Re: [PATCH v10 6/8] powerpc: Move ima_get_kexec_buffer() and ima_free_kexec_buffer() to ima

Thiago Jung Bauermann
2020-12-05T21:03:53Z

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