linux-kernel - Re: [PATCH v2 10/14] platform/x86/intel/ifs: Add metadata validation

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Message-ID: <ecf5632b-5fba-ad84-41be-a335b164809f@redhat.com>
Date:   Thu, 10 Nov 2022 22:18:20 +0100
From:   Hans de Goede <hdegoede@...hat.com>
To:     Jithu Joseph <jithu.joseph@...el.com>, markgross@...nel.org
Cc:     tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
        dave.hansen@...ux.intel.com, x86@...nel.org, hpa@...or.com,
        gregkh@...uxfoundation.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, thiago.macieira@...el.com,
        athenas.jimenez.gonzalez@...el.com, sohil.mehta@...el.com
Subject: Re: [PATCH v2 10/14] platform/x86/intel/ifs: Add metadata validation

Hi,

On 11/7/22 23:53, Jithu Joseph wrote:
> The data portion of IFS test image file contains a metadata
> region containing possibly multiple metadata structures in
> addition to test data and hashes.
> 
> Introduce the layout of this meta_data structure and validate
> the sanity of certain fields of the new image before loading.
> 
> Tweak references to IFS test image chunks to reflect the updated
> layout of the test image.
> 
> Reviewed-by: Tony Luck <tony.luck@...el.com>
> Signed-off-by: Jithu Joseph <jithu.joseph@...el.com>

Thanks, patch looks good to me:

Reviewed-by: Hans de Goede <hdegoede@...hat.com>

Regards,

Hans



> ---
>  drivers/platform/x86/intel/ifs/ifs.h  |  2 +
>  drivers/platform/x86/intel/ifs/load.c | 53 +++++++++++++++++++++++++++
>  2 files changed, 55 insertions(+)
> 
> diff --git a/drivers/platform/x86/intel/ifs/ifs.h b/drivers/platform/x86/intel/ifs/ifs.h
> index 3ff1d9aaeaa9..98ca91bdd5ca 100644
> --- a/drivers/platform/x86/intel/ifs/ifs.h
> +++ b/drivers/platform/x86/intel/ifs/ifs.h
> @@ -196,6 +196,7 @@ union ifs_status {
>   * @valid_chunks: number of chunks which could be validated.
>   * @status: it holds simple status pass/fail/untested
>   * @scan_details: opaque scan status code from h/w
> + * @cur_batch: number indicating the currently loaded test file
>   */
>  struct ifs_data {
>  	int	integrity_cap_bit;
> @@ -205,6 +206,7 @@ struct ifs_data {
>  	int	valid_chunks;
>  	int	status;
>  	u64	scan_details;
> +	int	cur_batch;
>  };
>  
>  struct ifs_work {
> diff --git a/drivers/platform/x86/intel/ifs/load.c b/drivers/platform/x86/intel/ifs/load.c
> index 7c0d8602817b..f361fd42a320 100644
> --- a/drivers/platform/x86/intel/ifs/load.c
> +++ b/drivers/platform/x86/intel/ifs/load.c
> @@ -8,7 +8,23 @@
>  
>  #include "ifs.h"
>  
> +struct meta_data {
> +	unsigned int meta_type;		// metadata type
> +	unsigned int meta_size;		// size of this entire struct including hdrs.
> +	unsigned int test_type;		// IFS test type
> +	unsigned int fusa_info;		// Fusa info
> +	unsigned int total_images;	// Total number of images
> +	unsigned int current_image;	// Current Image #
> +	unsigned int total_chunks;	// Total number of chunks in this image
> +	unsigned int starting_chunk;	// Starting chunk number in this image
> +	unsigned int size_per_chunk;	// size of each chunk
> +	unsigned int chunks_per_stride;	// number of chunks in a stride
> +	unsigned int reserved[54];	// Align to 256 bytes for chunk alignment.
> +};
> +
>  #define IFS_HEADER_SIZE	(sizeof(struct microcode_header_intel))
> +#define META_TYPE_IFS	1
> +#define IFS_CHUNK_ALIGNMENT	256
>  static  struct microcode_header_intel *ifs_header_ptr;	/* pointer to the ifs image header */
>  static u64 ifs_hash_ptr;			/* Address of ifs metadata (hash) */
>  static u64 ifs_test_image_ptr;			/* 256B aligned address of test pattern */
> @@ -129,6 +145,40 @@ static void copy_hashes_authenticate_chunks(struct work_struct *work)
>  	complete(&ifs_done);
>  }
>  
> +static int validate_ifs_metadata(struct device *dev)
> +{
> +	struct ifs_data *ifsd = ifs_get_data(dev);
> +	struct meta_data *ifs_meta;
> +	char test_file[64];
> +	int ret = -EINVAL;
> +
> +	snprintf(test_file, sizeof(test_file), "%02x-%02x-%02x-%02x.scan",
> +		 boot_cpu_data.x86, boot_cpu_data.x86_model,
> +		 boot_cpu_data.x86_stepping, ifsd->cur_batch);
> +
> +	ifs_meta = (struct meta_data *)ifs_find_meta_data(ifs_header_ptr, META_TYPE_IFS);
> +	if (!ifs_meta) {
> +		dev_err(dev, "IFS Metadata missing in file %s\n", test_file);
> +		return ret;
> +	}
> +
> +	ifs_test_image_ptr = (u64)ifs_meta + sizeof(struct meta_data);
> +
> +	/* Scan chunk start must be 256 byte aligned */
> +	if (!IS_ALIGNED(ifs_test_image_ptr, IFS_CHUNK_ALIGNMENT)) {
> +		dev_err(dev, "Scan pattern offset is not 256 byte aligned in %s\n", test_file);
> +		return ret;
> +	}
> +
> +	if (ifs_meta->current_image != ifsd->cur_batch) {
> +		dev_warn(dev, "Mismatch between filename %s and batch metadata 0x%02x\n",
> +			 test_file, ifs_meta->current_image);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
>  /*
>   * IFS requires scan chunks authenticated per each socket in the platform.
>   * Once the test chunk is authenticated, it is automatically copied to secured memory
> @@ -145,6 +195,9 @@ static int scan_chunks_sanity_check(struct device *dev)
>  	if (!package_authenticated)
>  		return ret;
>  
> +	ret = validate_ifs_metadata(dev);
> +	if (ret)
> +		return ret;
>  
>  	ifsd->loading_error = false;
>  	ifsd->loaded_version = ifs_header_ptr->rev;