From: huhai <15815827059@163.com>
To: "Sudeep Holla" <sudeep.holla@arm.com>
Cc: cristian.marussi@arm.com, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, luriwen@kylinos.cn,
liuyun01@kylinos.cn, huhai <huhai@kylinos.cn>,
k2ci <kernel-bot@kylinos.cn>
Subject: Re:Re: [PATCH] firmware: arm_scpi: Fix error handle when scpi probe failed
Date: Fri, 1 Jul 2022 18:04:53 +0800 (CST) [thread overview]
Message-ID: <1752bac0.5d05.181b93873da.Coremail.15815827059@163.com> (raw)
In-Reply-To: <20220701094212.snsnbdjc7hia5oti@bogus>
>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);
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next prev parent reply other threads:[~2022-07-01 10:06 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-01 6:16 [PATCH] firmware: arm_scpi: Fix error handle when scpi probe failed huhai
2022-07-01 9:42 ` Sudeep Holla
2022-07-01 9:52 ` huhai
2022-07-01 10:00 ` Sudeep Holla
2022-07-01 10:04 ` huhai [this message]
2022-07-01 12:34 ` Sudeep Holla
2022-07-01 14:38 ` huhai
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