Re: [PATCH v3] firmware_loader: Add debug message with checksum for FW file

[Russ Weight]

On 3/2/23 10:46, Amadeusz Sławiński wrote:
> Enable dynamic-debug logging of firmware filenames and SHA256 checksums
> to clearly identify the firmware files that are loaded by the system.
>
> Example output:
> [   34.944619] firmware_class:_request_firmware: i915 0000:00:02.0: Loaded FW: i915/kbl_dmc_ver1_04.bin, sha256: 2cde41c3e5ad181423bcc3e98ff9c49f743c88f18646af4d0b3c3a9664b831a1
> [   48.155884] firmware_class:_request_firmware: snd_soc_avs 0000:00:1f.3: Loaded FW: intel/avs/cnl/dsp_basefw.bin, sha256: 43f6ac1b066e9bd0423d914960fbbdccb391af27d2b1da1085eee3ea8df0f357
> [   49.579540] firmware_class:_request_firmware: snd_soc_avs 0000:00:1f.3: Loaded FW: intel/avs/rt274-tplg.bin, sha256: 4b3580da96dc3d2c443ba20c6728d8b665fceb3ed57223c3a57582bbad8e2413
> [   49.798196] firmware_class:_request_firmware: snd_soc_avs 0000:00:1f.3: Loaded FW: intel/avs/hda-8086280c-tplg.bin, sha256: 5653172579b2be1b51fd69f5cf46e2bac8d63f2a1327924311c13b2f1fe6e601
> [   49.859627] firmware_class:_request_firmware: snd_soc_avs 0000:00:1f.3: Loaded FW: intel/avs/dmic-tplg.bin, sha256: 00fb7fbdb74683333400d7e46925dae60db448b88638efcca0b30215db9df63f
>
> Reviewed-by: Cezary Rojewski <cezary.rojewski@xxxxxxxxx>
> Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@xxxxxxxxxxxxxxx>
> ---
>
> Changes in v3:
>  * add DYNAMIC_DEBUG and FW_LOADER as dependencies before option can be
> enabled (kernel test robot)
>
> Changes in v2:
>  * allocate buffers (Greg)
>  * introduce CONFIG_ option to allow for CONFIG_CRYPTO and CONFIG_CRYPTO_SHA256
> dependencies without introducing circular dependency (Greg)
>  * add new line between includes and function name (Cezary)
>
> ---
>  drivers/base/firmware_loader/Kconfig | 12 +++++++
>  drivers/base/firmware_loader/main.c  | 48 +++++++++++++++++++++++++++-
>  2 files changed, 59 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/base/firmware_loader/Kconfig b/drivers/base/firmware_loader/Kconfig
> index 5166b323a0f8..a2f8f75e0718 100644
> --- a/drivers/base/firmware_loader/Kconfig
> +++ b/drivers/base/firmware_loader/Kconfig
> @@ -3,6 +3,7 @@ menu "Firmware loader"
>  
>  config FW_LOADER
>  	tristate "Firmware loading facility" if EXPERT
> +	select FW_LOADER_DEBUG if DYNAMIC_DEBUG
>  	default y
>  	help
>  	  This enables the firmware loading facility in the kernel. The kernel
> @@ -24,6 +25,17 @@ config FW_LOADER
>  	  You also want to be sure to enable this built-in if you are going to
>  	  enable built-in firmware (CONFIG_EXTRA_FIRMWARE).
>  
> +config FW_LOADER_DEBUG
> +	bool "Additional debug logs"

This is the prompt that shows up when I do "make menuconfig". How about
something more descriptive?

"Log filenames and checksums for loaded firmware"

> +	depends on DYNAMIC_DEBUG
> +	depends on FW_LOADER
> +	depends on CRYPTO
> +	depends on CRYPTO_SHA256
> +	default FW_LOADER
> +	help
> +	  Select this if additional information about loaded firmware file in
> +	  form of sha256sum should be dumped.

How about:

"Select this option to log firmware filenames and SHA256 checksums to the
kernel log for each firmware file that is loaded."

Thanks,
- Russ

> +
>  if FW_LOADER
>  
>  config FW_LOADER_PAGED_BUF
> diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
> index 017c4cdb219e..b2c292ca95e8 100644
> --- a/drivers/base/firmware_loader/main.c
> +++ b/drivers/base/firmware_loader/main.c
> @@ -791,6 +791,50 @@ static void fw_abort_batch_reqs(struct firmware *fw)
>  	mutex_unlock(&fw_lock);
>  }
>  
> +#if defined(CONFIG_FW_LOADER_DEBUG)
> +#include <crypto/hash.h>
> +#include <crypto/sha2.h>
> +
> +static void fw_log_firmware_info(const struct firmware *fw, const char *name, struct device *device)
> +{
> +	struct shash_desc *shash;
> +	struct crypto_shash *alg;
> +	u8 *sha256buf;
> +	char *outbuf;
> +
> +	alg = crypto_alloc_shash("sha256", 0, 0);
> +	if (!alg)
> +		return;
> +
> +	sha256buf = kmalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);
> +	outbuf = kmalloc(SHA256_BLOCK_SIZE + 1, GFP_KERNEL);
> +	shash = kmalloc(sizeof(*shash) + crypto_shash_descsize(alg), GFP_KERNEL);
> +	if (!sha256buf || !outbuf || !shash)
> +		goto out_free;
> +
> +	shash->tfm = alg;
> +
> +	if (crypto_shash_digest(shash, fw->data, fw->size, sha256buf) < 0)
> +		goto out_shash;
> +
> +	for (int i = 0; i < SHA256_DIGEST_SIZE; i++)
> +		sprintf(&outbuf[i * 2], "%02x", sha256buf[i]);
> +	outbuf[SHA256_BLOCK_SIZE] = 0;
> +	dev_dbg(device, "Loaded FW: %s, sha256: %s\n", name, outbuf);
> +
> +out_shash:
> +	crypto_free_shash(alg);
> +out_free:
> +	kfree(shash);
> +	kfree(outbuf);
> +	kfree(sha256buf);
> +}
> +#else
> +static void fw_log_firmware_info(const struct firmware *fw, const char *name,
> +				 struct device *device)
> +{}
> +#endif
> +
>  /* called from request_firmware() and request_firmware_work_func() */
>  static int
>  _request_firmware(const struct firmware **firmware_p, const char *name,
> @@ -861,11 +905,13 @@ _request_firmware(const struct firmware **firmware_p, const char *name,
>  	revert_creds(old_cred);
>  	put_cred(kern_cred);
>  
> - out:
> +out:
>  	if (ret < 0) {
>  		fw_abort_batch_reqs(fw);
>  		release_firmware(fw);
>  		fw = NULL;
> +	} else {
> +		fw_log_firmware_info(fw, name, device);
>  	}
>  
>  	*firmware_p = fw;