| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2021-47349: mwifiex: bring down link before deleting interface |
| |
| Description |
| =========== |
| |
| 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] |
| |
| The Linux kernel CVE team has assigned CVE-2021-47349 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.12 with commit a05829a7222e9d10c416dd2dbbf3929fe6646b89 and fixed in 5.12.18 with commit a3041d39d3c14da97fa3476835aba043ba810cf0 |
| Issue introduced in 5.12 with commit a05829a7222e9d10c416dd2dbbf3929fe6646b89 and fixed in 5.13.3 with commit 35af69c7c0490fdccfc159c6a87e4d1dc070838a |
| Issue introduced in 5.12 with commit a05829a7222e9d10c416dd2dbbf3929fe6646b89 and fixed in 5.14 with commit 1f9482aa8d412b4ba06ce6ab8e333fb8ca29a06e |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2021-47349 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| drivers/net/wireless/marvell/mwifiex/main.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/a3041d39d3c14da97fa3476835aba043ba810cf0 |
| https://git.kernel.org/stable/c/35af69c7c0490fdccfc159c6a87e4d1dc070838a |
| https://git.kernel.org/stable/c/1f9482aa8d412b4ba06ce6ab8e333fb8ca29a06e |
