Zekun Shen <bruceshenzk@xxxxxxxxx> writes: > 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. Ok, so you didn't test this on a real device at all. I'll mention that in the commit log and also copy what you wrote above. -- https://patchwork.kernel.org/project/linux-wireless/list/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
