[PATCH 6.6 004/396] wifi: brcmfmac: Fix use-after-free bug in brcmf_cfg80211_detach

Greg Kroah-Hartman
2024-04-01T16:35:57Z

From: Zheng Wang <zyytlz.wz@163.com>

[ Upstream commit 0f7352557a35ab7888bc7831411ec8a3cbe20d78 ]

This is the candidate patch of CVE-2023-47233 :
https://nvd.nist.gov/vuln/detail/CVE-2023-47233

In brcm80211 driver,it starts with the following invoking chain
to start init a timeout worker:

->brcmf_usb_probe
->brcmf_usb_probe_cb
->brcmf_attach
->brcmf_bus_started
->brcmf_cfg80211_attach
->wl_init_priv
->brcmf_init_escan
->INIT_WORK(&cfg->escan_timeout_work,
brcmf_cfg80211_escan_timeout_worker);

If we disconnect the USB by hotplug, it will call
brcmf_usb_disconnect to make cleanup. The invoking chain is :

brcmf_usb_disconnect
->brcmf_usb_disconnect_cb
->brcmf_detach
->brcmf_cfg80211_detach
->kfree(cfg);

While the timeout woker may still be running. This will cause
a use-after-free bug on cfg in brcmf_cfg80211_escan_timeout_worker.

Fix it by deleting the timer and canceling the worker in
brcmf_cfg80211_detach.

Fixes: e756af5b30b0 ("brcmfmac: add e-scan support.")
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
Cc: stable@vger.kernel.org
[arend.vanspriel@broadcom.com: keep timer delete as is and cancel work just before free]
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20240107072504.392713-1-arend.vanspriel@broadcom.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
index df9c26593dbe1..567e3a0675d88 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
@@ -1179,8 +1179,7 @@ s32 brcmf_notify_escan_complete(struct brcmf_cfg80211_info *cfg,
scan_request = cfg->scan_request;
cfg->scan_request = NULL;

- if (timer_pending(&cfg->escan_timeout))
- del_timer_sync(&cfg->escan_timeout);
+ timer_delete_sync(&cfg->escan_timeout);

if (fw_abort) {
/* Do a scan abort to stop the driver's scan engine */
@@ -8441,6 +8440,7 @@ void brcmf_cfg80211_detach(struct brcmf_cfg80211_info *cfg)
brcmf_btcoex_detach(cfg);
wiphy_unregister(cfg->wiphy);
wl_deinit_priv(cfg);
+ cancel_work_sync(&cfg->escan_timeout_work);
brcmf_free_wiphy(cfg->wiphy);
kfree(cfg);
}
--
2.43.0