[PATCH 0/2] cfg80211/ath: custom regulatory bug fixes

[PATCH 0/2] cfg80211/ath: custom regulatory bug fixes

[Luis R. Rodriguez]

Here are a couple of fixes for the recent change we did where we
moved the core regulatory hint to the queue. In a really slow box
or if you are doing crazy testing this can potentilly occur. I take
it the patch "cfg80211: put core regulatory request into queue"
will note make it in until 2.6.38, so these are not a stable fixes.

I was able to force the condition by doing:

diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index 99d4183..e6f483d0 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -1481,7 +1481,7 @@ static void reg_process_pending_hints(void)
 
 	spin_unlock(&reg_requests_lock);
 
-	reg_process_hint(reg_request);
+	//reg_process_hint(reg_request);
 
 out:
 	mutex_unlock(&reg_mutex);

This mimics the situation of either having a slow box or you
doing some crazy module load/unload testing.

Luis R. Rodriguez (2):
  cfg80211: fix null pointer dereference with a custom regulatory
    request
  ath: fix NULL pointer dereference on reg_notifier()

 drivers/net/wireless/ath/regd.c |    8 ++++++++
 include/net/cfg80211.h          |    4 +++-
 net/wireless/reg.c              |    3 ++-
 3 files changed, 13 insertions(+), 2 deletions(-)

-- 
1.7.3.2.90.gd4c43

[PATCH 1/2] cfg80211: fix null pointer dereference with a custom regulatory request

[Luis R. Rodriguez]

Once we moved the core regulatory request to the queue and let
the scheduler process it last_request will have been left NULL
until the schedular decides to process the first request. When
this happens and we are loading a driver with a custom regulatory
request like all Atheros drivers we end up with a NULL pointer
dereference. We fix this by checking if the request was a
custom one.

BUG: unable to handle kernel NULL pointer dereference at 0000000000000004
IP: [<ffffffffa016de87>] freq_reg_info_regd.clone.2+0x27/0x130 [cfg80211]
PGD 71f91067 PUD 712b2067 PMD 0
Oops: 0000 [#1] PREEMPT SMP
last sysfs file: /sys/devices/pci0000:00/0000:00:1d.7/usb2/2-1/firmware/2-1/loading
CPU 0
Modules linked in: ath9k_htc(+) ath9k_common ath9k_hw ath <etc>
Pid: 3094, comm: insmod Tainted: G        W   2.6.37-rc5-wl #16 INVALID/28427ZQ
RIP: 0010:[<ffffffffa016de87>]  [<ffffffffa016de87>] freq_reg_info_regd.clone.2+0x27/0x130 [cfg80211]
RSP: 0018:ffff88007045db78  EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffffffffa047d9a0 RCX: ffff88007045dbd0
RDX: 0000000000004e20 RSI: 000000000024cde0 RDI: ffff8800700483e0
RBP: ffff88007045db98 R08: ffffffffa02f5b40 R09: 0000000000000001
R10: 000000000000000e R11: 0000000000000001 R12: 0000000000000000
R13: ffff88007004e3b0 R14: 0000000000000000 R15: ffff880070048340
FS:  00007f635a707700(0000) GS:ffff880077400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000004 CR3: 00000000708a9000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process insmod (pid: 3094, threadinfo ffff88007045c000, task ffff8800713e3ec0)
Stack:
 ffffffffa047d9a0 0000000000000000 ffff88007004e3b0 0000000000000000
 ffff88007045dc08 ffffffffa016e147 000000007045dc08 0000000000000002
 ffff8800700483e0 ffffffffa02f5b40 ffff88007045dbd8 0000000000000000
Call Trace:
 [<ffffffffa016e147>] wiphy_apply_custom_regulatory+0x137/0x1d0 [cfg80211]
 [<ffffffffa047a690>] ? ath9k_reg_notifier+0x0/0x50 [ath9k_htc]
 [<ffffffffa02f47f7>] ath_regd_init+0x347/0x430 [ath]
 [<ffffffffa047b1f5>] ath9k_htc_probe_device+0x6c5/0x960 [ath9k_htc]
 [<ffffffffa0472a2c>] ath9k_htc_hw_init+0xc/0x30 [ath9k_htc]
 [<ffffffffa04747e6>] ath9k_hif_usb_probe+0x216/0x3b0 [ath9k_htc]
 [<ffffffffa03bb6bc>] usb_probe_interface+0x10c/0x210 [usbcore]
 [<ffffffff812aec26>] driver_probe_device+0x96/0x1c0
 [<ffffffff812aedf3>] __driver_attach+0xa3/0xb0
 [<ffffffff812aed50>] ? __driver_attach+0x0/0xb0
 [<ffffffff812adaae>] bus_for_each_dev+0x5e/0x90
 [<ffffffff812ae8c9>] driver_attach+0x19/0x20
 [<ffffffff812ae438>] bus_add_driver+0x168/0x320
 [<ffffffff812af071>] driver_register+0x71/0x140
 [<ffffffff811fc4a8>] ? __raw_spin_lock_init+0x38/0x70
 [<ffffffffa03ba39c>] usb_register_driver+0xdc/0x190 [usbcore]
 [<ffffffffa03a2000>] ? ath9k_htc_init+0x0/0x4f [ath9k_htc]
 [<ffffffffa047499e>] ath9k_hif_usb_init+0x1e/0x20 [ath9k_htc]
 [<ffffffffa03a202b>] ath9k_htc_init+0x2b/0x4f [ath9k_htc]
 [<ffffffff8100212f>] do_one_initcall+0x3f/0x180
 [<ffffffff8109ef5b>] sys_init_module+0xbb/0x200
 [<ffffffff8100bf52>] system_call_fastpath+0x16/0x1b
Code: <etc, who cares>
RIP  [<ffffffffa016de87>] freq_reg_info_regd.clone.2+0x27/0x130 [cfg80211]
 RSP <ffff88007045db78>
CR2: 0000000000000004
---[ end trace 79e4193601c8b713 ]---

