Messages in this thread | | | Date | Fri, 1 Jul 2022 18:04:53 +0800 (CST) | From | huhai <> | Subject | Re:Re: [PATCH] firmware: arm_scpi: Fix error handle when scpi probe failed |
| |
>On Fri, Jul 01, 2022 at 02:16:06PM +0800, huhai wrote: >> From: huhai <huhai@kylinos.cn> >> >> When scpi probe fails, do not just return the error code, but also reset >> the global scpi_info to NULL, otherwise scpi_hwmon_probe() may get a UAF >> and cause panic: >> > >Interesting, which platform are you using this on ? SCPI is deprecated for >a while, please switch to SCMI which is well maintained both in terms of >specification and support in the kernel. I also assume this is 64-bit >platform, so I don't want you to get stuck in future because of lack
>of some feature in SCPI. Please see if you can migrate to SCMI.
Thinks for sharing this massage, and my platform is FT2000+(ARM64).
> >> scpi_protocol FTSC0001:00: incorrect or no SCP firmware found >> ... ... >> Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 >> Mem abort info: >> > >[...] >
>I think we don't see to make it complex. Can't it be as simple as:
scpi_info is a global variable, we must set it to NULL when it is not valid
>Regards, >Sudeep > >-->8 > >diff --git i/drivers/firmware/arm_scpi.c w/drivers/firmware/arm_scpi.c >index ddf0b9ff9e15..6fa1a5b193b8 100644 >--- i/drivers/firmware/arm_scpi.c >+++ w/drivers/firmware/arm_scpi.c >@@ -799,7 +799,7 @@ static struct scpi_ops scpi_ops = { > > struct scpi_ops *get_scpi_ops(void) > { >- return scpi_info ? scpi_info->scpi_ops : NULL;
>+ return scpi_info && scpi_info->scpi_ops ? scpi_info->scpi_ops : NULL;
I don't think it work well, because it's a UAF and scpi_info->scpi_ops could be any value set by others.
> } > EXPORT_SYMBOL_GPL(get_scpi_ops);
| |