CVE-2021-47349
mwifiex: bring down link before deleting interface
Severity Score
Exploit Likelihood
Affected Versions
Public Exploits
0Exploited in Wild
-Decision
Descriptions
In the Linux kernel, the following vulnerability has been resolved: mwifiex: bring down link before deleting interface We can deadlock when rmmod'ing the driver or going through firmware
reset, because the cfg80211_unregister_wdev() has to bring down the link
for us, ... which then grab the same wiphy lock. nl80211_del_interface() already handles a very similar case, with a nice
description: /* * We hold RTNL, so this is safe, without RTNL opencount cannot * reach 0, and thus the rdev cannot be deleted. * * We need to do it for the dev_close(), since that will call * the netdev notifiers, and we need to acquire the mutex there * but don't know if we get there from here or from some other * place (e.g. "ip link set ... down"). */ mutex_unlock(&rdev->wiphy.mtx);
... Do similarly for mwifiex teardown, by ensuring we bring the link down
first. Sample deadlock trace: [ 247.103516] INFO: task rmmod:2119 blocked for more than 123 seconds.
[ 247.110630] Not tainted 5.12.4 #5
[ 247.115796] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 247.124557] task:rmmod state:D stack: 0 pid: 2119 ppid: 2114 flags:0x00400208
[ 247.133905] Call trace:
[ 247.136644] __switch_to+0x130/0x170
[ 247.140643] __schedule+0x714/0xa0c
[ 247.144548] schedule_preempt_disabled+0x88/0xf4
[ 247.149714] __mutex_lock_common+0x43c/0x750
[ 247.154496] mutex_lock_nested+0x5c/0x68
[ 247.158884] cfg80211_netdev_notifier_call+0x280/0x4e0 [cfg80211]
[ 247.165769] raw_notifier_call_chain+0x4c/0x78
[ 247.170742] call_netdevice_notifiers_info+0x68/0xa4
[ 247.176305] __dev_close_many+0x7c/0x138
[ 247.180693] dev_close_many+0x7c/0x10c
[ 247.184893] unregister_netdevice_many+0xfc/0x654
[ 247.190158] unregister_netdevice_queue+0xb4/0xe0
[ 247.195424] _cfg80211_unregister_wdev+0xa4/0x204 [cfg80211]
[ 247.201816] cfg80211_unregister_wdev+0x20/0x2c [cfg80211]
[ 247.208016] mwifiex_del_virtual_intf+0xc8/0x188 [mwifiex]
[ 247.214174] mwifiex_uninit_sw+0x158/0x1b0 [mwifiex]
[ 247.219747] mwifiex_remove_card+0x38/0xa0 [mwifiex]
[ 247.225316] mwifiex_pcie_remove+0xd0/0xe0 [mwifiex_pcie]
[ 247.231451] pci_device_remove+0x50/0xe0
[ 247.235849] device_release_driver_internal+0x110/0x1b0
[ 247.241701] driver_detach+0x5c/0x9c
[ 247.245704] bus_remove_driver+0x84/0xb8
[ 247.250095] driver_unregister+0x3c/0x60
[ 247.254486] pci_unregister_driver+0x2c/0x90
[ 247.259267] cleanup_module+0x18/0xcdc [mwifiex_pcie]
En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: mwifiex: desactivar el enlace antes de eliminar la interfaz. Podemos bloquearnos al modificar el controlador o restablecer el firmware, porque cfg80211_unregister_wdev() tiene que desactivar el enlace por nosotros. .. que luego agarra el mismo candado wiphy. nl80211_del_interface() ya maneja un caso muy similar, con una buena descripción: /* * Mantenemos RTNL, por lo que esto es seguro, sin RTNL opencount no puede * llegar a 0 y, por lo tanto, rdev no se puede eliminar. * * Necesitamos hacerlo para dev_close(), ya que eso llamará * a los notificadores de netdev, y necesitamos adquirir el mutex allí * pero no sabemos si llegamos allí desde aquí o desde algún otro * lugar (por ejemplo "enlace IP configurado... inactivo"). */ mutex_unlock(&rdev->wiphy.mtx); ... Haga lo mismo con el desmontaje de mwifiex, asegurándose de que primero desconectamos el enlace. Ejemplo de seguimiento de interbloqueo: [247.103516] INFORMACIÓN: tarea rmmod:2119 bloqueada durante más de 123 segundos. [247.110630] No contaminado 5.12.4 #5 [247.115796] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" desactiva este mensaje. [247.124557] tarea:rmmod estado:D pila: 0 pid: 2119 ppid: 2114 banderas:0x00400208 [247.133905] Rastreo de llamadas: [247.136644] __switch_to+0x130/0x170 [ 247.140643] 14/0xa0c [247.144548] Schedule_preempt_disabled+0x88/ 0xf4 [ 247.149714] __mutex_lock_common+0x43c/0x750 [ 247.154496] mutex_lock_nested+0x5c/0x68 [ 247.158884] cfg80211_netdev_notifier_call+0x280/0x4e0 [cfg80211] [ 47.165769] raw_notifier_call_chain+0x4c/0x78 [ 247.170742] call_netdevice_notifiers_info+0x68/0xa4 [ 247.176305] __dev_close_many+0x7c /0x138 [ 247.180693] dev_close_many+0x7c/0x10c [ 247.184893] unregister_netdevice_many+0xfc/0x654 [ 247.190158] unregister_netdevice_queue+0xb4/0xe0 [ 247.195424] 11_unregister_wdev+0xa4/0x204 [cfg80211] [ 247.201816] cfg80211_unregister_wdev+0x20/0x2c [cfg80211] [ 247.208016 ] mwifiex_del_virtual_intf+0xc8/0x188 [mwifiex] [ 247.214174] mwifiex_uninit_sw+0x158/0x1b0 [mwifiex] [ 247.219747] mwifiex_remove_card+0x38/0xa0 [mwifiex] [ 247.225316 ] mwifiex_pcie_remove+0xd0/0xe0 [mwifiex_pcie] [ 247.231451] pci_device_remove+0x50/0xe0 [ 247.235849] device_release_driver_internal+0x110/0x1b0 [ 247.241701] driver_detach+0x5c/0x9c [ 247.245704] bus_remove_driver+0x84/0xb8 [ 247.250095] driver_unregister+0x3c/0x60 [ 2 47.254486] pci_unregister_driver+0x2c/0x90 [ 247.259267] cleanup_module+0x18/0xcdc [mwifiex_pcie ]
