wifi: ath12k: fix uaf in ath12k_core_init()

When the execution of ath12k_core_hw_group_assign() or
ath12k_core_hw_group_create() fails, the registered notifier chain is not
unregistered properly. Its memory is freed after rmmod, which may trigger
to a use-after-free (UAF) issue if there is a subsequent access to this
notifier chain.

Fixes the issue by calling ath12k_core_panic_notifier_unregister() in
failure cases.

Call trace:
 notifier_chain_register+0x4c/0x1f0 (P)
 atomic_notifier_chain_register+0x38/0x68
 ath12k_core_init+0x50/0x4e8 [ath12k]
 ath12k_pci_probe+0x5f8/0xc28 [ath12k]
 pci_device_probe+0xbc/0x1a8
 really_probe+0xc8/0x3a0
 __driver_probe_device+0x84/0x1b0
 driver_probe_device+0x44/0x130
 __driver_attach+0xcc/0x208
 bus_for_each_dev+0x84/0x100
 driver_attach+0x2c/0x40
 bus_add_driver+0x130/0x260
 driver_register+0x70/0x138
 __pci_register_driver+0x68/0x80
 ath12k_pci_init+0x30/0x68 [ath12k]
 ath12k_init+0x28/0x78 [ath12k]

Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3

Fixes: 6f245ea ("wifi: ath12k: introduce device group abstraction")
Signed-off-by: Miaoqing Pan <[email protected]>
Reviewed-by: Baochen Qiang <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jeff Johnson <[email protected]>

Author: miaoqing-quic

drivers/net/wireless/ath/ath12k/core.c

@@ -2129,7 +2129,8 @@ int ath12k_core_init(struct ath12k_base *ab)
 	if (!ag) {
 		mutex_unlock(&ath12k_hw_group_mutex);
 		ath12k_warn(ab, "unable to get hw group\n");
-		return -ENODEV;
+		ret = -ENODEV;
+		goto err_unregister_notifier;
 	}
 
 	mutex_unlock(&ath12k_hw_group_mutex);
@@ -2144,17 +2145,20 @@ int ath12k_core_init(struct ath12k_base *ab)
 		if (ret) {
 			mutex_unlock(&ag->mutex);
 			ath12k_warn(ab, "unable to create hw group\n");
-			goto err;
+			goto err_destroy_hw_group;
 		}
 	}
 
 	mutex_unlock(&ag->mutex);
 
 	return 0;
 
-err:
+err_destroy_hw_group:
 	ath12k_core_hw_group_destroy(ab->ag);
 	ath12k_core_hw_group_unassign(ab);
+err_unregister_notifier:
+	ath12k_core_panic_notifier_unregister(ab);
+
 	return ret;
 }