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From:   Thiago Jung Bauermann <bauerman@linux.ibm.com>
To:     Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Cc:     zohar@linux.ibm.com, robh@kernel.org, gregkh@linuxfoundation.org,
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Subject: Re: [PATCH v10 6/8] powerpc: Move ima_get_kexec_buffer() and
 ima_free_kexec_buffer() to ima
In-reply-to: <20201204195149.611-7-nramas@linux.microsoft.com>
Date:   Sat, 05 Dec 2020 18:02:07 -0300
Message-ID: <87mtysm0fk.fsf@manicouagan.localdomain>
MIME-Version: 1.0
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Lakshmi Ramasubramanian <nramas@linux.microsoft.com> writes:

> ima_get_kexec_buffer() retrieves the address and size of the buffer
> used for carrying forward the IMA measurement logs on kexec from
> the device tree.
>
> ima_free_kexec_buffer() removes the chosen node
> "linux,ima-kexec-buffer" from the device tree, and frees the buffer
> used for carrying forward the IMA measurement logs on kexec.
>
> These functions do not have architecture specific code, but are
> currently limited to powerpc. Move ima_get_kexec_buffer() and
> ima_free_kexec_buffer() to ima_kexec.c in IMA so that they are
> accessible for other architectures as well.
>
> With the above change the functions in arch/powerpc/kexec/ima.c are
> defined only when the kernel config CONFIG_IMA_KEXEC is enabled.
> Update the Makefile to build arch/powerpc/kexec/ima.c only when
> CONFIG_IMA_KEXEC is enabled and remove "#ifdef CONFIG_IMA_KEXEC"
> in arch/powerpc/kexec/ima.c.

Nice.

> Co-developed-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
> Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>

Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>

Just a small nit below:

> ---
>  arch/powerpc/include/asm/ima.h     |  3 --
>  arch/powerpc/kexec/Makefile        |  7 +---
>  arch/powerpc/kexec/ima.c           | 50 -----------------------------
>  security/integrity/ima/ima_kexec.c | 51 ++++++++++++++++++++++++++++++
>  4 files changed, 52 insertions(+), 59 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/ima.h b/arch/powerpc/include/asm/ima.h
> index a2fc71bc3b23..d8444d27f0d8 100644
> --- a/arch/powerpc/include/asm/ima.h
> +++ b/arch/powerpc/include/asm/ima.h
> @@ -6,9 +6,6 @@
>  
>  struct kimage;
>  
> -int ima_get_kexec_buffer(void **addr, size_t *size);
> -int ima_free_kexec_buffer(void);
> -
>  #ifdef CONFIG_IMA_KEXEC
>  int arch_ima_add_kexec_buffer(struct kimage *image, unsigned long load_addr,
>  			      size_t size);
> diff --git a/arch/powerpc/kexec/Makefile b/arch/powerpc/kexec/Makefile
> index 4aff6846c772..f54a9dbff4c8 100644
> --- a/arch/powerpc/kexec/Makefile
> +++ b/arch/powerpc/kexec/Makefile
> @@ -9,12 +9,7 @@ obj-$(CONFIG_PPC32)		+= relocate_32.o
>  
>  obj-$(CONFIG_KEXEC_FILE)	+= file_load.o ranges.o file_load_$(BITS).o elf_$(BITS).o
>  
> -ifdef CONFIG_HAVE_IMA_KEXEC
> -ifdef CONFIG_IMA
> -obj-y				+= ima.o
> -endif
> -endif
> -
> +obj-$(CONFIG_IMA_KEXEC)		+= ima.o
>  
>  # Disable GCOV, KCOV & sanitizers in odd or sensitive code
>  GCOV_PROFILE_core_$(BITS).o := n
> diff --git a/arch/powerpc/kexec/ima.c b/arch/powerpc/kexec/ima.c
> index 68017123b07d..bf7084c0c4da 100644
> --- a/arch/powerpc/kexec/ima.c
> +++ b/arch/powerpc/kexec/ima.c
> @@ -13,55 +13,6 @@
>  #include <linux/libfdt.h>
>  #include <asm/ima.h>

With this patch, the following includes become unnecessary and can be
removed from this file:

#include <linux/of.h>
#include <linux/memblock.h>

> -/**
> - * ima_get_kexec_buffer - get IMA buffer from the previous kernel
> - * @addr:	On successful return, set to point to the buffer contents.
> - * @size:	On successful return, set to the buffer size.
> - *
> - * Return: 0 on success, negative errno on error.
> - */
> -int ima_get_kexec_buffer(void **addr, size_t *size)
> -{
> -	int ret;
> -	unsigned long tmp_addr;
> -	size_t tmp_size;
> -
> -	ret = get_ima_kexec_buffer(NULL, 0, &tmp_addr, &tmp_size);
> -	if (ret)
> -		return ret;
> -
> -	*addr = __va(tmp_addr);
> -	*size = tmp_size;
> -
> -	return 0;
> -}
> -
> -/**
> - * ima_free_kexec_buffer - free memory used by the IMA buffer
> - */
> -int ima_free_kexec_buffer(void)
> -{
> -	int ret;
> -	unsigned long addr;
> -	size_t size;
> -	struct property *prop;
> -
> -	prop = of_find_property(of_chosen, "linux,ima-kexec-buffer", NULL);
> -	if (!prop)
> -		return -ENOENT;
> -
> -	ret = get_ima_kexec_buffer(NULL, 0, &addr, &size);
> -	if (ret)
> -		return ret;
> -
> -	ret = of_remove_property(of_chosen, prop);
> -	if (ret)
> -		return ret;
> -
> -	return memblock_free(addr, size);
> -}
> -
> -#ifdef CONFIG_IMA_KEXEC
>  /**
>   * arch_ima_add_kexec_buffer - do arch-specific steps to add the IMA buffer
>   *
> @@ -154,4 +105,3 @@ int setup_ima_buffer(const struct kimage *image, void *fdt, int chosen_node)
>  
>  	return 0;
>  }
> -#endif /* CONFIG_IMA_KEXEC */

-- 
Thiago Jung Bauermann
IBM Linux Technology Center