[PATCH AUTOSEL 5.4 10/22] wifi: cfg80211: make hash table duplicates more survivable

[PATCH AUTOSEL 5.4 10/22] wifi: cfg80211: make hash table duplicates more survivable

[Sasha Levin]

From: Johannes Berg <johannes.berg@intel.com>

[ Upstream commit 7f12e26a194d0043441f870708093d9c2c3bad7d ]

Jiazi Li reported that they occasionally see hash table duplicates
as evidenced by the WARN_ON() in rb_insert_bss() in this code.  It
isn't clear how that happens, nor have I been able to reproduce it,
but if it does happen, the kernel crashes later, when it tries to
unhash the entry that's now not hashed.

Try to make this situation more survivable by removing the BSS from
the list(s) as well, that way it's fully leaked here (as had been
the intent in the hash insert error path), and no longer reachable
through the list(s) so it shouldn't be unhashed again later.

Link: https://lore.kernel.org/r/20231026013528.GA24122@Jiazi.Li
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Link: https://msgid.link/20240607181726.36835-2-johannes@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/wireless/scan.c | 46 +++++++++++++++++++++++++++++++++------------
 1 file changed, 34 insertions(+), 12 deletions(-)

diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index c74882e3c3096..b28e652514e80 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -1003,7 +1003,7 @@ struct cfg80211_bss *cfg80211_get_bss(struct wiphy *wiphy,
 }
 EXPORT_SYMBOL(cfg80211_get_bss);
 
-static void rb_insert_bss(struct cfg80211_registered_device *rdev,
+static bool rb_insert_bss(struct cfg80211_registered_device *rdev,
 			  struct cfg80211_internal_bss *bss)
 {
 	struct rb_node **p = &rdev->bss_tree.rb_node;
@@ -1019,7 +1019,7 @@ static void rb_insert_bss(struct cfg80211_registered_device *rdev,
 
 		if (WARN_ON(!cmp)) {
 			/* will sort of leak this BSS */
-			return;
+			return false;
 		}
 
 		if (cmp < 0)
@@ -1030,6 +1030,7 @@ static void rb_insert_bss(struct cfg80211_registered_device *rdev,
 
 	rb_link_node(&bss->rbn, parent, p);
 	rb_insert_color(&bss->rbn, &rdev->bss_tree);
+	return true;
 }
 
 static struct cfg80211_internal_bss *
@@ -1056,6 +1057,34 @@ rb_find_bss(struct cfg80211_registered_device *rdev,
 	return NULL;
 }
 
+static void cfg80211_insert_bss(struct cfg80211_registered_device *rdev,
+				struct cfg80211_internal_bss *bss)
+{
+	lockdep_assert_held(&rdev->bss_lock);
+
+	if (!rb_insert_bss(rdev, bss))
+		return;
+	list_add_tail(&bss->list, &rdev->bss_list);
+	rdev->bss_entries++;
+}
+
+static void cfg80211_rehash_bss(struct cfg80211_registered_device *rdev,
+                                struct cfg80211_internal_bss *bss)
+{
+	lockdep_assert_held(&rdev->bss_lock);
+
+	rb_erase(&bss->rbn, &rdev->bss_tree);
+	if (!rb_insert_bss(rdev, bss)) {
+		list_del(&bss->list);
+		if (!list_empty(&bss->hidden_list))
+			list_del_init(&bss->hidden_list);
+		if (!list_empty(&bss->pub.nontrans_list))
+			list_del_init(&bss->pub.nontrans_list);
+		rdev->bss_entries--;
+	}
+	rdev->bss_generation++;
+}
+
 static bool cfg80211_combine_bsses(struct cfg80211_registered_device *rdev,
 				   struct cfg80211_internal_bss *new)
 {
@@ -1331,9 +1360,7 @@ cfg80211_bss_update(struct cfg80211_registered_device *rdev,
 			bss_ref_get(rdev, pbss);
 		}
 
-		list_add_tail(&new->list, &rdev->bss_list);
-		rdev->bss_entries++;
-		rb_insert_bss(rdev, new);
+		cfg80211_insert_bss(rdev, new);
 		found = new;
 	}
 
@@ -2142,10 +2169,7 @@ void cfg80211_update_assoc_bss_entry(struct wireless_dev *wdev,
 		if (!WARN_ON(!__cfg80211_unlink_bss(rdev, new)))
 			rdev->bss_generation++;
 	}
-
-	rb_erase(&cbss->rbn, &rdev->bss_tree);
-	rb_insert_bss(rdev, cbss);
-	rdev->bss_generation++;
+	cfg80211_rehash_bss(rdev, cbss);
 
 	list_for_each_entry_safe(nontrans_bss, tmp,
 				 &cbss->pub.nontrans_list,
@@ -2153,9 +2177,7 @@ void cfg80211_update_assoc_bss_entry(struct wireless_dev *wdev,
 		bss = container_of(nontrans_bss,
 				   struct cfg80211_internal_bss, pub);
 		bss->pub.channel = chan;
-		rb_erase(&bss->rbn, &rdev->bss_tree);
-		rb_insert_bss(rdev, bss);
-		rdev->bss_generation++;
+		cfg80211_rehash_bss(rdev, bss);
 	}
 
 done:
-- 
2.43.0

[PATCH AUTOSEL 5.4 22/22] wifi: mwifiex: Do not return unused priv in mwifiex_get_priv_by_id()

[Sasha Levin]

From: Sascha Hauer <s.hauer@pengutronix.de>

[ Upstream commit c145eea2f75ff7949392aebecf7ef0a81c1f6c14 ]

mwifiex_get_priv_by_id() returns the priv pointer corresponding to
the bss_num and bss_type, but without checking if the priv is actually
currently in use.
Unused priv pointers do not have a wiphy attached to them which can
lead to NULL pointer dereferences further down the callstack.  Fix
this by returning only used priv pointers which have priv->bss_mode
set to something else than NL80211_IFTYPE_UNSPECIFIED.

