From: Zekun Shen bruceshenzk@gmail.com
[ Upstream commit bad60b8d1a7194df38fd7fe4b22f3f4dcf775099 ]
The idx in __ath10k_htt_rx_ring_fill_n function lives in consistent dma region writable by the device. Malfunctional or malicious device could manipulate such idx to have a OOB write. Either by htt->rx_ring.netbufs_ring[idx] = skb; or by ath10k_htt_set_paddrs_ring(htt, paddr, idx);
The idx can also be negative as it's signed, giving a large memory space to write to.
It's possibly exploitable by corruptting a legit pointer with a skb pointer. And then fill skb with payload as rougue object.
Part of the log here. Sometimes it appears as UAF when writing to a freed memory by chance.
[ 15.594376] BUG: unable to handle page fault for address: ffff887f5c1804f0 [ 15.595483] #PF: supervisor write access in kernel mode [ 15.596250] #PF: error_code(0x0002) - not-present page [ 15.597013] PGD 0 P4D 0 [ 15.597395] Oops: 0002 [#1] SMP KASAN PTI [ 15.597967] CPU: 0 PID: 82 Comm: kworker/u2:2 Not tainted 5.6.0 #69 [ 15.598843] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014 [ 15.600438] Workqueue: ath10k_wq ath10k_core_register_work [ath10k_core] [ 15.601389] RIP: 0010:__ath10k_htt_rx_ring_fill_n (linux/drivers/net/wireless/ath/ath10k/htt_rx.c:173) ath10k_core
Signed-off-by: Zekun Shen bruceshenzk@gmail.com Signed-off-by: Kalle Valo kvalo@codeaurora.org Link: https://lore.kernel.org/r/20200623221105.3486-1-bruceshenzk@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/wireless/ath/ath10k/htt_rx.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/drivers/net/wireless/ath/ath10k/htt_rx.c b/drivers/net/wireless/ath/ath10k/htt_rx.c index a3c2180475971..fce2064ebc469 100644 --- a/drivers/net/wireless/ath/ath10k/htt_rx.c +++ b/drivers/net/wireless/ath/ath10k/htt_rx.c @@ -100,6 +100,14 @@ static int __ath10k_htt_rx_ring_fill_n(struct ath10k_htt *htt, int num) BUILD_BUG_ON(HTT_RX_RING_FILL_LEVEL >= HTT_RX_RING_SIZE / 2);
idx = __le32_to_cpu(*htt->rx_ring.alloc_idx.vaddr); + + if (idx < 0 || idx >= htt->rx_ring.size) { + ath10k_err(htt->ar, "rx ring index is not valid, firmware malfunctioning?\n"); + idx &= htt->rx_ring.size_mask; + ret = -ENOMEM; + goto fail; + } + while (num > 0) { skb = dev_alloc_skb(HTT_RX_BUF_SIZE + HTT_RX_DESC_ALIGN); if (!skb) {