms@kernel.org, ast@kernel.org, sdf@fomichev.me, john.fastabend@gmail.com, Kery Qi Subject: [PATCH bpf] xsk: fix init race causing NPD/UAF in xsk_create() Date: Fri, 9 Jan 2026 18:04:20 +0800 Message-ID: <20260109100420.1967-2-qikeyu2017@gmail.com> X-Mailer: git-send-email 2.50.1.windows.1 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit xsk_init() previously registered the PF_XDP socket family before the per-net subsystem and other prerequisites (netdevice notifier, caches) were fully initialized. This exposed .create = xsk_create() to user space while per-netns state (net->xdp.lock/list) was still uninitialized. A task with CAP_NET_RAW could trigger this during boot/module load by calling socket(PF_XDP, SOCK_RAW, 0) concurrently with xsk_init(), leading to a NULL pointer dereference or use-after-free in the list manipulation. To fix this, move sock_register() to the end of the initialization sequence, ensuring that all required kernel structures are ready before exposing the AF_XDP interface to userspace. Accordingly, reorder the error unwind path to ensure proper cleanup in reverse order of initialization. Also, explicitly add kmem_cache_destroy() in the error path to prevent leaking xsk_tx_generic_cache if the registration fails. Fixes: c0c77d8fb787 ("xsk: add user memory registration support sockopt") Signed-off-by: Kery Qi --- net/xdp/xsk.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index f093c3453f64..58e9c61c29e0 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -23,6 +23,7 @@ #include #include #include +#include #include #include #include @@ -1922,10 +1923,6 @@ static int __init xsk_init(void) if (err) goto out; - err = sock_register(&xsk_family_ops); - if (err) - goto out_proto; - err = register_pernet_subsys(&xsk_net_ops); if (err) goto out_sk; @@ -1942,16 +1939,21 @@ static int __init xsk_init(void) goto out_unreg_notif; } + err = sock_register(&xsk_family_ops); + if (err) + goto out_proto; + return 0; +out_proto: + proto_unregister(&xsk_proto); + kmem_cache_destroy(xsk_tx_generic_cache); out_unreg_notif: unregister_netdevice_notifier(&xsk_netdev_notifier); out_pernet: unregister_pernet_subsys(&xsk_net_ops); out_sk: sock_unregister(PF_XDP); -out_proto: - proto_unregister(&xsk_proto); out: return err; } -- 2.34.1