rsi: Fix use-after-free in rsi_rx_done_handler()

When freeing rx_cb->rx_skb, the pointer is not set to NULL,
a later rsi_rx_done_handler call will try to read the freed
address.
This bug will very likley lead to double free, although
detected early as use-after-free bug.

The bug is triggerable with a compromised/malfunctional usb
device. After applying the patch, the same input no longer
triggers the use-after-free.

Attached is the kasan report from fuzzing.

BUG: KASAN: use-after-free in rsi_rx_done_handler+0x354/0x430 [rsi_usb]
Read of size 4 at addr ffff8880188e5930 by task modprobe/231
Call Trace:
 <IRQ>
 dump_stack+0x76/0xa0
 print_address_description.constprop.0+0x16/0x200
 ? rsi_rx_done_handler+0x354/0x430 [rsi_usb]
 ? rsi_rx_done_handler+0x354/0x430 [rsi_usb]
 __kasan_report.cold+0x37/0x7c
 ? dma_direct_unmap_page+0x90/0x110
 ? rsi_rx_done_handler+0x354/0x430 [rsi_usb]
 kasan_report+0xe/0x20
 rsi_rx_done_handler+0x354/0x430 [rsi_usb]
 __usb_hcd_giveback_urb+0x1e4/0x380
 usb_giveback_urb_bh+0x241/0x4f0
 ? __usb_hcd_giveback_urb+0x380/0x380
 ? apic_timer_interrupt+0xa/0x20
 tasklet_action_common.isra.0+0x135/0x330
 __do_softirq+0x18c/0x634
 ? handle_irq_event+0xcd/0x157
 ? handle_edge_irq+0x1eb/0x7b0
 irq_exit+0x114/0x140
 do_IRQ+0x91/0x1e0
 common_interrupt+0xf/0xf
 </IRQ>

Reported-by: Brendan Dolan-Gavitt <brendandg@nyu.edu>
Signed-off-by: Zekun Shen <bruceshenzk@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/YXxQL/vIiYcZUu/j@10-18-43-117.dynapool.wireless.nyu.edu
This commit is contained in:
Zekun Shen 2021-10-29 15:49:03 -04:00 committed by Kalle Valo
parent 7a6cfe28ae
commit b07e3c6ebc
1 changed files with 7 additions and 1 deletions

View File

@ -269,8 +269,12 @@ static void rsi_rx_done_handler(struct urb *urb)
struct rsi_91x_usbdev *dev = (struct rsi_91x_usbdev *)rx_cb->data;
int status = -EINVAL;
if (!rx_cb->rx_skb)
return;
if (urb->status) {
dev_kfree_skb(rx_cb->rx_skb);
rx_cb->rx_skb = NULL;
return;
}
@ -294,8 +298,10 @@ out:
if (rsi_rx_urb_submit(dev->priv, rx_cb->ep_num, GFP_ATOMIC))
rsi_dbg(ERR_ZONE, "%s: Failed in urb submission", __func__);
if (status)
if (status) {
dev_kfree_skb(rx_cb->rx_skb);
rx_cb->rx_skb = NULL;
}
}
static void rsi_rx_urb_kill(struct rsi_hw *adapter, u8 ep_num)