| Message ID | 20240619070824.537856-1-s.hauer@pengutronix.de |
|---|---|
| State | New |
| Headers | show |
| Series | [RFC] mwifiex: Fix NULL pointer deref | expand |
Brian Norris <briannorris@chromium.org> writes: > On Fri, Jun 21, 2024 at 11:07:27AM +0200, Sascha Hauer wrote: >> I am running plain 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" >> } >> >> wait for the AP to be established, <ctrl-c> wpa_supplicant and start it >> again. > > Thanks. I still can't reproduce, but that's OK. From your fuller > description now, it seems it depends on the particulars of the bss > indices in use, and maybe my device/firmware is behaving differently. > Anyway, your current description and patch below make a lot more sense. Indeed, this makes a lot more sense. Thank you both for getting to the bottom of it!
Hello Sascha, On Fri, Jun 21, 2024 at 11:07:27AM +0200, Sascha Hauer wrote: > On Thu, Jun 20, 2024 at 12:48:01PM -0700, Brian Norris wrote: > > Hi Sascha, > > > > On Wed, Jun 19, 2024 at 11:05:28AM +0300, Kalle Valo wrote: > > > Sascha Hauer <s.hauer@pengutronix.de> writes: > > > > > > > When an Access Point is repeatedly started it happens that the > > > > interrupts handler is called with priv->wdev.wiphy being NULL, but > > > > dereferenced in mwifiex_parse_single_response_buf() resulting in: > > > > > > > > | Unable to handle kernel NULL pointer dereference at virtual address 0000000000000140 > > ... > > > > | 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 ]--- > > > > > > > > Fix this by adding a NULL check before dereferencing this pointer. > > > > > > > > Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> > > > > > > > > --- > > > > > > > > This is the most obvious fix for this problem, but I am not sure if we > > > > might want to catch priv->wdev.wiphy being NULL earlier in the call > > > > chain. > > > > > > I haven't looked at the call but the symptoms sound like that either we > > > are enabling the interrupts too early or there's some kind of locking > > > problem so that an other cpu doesn't see the change. > > > > I agree with Kalle that there's a different underlying bug involved, and > > (my conclusion:) we shouldn't whack-a-mole the NULL pointer without > > addressing the underlying problem. > > > > Looking a bit closer (and without much other context to go on): I believe > > that one potential underlying problem is the complete lack of locking > > between cfg80211 entry points (such as mwifiex_add_virtual_intf() or > > mwifiex_cfg80211_change_virtual_intf()) and most stuff in the main loop > > (mwifiex_main_process()). The former call sites only hold the wiphy > > lock, and the latter tends to ... mostly not hold any locks, but rely on > > sequentialization with itself, and using its |main_proc_lock| for setup > > and teardown. It's all really bad and ready to fall down like a house of > > cards at any moment. Unfortunately, no one has spent time on > > rearchitecting this driver. > > > > So it's possible that mwifiex_process_event() (mwifiex_get_priv_by_id() > > / mwifiex_get_priv()) is getting a hold of a not-fully-initialized > > 'priv' structure. > > > > BTW, in case I can reproduce and poke at your scenario, what exactly > > is your test case? Are you just starting / killing / restarting hostapd > > in a loop? > > I am running plain 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" > } > > wait for the AP to be established, <ctrl-c> wpa_supplicant and start it > again. > > It doesn't seem to be a locking problem, see the patch below which fixes > my problem. At some point during incoming events the correct adapter->priv[] > is selected based on bss_num and bss_type. when adapter->priv[0] is used > for AP mode then an incoming event with type MWIFIEX_BSS_TYPE_STA leads > to adapter->priv[1] being picked which is unused and doesn't have a > wiphy attached to it. > > Sascha > > -------------------------8<---------------------------- > > From 3357963821294ff7de26259a154a1cb5bab760cb Mon Sep 17 00:00:00 2001 > From: Sascha Hauer <s.hauer@pengutronix.de> > Date: Tue, 18 Jun 2024 12:20:20 +0200 > Subject: [PATCH] mwifiex: Do not return unused priv in > mwifiex_get_priv_by_id() > > 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. > > Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> > --- > 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 175882485a195..c5164ae41b547 100644 > --- a/drivers/net/wireless/marvell/mwifiex/main.h > +++ b/drivers/net/wireless/marvell/mwifiex/main.h > @@ -1287,6 +1287,9 @@ 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; The change looks fine to me. I am just wondering if this might have anything to do with commit a17b9f590f6e ("wifi: mwifiex: Fix interface type change"), maybe you have already looked into it? Before that commit a wrong priv pointer was picked (different scenario from what you describe however). Francesco
On Mon, Jun 24, 2024 at 06:20:14PM +0200, Francesco Dolcini wrote: > Hello Sascha, > > On Fri, Jun 21, 2024 at 11:07:27AM +0200, Sascha Hauer wrote: > > On Thu, Jun 20, 2024 at 12:48:01PM -0700, Brian Norris wrote: > > > Hi Sascha, > > > > > > On Wed, Jun 19, 2024 at 11:05:28AM +0300, Kalle Valo wrote: > > > > Sascha Hauer <s.hauer@pengutronix.de> writes: > > > > > > > > > When an Access Point is repeatedly started it happens that the > > > > > interrupts handler is called with priv->wdev.wiphy being NULL, but > > > > > dereferenced in mwifiex_parse_single_response_buf() resulting in: > > > > > > > > > > | Unable to handle kernel NULL pointer dereference at virtual address 0000000000000140 > > > ... > > > > > | 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 ]--- > > > > > > > > > > Fix this by adding a NULL check before dereferencing this pointer. > > > > > > > > > > Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> > > > > > > > > > > --- > > > > > > > > > > This is the most obvious fix for this problem, but I am not sure if we > > > > > might want to catch priv->wdev.wiphy being NULL earlier in the call > > > > > chain. > > > > > > > > I haven't looked at the call but the symptoms sound like that either we > > > > are enabling the interrupts too early or there's some kind of locking > > > > problem so that an other cpu doesn't see the change. > > > > > > I agree with Kalle that there's a different underlying bug involved, and > > > (my conclusion:) we shouldn't whack-a-mole the NULL pointer without > > > addressing the underlying problem. > > > > > > Looking a bit closer (and without much other context to go on): I believe > > > that one potential underlying problem is the complete lack of locking > > > between cfg80211 entry points (such as mwifiex_add_virtual_intf() or > > > mwifiex_cfg80211_change_virtual_intf()) and most stuff in the main loop > > > (mwifiex_main_process()). The former call sites only hold the wiphy > > > lock, and the latter tends to ... mostly not hold any locks, but rely on > > > sequentialization with itself, and using its |main_proc_lock| for setup > > > and teardown. It's all really bad and ready to fall down like a house of > > > cards at any moment. Unfortunately, no one has spent time on > > > rearchitecting this driver. > > > > > > So it's possible that mwifiex_process_event() (mwifiex_get_priv_by_id() > > > / mwifiex_get_priv()) is getting a hold of a not-fully-initialized > > > 'priv' structure. > > > > > > BTW, in case I can reproduce and poke at your scenario, what exactly > > > is your test case? Are you just starting / killing / restarting hostapd > > > in a loop? > > > > I am running plain 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" > > } > > > > wait for the AP to be established, <ctrl-c> wpa_supplicant and start it > > again. > > > > It doesn't seem to be a locking problem, see the patch below which fixes > > my problem. At some point during incoming events the correct adapter->priv[] > > is selected based on bss_num and bss_type. when adapter->priv[0] is used > > for AP mode then an incoming event with type MWIFIEX_BSS_TYPE_STA leads > > to adapter->priv[1] being picked which is