From a5f7a5bb3b7f28ba7e4fa246775b29a0e5537255 Mon Sep 17 00:00:00 2001 From: Jinke Han Date: Tue, 8 Sep 2026 15:37:42 +0800 Subject: x86/kprobes: Fix crash when probing CS CALL instructions When using eBPF to probe CS CALL instructions within a function, a crash can be triggered. The eBPF tool probes offset 257 of the __hrtimer_run_queues() function: <__hrtimer_run_queues+249>: nopl 0x0(%rax,%rax,1) <__hrtimer_run_queues+254>: mov %r14,%rdi <__hrtimer_run_queues+257>: cs call <__x86_indirect_thunk_r12> <__hrtimer_run_queues+263>: mov %eax,%r12d <__hrtimer_run_queues+266>: xchg %ax,%ax <__hrtimer_run_queues+268>: mov %r13,%rdi Which triggers this crash: BUG: unable to handle page fault for address: 00000000000f41c9 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP NOPTI CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P RIP: 0010:__hrtimer_run_queues+0x106/0x230 Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is at the 6th byte of the above CS CALL instruction. Since the CS CALL instruction occupies 6 bytes, the exception occurred in the middle of that call instruction. The root cause is that when using eBPF tools to probe in the middle of a function, a kprobe with INT3 is used as the underlying implementation. During single-step emulation of the original CALL instruction, int3_emulate_call() assumes that the probed CALL instruction is 5 bytes long. However, the actual CS-prefixed CALL instruction occupies 6 bytes, so it constructs an incorrect exception return address. When the CPU returns from the kprobe handler, the next instruction to be executed is at the address of the last byte of that CS CALL instruction. Coincidentally, starting from that address, the CPU fetches and decodes a completely different instruction, which ultimately triggers a kernel crash. Fix the issue by using the actual instruction length obtained from the instruction decoder when constructing the exception return address, rather than relying on the hardcoded CALL_INSN_SIZE macro. [ mingo: Refined the changelog ] Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step") Suggested-by: Masami Hiramatsu (Google) Signed-off-by: Jinke Han Signed-off-by: Ingo Molnar Reviewed-by: Masami Hiramatsu (Google) Acked-by: Yafang Shao Acked-by: Borislav Petkov Cc: Peter Zijlstra Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000 --- net/mac802154/rx.c | 526 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 526 insertions(+) create mode 100644 net/mac802154/rx.c (limited to 'net/mac802154/rx.c') diff --git a/net/mac802154/rx.c b/net/mac802154/rx.c new file mode 100644 index 000000000..19b5382e8 --- /dev/null +++ b/net/mac802154/rx.c @@ -0,0 +1,526 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2007-2012 Siemens AG + * + * Written by: + * Pavel Smolenskiy + * Maxim Gorbachyov + * Dmitry Eremin-Solenikov + * Alexander Smirnov + */ + +#include +#include +#include +#include +#include + +#include +#include +#include + +#include "ieee802154_i.h" + +static int ieee802154_deliver_skb(struct sk_buff *skb) +{ + skb->ip_summed = CHECKSUM_UNNECESSARY; + skb->protocol = htons(ETH_P_IEEE802154); + + return netif_receive_skb(skb); +} + +void mac802154_rx_beacon_worker(struct work_struct *work) +{ + struct ieee802154_local *local = + container_of(work, struct ieee802154_local, rx_beacon_work); + struct