Reported-by: Sujith Manoharan <Sujith.Manoharan@atheros.com>
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
---
 include/net/cfg80211.h |    4 +++-
 net/wireless/reg.c     |    3 ++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 22be7c6..ef82664 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1419,7 +1419,9 @@ struct ieee80211_txrx_stypes {
 
 /**
  * struct wiphy - wireless hardware description
- * @reg_notifier: the driver's regulatory notification callback
+ * @reg_notifier: the driver's regulatory notification callback,
+ *	note that if your driver uses wiphy_apply_custom_regulatory()
+ *	the reg_notifier's request can be passed as NULL
  * @regd: the driver's regulatory domain, if one was requested via
  * 	the regulatory_hint() API. This can be used by the driver
  *	on the reg_notifier() if it chooses to ignore future
diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index 5ed615f..99d4183 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -661,7 +661,8 @@ static int freq_reg_info_regd(struct wiphy *wiphy,
 	 * Follow the driver's regulatory domain, if present, unless a country
 	 * IE has been processed or a user wants to help complaince further
 	 */
-	if (last_request->initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE &&
+	if (!custom_regd &&
+	    last_request->initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE &&
 	    last_request->initiator != NL80211_REGDOM_SET_BY_USER &&
 	    wiphy->regd)
 		regd = wiphy->regd;
-- 
1.7.3.2.90.gd4c43

[PATCH 2/2] ath: fix NULL pointer dereference on reg_notifier()

[Luis R. Rodriguez]

