[PATCH AUTOSEL 4.14 43/61] cfg80211: fix use-after-free in reg_process_hint()

Sasha Levin
2018-10-16T04:24:40Z

From: Yu Zhao <yuzhao@google.com>

[ Upstream commit 1db58529454742f67ebd96e3588315e880b72837 ]

reg_process_hint_country_ie() can free regulatory_request and return
REG_REQ_ALREADY_SET. We shouldn't use regulatory_request after it's
called. KASAN error was observed when this happens.

BUG: KASAN: use-after-free in reg_process_hint+0x839/0x8aa [cfg80211]
Read of size 4 at addr ffff8800c430d434 by task kworker/1:3/89
<snipped>
Workqueue: events reg_todo [cfg80211]
Call Trace:
dump_stack+0xc1/0x10c
? _atomic_dec_and_lock+0x1ad/0x1ad
? _raw_spin_lock_irqsave+0xa0/0xd2
print_address_description+0x86/0x26f
? reg_process_hint+0x839/0x8aa [cfg80211]
kasan_report+0x241/0x29b
reg_process_hint+0x839/0x8aa [cfg80211]
reg_todo+0x204/0x5b9 [cfg80211]
process_one_work+0x55f/0x8d0
? worker_detach_from_pool+0x1b5/0x1b5
? _raw_spin_unlock_irq+0x65/0xdd
? _raw_spin_unlock_irqrestore+0xf3/0xf3
worker_thread+0x5dd/0x841
? kthread_parkme+0x1d/0x1d
kthread+0x270/0x285
? pr_cont_work+0xe3/0xe3
? rcu_read_unlock_sched_notrace+0xca/0xca
ret_from_fork+0x22/0x40

Allocated by task 2718:
set_track+0x63/0xfa
__kmalloc+0x119/0x1ac
regulatory_hint_country_ie+0x38/0x329 [cfg80211]
__cfg80211_connect_result+0x854/0xadd [cfg80211]
cfg80211_rx_assoc_resp+0x3bc/0x4f0 [cfg80211]
smsc95xx v1.0.6
ieee80211_sta_rx_queued_mgmt+0x1803/0x7ed5 [mac80211]
ieee80211_iface_work+0x411/0x696 [mac80211]
process_one_work+0x55f/0x8d0
worker_thread+0x5dd/0x841
kthread+0x270/0x285
ret_from_fork+0x22/0x40

Freed by task 89:
set_track+0x63/0xfa
kasan_slab_free+0x6a/0x87
kfree+0xdc/0x470
reg_process_hint+0x31e/0x8aa [cfg80211]
reg_todo+0x204/0x5b9 [cfg80211]
process_one_work+0x55f/0x8d0
worker_thread+0x5dd/0x841
kthread+0x270/0x285
ret_from_fork+0x22/0x40
<snipped>

Signed-off-by: Yu Zhao <yuzhao@google.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/wireless/reg.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index 6f032c7b8732..bd91de416035 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -2170,11 +2170,12 @@ static void reg_process_hint(struct regulatory_request *reg_request)
{
struct wiphy *wiphy = NULL;
enum reg_request_treatment treatment;
+ enum nl80211_reg_initiator initiator = reg_request->initiator;

if (reg_request->wiphy_idx != WIPHY_IDX_INVALID)
wiphy = wiphy_idx_to_wiphy(reg_request->wiphy_idx);

- switch (reg_request->initiator) {
+ switch (initiator) {
case NL80211_REGDOM_SET_BY_CORE:
treatment = reg_process_hint_core(reg_request);
break;
@@ -2192,7 +2193,7 @@ static void reg_process_hint(struct regulatory_request *reg_request)
treatment = reg_process_hint_country_ie(wiphy, reg_request);
break;
default:
- WARN(1, "invalid initiator %d\n", reg_request->initiator);
+ WARN(1, "invalid initiator %d\n", initiator);
goto out_free;
}

@@ -2207,7 +2208,7 @@ static void reg_process_hint(struct regulatory_request *reg_request)
*/
if (treatment == REG_REQ_ALREADY_SET && wiphy &&
wiphy->regulatory_flags & REGULATORY_STRICT_REG) {
- wiphy_update_regulatory(wiphy, reg_request->initiator);
+ wiphy_update_regulatory(wiphy, initiator);
wiphy_all_share_dfs_chan_state(wiphy);
reg_check_channels();
}
--
2.17.1