linux-kernel - Re: [PATCH 06/10] platform/x86/intel/ifs: Validate image size

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Date:   Fri, 15 Sep 2023 11:06:30 -0700
From:   "Joseph, Jithu" <jithu.joseph@...el.com>
To:     Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
CC:     <hdegoede@...hat.com>, <markgross@...nel.org>,
        <tglx@...utronix.de>, <mingo@...hat.com>, <bp@...en8.de>,
        <dave.hansen@...ux.intel.com>, <x86@...nel.org>, <hpa@...or.com>,
        <rostedt@...dmis.org>, <ashok.raj@...el.com>,
        <tony.luck@...el.com>, <linux-kernel@...r.kernel.org>,
        <platform-driver-x86@...r.kernel.org>, <patches@...ts.linux.dev>,
        <ravi.v.shankar@...el.com>, <pengfei.xu@...el.com>
Subject: Re: [PATCH 06/10] platform/x86/intel/ifs: Validate image size



On 9/15/2023 9:57 AM, Ilpo Järvinen wrote:
> On Wed, 13 Sep 2023, Jithu Joseph wrote:
> 
>> Perform additional validation prior to loading IFS image.
>>
>> Error out if the size of the file being loaded doesn't
>> match the size specified in the header.
> 
> Please fix these short lines in all your patches.

Will do

>  
>> Signed-off-by: Jithu Joseph <jithu.joseph@...el.com>
>> Reviewed-by: Tony Luck <tony.luck@...el.com>
>> Tested-by: Pengfei Xu <pengfei.xu@...el.com>
>> ---
>>  drivers/platform/x86/intel/ifs/load.c | 8 ++++++++
>>  1 file changed, 8 insertions(+)
>>
>> diff --git a/drivers/platform/x86/intel/ifs/load.c b/drivers/platform/x86/intel/ifs/load.c
>> index e8fb03dd8bcf..778a3b89a24d 100644
>> --- a/drivers/platform/x86/intel/ifs/load.c
>> +++ b/drivers/platform/x86/intel/ifs/load.c
>> @@ -376,6 +376,7 @@ int ifs_load_firmware(struct device *dev)
>>  {
>>  	const struct ifs_test_caps *test = ifs_get_test_caps(dev);
>>  	struct ifs_data *ifsd = ifs_get_data(dev);
>> +	unsigned int expected_size;
>>  	const struct firmware *fw;
>>  	char scan_path[64];
>>  	int ret = -EINVAL;
>> @@ -390,6 +391,13 @@ int ifs_load_firmware(struct device *dev)
>>  		goto done;
>>  	}
>>  
>> +	expected_size = ((struct microcode_header_intel *)fw->data)->totalsize;
>> +	if (fw->size != expected_size) {
>> +		dev_err(dev, "File size mismatch (expected %d, actual %ld). Corrupted IFS image.\n",
>> +			expected_size, fw->size);
>> +		return -EBADFD;
>> +	}
>> +
>>  	ret = image_sanity_check(dev, (struct microcode_header_intel *)fw->data);
> 
> It looks than a bit odd to add the check here and not into a function 
> called image_sanity_check()?!?

image_sanity_check() validates the contents of the image, whereas the new check
in some sense validates request_firmware_direct() results. Hence it was placed
outside of content validation / closer to request_firmware_direct()


Jithu