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

[Amadeusz Sławiński]

On 2/24/2023 1:54 PM, Amadeusz Sławiński wrote:
> On 2/24/2023 1:46 PM, Greg Kroah-Hartman wrote:
> > On Fri, Feb 24, 2023 at 09:19:18PM +0100, 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: Russ Weight <russell.h.weight@xxxxxxxxx>
> > > Reviewed-by: Cezary Rojewski <cezary.rojewski@xxxxxxxxx>
> > > Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@xxxxxxxxxxxxxxx>
> > > ---
> > >   drivers/base/firmware_loader/main.c | 45 ++++++++++++++++++++++++++++-
> > >   1 file changed, 44 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/base/firmware_loader/main.c 
> > > b/drivers/base/firmware_loader/main.c
> > > index 017c4cdb219e..a6e1fb10763d 100644
> > > --- a/drivers/base/firmware_loader/main.c
> > > +++ b/drivers/base/firmware_loader/main.c
> > > @@ -791,6 +791,47 @@ static void fw_abort_batch_reqs(struct firmware 
> > > *fw)
> > >       mutex_unlock(&fw_lock);
> > >   }
> > > +#if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)
> > > +#include <crypto/hash.h>
> > > +#include <crypto/sha2.h>
> > > +#define SHA256_STRING_SIZE (SHA256_DIGEST_SIZE * 2)
> > > +static void fw_log_firmware_info(const struct firmware *fw, const 
> > > char *name, struct device *device)
> > > +{
> > > +    char outbuf[SHA256_STRING_SIZE + 1];
> > > +    u8 sha256buf[SHA256_DIGEST_SIZE];
> >
> > Nit, these are big, are you _SURE_ you can put them on the stack ok?
> > Why not dynamically allocate them?
>
> Well, those arrays are not that big? First one is 65 bytes and other one 
> 32. Although now that I looked again at the header, there is 
> SHA256_BLOCK_SIZE define for string size, so I will change 
> SHA256_STRING_SIZE to that instead.
>
> > > +    struct shash_desc *shash;
> > > +    struct crypto_shash *alg;
> > > +
> > > +    alg = crypto_alloc_shash("sha256", 0, 0);
> >
> > Do we need to select this in the .config as well?
>
> Most likely.

So I'm having a bit of problem here, as something like:
diff --git a/drivers/base/firmware_loader/Kconfig 
b/drivers/base/firmware_loader/Kconfig
index 5166b323a0f8..95cf2d8af5c4 100644
--- a/drivers/base/firmware_loader/Kconfig
+++ b/drivers/base/firmware_loader/Kconfig
@@ -3,6 +3,8 @@ menu "Firmware loader"

 config FW_LOADER
        tristate "Firmware loading facility" if EXPERT
+       select CRYPTO_SHA256 if DYNAMIC_DEBUG
+       select CRYPTO if DYNAMIC_DEBUG
        default y
        help
          This enables the firmware loading facility in the kernel. The 
kernel
being the most simple potential fix doesn't seem to work due to circular 
dependencies. Seems like quite a few cryptography accelerators require 
FW_LOADER and it causes problems.

I tried few more things, but none of them seem to work. Any advice on 
what I can do here?

> > > +    if (!alg)
> > > +        return;
> > > +
> > > +    shash = kmalloc(sizeof(*shash) + crypto_shash_descsize(alg), 
> > > GFP_KERNEL);
> >
> > kmalloc_array()?
>
> Yes.

And taking one more look, it isn't array allocation but struct followed 
by VLA used to store additional data, so it will stay as is.