Re: [PATCH v2] Carry forward IMA measurement log on kexec on x86_64

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

> diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
> index 13753136f03f..419c50cfe6b9 100644
> --- a/security/integrity/ima/ima_kexec.c
> +++ b/security/integrity/ima/ima_kexec.c
> @@ -10,6 +10,7 @@
>  #include <linux/seq_file.h>
>  #include <linux/vmalloc.h>
>  #include <linux/kexec.h>
> +#include <linux/memblock.h>
>  #include <linux/of.h>
>  #include <linux/ima.h>
>  #include "ima.h"
> @@ -134,10 +135,66 @@ void ima_add_kexec_buffer(struct kimage *image)
>  }
>  #endif /* IMA_KEXEC */
>  
> +#ifndef CONFIG_OF
> +static phys_addr_t ima_early_kexec_buffer_phys;
> +static size_t ima_early_kexec_buffer_size;
> +
> +void __init ima_set_kexec_buffer(phys_addr_t phys_addr, size_t size)
> +{
> +	if (size == 0)
> +		return;
> +
> +	ima_early_kexec_buffer_phys = phys_addr;
> +	ima_early_kexec_buffer_size = size;
> +}
> +
> +int __init ima_free_kexec_buffer(void)
> +{
> +	int rc;
> +
> +	if (!IS_ENABLED(CONFIG_HAVE_IMA_KEXEC))
> +		return -ENOTSUPP;
> +
> +	if (ima_early_kexec_buffer_size == 0)
> +		return -ENOENT;
> +
> +	rc = memblock_phys_free(ima_early_kexec_buffer_phys,
> +				ima_early_kexec_buffer_size);
> +	if (rc)
> +		return rc;
> +
> +	ima_early_kexec_buffer_phys = 0;
> +	ima_early_kexec_buffer_size = 0;
> +
> +	return 0;
> +}
> +
> +int __init ima_get_kexec_buffer(void **addr, size_t *size)
> +{
> +	if (!IS_ENABLED(CONFIG_HAVE_IMA_KEXEC))
> +		return -ENOTSUPP;
> +
> +	if (ima_early_kexec_buffer_size == 0)
> +		return -ENOENT;
> +
> +	*addr = __va(ima_early_kexec_buffer_phys);
> +	*size = ima_early_kexec_buffer_size;
> +
> +	return 0;
> +}
> +

Originally both ima_get_kexec_buffer() and ima_free_kexec_buffer() were
architecture specific.  Refer to commit 467d27824920 ("powerpc: ima:
get the kexec buffer passed by the previous kernel").  Is there any
need for defining them here behind an "#ifndef CONFIG_OF"?

> +#else
> +
> +void __init ima_set_kexec_buffer(phys_addr_t phys_addr, size_t size)
> +{
> +	pr_warn("CONFIG_OF enabled, ignoring call to set buffer details.\n");
> +}
> +#endif /* CONFIG_OF */
> +

Only when "HAVE_IMA_KEXEC" is defined is this file included.  Why is
this warning needed?

thanks,

Mimi

>  /*
>   * Restore the measurement list from the previous kernel.
>   */
> -void ima_load_kexec_buffer(void)
> +void __init ima_load_kexec_buffer(void)
>  {
>  	void *kexec_buffer = NULL;
>  	size_t kexec_buffer_size = 0;