From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8141334B437; Sat, 17 Oct 2026 16:56:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792256190; cv=none; b=SnlCnyHgstuNwFzkBkCrJIFDYPWhB3gQor7Jtg+j6ZSFgiLtESXMFeoWQcgfj5f2OtWqIjpgFCC6qH5hZcIYl4U+Yw1AnWEN2chs4Cedk5g3k3ijPV0CXr6SmTQNXiii88VhBhIIuQB4KMCHR8rGh9FBkiPY5cT7Aua2qEbV5ew= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792256190; c=relaxed/simple; bh=C3zFGq/cNYnighre8Qx7hOGqc8lgfZAad4RX5meEjcQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PhhB/BKYwT+sB6YOZoMQ0D2AbSbV70EKHaeNSqv0wIQIlBVwG9qORMKK7FzXorsJkMXCwKk3I/Okh9TRIDOI7JZF2VdKx8FbAb1cwkYjeRqnOvoMMUWkMywnnykBy0hn0CrtFnXypYdEqw2KB9A52URFWPajScZh0INaQD6j+LU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=uZb/oShM; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="uZb/oShM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C9BAC1F000C4; Sat, 17 Oct 2026 16:56:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792256189; bh=LJoeLQ+Z1E60o3+liJ1+0bfAoillXWrcYwPNLFNOX0Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=uZb/oShMxT0XoK96lOCaxzMD8R3ZV8Pr5cw8EnYCVpsetzsOLql2FUME/NsuQ0qg7 71dsQ+qeoHHJDBuvCCXK2u+303kNBtLugvKFexbgBs2GDkeEu5hB1YNOzOOxC+ljwq GTka3UINGqZIiV1zUYctAF3P80LhmR/+YYMyMYTk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jiayuan Chen , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.6 0153/1674] bpf, xdp: move offload check into dev_xdp_install() Date: Sat, 17 Oct 2026 17:40:25 +0200 Message-ID: <20261017160435.091474483@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160431.119607952@linuxfoundation.org> References: <20261017160431.119607952@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiayuan Chen [ Upstream commit ad27ed7d2309419a129078d781504f486b1b469a ] bpf_xdp_link_update() calls dev_xdp_install() directly and skips dev_xdp_attach(), so the checks in dev_xdp_attach() do not run. A user can make an XDP link with a normal program and then swap in an offloaded or device-bound program with BPF_LINK_UPDATE, which puts it on the software path. dev_xdp_install() is the one place all three paths go through: "ip link set xdp" and BPF_LINK_CREATE reach it via dev_xdp_attach(), and BPF_LINK_UPDATE calls it directly. So move the program checks (offloaded, bound to another device, device-bound in generic mode, native vs generic, DEVMAP and CPUMAP) there, and keep only the netlink-flag check (XDP_FLAGS_UPDATE_IF_NOEXIST) in dev_xdp_attach(). Fixes: 026a4c28e1db3 ("bpf, xdp: Implement LINK_UPDATE for BPF XDP link") Signed-off-by: Jiayuan Chen Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/core/dev.c | 59 +++++++++++++++++++++++++++++---------------------------- 1 file changed, 31 insertions(+), 28 deletions(-) --- a/net/core/dev.c +++ b/net/core/dev.c @@ -9304,6 +9304,37 @@ static int dev_xdp_install(struct net_de struct netdev_bpf xdp; int err; + if (prog) { + enum bpf_xdp_mode other_mode = mode == XDP_MODE_SKB + ? XDP_MODE_DRV : XDP_MODE_SKB; + bool offload = mode == XDP_MODE_HW; + + if (!offload && dev_xdp_prog(dev, other_mode)) { + NL_SET_ERR_MSG(extack, "Native and generic XDP can't be active at the same time"); + return -EEXIST; + } + if (!offload && bpf_prog_is_offloaded(prog->aux)) { + NL_SET_ERR_MSG(extack, "Using offloaded program without HW_MODE flag is not supported"); + return -EINVAL; + } + if (bpf_prog_is_dev_bound(prog->aux) && !bpf_offload_dev_match(prog, dev)) { + NL_SET_ERR_MSG(extack, "Program bound to different device"); + return -EINVAL; + } + if (bpf_prog_is_dev_bound(prog->aux) && mode == XDP_MODE_SKB) { + NL_SET_ERR_MSG(extack, "Can't attach device-bound programs in generic mode"); + return -EINVAL; + } + if (prog->expected_attach_type == BPF_XDP_DEVMAP) { + NL_SET_ERR_MSG(extack, "BPF_XDP_DEVMAP programs can not be attached to a device"); + return -EINVAL; + } + if (prog->expected_attach_type == BPF_XDP_CPUMAP) { + NL_SET_ERR_MSG(extack, "BPF_XDP_CPUMAP programs can not be attached to a device"); + return -EINVAL; + } + } + memset(&xdp, 0, sizeof(xdp)); xdp.command = mode == XDP_MODE_HW ? XDP_SETUP_PROG_HW : XDP_SETUP_PROG; xdp.extack = extack; @@ -9432,38 +9463,10 @@ static int dev_xdp_attach(struct net_dev new_prog = link->link.prog; if (new_prog) { - bool offload = mode == XDP_MODE_HW; - enum bpf_xdp_mode other_mode = mode == XDP_MODE_SKB - ? XDP_MODE_DRV : XDP_MODE_SKB; - if ((flags & XDP_FLAGS_UPDATE_IF_NOEXIST) && cur_prog) { NL_SET_ERR_MSG(extack, "XDP program already attached"); return -EBUSY; } - if (!offload && dev_xdp_prog(dev, other_mode)) { - NL_SET_ERR_MSG(extack, "Native and generic XDP can't be active at the same time"); - return -EEXIST; - } - if (!offload && bpf_prog_is_offloaded(new_prog->aux)) { - NL_SET_ERR_MSG(extack, "Using offloaded program without HW_MODE flag is not supported"); - return -EINVAL; - } - if (bpf_prog_is_dev_bound(new_prog->aux) && !bpf_offload_dev_match(new_prog, dev)) { - NL_SET_ERR_MSG(extack, "Program bound to different device"); - return -EINVAL; - } - if (bpf_prog_is_dev_bound(new_prog->aux) && mode == XDP_MODE_SKB) { - NL_SET_ERR_MSG(extack, "Can't attach device-bound programs in generic mode"); - return -EINVAL; - } - if (new_prog->expected_attach_type == BPF_XDP_DEVMAP) { - NL_SET_ERR_MSG(extack, "BPF_XDP_DEVMAP programs can not be attached to a device"); - return -EINVAL; - } - if (new_prog->expected_attach_type == BPF_XDP_CPUMAP) { - NL_SET_ERR_MSG(extack, "BPF_XDP_CPUMAP programs can not be attached to a device"); - return -EINVAL; - } } /* don't call drivers if the effective program didn't change */