From 30382dd1cf3a141bfaa568ee183c1892090fa79a Mon Sep 17 00:00:00 2001 From: Kalle Valo Date: Fri, 19 Apr 2019 10:28:56 +0300 Subject: [PATCH] ath10k: fix use-after-free on SDIO data frames With SDIO there's a use after free after a data frame is transfered, call stack below. This happens because ath10k_htt_tx_hl() directly transmits the skb provided by mac80211 using ath10k_htc_send(), all other HTT functions use separate skb created with ath10k_htc_alloc_skb() to transmit the HTC packet. After the packet is transmitted mac80211 frees the skb in ieee80211_tx_status() but HTT layer expects that it still owns the skb, and frees it in ath10k_htt_htc_tx_complete(). To fix this take a reference of skb before sending it to HTC layer to make sure we still own the skb. Tested on QCA6174 SDIO with firmware WLAN.RMH.4.4.1-00007-QCARMSWP-1. ath10k_htt_tx_hl() is only used by SDIO and USB so other busses (PCI, AHB and SNOC) should be unaffected. call stack of use-after-free: dump_backtrace+0x0/0x2d8 show_stack+0x20/0x2c __dump_stack+0x20/0x28 dump_stack+0xc8/0xec print_address_description+0x74/0x240 kasan_report+0x258/0x274 __asan_report_load4_noabort+0x20/0x28 skb_pull+0xbc/0x114 ath10k_htc_notify_tx_completion+0x190/0x2a4 [ath10k_core] ath10k_sdio_write_async_work+0x1e4/0x2c4 [ath10k_sdio] process_one_work+0x3d8/0x8b0 worker_thread+0x518/0x7e0 kthread+0x260/0x278 ret_from_fork+0x10/0x18 Allocated by one task: kasan_kmalloc+0xa0/0x13c kasan_slab_alloc+0x14/0x1c kmem_cache_alloc+0x144/0x208 __alloc_skb+0xec/0x394 alloc_skb_with_frags+0x8c/0x374 sock_alloc_send_pskb+0x520/0x5d4 sock_alloc_send_skb+0x40/0x50 __ip_append_data+0xf5c/0x1858 ip_make_skb+0x194/0x1d4 udp_sendmsg+0xf24/0x1ab8 inet_sendmsg+0x1b0/0x2e0 sock_sendmsg+0x88/0xa0 __sys_sendto+0x220/0x3a8 __arm64_sys_sendto+0x78/0x80 el0_svc_common+0x120/0x1e0 el0_svc_compat_handler+0x64/0x80 el0_svc_compat+0x8/0x18 Freed by another task: __kasan_slab_free+0x120/0x1d4 kasan_slab_free+0x10/0x1c kmem_cache_free+0x74/0x504 kfree_skbmem+0x88/0xc8 __kfree_skb+0x24/0x2c consume_skb+0x114/0x18c __ieee80211_tx_status+0xb7c/0xf60 [mac80211] ieee80211_tx_status+0x224/0x270 [mac80211] ath10k_txrx_tx_unref+0x564/0x950 [ath10k_core] ath10k_htt_t2h_msg_handler+0x178c/0x2a38 [ath10k_core] ath10k_htt_htc_t2h_msg_handler+0x20/0x30 [ath10k_core] ath10k_sdio_irq_handler+0xcc0/0x1654 [ath10k_sdio] process_sdio_pending_irqs+0xec/0x358 sdio_run_irqs+0x68/0xe4 sdio_irq_work+0x1c/0x28 process_one_work+0x3d8/0x8b0 worker_thread+0x518/0x7e0 kthread+0x260/0x278 ret_from_fork+0x10/0x18 Reported-by: Wen Gong Tested-by: Wen Gong Signed-off-by: Kalle Valo --- drivers/net/wireless/ath/ath10k/htt_tx.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/net/wireless/ath/ath10k/htt_tx.c b/drivers/net/wireless/ath/ath10k/htt_tx.c index 88f880b601d8..78f07b7a3b21 100644 --- a/drivers/net/wireless/ath/ath10k/htt_tx.c +++ b/drivers/net/wireless/ath/ath10k/htt_tx.c @@ -1302,6 +1302,13 @@ static int ath10k_htt_tx_hl(struct ath10k_htt *htt, enum ath10k_hw_txrx_mode txm msdu_id = res; } + /* As msdu is freed by mac80211 (in ieee80211_tx_status()) and by + * ath10k (in ath10k_htt_htc_tx_complete()) we have to increase + * reference by one to avoid a use-after-free case and a double + * free. + */ + skb_get(msdu); + skb_push(msdu, sizeof(*cmd_hdr)); skb_push(msdu, sizeof(*tx_desc)); cmd_hdr = (struct htt_cmd_hdr *)msdu->data; -- 2.30.2