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Message-ID: <bfd6e869-dccf-bd00-d8fc-da2c33715c8d@sholland.org>
Date:   Sun, 12 Feb 2023 15:11:30 -0600
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Subject: Re: [PATCH 1/2] rtc: sun6i: Prevent an out-of-bounds read
Content-Language: en-US
To:     Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc:     Alessandro Zummo <a.zummo@towertech.it>,
        Chen-Yu Tsai <wens@csie.org>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        linux-arm-kernel@lists.infradead.org, linux-rtc@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-sunxi@lists.linux.dev
References: <20221229184011.62925-1-samuel@sholland.org>
 <Y+V4iMaZ7WzCWzSc@mail.local>
From:   Samuel Holland <samuel@sholland.org>
In-Reply-To: <Y+V4iMaZ7WzCWzSc@mail.local>
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On 2/9/23 16:49, Alexandre Belloni wrote:
> Hello,
> 
> What should I do with this series, I'm not sure you came to an
> agreement.
> Also, 2/2 doesn't apply so you'd have to rebase.

I will send v2 after the merge window, possibly including only patch 2.

Regards,
Samuel

> On 29/12/2022 12:40:10-0600, Samuel Holland wrote:
>> If there is more than one parent clock in the devicetree, the
>> driver sets .num_parents to a larger value than the number of array
>> elements, which causes an out-of-bounds read in the clock framework.
>>
>> Fix this by coercing the parent count to a Boolean value, like the
>> driver expects.
>>
>> Fixes: 3855c2c3e546 ("rtc: sun6i: Expose the 32kHz oscillator")
>> Signed-off-by: Samuel Holland <samuel@sholland.org>
>> ---
>>
>>  drivers/rtc/rtc-sun6i.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/rtc/rtc-sun6i.c b/drivers/rtc/rtc-sun6i.c
>> index ed5516089e9a..a22358a44e32 100644
>> --- a/drivers/rtc/rtc-sun6i.c
>> +++ b/drivers/rtc/rtc-sun6i.c
>> @@ -294,7 +294,7 @@ static void __init sun6i_rtc_clk_init(struct device_node *node,
>>  
>>  	init.parent_names = parents;
>>  	/* ... number of clock parents will be 1. */
>> -	init.num_parents = of_clk_get_parent_count(node) + 1;
>> +	init.num_parents = !!of_clk_get_parent_count(node) + 1;
>>  	of_property_read_string_index(node, "clock-output-names", 0,
>>  				      &init.name);
>>  
>> -- 
>> 2.37.4
>>
>