cfg802154_mac_pkt *mac_pkt; + + for (;;) { + spin_lock_bh(&local->rx_lock); + mac_pkt = list_first_entry_or_null(&local->rx_beacon_list, + struct cfg802154_mac_pkt, node); + if (mac_pkt) + list_del(&mac_pkt->node); + spin_unlock_bh(&local->rx_lock); + if (!mac_pkt) + break; + + mac802154_process_beacon(local, mac_pkt->skb, + mac_pkt->page, mac_pkt->channel); + + netdev_put(mac_pkt->sdata->dev, &mac_pkt->dev_tracker); + kfree_skb(mac_pkt->skb); + kfree(mac_pkt); + } +} + +static bool mac802154_should_answer_beacon_req(struct ieee802154_local *local) +{ + struct cfg802154_beacon_request *beacon_req; + unsigned int interval; + + rcu_read_lock(); + beacon_req = rcu_dereference(local->beacon_req); + if (!beacon_req) { + rcu_read_unlock(); + return false; + } + + interval = beacon_req->interval; + rcu_read_unlock(); + + if (!mac802154_is_beaconing(local)) + return false; + + return interval == IEEE802154_ACTIVE_SCAN_DURATION; +} + +static void mac802154_rx_mac_cmd(struct ieee802154_local *local, + struct cfg802154_mac_pkt *mac_pkt) +{ + u8 mac_cmd; + int rc; + + rc = ieee802154_get_mac_cmd(mac_pkt->skb, &mac_cmd); + if (rc) + return; + + switch (mac_cmd) { + case IEEE802154_CMD_BEACON_REQ: + dev_dbg(&mac_pkt->sdata->dev->dev, "processing BEACON REQ\n"); + if (!mac802154_should_answer_beacon_req(local)) + break; + + queue_delayed_work(local->mac_wq, &local->beacon_work, 0); + break; + + case IEEE802154_CMD_ASSOCIATION_RESP: + dev_dbg(&mac_pkt->sdata->dev->dev, "processing ASSOC RESP\n"); + if (!mac802154_is_associating(local)) + break; + + mac802154_process_association_resp(mac_pkt->sdata, mac_pkt->skb); + break; + + case IEEE802154_CMD_ASSOCIATION_REQ: + dev_dbg(&mac_pkt->sdata->dev->dev, "processing ASSOC REQ\n"); + if (mac_pkt->sdata->wpan_dev.iftype != NL802154_IFTYPE_COORD) + break; + + mac802154_process_association_req(mac_pkt->sdata, mac_pkt->skb); + break; + + case IEEE802154_CMD_DISASSOCIATION_NOTIFY: + dev_dbg(&mac_pkt->sdata->dev->dev, "processing DISASSOC NOTIF\n"); + if (mac_pkt->sdata->wpan_dev.iftype != NL802154_IFTYPE_COORD) + break; + + mac802154_process_disassociation_notif(mac_pkt->sdata, mac_pkt->skb); + break; + + default: + break; + } +} + +void mac802154_rx_mac_cmd_worker(struct work_struct *work) +{ + struct ieee802154_local *local = + container_of(work, struct ieee802154_local, rx_mac_cmd_work); + struct cfg802154_mac_pkt *mac_pkt; + + for (;;) { + spin_lock_bh(&local->rx_lock); + mac_pkt = list_first_entry_or_null(&local->rx_mac_cmd_list, + struct cfg802154_mac_pkt, node); + if (mac_pkt) + list_del(&mac_pkt->node); + spin_unlock_bh(&local->rx_lock); + if (!mac_pkt) + break; + + /* A stopped interface cannot transmit; skipping avoids a + * needless association response (and the !netif_running() + * warning it would trip) during teardown. The beacon worker + * needs no such check as it never transmits. + */ + if (ieee802154_sdata_running(mac_pkt->sdata)) + mac802154_rx_mac_cmd(local, mac_pkt); + + netdev_put(mac_pkt->sdata->dev, &mac_pkt->dev_tracker); + kfree_skb(mac_pkt->skb); + kfree(mac_pkt); + } +} + +/** + * mac802154_flush_list - free queued RX frames on @list + * @list: rx_beacon_list or rx_mac_cmd_list + * @sdata: only free frames received on this interface, or %NULL for all + * + * Each frame pins the net_device it was received on (via netdev_hold()), + * so