In the Linux kernel, the following vulnerability has been resolved: mwifiex: bring down link before deleting interface We can deadlock when rmmod'ing the driver or going through firmware reset, because the cfg80211_unregister_wdev() has to bring down the link for us, ... which then grab the same wiphy lock. nl80211_del_interface() already handles a very similar case, with a nice description: /* * We hold RTNL, so this is safe, without RTNL opencount cannot * reach 0, and thus the rdev cannot be deleted. * * We need to do it for the dev_close(), since that will call * the netdev notifiers, and we need to acquire the mutex there * but don't know if we get there from here or from some other * place (e.g. "ip link set ... down"). */ mutex_unlock(&rdev->wiphy.mtx); ... Do similarly for mwifiex teardown, by ensuring we bring the link down first. Sample deadlock trace: [ 247.103516] INFO: task rmmod:2119 blocked for more than 123 seconds. [ 247.110630] Not tainted 5.12.4 #5 [ 247.115796] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 247.124557] task:rmmod state:D stack: 0 pid: 2119 ppid: 2114 flags:0x00400208 [ 247.133905] Call trace: [ 247.136644] __switch_to+0x130/0x170 [ 247.140643] __schedule+0x714/0xa0c [ 247.144548] schedule_preempt_disabled+0x88/0xf4 [ 247.149714] __mutex_lock_common+0x43c/0x750 [ 247.154496] mutex_lock_nested+0x5c/0x68 [ 247.158884] cfg80211_netdev_notifier_call+0x280/0x4e0 [cfg80211] [ 247.165769] raw_notifier_call_chain+0x4c/0x78 [ 247.170742] call_netdevice_notifiers_info+0x68/0xa4 [ 247.176305] __dev_close_many+0x7c/0x138 [ 247.180693] dev_close_many+0x7c/0x10c [ 247.184893] unregister_netdevice_many+0xfc/0x654 [ 247.190158] unregister_netdevice_queue+0xb4/0xe0 [ 247.195424] _cfg80211_unregister_wdev+0xa4/0x204 [cfg80211] [ 247.201816] cfg80211_unregister_wdev+0x20/0x2c [cfg80211] [ 247.208016] mwifiex_del_virtual_intf+0xc8/0x188 [mwifiex] [ 247.214174] mwifiex_uninit_sw+0x158/0x1b0 [mwifiex] [ 247.219747] mwifiex_remove_card+0x38/0xa0 [mwifiex] [ 247.225316] mwifiex_pcie_remove+0xd0/0xe0 [mwifiex_pcie] [ 247.231451] pci_device_remove+0x50/0xe0 [ 247.235849] device_release_driver_internal+0x110/0x1b0 [ 247.241701] driver_detach+0x5c/0x9c [ 247.245704] bus_remove_driver+0x84/0xb8 [ 247.250095] driver_unregister+0x3c/0x60 [ 247.254486] pci_unregister_driver+0x2c/0x90 [ 247.259267] cleanup_module+0x18/0xcdc [mwifiex_pcie]
CVSS Scores
SSVC
- Decision:Track
Timeline
- 2024-05-21 CVE Reserved
- 2024-05-21 CVE Published
- 2024-05-22 EPSS Updated
- 2024-12-19 CVE Updated
- ---------- Exploited in Wild
- ---------- KEV Due Date
- ---------- First Exploit
CWE
CAPEC
References (4)
URL | Tag | Source |
---|---|---|
https://git.kernel.org/stable/c/a05829a7222e9d10c416dd2dbbf3929fe6646b89 | Vuln. Introduced |
URL | Date | SRC |
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URL | Date | SRC |
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Affected Vendors, Products, and Versions
Vendor | Product | Version | Other | Status | ||||||
---|---|---|---|---|---|---|---|---|---|---|
Vendor | Product | Version | Other | Status | <-- --> | Vendor | Product | Version | Other | Status |
Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.12 < 5.12.18 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.12 < 5.12.18" | en |
Affected
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Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.12 < 5.13.3 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.12 < 5.13.3" | en |
Affected
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Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.12 < 5.14 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.12 < 5.14" | en |
Affected
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