Re: [PATCH v4 24/24] integrity/powerpc: Support loading keys from pseries secvar

[Mimi Zohar <zohar@linux.ibm.com>]

On Fri, 2023-01-20 at 18:43 +1100, Andrew Donnellan wrote:
> From: Russell Currey <ruscur@russell.cc>
> 
> The secvar object format is only in the device tree under powernv.
> We now have an API call to retrieve it in a generic way, so we should
> use that instead of having to handle the DT here.
> 
> Add support for pseries secvar, with the "ibm,plpks-sb-v1" format.
> The object format is expected to be the same, so there shouldn't be any
> functional differences between objects retrieved from powernv and
> pseries.
> 
> Signed-off-by: Russell Currey <ruscur@russell.cc>
> Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
> 
> ---
> 
> v3: New patch
> 
> v4: Pass format buffer size (stefanb, npiggin)
> ---
>  .../integrity/platform_certs/load_powerpc.c     | 17 ++++++++++-------
>  1 file changed, 10 insertions(+), 7 deletions(-)
> 
> diff --git a/security/integrity/platform_certs/load_powerpc.c b/security/integrity/platform_certs/load_powerpc.c
> index dee51606d5f4..d4ce91bf3fec 100644
> --- a/security/integrity/platform_certs/load_powerpc.c
> +++ b/security/integrity/platform_certs/load_powerpc.c
> @@ -10,7 +10,6 @@
>  #include <linux/cred.h>
>  #include <linux/err.h>
>  #include <linux/slab.h>
> -#include <linux/of.h>
>  #include <asm/secure_boot.h>
>  #include <asm/secvar.h>
>  #include "keyring_handler.h"
> @@ -59,16 +58,22 @@ static int __init load_powerpc_certs(void)
>  	void *db = NULL, *dbx = NULL;
>  	u64 dbsize = 0, dbxsize = 0;
>  	int rc = 0;
> -	struct device_node *node;
> +	ssize_t len;
> +	char buf[32];
>  
>  	if (!secvar_ops)
>  		return -ENODEV;
>  
> -	/* The following only applies for the edk2-compat backend. */
> -	node = of_find_compatible_node(NULL, NULL, "ibm,edk2-compat-v1");
> -	if (!node)
> +	len = secvar_ops->format(buf, 32);

"powerpc/secvar: Handle format string in the consumer"  defines
opal_secvar_format() for the object format "ibm,secvar-backend".  Here
shouldn't it being returning the format for "ibm,edk2-compat-v1"?

Mimi

> +	if (len <= 0)
>  		return -ENODEV;
>  
> +	// Check for known secure boot implementations from OPAL or PLPKS
> +	if (strcmp("ibm,edk2-compat-v1", buf) && strcmp("ibm,plpks-sb-v1", buf)) {
> +		pr_err("Unsupported secvar implementation \"%s\", not loading certs\n", buf);
> +		return -ENODEV;
> +	}
> +
>  	/*
>  	 * Get db, and dbx. They might not exist, so it isn't an error if we
>  	 * can't get them.
> @@ -103,8 +108,6 @@ static int __init load_powerpc_certs(void)
>  		kfree(dbx);
>  	}
>  
> -	of_node_put(node);
> -
>  	return rc;
>  }
>  late_initcall(load_powerpc_certs);