release that reference as the frame is dropped. Caller must hold + * local->rx_lock. + */ +void mac802154_flush_list(struct list_head *list, + struct ieee802154_sub_if_data *sdata) +{ + struct cfg802154_mac_pkt *mac_pkt, *tmp; + + list_for_each_entry_safe(mac_pkt, tmp, list, node) { + if (sdata && mac_pkt->sdata != sdata) + continue; + list_del(&mac_pkt->node); + netdev_put(mac_pkt->sdata->dev, &mac_pkt->dev_tracker); + kfree_skb(mac_pkt->skb); + kfree(mac_pkt); + } +} + +/** + * mac802154_flush_queued_pkts - drop queued RX work referencing @sdata + * @local: the mac802154 device + * @sdata: interface being removed + * + * The workers dereference the queued frame's interface directly + * (mac_pkt->sdata) or through skb->dev in mac802154_process_beacon(). Drop + * the not-yet-started entries belonging to @sdata before it is unregistered + * so their netdev reference is released; an entry already dequeued by a + * running worker keeps its own reference until the worker completes, which + * unregister_netdevice() then waits out. + */ +void mac802154_flush_queued_pkts(struct ieee802154_local *local, + struct ieee802154_sub_if_data *sdata) +{ + spin_lock_bh(&local->rx_lock); + mac802154_flush_list(&local->rx_beacon_list, sdata); + mac802154_flush_list(&local->rx_mac_cmd_list, sdata); + spin_unlock_bh(&local->rx_lock); +} + +static int +ieee802154_subif_frame(struct ieee802154_sub_if_data *sdata, + struct sk_buff *skb, const struct ieee802154_hdr *hdr) +{ + struct wpan_phy *wpan_phy = sdata->local->hw.phy; + struct wpan_dev *wpan_dev = &sdata->wpan_dev; + struct cfg802154_mac_pkt *mac_pkt; + __le16 span, sshort; + int rc; + + pr_debug("getting packet via slave interface %s\n", sdata->dev->name); + + span = wpan_dev->pan_id; + sshort = wpan_dev->short_addr; + + /* Level 3 filtering: Only beacons are accepted during scans */ + if (sdata->required_filtering == IEEE802154_FILTERING_3_SCAN && + sdata->required_filtering > wpan_phy->filtering) { + if (mac_cb(skb)->type != IEEE802154_FC_TYPE_BEACON) { + dev_dbg(&sdata->dev->dev, + "drop non-beacon frame (0x%x) during scan\n", + mac_cb(skb)->type); + goto fail; + } + } + + switch (mac_cb(skb)->dest.mode) { + case IEEE802154_ADDR_NONE: + if (hdr->source.mode == IEEE802154_ADDR_NONE) + /* ACK comes with both addresses empty */ + skb->pkt_type = PACKET_HOST; + else if (!wpan_dev->parent) + /* No dest means PAN coordinator is the recipient */ + skb->pkt_type = PACKET_HOST; + else + /* We are not the PAN coordinator, just relaying */ + skb->pkt_type = PACKET_OTHERHOST; + break; + case IEEE802154_ADDR_LONG: + if (mac_cb(skb)->dest.pan_id != span && + mac_cb(skb)->dest.pan_id != cpu_to_le16(IEEE802154_PANID_BROADCAST)) + skb->pkt_type = PACKET_OTHERHOST; + else if (mac_cb(skb)->dest.extended_addr == wpan_dev->extended_addr) + skb->pkt_type = PACKET_HOST; + else + skb->pkt_type = PACKET_OTHERHOST; + break; + case IEEE802154_ADDR_SHORT: + if (mac_cb(skb)->dest.pan_id != span && + mac_cb(skb)->dest.pan_id != cpu_to_le16(IEEE802154_PANID_BROADCAST)) + skb->pkt_type = PACKET_OTHERHOST; + else if (mac_cb(skb)->dest.short_addr == sshort) + skb->pkt_type = PACKET_HOST; + else if (mac_cb(skb)->dest.short_addr == + cpu_to_le16(IEEE802154_ADDR_BROADCAST)) + skb->pkt_type = PACKET_BROADCAST; + else + skb->pkt_type = PACKET_OTHERHOST; + break; + default: + pr_debug("invalid dest mode\n"); + goto fail; + } + + skb->dev = sdata->dev; + + /* TODO this should be moved after netif_receive_skb call, otherwise + * wireshark will show a mac header with security fields and the + * payload is already decrypted. + */ + rc = mac802154_llsec_decrypt(&sdata->sec, skb); + if (rc) { + pr_debug("decryption failed: %i\n", rc); + goto fail; + } + + sdata->dev->stats.rx_packets++; + sdata->dev->stats.rx_bytes += skb->len; + + switch (mac_cb(skb)->type) { + case IEEE802154_FC_TYPE_BEACON: + dev_dbg(&sdata->dev->dev, "BEACON received\n"); + if (!mac802154_is_scanning(sdata->local)) + goto fail; + + mac_pkt = kzalloc_obj(*mac_pkt, GFP_ATOMIC); + if (!mac_pkt) + goto fail; + + mac_pkt->skb = skb_get(skb); + mac_pkt->sdata = sdata; + mac_pkt->page = sdata->local->scan_page; + mac_pkt->channel = sdata->local->scan_channel; + netdev_hold(sdata->dev, &mac_pkt->dev_tracker, GFP_ATOMIC); + spin_lock(&sdata->local->rx_lock); + list_add_tail(&mac_pkt->node, &sdata->local->rx_beacon_list); + spin_unlock(&sdata->local->rx_lock); + queue_work(sdata->local->mac_wq, &sdata->local->rx_beacon_work); + return NET_RX_SUCCESS; + + case IEEE802154_FC_TYPE_MAC_CMD: + dev_dbg(&sdata->dev->dev, "MAC COMMAND received\n"); + mac_pkt = kzalloc_obj(*mac_pkt, GFP_ATOMIC); + if (!mac_pkt) + goto fail; + + mac_pkt->skb = skb_get(skb); + mac_pkt->sdata = sdata; + netdev_hold(sdata->dev, &mac_pkt->dev_tracker, GFP_ATOMIC); + spin_lock(&sdata->local->rx_lock); + list_add_tail(&mac_pkt->node, &sdata->local->rx_mac_cmd_list); + spin_unlock(&sdata->local->rx_lock); + queue_work(sdata->local->mac_wq, &sdata->local->rx_mac_cmd_work); + return NET_RX_SUCCESS; + + case IEEE802154_FC_TYPE_ACK: + goto fail; + + case IEEE802154_FC_TYPE_DATA: + return ieee802154_deliver_skb(skb); + default: + pr_warn_ratelimited("ieee802154: bad frame received " + "(type = %d)\n", mac_cb(skb)->type); + goto fail; + } + +fail: + kfree_skb(skb); + return NET_RX_DROP; +} + +static void +ieee802154_print_addr(const char *name, const struct ieee802154_addr *addr) +{ + if (addr->mode == IEEE802154_ADDR_NONE) { + pr_debug("%s not present\n", name); + return; + } + + pr_debug("%s PAN ID: %04x\n", name, le16_to_cpu(addr->pan_id)); + if (addr->mode == IEEE802154_ADDR_SHORT) { + pr_debug("%s is short: %04x\n", name, + le16_to_cpu(addr->short_addr)); + } else { + u64 hw = swab64((__force u64)addr->extended_addr); + + pr_debug("%s is hardware: %8phC\n", name, &hw); + } +} + +static int +ieee802154_parse_frame_start(struct sk_buff *skb, struct ieee802154_hdr *hdr) +{ + int hlen; + struct ieee802154_mac_cb *cb = mac_cb(skb); + + skb_reset_mac_header(skb); + + hlen = ieee802154_hdr_pull(skb, hdr); + if (hlen < 0) + return -EINVAL; + + skb->mac_len = hlen; + + pr_debug("fc: %04x dsn: %02x\n", le16_to_cpup((__le16 *)&hdr->fc), + hdr->seq); + + cb->type = hdr->fc.type; + cb->ackreq = hdr->fc.ack_request; + cb->secen = hdr->fc.security_enabled; + + ieee802154_print_addr("destination", &hdr->dest); + ieee802154_print_addr("source", &hdr->source); + + cb->source = hdr->source; + cb->dest = hdr->dest; + + if (hdr->fc.security_enabled) { + u64 key; + + pr_debug("seclevel %i\n", hdr->sec.level); + + switch (hdr->sec.key_id_mode) { + case IEEE802154_SCF_KEY_IMPLICIT: + pr_debug("implicit key\n"); + break; + + case IEEE802154_SCF_KEY_INDEX: + pr_debug("key %02x\n", hdr->sec.key_id); + break; + + case IEEE802154_SCF_KEY_SHORT_INDEX: + pr_debug("key %04x:%04x %02x\n", + le32_to_cpu(hdr->sec.short_src) >> 16, + le32_to_cpu(hdr->sec.short_src) & 0xffff, + hdr->sec.key_id); + break; + + case IEEE802154_SCF_KEY_HW_INDEX: + key = swab64((__force u64)hdr->sec.extended_src); + pr_debug("key source %8phC %02x\n", &key, + hdr->sec.key_id); + break; + } + } + + return 0; +} + +static void +__ieee802154_rx_handle_packet(struct ieee802154_local *local, + struct sk_buff *skb) +{ + int ret; + struct ieee802154_sub_if_data *sdata; + struct ieee802154_hdr hdr; + struct sk_buff *skb2; + + ret = ieee802154_parse_frame_start(skb, &hdr); + if (ret) { + pr_debug("got invalid frame\n"); + return; + } + + list_for_each_entry_rcu(sdata, &local->interfaces, list) { + if (sdata->wpan_dev.iftype == NL802154_IFTYPE_MONITOR) + continue; + + if (!ieee802154_sdata_running(sdata)) + continue; + + /* Do not deliver packets received on interfaces expecting + * AACK=1 if the address filters where disabled. + */ + if (local->hw.phy->filtering < IEEE802154_FILTERING_4_FRAME_FIELDS && + sdata->required_filtering == IEEE802154_FILTERING_4_FRAME_FIELDS) + continue; + + skb2 = skb_clone(skb, GFP_ATOMIC); + if (skb2) { + skb2->dev = sdata->dev; + ieee802154_subif_frame(sdata, skb2, &hdr); + } + } +} + +static void +ieee802154_monitors_rx(struct ieee802154_local *local, struct sk_buff *skb) +{ + struct sk_buff *skb2; + struct ieee802154_sub_if_data *sdata; + + skb_reset_mac_header(skb); + skb->ip_summed = CHECKSUM_UNNECESSARY; + skb->pkt_type = PACKET_OTHERHOST; + skb->protocol = htons(ETH_P_IEEE802154); + + list_for_each_entry_rcu(sdata, &local->interfaces, list) { + if (sdata->wpan_dev.iftype != NL802154_IFTYPE_MONITOR) + continue; + + if (!ieee802154_sdata_running(sdata)) + continue; + + skb2 = skb_clone(skb, GFP_ATOMIC); + if (skb2) { + skb2->dev = sdata->dev; + ieee802154_deliver_skb(skb2); + + sdata->dev->stats.rx_packets++; + sdata->dev->stats.rx_bytes += skb->len; + } + } +} + +void ieee802154_rx(struct ieee802154_local *local, struct sk_buff *skb) +{ + u16 crc; + + WARN_ON_ONCE(softirq_count() == 0); + + if (local->suspended) + goto free_skb; + + /* TODO: When a transceiver omits the checksum here, we + * add an own calculated one. This is currently an ugly + * solution because the monitor needs a crc here. + */ + if (local->hw.flags & IEEE802154_HW_RX_OMIT_CKSUM) { + crc = crc_ccitt(0, skb->data, skb->len); + put_unaligned_le16(crc, skb_put(skb, 2)); + } + + rcu_read_lock(); + + ieee802154_monitors_rx(local, skb); + + /* Level 1 filtering: Check the FCS by software when relevant */ + if (local->hw.phy->filtering == IEEE802154_FILTERING_NONE) { + crc = crc_ccitt(0, skb->data, skb->len); + if (crc) + goto drop; + } + /* remove crc */ + skb_trim(skb, skb->len - 2); + + __ieee802154_rx_handle_packet(local, skb); + +drop: + rcu_read_unlock(); +free_skb: + kfree_skb(skb); +} + +void +ieee802154_rx_irqsafe(struct ieee802154_hw *hw, struct sk_buff *skb, u8 lqi) +{ + struct ieee802154_local *local = hw_to_local(hw); + struct ieee802154_mac_cb *cb = mac_cb_init(skb); + + cb->lqi = lqi; + skb->pkt_type = IEEE802154_RX_MSG; + skb_queue_tail(&local->skb_queue, skb); + tasklet_schedule(&local->tasklet); +} +EXPORT_SYMBOL(ieee802154_rx_irqsafe); -- cgit v1.3.1