CVE-2022-49238

In the Linux kernel, the following vulnerability has been resolved:

ath11k: free peer for station when disconnect from AP for QCA6390/WCN6855

Commit b4a0f54156ac (ath11k: move peer delete after vdev stop of station for QCA6390 and WCN6855) is to fix firmware crash by changing the WMI command sequence, but actually skip all the peer delete operation, then it lead commit 58595c9874c6 (ath11k: Fixing dangling pointer issue upon peer delete failure) not take effect, and then happened a use-after-free warning from KASAN. because the peer->sta is not set to NULL and then used later.

Change to only skip the WMI_PEER_DELETE_CMDID for QCA6390/WCN6855.

log of user-after-free:

[ 534.888665] BUG: KASAN: use-after-free in ath11k_dp_rx_update_peer_stats+0x912/0xc10 [ath11k] [ 534.888696] Read of size 8 at addr ffff8881396bb1b8 by task rtcwake/2860

[ 534.888705] CPU: 4 PID: 2860 Comm: rtcwake Kdump: loaded Tainted: G W 5.15.0-wt-ath+ #523 [ 534.888712] Hardware name: Intel(R) Client Systems NUC8i7HVK/NUC8i7HVB, BIOS HNKBLi70.86A.0067.2021.0528.1339 05/28/2021 [ 534.888716] Call Trace: [ 534.888720] [ 534.888726] dump_stack_lvl+0x57/0x7d [ 534.888736] print_address_description.constprop.0+0x1f/0x170 [ 534.888745] ? ath11k_dp_rx_update_peer_stats+0x912/0xc10 [ath11k] [ 534.888771] kasan_report.cold+0x83/0xdf [ 534.888783] ? ath11k_dp_rx_update_peer_stats+0x912/0xc10 [ath11k] [ 534.888810] ath11k_dp_rx_update_peer_stats+0x912/0xc10 [ath11k] [ 534.888840] ath11k_dp_rx_process_mon_status+0x529/0xa70 [ath11k] [ 534.888874] ? ath11k_dp_rx_mon_status_bufs_replenish+0x3f0/0x3f0 [ath11k] [ 534.888897] ? check_prev_add+0x20f0/0x20f0 [ 534.888922] ? __lock_acquire+0xb72/0x1870 [ 534.888937] ? find_held_lock+0x33/0x110 [ 534.888954] ath11k_dp_rx_process_mon_rings+0x297/0x520 [ath11k] [ 534.888981] ? rcu_read_unlock+0x40/0x40 [ 534.888990] ? ath11k_dp_rx_pdev_alloc+0xd90/0xd90 [ath11k] [ 534.889026] ath11k_dp_service_mon_ring+0x67/0xe0 [ath11k] [ 534.889053] ? ath11k_dp_rx_process_mon_rings+0x520/0x520 [ath11k] [ 534.889075] call_timer_fn+0x167/0x4a0 [ 534.889084] ? add_timer_on+0x3b0/0x3b0 [ 534.889103] ? lockdep_hardirqs_on_prepare.part.0+0x18c/0x370 [ 534.889117] __run_timers.part.0+0x539/0x8b0 [ 534.889123] ? ath11k_dp_rx_process_mon_rings+0x520/0x520 [ath11k] [ 534.889157] ? call_timer_fn+0x4a0/0x4a0 [ 534.889164] ? mark_lock_irq+0x1c30/0x1c30 [ 534.889173] ? clockevents_program_event+0xdd/0x280 [ 534.889189] ? mark_held_locks+0xa5/0xe0 [ 534.889203] run_timer_softirq+0x97/0x180 [ 534.889213] __do_softirq+0x276/0x86a [ 534.889230] __irq_exit_rcu+0x11c/0x180 [ 534.889238] irq_exit_rcu+0x5/0x20 [ 534.889244] sysvec_apic_timer_interrupt+0x8e/0xc0 [ 534.889251] [ 534.889254] [ 534.889259] asm_sysvec_apic_timer_interrupt+0x12/0x20 [ 534.889265] RIP: 0010:_raw_spin_unlock_irqrestore+0x38/0x70 [ 534.889271] Code: 74 24 10 e8 ea c2 bf fd 48 89 ef e8 12 53 c0 fd 81 e3 00 02 00 00 75 25 9c 58 f6 c4 02 75 2d 48 85 db 74 01 fb bf 01 00 00 00 13 a7 b5 fd 65 8b 05 cc d9 9c 5e 85 c0 74 0a 5b 5d c3 e8 a0 ee [ 534.889276] RSP: 0018:ffffc90002e5f880 EFLAGS: 00000206 [ 534.889284] RAX: 0000000000000006 RBX: 0000000000000200 RCX: ffffffff9f256f10 [ 534.889289] RDX: 0000000000000000 RSI: ffffffffa1c6e420 RDI: 0000000000000001 [ 534.889293] RBP: ffff8881095e6200 R08: 0000000000000001 R09: ffffffffa40d2b8f [ 534.889298] R10: fffffbfff481a571 R11: 0000000000000001 R12: ffff8881095e6e68 [ 534.889302] R13: ffffc90002e5f908 R14: 0000000000000246 R15: 0000000000000000 [ 534.889316] ? mark_lock+0xd0/0x14a0 [ 534.889332] klist_next+0x1d4/0x450 [ 534.889340] ? dpm_wait_for_subordinate+0x2d0/0x2d0 [ 534.889350] device_for_each_child+0xa8/0x140 [ 534.889360] ? device_remove_class_symlinks+0x1b0/0x1b0 [ 534.889370] ? __lock_release+0x4bd/0x9f0 [ 534.889378] ? dpm_suspend+0x26b/0x3f0 [ 534.889390] dpm_wait_for_subordinate+ —truncated—

Weakness

Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.

Affected Software

Extended Description

The use of previously-freed memory can have any number of adverse consequences, ranging from the corruption of valid data to the execution of arbitrary code, depending on the instantiation and timing of the flaw. The simplest way data corruption may occur involves the system’s reuse of the freed memory. Use-after-free errors have two common and sometimes overlapping causes:

In this scenario, the memory in question is allocated to another pointer validly at some point after it has been freed. The original pointer to the freed memory is used again and points to somewhere within the new allocation. As the data is changed, it corrupts the validly used memory; this induces undefined behavior in the process. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.

Potential Mitigations

References

• https://git.kernel.org/stable/c/212ad7cb7d7592669c067125949e0a8e31ce6a0b
• https://git.kernel.org/stable/c/400705c50bbf184794c885d1efad7fe9ccf1471a