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 914C347F2CE; Thu, 20 Aug 2026 17:55:06 +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=1787248507; cv=none; b=WfLwMhwqAyM2lIGYDM2fx8jHAiaeI5wevusqm/fDCM1PAq7hSpzKd5JpmG+vAURnxKzBoICoGSUSRUbApgLt7LMQE77Lp9X4klkipcF3WYyk/qfhPe5ZJFI93bwHSnCRUT+4L5Z+s5y5R4tW0xknHpJJ86v1d2ZkBjLG2X7VIw4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787248507; c=relaxed/simple; bh=0aSOrRiP99XDsLM1YIsnQkqvRltZOugicVe6RIVQ1r0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=B2dCXtDz/0MR2mhnTF827MLVNxphpbIH0+HHRBb2byaguJCRnV8XKt4PxtM0Wzyb86+0TEHU2KYqSvzutbe5eV2JH4VEN4ylyy1zywO7P0InsRQHVNHK+gZte//bLp6u/Z7Fj4EAQH1SOaueotbcN/0ouPDAAFbUIfJNOfTSToU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=KvwjasZt; 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="KvwjasZt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ECB931F000E9; Thu, 20 Aug 2026 17:55:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1787248506; bh=+QSQp4NdPNFwv0v0/Z0k9jTDuoGOkXFEMxSoZIJXOyA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=KvwjasZtqF8NTbYnydC0ytIaS9e2CH7eRoutFKPf7dBMiboizpU5OQDS01343ZUvT N4XlukHM9r0CxtoYr0GYF/xf9Z5kSInpSRhJ+//8y8G1Mx8K9GeJQkRWYOxFblerH6 LOobiIhKbbb+y4BWxrGypXbUnLOO12EGtEAL2AXs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Matt Fleming , =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= , Lorenzo Bianconi , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.1 251/303] veth: convert frag_list skbs before running XDP Date: Thu, 20 Aug 2026 16:56:27 +0200 Message-ID: <20260820145300.993353287@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260820145253.200766705@linuxfoundation.org> References: <20260820145253.200766705@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Matt Fleming [ Upstream commit d0d6415963040c401e7a7e4e482a698ba52448cb ] A frag_list skb can reach veth with data_len set but nr_frags zero. veth_convert_skb_to_xdp_buff() only converts skbs that are shared, locked, have frags[], or do not have enough headroom. It later uses skb_is_nonlinear() to decide whether to set XDP_FLAGS_HAS_FRAGS and xdp_frags_size. That exposes frag_list data to XDP as if it were stored in frags[], but frags[] is empty. AF_XDP copy mode can then trust the bogus XDP fragment metadata, walk an empty fragment entry, and crash in memcpy() from __xsk_rcv(). Route non-linear skbs through skb_pp_cow_data() before exposing them to XDP, and only advertise XDP frags when the resulting skb has frags[]. skb_copy_bits() already handles frag_list input, and skb_pp_cow_data() builds frags[] output with skb_add_rx_frag(), which is the representation XDP multi-buffer expects. Fixes: 718a18a0c8a6 ("veth: Rework veth_xdp_rcv_skb in order to accept non-linear skb") Cc: stable@vger.kernel.org Signed-off-by: Matt Fleming Reviewed-by: Toke Høiland-Jørgensen Acked-by: Lorenzo Bianconi Link: https://patch.msgid.link/20260722191925.2192070-1-matt@readmodwrite.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/net/veth.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/net/veth.c +++ b/drivers/net/veth.c @@ -695,7 +695,7 @@ static int veth_convert_skb_to_xdp_buff( u32 frame_sz; if (skb_shared(skb) || skb_head_is_locked(skb) || - skb_shinfo(skb)->nr_frags || + skb_is_nonlinear(skb) || skb_headroom(skb) < XDP_PACKET_HEADROOM) { u32 size, len, max_head_size, off; struct sk_buff *nskb; @@ -770,7 +770,7 @@ static int veth_convert_skb_to_xdp_buff( xdp_prepare_buff(xdp, skb->head, skb_headroom(skb), skb_headlen(skb), true); - if (skb_is_nonlinear(skb)) { + if (skb_shinfo(skb)->nr_frags) { skb_shinfo(skb)->xdp_frags_size = skb->data_len; xdp_buff_set_frags_flag(xdp); } else {