CyberRota Analysis
AI-GeneratedThe vulnerability in the Linux kernel affects the ath12k driver, specifically during the handling of station links in wireless communication. A NULL pointer dereference can occur when operations attempt to access uninitialized link structures, leading to potential system crashes during critical functions such as station removal or key setting. Organizations utilizing affected Linux systems, particularly those relying on ath12k for wireless connectivity, should prioritize this issue to prevent service disruptions and maintain system stability.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: wifi: ath12k: fix NULL deref in change_sta_links for unready link _ieee80211_set_active_links() calls _ieee80211_link_use_channel() for each newly-added link and WARN_ON_ONCE()s if it fails. The call uses assign_on_failure=true, which allows mac80211 to continue despite driver failures, but when a mac80211-level channel validation fails (e.g., combinations check, DFS, or no available radio), drv_assign_vif_chanctx() is never reached. Since ath12k_mac_vdev_create() is only called from that path, arvif->is_created remains false and arvif->ar remains NULL for the failed link. The subsequent drv_change_sta_links() call reaches ath12k_mac_op_change_sta_links(), which allocates an arsta and sets ahsta->links_map |= BIT(link_id) for the broken link before checking whether the link is ready. When the vdev was never created, only station_add() is skipped, but the link remains in links_map. Any subsequent operation iterating links_map and dereferencing arvif->ar without a NULL check will crash. Two observed examples are NULL deref in ath12k_mac_ml_station_remove() on disconnect and in ath12k_mac_op_set_key() when wpa_supplicant installs PTK keys. BUG: Unable to handle kernel NULL pointer dereference at 0x00000000 pc : ath12k_mac_station_post_remove+0x40/0xe8 [ath12k] Call trace: ath12k_mac_station_post_remove+0x40/0xe8 [ath12k] ath12k_mac_op_sta_state+0xb60/0x1720 [ath12k] drv_sta_state+0x100/0xbd8 [mac80211] __sta_info_destroy_part2+0x148/0x178 [mac80211] ieee80211_set_disassoc+0x500/0x678 [mac80211] BUG: Unable to handle kernel NULL pointer dereference at 0x00000000 pc : ath12k_mac_op_set_key+0x1f8/0x2c0 [ath12k] Call trace: ath12k_mac_op_set_key+0x1f8/0x2c0 [ath12k] drv_set_key+0x70/0x100 [mac80211] ieee80211_key_enable_hw_accel+0x78/0x260 [mac80211] ieee80211_add_key+0x16c/0x2ac [mac80211] nl80211_new_key+0x138/0x280 [cfg80211] Fix this by checking arvif->is_created before calling ath12k_mac_alloc_assign_link_sta(). This prevents the broken link from entering links_map, so all subsequent operations iterating the bitmap are protected. The reliability of arvif->is_created across all error paths is ensured by the preceding patch. Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.1.c5-00302-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1.115823.3