wifi: cfg80211: restrict NL80211_ATTR_TXQ_QUANTUM values

syzbot is able to trigger softlockups, setting NL80211_ATTR_TXQ_QUANTUM
to 2^31.

We had a similar issue in sch_fq, fixed with commit
d9e15a273306 ("pkt_sched: fq: do not accept silly TCA_FQ_QUANTUM")

watchdog: BUG: soft lockup - CPU#1 stuck for 26s! [kworker/1:0:24]
Modules linked in:
irq event stamp: 131135
 hardirqs last  enabled at (131134): [<ffff80008ae8778c>] __exit_to_kernel_mode arch/arm64/kernel/entry-common.c:85 [inline]
 hardirqs last  enabled at (131134): [<ffff80008ae8778c>] exit_to_kernel_mode+0xdc/0x10c arch/arm64/kernel/entry-common.c:95
 hardirqs last disabled at (131135): [<ffff80008ae85378>] __el1_irq arch/arm64/kernel/entry-common.c:533 [inline]
 hardirqs last disabled at (131135): [<ffff80008ae85378>] el1_interrupt+0x24/0x68 arch/arm64/kernel/entry-common.c:551
 softirqs last  enabled at (125892): [<ffff80008907e82c>] neigh_hh_init net/core/neighbour.c:1538 [inline]
 softirqs last  enabled at (125892): [<ffff80008907e82c>] neigh_resolve_output+0x268/0x658 net/core/neighbour.c:1553
 softirqs last disabled at (125896): [<ffff80008904166c>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
CPU: 1 PID: 24 Comm: kworker/1:0 Not tainted 6.9.0-rc7-syzkaller-gfda5695d692c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: mld mld_ifc_work
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
 pc : __list_del include/linux/list.h:195 [inline]
 pc : __list_del_entry include/linux/list.h:218 [inline]
 pc : list_move_tail include/linux/list.h:310 [inline]
 pc : fq_tin_dequeue include/net/fq_impl.h:112 [inline]
 pc : ieee80211_tx_dequeue+0x6b8/0x3b4c net/mac80211/tx.c:3854
 lr : __list_del_entry include/linux/list.h:218 [inline]
 lr : list_move_tail include/linux/list.h:310 [inline]
 lr : fq_tin_dequeue include/net/fq_impl.h:112 [inline]
 lr : ieee80211_tx_dequeue+0x67c/0x3b4c net/mac80211/tx.c:3854
sp : ffff800093d36700
x29: ffff800093d36a60 x28: ffff800093d36960 x27: dfff800000000000
x26: ffff0000d800ad50 x25: ffff0000d800abe0 x24: ffff0000d800abf0
x23: ffff0000e0032468 x22: ffff0000e00324d4 x21: ffff0000d800abf0
x20: ffff0000d800abf8 x19: ffff0000d800abf0 x18: ffff800093d363c0
x17: 000000000000d476 x16: ffff8000805519dc x15: ffff7000127a6cc8
x14: 1ffff000127a6cc8 x13: 0000000000000004 x12: ffffffffffffffff
x11: ffff7000127a6cc8 x10: 0000000000ff0100 x9 : 0000000000000000
x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000
x5 : ffff80009287aa08 x4 : 0000000000000008 x3 : ffff80008034c7fc
x2 : ffff0000e0032468 x1 : 00000000da0e46b8 x0 : ffff0000e0032470
Call trace:
  __list_del include/linux/list.h:195 [inline]
  __list_del_entry include/linux/list.h:218 [inline]
  list_move_tail include/linux/list.h:310 [inline]
  fq_tin_dequeue include/net/fq_impl.h:112 [inline]
  ieee80211_tx_dequeue+0x6b8/0x3b4c net/mac80211/tx.c:3854
  wake_tx_push_queue net/mac80211/util.c:294 [inline]
  ieee80211_handle_wake_tx_queue+0x118/0x274 net/mac80211/util.c:315
  drv_wake_tx_queue net/mac80211/driver-ops.h:1350 [inline]
  schedule_and_wake_txq net/mac80211/driver-ops.h:1357 [inline]
  ieee80211_queue_skb+0x18e8/0x2244 net/mac80211/tx.c:1664
  ieee80211_tx+0x260/0x400 net/mac80211/tx.c:1966
  ieee80211_xmit+0x278/0x354 net/mac80211/tx.c:2062
  __ieee80211_subif_start_xmit+0xab8/0x122c net/mac80211/tx.c:4338
  ieee80211_subif_start_xmit+0xe0/0x438 net/mac80211/tx.c:4532
  __netdev_start_xmit include/linux/netdevice.h:4903 [inline]
  netdev_start_xmit include/linux/netdevice.h:4917 [inline]
  xmit_one net/core/dev.c:3531 [inline]
  dev_hard_start_xmit+0x27c/0x938 net/core/dev.c:3547
  __dev_queue_xmit+0x1678/0x33fc net/core/dev.c:4341
  dev_queue_xmit include/linux/netdevice.h:3091 [inline]
  neigh_resolve_output+0x558/0x658 net/core/neighbour.c:1563
  neigh_output include/net/neighbour.h:542 [inline]
  ip6_finish_output2+0x104c/0x1ee8 net/ipv6/ip6_output.c:137
  ip6_finish_output+0x428/0x7a0 net/ipv6/ip6_output.c:222
  NF_HOOK_COND include/linux/netfilter.h:303 [inline]
  ip6_output+0x270/0x594 net/ipv6/ip6_output.c:243
  dst_output include/net/dst.h:450 [inline]
  NF_HOOK+0x160/0x4f0 include/linux/netfilter.h:314
  mld_sendpack+0x7b4/0x10f4 net/ipv6/mcast.c:1818
  mld_send_cr net/ipv6/mcast.c:2119 [inline]
  mld_ifc_work+0x840/0xd0c net/ipv6/mcast.c:2650
  process_one_work+0x7b8/0x15d4 kernel/workqueue.c:3267
  process_scheduled_works kernel/workqueue.c:3348 [inline]
  worker_thread+0x938/0xef4 kernel/workqueue.c:3429
  kthread+0x288/0x310 kernel/kthread.c:388
  ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860

Fixes: 52539ca89f36 ("cfg80211: Expose TXQ stats and parameters to userspace")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20240615160800.250667-1-edumazet@google.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 3c0bca4238d357c01b6fe92bb0f2b2b8a2917725..72c7bf55858166b8fc12114f090bf085d652db6b 100644 (file)
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -468,6 +468,10 @@ static const struct netlink_range_validation nl80211_punct_bitmap_range = {
        .max = 0xffff,
 };
 
+static const struct netlink_range_validation q_range = {
+       .max = INT_MAX,
+};
+
 static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
        [0] = { .strict_start_type = NL80211_ATTR_HE_OBSS_PD },
        [NL80211_ATTR_WIPHY] = { .type = NLA_U32 },
@@ -754,7 +758,7 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
 
        [NL80211_ATTR_TXQ_LIMIT] = { .type = NLA_U32 },
        [NL80211_ATTR_TXQ_MEMORY_LIMIT] = { .type = NLA_U32 },
-       [NL80211_ATTR_TXQ_QUANTUM] = { .type = NLA_U32 },
+       [NL80211_ATTR_TXQ_QUANTUM] = NLA_POLICY_FULL_RANGE(NLA_U32, &q_range),
        [NL80211_ATTR_HE_CAPABILITY] =
                NLA_POLICY_VALIDATE_FN(NLA_BINARY, validate_he_capa,
                                       NL80211_HE_MAX_CAPABILITY_LEN),