unused and doesn't have a > > wiphy attached to it. > > > > Sascha > > > > -------------------------8<---------------------------- > > > > From 3357963821294ff7de26259a154a1cb5bab760cb Mon Sep 17 00:00:00 2001 > > From: Sascha Hauer <s.hauer@pengutronix.de> > > Date: Tue, 18 Jun 2024 12:20:20 +0200 > > Subject: [PATCH] mwifiex: Do not return unused priv in > > mwifiex_get_priv_by_id() > > > > 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. > > > > Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> > > --- > > 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 175882485a195..c5164ae41b547 100644 > > --- a/drivers/net/wireless/marvell/mwifiex/main.h > > +++ b/drivers/net/wireless/marvell/mwifiex/main.h > > @@ -1287,6 +1287,9 @@ 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; > > The change looks fine to me. > > I am just wondering if this might have anything to do with > commit a17b9f590f6e ("wifi: mwifiex: Fix interface type change"), maybe you have already looked into it? It looks somehow related. I just gave it a try and it at least doesn't fix my issue. Sascha
On Tue, Jul 02, 2024 at 03:32:16PM +0200, Sascha Hauer wrote: > On Mon, Jun 24, 2024 at 06:20:14PM +0200, Francesco Dolcini wrote: > > On Fri, Jun 21, 2024 at 11:07:27AM +0200, Sascha Hauer wrote: ... > > > > > > From 3357963821294ff7de26259a154a1cb5bab760cb Mon Sep 17 00:00:00 2001 > > > From: Sascha Hauer <s.hauer@pengutronix.de> > > > Date: Tue, 18 Jun 2024 12:20:20 +0200 > > > Subject: [PATCH] mwifiex: Do not return unused priv in > > > mwifiex_get_priv_by_id() > > > > > > 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. > > > > > > Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Reviewed-by: Francesco Dolcini <francesco.dolcini@toradex.com> I guess you should send it as a proper patch? ... > > I am just wondering if this might have anything to do with > > commit a17b9f590f6e ("wifi: mwifiex: Fix interface type change"), maybe you have already looked into it? > > It looks somehow related. I just gave it a try and it at least doesn't > fix my issue. thanks for trying it out. Francesco
On Tue, Jul 02, 2024 at 10:36:11PM +0200, Francesco Dolcini wrote: > On Tue, Jul 02, 2024 at 03:32:16PM +0200, Sascha Hauer wrote: > > On Mon, Jun 24, 2024 at 06:20:14PM +0200, Francesco Dolcini wrote: > > > On Fri, Jun 21, 2024 at 11:07:27AM +0200, Sascha Hauer wrote: > > ... > > > > > > > > > From 3357963821294ff7de26259a154a1cb5bab760cb Mon Sep 17 00:00:00 2001 > > > > From: Sascha Hauer <s.hauer@pengutronix.de> > > > > Date: Tue, 18 Jun 2024 12:20:20 +0200 > > > > Subject: [PATCH] mwifiex: Do not return unused priv in > > > > mwifiex_get_priv_by_id() > > > > > > > > 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. > > > > > > > > Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> > > Reviewed-by: Francesco Dolcini <francesco.dolcini@toradex.com> > > I guess you should send it as a proper patch? Yes, I just did this. Sascha
diff --git a/drivers/net/wireless/marvell/mwifiex/scan.c b/drivers/net/wireless/marvell/mwifiex/scan.c index 0326b121747cb..6211ae97da4b2 100644 --- a/drivers/net/wireless/marvell/mwifiex/scan.c +++ b/drivers/net/wireless/marvell/mwifiex/scan.c @@ -1843,6 +1843,9 @@ mwifiex_parse_single_response_buf(struct mwifiex_private *priv, u8 **bss_info, return 0; } + if (!priv->wdev.wiphy) + return 0; + band = BAND_G; if (radio_type) band = mwifiex_radio_type_to_band(*radio_type &
When an Access Point is repeatedly started it happens that the interrupts handler is called with priv->wdev.wiphy being NULL, but dereferenced in mwifiex_parse_single_response_buf() resulting in: | 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 ]--- Fix this by adding a NULL check before dereferencing this pointer. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> --- This is the most obvious fix for this problem, but I am not sure if we might want to catch priv->wdev.wiphy being NULL earlier in the call chain. --- drivers/net/wireless/marvell/mwifiex/scan.c | 3 +++ 1 file changed, 3 insertions(+)