Said NULL pointer dereference happened when an Accesspoint was started
with wpa_supplicant -i mlan0 with this config:

network={
        ssid="somessid"
        mode=2
        frequency=2412
        key_mgmt=WPA-PSK WPA-PSK-SHA256
        proto=RSN
        group=CCMP
        pairwise=CCMP
        psk="12345678"
}

When waiting for the AP to be established, interrupting wpa_supplicant
with <ctrl-c> and starting it again this happens:

| Unable to handle kernel NULL pointer dereference at virtual address 0000000000000140
| Mem abort info:
|   ESR = 0x0000000096000004
|   EC = 0x25: DABT (current EL), IL = 32 bits
|   SET = 0, FnV = 0
|   EA = 0, S1PTW = 0
|   FSC = 0x04: level 0 translation fault
| Data abort info:
|   ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
|   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
|   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
| user pgtable: 4k pages, 48-bit VAs, pgdp=0000000046d96000
| [0000000000000140] pgd=0000000000000000, p4d=0000000000000000
| Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
| Modules linked in: caam_jr caamhash_desc spidev caamalg_desc crypto_engine authenc libdes mwifiex_sdio
+mwifiex crct10dif_ce cdc_acm onboard_usb_hub fsl_imx8_ddr_perf imx8m_ddrc rtc_ds1307 lm75 rtc_snvs
+imx_sdma caam imx8mm_thermal spi_imx error imx_cpufreq_dt fuse ip_tables x_tables ipv6
| CPU: 0 PID: 8 Comm: kworker/0:1 Not tainted 6.9.0-00007-g937242013fce-dirty #18
| Hardware name: somemachine (DT)
| Workqueue: events sdio_irq_work
| pstate: 00000005 (nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
| pc : mwifiex_get_cfp+0xd8/0x15c [mwifiex]
| lr : mwifiex_get_cfp+0x34/0x15c [mwifiex]
| sp : ffff8000818b3a70
| x29: ffff8000818b3a70 x28: ffff000006bfd8a5 x27: 0000000000000004
| x26: 000000000000002c x25: 0000000000001511 x24: 0000000002e86bc9
| x23: ffff000006bfd996 x22: 0000000000000004 x21: ffff000007bec000
| x20: 000000000000002c x19: 0000000000000000 x18: 0000000000000000
| x17: 000000040044ffff x16: 00500072b5503510 x15: ccc283740681e517
| x14: 0201000101006d15 x13: 0000000002e8ff43 x12: 002c01000000ffb1
| x11: 0100000000000000 x10: 02e8ff43002c0100 x9 : 0000ffb100100157
| x8 : ffff000003d20000 x7 : 00000000000002f1 x6 : 00000000ffffe124
| x5 : 0000000000000001 x4 : 0000000000000003 x3 : 0000000000000000
| x2 : 0000000000000000 x1 : 0001000000011001 x0 : 0000000000000000
| Call trace:
|  mwifiex_get_cfp+0xd8/0x15c [mwifiex]
|  mwifiex_parse_single_response_buf+0x1d0/0x504 [mwifiex]
|  mwifiex_handle_event_ext_scan_report+0x19c/0x2f8 [mwifiex]
|  mwifiex_process_sta_event+0x298/0xf0c [mwifiex]
|  mwifiex_process_event+0x110/0x238 [mwifiex]
|  mwifiex_main_process+0x428/0xa44 [mwifiex]
|  mwifiex_sdio_interrupt+0x64/0x12c [mwifiex_sdio]
|  process_sdio_pending_irqs+0x64/0x1b8
|  sdio_irq_work+0x4c/0x7c
|  process_one_work+0x148/0x2a0
|  worker_thread+0x2fc/0x40c
|  kthread+0x110/0x114
|  ret_from_fork+0x10/0x20
| Code: a94153f3 a8c37bfd d50323bf d65f03c0 (f940a000)
| ---[ end trace 0000000000000000 ]---

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://patch.msgid.link/20240703072409.556618-1-s.hauer@pengutronix.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/wireless/marvell/mwifiex/main.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/wireless/marvell/mwifiex/main.h b/drivers/net/wireless/marvell/mwifiex/main.h
index fa5634af40f7c..2e7f31bf38002 100644
--- a/drivers/net/wireless/marvell/mwifiex/main.h
+++ b/drivers/net/wireless/marvell/mwifiex/main.h
@@ -1307,6 +1307,9 @@ mwifiex_get_priv_by_id(struct mwifiex_adapter *adapter,
 
 	for (i = 0; i < adapter->priv_num; i++) {
 		if (adapter->priv[i]) {
+			if (adapter->priv[i]->bss_mode == NL80211_IFTYPE_UNSPECIFIED)
+				continue;
+
 			if ((adapter->priv[i]->bss_num == bss_num) &&
 			    (adapter->priv[i]->bss_type == bss_type))
 				break;
-- 
2.43.0