On Fri, Oct 29, 2021 at 06:53:30AM +0300, Kalle Valo wrote: > Zekun Shen <bruceshenzk@xxxxxxxxx> writes: > > > Unexpected WDCMSG_TARGET_START replay can lead to null-ptr-deref > > when ar->tx_cmd->odata is NULL. The patch adds a null check to > > prevent such case. > > > > KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] > > ar5523_cmd+0x46a/0x581 [ar5523] > > ar5523_probe.cold+0x1b7/0x18da [ar5523] > > ? ar5523_cmd_rx_cb+0x7a0/0x7a0 [ar5523] > > ? __pm_runtime_set_status+0x54a/0x8f0 > > ? _raw_spin_trylock_bh+0x120/0x120 > > ? pm_runtime_barrier+0x220/0x220 > > ? __pm_runtime_resume+0xb1/0xf0 > > usb_probe_interface+0x25b/0x710 > > really_probe+0x209/0x5d0 > > driver_probe_device+0xc6/0x1b0 > > device_driver_attach+0xe2/0x120 > > > > Signed-off-by: Zekun Shen <bruceshenzk@xxxxxxxxx> > > How did you test this? I found the bug using a custome USBFuzz port. It's a research work to fuzz USB stack/drivers. I modified it to fuzz ath9k driver only, providing hand-crafted usb descriptors to QEMU. After fixing the code (fourth byte in usb packet) to WDCMSG_TARGET_START, I got the null-ptr-deref bug. I believe the bug is triggerable whenever cmd->odata is NULL. After patching, I tested with the same input and no longer see the KASAN report. > > -- > https://patchwork.kernel.org/project/linux-wireless/list/ > > https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