The reg_notifier() was recently updated as being capable of
having the request passed as NULL, fix ath to follow this API
change. Without this we end up oopsing:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000004
IP: [<ffffffffa02fb8cb>] ath_reg_notifier_apply+0x5b/0xa0 [ath]
PGD b4c4c067 PUD b4c4d067 PMD 0
Oops: 0000 [#1] SMP DEBUG_PAGEALLOC
last sysfs file: /sys/devices/pci0000:00/0000:00:1b.0/uevent
CPU 1
Modules linked in: <etc>
Pid: 436, comm: modprobe Not tainted 2.6.37-rc5-wl+ #36 6460DWU/6460DWU
RIP: 0010:[<ffffffffa02fb8cb>]  [<ffffffffa02fb8cb>] ath_reg_notifier_apply+0x5b/0xa0 [ath]
RSP: 0018:ffff8800b6f6baa8  EFLAGS: 00010246
RAX: ffff8800b527b254 RBX: ffff8800b532c180 RCX: 0000000000000018
RDX: ffff8800b530c108 RSI: 0000000000000000 RDI: ffff8800b532c180
RBP: ffff8800b6f6baa8 R08: ffff8800b532f268 R09: 0000000000000235
R10: 00000000000016ad R11: 0000000000000018 R12: 0000000000000000
R13: 0000000000000016 R14: ffff8800b532f268 R15: 0000000000000011
FS:  00007f0c53104700(0000) GS:ffff8800bed00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000004 CR3: 00000000b6531000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process modprobe (pid: 436, threadinfo ffff8800b6f6a000, task ffff8800b404dc40)
Stack:
 ffff8800b6f6bac8 ffffffffa03ea651 ffff8800b532c180 ffff8800b527b254
 ffff8800b6f6bb38 ffffffffa01835ca ffffffffa019ed00 00000000a019ed80
 0000000000000002 ffff880000000002 ffffffffa0366140 0000000010aee572
Call Trace:
 [<ffffffffa03ea651>] ath9k_reg_notifier+0x41/0x50 [ath9k]
 [<ffffffffa01835ca>] wiphy_update_regulatory+0x4ba/0x5a0 [cfg80211]
 [<ffffffffa0366140>] ? ieee80211_register_hw+0xa0/0x5b0 [mac80211]
 [<ffffffffa0366140>] ? ieee80211_register_hw+0xa0/0x5b0 [mac80211]
 [<ffffffffa017f994>] wiphy_register+0x1d4/0x360 [cfg80211]
 [<ffffffff8114b918>] ? __kmalloc+0x108/0x1c0
 [<ffffffffa0366223>] ieee80211_register_hw+0x183/0x5b0 [mac80211]
 [<ffffffffa03eb49b>] ath9k_init_device+0x66b/0x850 [ath9k]
 [<ffffffffa03f9dd6>] ath_pci_probe+0x2f6/0x3c0 [ath9k]
 [<ffffffff81037529>] ? default_spin_lock_flags+0x9/0x10
 [<ffffffff812e19cf>] local_pci_probe+0x5f/0xd0
 [<ffffffff812e2bf1>] pci_device_probe+0x101/0x120
 [<ffffffff81390aca>] ? driver_sysfs_add+0x7a/0xb0
 [<ffffffff81390c26>] driver_probe_device+0x96/0x1c0
 [<ffffffff81390deb>] __driver_attach+0x9b/0xa0
 [<ffffffff81390d50>] ? __driver_attach+0x0/0xa0
 [<ffffffff81390008>] bus_for_each_dev+0x68/0x90
 [<ffffffff81390a4e>] driver_attach+0x1e/0x20
 [<ffffffff81390309>] bus_add_driver+0xe9/0x290
 [<ffffffffa0407000>] ? ath9k_init+0x0/0x4d [ath9k]
 [<ffffffff81391130>] driver_register+0x80/0x150
 [<ffffffffa0407000>] ? ath9k_init+0x0/0x4d [ath9k]
 [<ffffffffa0407000>] ? ath9k_init+0x0/0x4d [ath9k]
 [<ffffffff812e2e76>] __pci_register_driver+0x56/0xd0
 [<ffffffffa03f9ec3>] ath_pci_init+0x23/0x30 [ath9k]
 [<ffffffffa040702b>] ath9k_init+0x2b/0x4d [ath9k]
 [<ffffffff81002053>] do_one_initcall+0x43/0x190
 [<ffffffff8109fb5b>] sys_init_module+0xbb/0x200
 [<ffffffff8100c042>] system_call_fastpath+0x16/0x1b
Code: <who even reads this anyway? haha, ok you do>
RIP  [<ffffffffa02fb8cb>] ath_reg_notifier_apply+0x5b/0xa0 [ath]
 RSP <ffff8800b6f6baa8>
CR2: 0000000000000004
---[ end trace 6d03d3c7eda9f06b ]---

Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
---
 drivers/net/wireless/ath/regd.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/drivers/net/wireless/ath/regd.c b/drivers/net/wireless/ath/regd.c
index 3f4244f..2b14775 100644
--- a/drivers/net/wireless/ath/regd.c
+++ b/drivers/net/wireless/ath/regd.c
@@ -342,6 +342,14 @@ int ath_reg_notifier_apply(struct wiphy *wiphy,
 	/* We always apply this */
 	ath_reg_apply_radar_flags(wiphy);
 
+	/*
+	 * This would happen when we have sent a custom regulatory request
+	 * a world regulatory domain and the scheduler hasn't yet processed
+	 * any pending requests in the queue.
+	 */
+	if (!request)
+		return 0;
+
 	switch (request->initiator) {
 	case NL80211_REGDOM_SET_BY_DRIVER:
 	case NL80211_REGDOM_SET_BY_CORE:
-- 
1.7.3.2.90.gd4c43