diff options
Diffstat (limited to 'package/kernel/mac80211/patches/329-v4.16-0002-brcmfmac-drop-Inter-Access-Point-Protocol-packets-by.patch')
| -rw-r--r-- | package/kernel/mac80211/patches/329-v4.16-0002-brcmfmac-drop-Inter-Access-Point-Protocol-packets-by.patch | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/package/kernel/mac80211/patches/329-v4.16-0002-brcmfmac-drop-Inter-Access-Point-Protocol-packets-by.patch b/package/kernel/mac80211/patches/329-v4.16-0002-brcmfmac-drop-Inter-Access-Point-Protocol-packets-by.patch new file mode 100644 index 0000000000..f05e23da05 --- /dev/null +++ b/package/kernel/mac80211/patches/329-v4.16-0002-brcmfmac-drop-Inter-Access-Point-Protocol-packets-by.patch @@ -0,0 +1,157 @@ +From 1259055170287a350cad453e9eac139c81609860 Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl> +Date: Thu, 15 Mar 2018 08:29:09 +0100 +Subject: [PATCH] brcmfmac: drop Inter-Access Point Protocol packets by default +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +Testing brcmfmac with more recent firmwares resulted in AP interfaces +not working in some specific setups. Debugging resulted in discovering +support for IAPP in Broadcom's firmwares. + +Older firmwares were only generating 802.11f frames. Newer ones like: +1) 10.10 (TOB) (r663589) +2) 10.10.122.20 (r683106) +for 4366b1 and 4366c0 respectively seem to also /respect/ 802.11f frames +in the Tx path by performing a STA disassociation. + +This obsoleted standard and its implementation is something that: +1) Most people don't need / want to use +2) Can allow local DoS attacks +3) Breaks AP interfaces in some specific bridge setups + +To solve issues it can cause this commit modifies brcmfmac to drop IAPP +packets. If affects: +1) Rx path: driver won't be sending these unwanted packets up. +2) Tx path: driver will reject packets that would trigger STA + disassociation perfromed by a firmware (possible local DoS attack). + +It appears there are some Broadcom's clients/users who care about this +feature despite the drawbacks. They can switch it on using a new module +param. + +This change results in only two more comparisons (check for module param +and check for Ethernet packet length) for 99.9% of packets. Its overhead +should be very minimal. + +Signed-off-by: Rafał Miłecki <rafal@milecki.pl> +Acked-by: Arend van Spriel <arend.vanspriel@broadcom.com> +Signed-off-by: Kalle Valo <kvalo@codeaurora.org> +--- + .../wireless/broadcom/brcm80211/brcmfmac/common.c | 5 ++ + .../wireless/broadcom/brcm80211/brcmfmac/common.h | 1 + + .../wireless/broadcom/brcm80211/brcmfmac/core.c | 57 ++++++++++++++++++++++ + 3 files changed, 63 insertions(+) + +--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c ++++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c +@@ -73,6 +73,10 @@ static int brcmf_roamoff; + module_param_named(roamoff, brcmf_roamoff, int, S_IRUSR); + MODULE_PARM_DESC(roamoff, "Do not use internal roaming engine"); + ++static int brcmf_iapp_enable; ++module_param_named(iapp, brcmf_iapp_enable, int, 0); ++MODULE_PARM_DESC(iapp, "Enable partial support for the obsoleted Inter-Access Point Protocol"); ++ + #ifdef DEBUG + /* always succeed brcmf_bus_started() */ + static int brcmf_ignore_probe_fail; +@@ -287,6 +291,7 @@ struct brcmf_mp_device *brcmf_get_module + settings->feature_disable = brcmf_feature_disable; + settings->fcmode = brcmf_fcmode; + settings->roamoff = !!brcmf_roamoff; ++ settings->iapp = !!brcmf_iapp_enable; + #ifdef DEBUG + settings->ignore_probe_fail = !!brcmf_ignore_probe_fail; + #endif +--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.h ++++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.h +@@ -58,6 +58,7 @@ struct brcmf_mp_device { + unsigned int feature_disable; + int fcmode; + bool roamoff; ++ bool iapp; + bool ignore_probe_fail; + struct brcmfmac_pd_cc *country_codes; + union { +--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c ++++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c +@@ -192,6 +192,37 @@ static void brcmf_netdev_set_multicast_l + schedule_work(&ifp->multicast_work); + } + ++/** ++ * brcmf_skb_is_iapp - checks if skb is an IAPP packet ++ * ++ * @skb: skb to check ++ */ ++static bool brcmf_skb_is_iapp(struct sk_buff *skb) ++{ ++ static const u8 iapp_l2_update_packet[6] __aligned(2) = { ++ 0x00, 0x01, 0xaf, 0x81, 0x01, 0x00, ++ }; ++ unsigned char *eth_data; ++#if !defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) ++ const u16 *a, *b; ++#endif ++ ++ if (skb->len - skb->mac_len != 6 || ++ !is_multicast_ether_addr(eth_hdr(skb)->h_dest)) ++ return false; ++ ++ eth_data = skb_mac_header(skb) + ETH_HLEN; ++#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) ++ return !(((*(const u32 *)eth_data) ^ (*(const u32 *)iapp_l2_update_packet)) | ++ ((*(const u16 *)(eth_data + 4)) ^ (*(const u16 *)(iapp_l2_update_packet + 4)))); ++#else ++ a = (const u16 *)eth_data; ++ b = (const u16 *)iapp_l2_update_packet; ++ ++ return !((a[0] ^ b[0]) | (a[1] ^ b[1]) | (a[2] ^ b[2])); ++#endif ++} ++ + static netdev_tx_t brcmf_netdev_start_xmit(struct sk_buff *skb, + struct net_device *ndev) + { +@@ -211,6 +242,23 @@ static netdev_tx_t brcmf_netdev_start_xm + goto done; + } + ++ /* Some recent Broadcom's firmwares disassociate STA when they receive ++ * an 802.11f ADD frame. This behavior can lead to a local DoS security ++ * issue. Attacker may trigger disassociation of any STA by sending a ++ * proper Ethernet frame to the wireless interface. ++ * ++ * Moreover this feature may break AP interfaces in some specific ++ * setups. This applies e.g. to the bridge with hairpin mode enabled and ++ * IFLA_BRPORT_MCAST_TO_UCAST set. IAPP packet generated by a firmware ++ * will get passed back to the wireless interface and cause immediate ++ * disassociation of a just-connected STA. ++ */ ++ if (!drvr->settings->iapp && brcmf_skb_is_iapp(skb)) { ++ dev_kfree_skb(skb); ++ ret = -EINVAL; ++ goto done; ++ } ++ + /* Make sure there's enough writable headroom*/ + ret = skb_cow_head(skb, drvr->hdrlen); + if (ret < 0) { +@@ -288,6 +336,15 @@ void brcmf_txflowblock(struct device *de + + void brcmf_netif_rx(struct brcmf_if *ifp, struct sk_buff *skb) + { ++ /* Most of Broadcom's firmwares send 802.11f ADD frame every time a new ++ * STA connects to the AP interface. This is an obsoleted standard most ++ * users don't use, so don't pass these frames up unless requested. ++ */ ++ if (!ifp->drvr->settings->iapp && brcmf_skb_is_iapp(skb)) { ++ brcmu_pkt_buf_free_skb(skb); ++ return; ++ } ++ + if (skb->pkt_type == PACKET_MULTICAST) + ifp->stats.multicast++; + |