From nobody Sat Feb 7 17:48:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 04F84C41513 for ; Fri, 28 Jul 2023 13:38:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235758AbjG1NiT (ORCPT ); Fri, 28 Jul 2023 09:38:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52940 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236982AbjG1NiO (ORCPT ); Fri, 28 Jul 2023 09:38:14 -0400 Received: from relay5-d.mail.gandi.net (relay5-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::225]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BA0DE30C2; Fri, 28 Jul 2023 06:37:43 -0700 (PDT) Received: by mail.gandi.net (Postfix) with ESMTPSA id 701451C0007; Fri, 28 Jul 2023 13:37:40 +0000 (UTC) From: Remi Pommarel To: Marek Lindner , Simon Wunderlich , Antonio Quartulli , Sven Eckelmann Cc: "David S. Miller" , Eric Dumazet , b.a.t.m.a.n@lists.open-mesh.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Remi Pommarel Subject: [PATCH net] batman-adv: Do not get eth header before batadv_check_management_packet Date: Fri, 28 Jul 2023 15:38:50 +0200 Message-Id: <20230728133850.5974-1-repk@triplefau.lt> X-Mailer: git-send-email 2.40.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-GND-Sasl: repk@triplefau.lt Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" If received skb in batadv_v_elp_packet_recv or batadv_v_ogm_packet_recv is either cloned or non linearized then its data buffer will be reallocated by batadv_check_management_packet when skb_cow or skb_linearize get called. Thus geting ethernet header address inside skb data buffer before batadv_check_management_packet had any chance to reallocate it could lead to the following kernel panic: Unable to handle kernel paging request at virtual address ffffff8020ab069a Mem abort info: ESR =3D 0x96000007 EC =3D 0x25: DABT (current EL), IL =3D 32 bits SET =3D 0, FnV =3D 0 EA =3D 0, S1PTW =3D 0 FSC =3D 0x07: level 3 translation fault Data abort info: ISV =3D 0, ISS =3D 0x00000007 CM =3D 0, WnR =3D 0 swapper pgtable: 4k pages, 39-bit VAs, pgdp=3D0000000040f45000 [ffffff8020ab069a] pgd=3D180000007fffa003, p4d=3D180000007fffa003, pud=3D= 180000007fffa003, pmd=3D180000007fefe003, pte=3D0068000020ab0706 Internal error: Oops: 96000007 [#1] SMP Modules linked in: ahci_mvebu libahci_platform libahci dvb_usb_af9035 dvb= _usb_dib0700 dib0070 dib7000m dibx000_common ath11k_pci ath10k_pci ath10k_c= ore mwl8k_new nf_nat_sip nf_conntrack_sip xhci_plat_hcd xhci_hcd nf_nat_ppt= p nf_conntrack_pptp at24 sbsa_gwdt CPU: 1 PID: 16 Comm: ksoftirqd/1 Not tainted 5.15.42-00066-g3242268d425c-= dirty #550 Hardware name: A8k (DT) pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=3D--) pc : batadv_is_my_mac+0x60/0xc0 lr : batadv_v_ogm_packet_recv+0x98/0x5d0 sp : ffffff8000183820 x29: ffffff8000183820 x28: 0000000000000001 x27: ffffff8014f9af00 x26: 0000000000000000 x25: 0000000000000543 x24: 0000000000000003 x23: ffffff8020ab0580 x22: 0000000000000110 x21: ffffff80168ae880 x20: 0000000000000000 x19: ffffff800b561000 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 00dc098924ae0032 x14: 0f0405433e0054b0 x13: ffffffff00000080 x12: 0000004000000001 x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000 x8 : 0000000000000000 x7 : ffffffc076dae000 x6 : ffffff8000183700 x5 : ffffffc00955e698 x4 : ffffff80168ae000 x3 : ffffff80059cf000 x2 : ffffff800b561000 x1 : ffffff8020ab0696 x0 : ffffff80168ae880 Call trace: batadv_is_my_mac+0x60/0xc0 batadv_v_ogm_packet_recv+0x98/0x5d0 batadv_batman_skb_recv+0x1b8/0x244 __netif_receive_skb_core.isra.0+0x440/0xc74 __netif_receive_skb_one_core+0x14/0x20 netif_receive_skb+0x68/0x140 br_pass_frame_up+0x70/0x80 br_handle_frame_finish+0x108/0x284 br_handle_frame+0x190/0x250 __netif_receive_skb_core.isra.0+0x240/0xc74 __netif_receive_skb_list_core+0x6c/0x90 netif_receive_skb_list_internal+0x1f4/0x310 napi_complete_done+0x64/0x1d0 gro_cell_poll+0x7c/0xa0 __napi_poll+0x34/0x174 net_rx_action+0xf8/0x2a0 _stext+0x12c/0x2ac run_ksoftirqd+0x4c/0x7c smpboot_thread_fn+0x120/0x210 kthread+0x140/0x150 ret_from_fork+0x10/0x20 Code: f9403844 eb03009f 54fffee1 f94 Thus ethernet header address should only be fetched after batadv_check_management_packet has been called. Fixes: 0da0035942d4 ("batman-adv: OGMv2 - add basic infrastructure") Signed-off-by: Remi Pommarel --- net/batman-adv/bat_v_elp.c | 3 ++- net/batman-adv/bat_v_ogm.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/net/batman-adv/bat_v_elp.c b/net/batman-adv/bat_v_elp.c index acff565849ae..1d704574e6bf 100644 --- a/net/batman-adv/bat_v_elp.c +++ b/net/batman-adv/bat_v_elp.c @@ -505,7 +505,7 @@ int batadv_v_elp_packet_recv(struct sk_buff *skb, struct batadv_priv *bat_priv =3D netdev_priv(if_incoming->soft_iface); struct batadv_elp_packet *elp_packet; struct batadv_hard_iface *primary_if; - struct ethhdr *ethhdr =3D (struct ethhdr *)skb_mac_header(skb); + struct ethhdr *ethhdr; bool res; int ret =3D NET_RX_DROP; =20 @@ -513,6 +513,7 @@ int batadv_v_elp_packet_recv(struct sk_buff *skb, if (!res) goto free_skb; =20 + ethhdr =3D eth_hdr(skb); if (batadv_is_my_mac(bat_priv, ethhdr->h_source)) goto free_skb; =20 diff --git a/net/batman-adv/bat_v_ogm.c b/net/batman-adv/bat_v_ogm.c index e710e9afe78f..84eac41d4658 100644 --- a/net/batman-adv/bat_v_ogm.c +++ b/net/batman-adv/bat_v_ogm.c @@ -985,7 +985,7 @@ int batadv_v_ogm_packet_recv(struct sk_buff *skb, { struct batadv_priv *bat_priv =3D netdev_priv(if_incoming->soft_iface); struct batadv_ogm2_packet *ogm_packet; - struct ethhdr *ethhdr =3D eth_hdr(skb); + struct ethhdr *ethhdr; int ogm_offset; u8 *packet_pos; int ret =3D NET_RX_DROP; @@ -999,6 +999,7 @@ int batadv_v_ogm_packet_recv(struct sk_buff *skb, if (!batadv_check_management_packet(skb, if_incoming, BATADV_OGM2_HLEN)) goto free_skb; =20 + ethhdr =3D eth_hdr(skb); if (batadv_is_my_mac(bat_priv, ethhdr->h_source)) goto free_skb; =20 --=20 2.40.0