[PATCH v12 2/4] powerpc: Move arch independent ima kexec functions to drivers/of/kexec.c
Lakshmi Ramasubramanian
nramas at linux.microsoft.com
Thu Dec 17 15:52:32 EST 2020
On 12/17/20 12:05 PM, Rob Herring wrote:
> On Thu, Dec 17, 2020 at 09:37:06AM -0800, Lakshmi Ramasubramanian wrote:
>> The functions defined in "arch/powerpc/kexec/ima.c" handle setting up
>> and freeing the resources required to carry over the IMA measurement
>> list from the current kernel to the next kernel across kexec system call.
>> These functions do not have architecture specific code, but are
>> currently limited to powerpc.
>>
>> Move setup_ima_buffer() call into of_kexec_setup_new_fdt().
>>
>> Move architecture independent functions from "arch/powerpc/kexec/ima.c"
>> to "drivers/of/kexec.c". Delete "arch/powerpc/kexec/ima.c" and
>> "arch/powerpc/include/asm/ima.h". Remove references to the deleted files
>> in powerpc and in ima.
>>
>> delete_fdt_mem_rsv() defined in "arch/powerpc/kexec/file_load.c"
>> is not used anymore. Remove this function.
>
> I think this patch should come first and then patch 1. Move then rework
> the code.
Sure - will reorder the patches.
>
>>
>> Signed-off-by: Lakshmi Ramasubramanian <nramas at linux.microsoft.com>
>> ---
>> arch/powerpc/include/asm/ima.h | 30 -----
>> arch/powerpc/include/asm/kexec.h | 1 -
>> arch/powerpc/kexec/Makefile | 7 -
>> arch/powerpc/kexec/file_load.c | 39 ------
>> arch/powerpc/kexec/ima.c | 182 --------------------------
>> drivers/of/kexec.c | 198 +++++++++++++++++++++++++++++
>> include/linux/of.h | 17 +++
>> security/integrity/ima/ima.h | 4 -
>> security/integrity/ima/ima_kexec.c | 2 +
>> 9 files changed, 217 insertions(+), 263 deletions(-)
>> delete mode 100644 arch/powerpc/include/asm/ima.h
>> delete mode 100644 arch/powerpc/kexec/ima.c
>>
>> diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c
>> index 66787be081fe..a6ab35f16dd2 100644
>> --- a/drivers/of/kexec.c
>> +++ b/drivers/of/kexec.c
>> @@ -10,10 +10,12 @@
>> */
>>
>> #include <linux/kernel.h>
>> +#include <linux/slab.h>
>> #include <linux/kexec.h>
>> #include <linux/libfdt.h>
>> #include <linux/of.h>
>> #include <linux/of_fdt.h>
>> +#include <linux/memblock.h>
>> #include <linux/random.h>
>> #include <linux/types.h>
>>
>> @@ -59,6 +61,141 @@ static int fdt_find_and_del_mem_rsv(void *fdt, unsigned long start, unsigned lon
>> return -ENOENT;
>> }
>>
>> +/**
>> + * get_addr_size_cells - Get address and size of root node
>> + *
>> + * @addr_cells: Return address of the root node
>> + * @size_cells: Return size of the root node
>> + *
>> + * Return: 0 on success, or negative errno on error.
>> + */
>> +static int get_addr_size_cells(int *addr_cells, int *size_cells)
>> +{
>> + struct device_node *root;
>> +
>> + root = of_find_node_by_path("/");
>> + if (!root)
>> + return -EINVAL;
>> +
>> + *addr_cells = of_n_addr_cells(root);
>> + *size_cells = of_n_size_cells(root);
>> +
>> + of_node_put(root);
>> +
>> + return 0;
>> +}
>> +
>> +/**
>> + * do_get_kexec_buffer - Get address and size of device tree property
>> + *
>> + * @prop: Device tree property
>> + * @len: Size of @prop
>> + * @addr: Return address of the node
>> + * @size: Return size of the node
>> + *
>> + * Return: 0 on success, or negative errno on error.
>> + */
>> +static int do_get_kexec_buffer(const void *prop, int len, unsigned long *addr,
>> + size_t *size)
>> +{
>> + int ret, addr_cells, size_cells;
>> +
>> + ret = get_addr_size_cells(&addr_cells, &size_cells);
>> + if (ret)
>> + return ret;
>> +
>> + if (len < 4 * (addr_cells + size_cells))
>> + return -ENOENT;
>> +
>> + *addr = of_read_number(prop, addr_cells);
>> + *size = of_read_number(prop + 4 * addr_cells, size_cells);
>> +
>> + return 0;
>> +}
>> +
>> +/**
>> + * 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, len;
>> + unsigned long tmp_addr;
>> + size_t tmp_size;
>> + const void *prop;
>> +
>> + prop = of_get_property(of_chosen, "linux,ima-kexec-buffer", &len);
>> + if (!prop)
>> + return -ENOENT;
>> +
>> + ret = do_get_kexec_buffer(prop, len, &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 = do_get_kexec_buffer(prop->value, prop->length, &addr, &size);
>> + if (ret)
>> + return ret;
>> +
>> + ret = of_remove_property(of_chosen, prop);
>> + if (ret)
>> + return ret;
>> +
>> + return memblock_free(addr, size);
>> +}
>> +
>> +/**
>> + * remove_ima_buffer - remove the IMA buffer property and reservation from @fdt
>> + *
>> + * @fdt: Flattened Device Tree to update
>> + * @chosen_node: Offset to the chosen node in the device tree
>> + *
>> + * The IMA measurement buffer is of no use to a subsequent kernel, so we always
>> + * remove it from the device tree.
>> + */
>> +void remove_ima_buffer(void *fdt, int chosen_node)
>
> static
Will update.
>
>> +{
>> + int ret, len;
>> + unsigned long addr;
>> + size_t size;
>> + const void *prop;
>> +
>> + prop = fdt_getprop(fdt, chosen_node, "linux,ima-kexec-buffer", &len);
>> + if (!prop)
>> + return;
>> +
>> + ret = do_get_kexec_buffer(prop, len, &addr, &size);
>> + fdt_delprop(fdt, chosen_node, "linux,ima-kexec-buffer");
>> + if (ret)
>> + return;
>> +
>> + ret = fdt_find_and_del_mem_rsv(fdt, addr, size);
>> + if (!ret)
>> + pr_debug("Removed old IMA buffer reservation.\n");
>> +}
>
> All the above needs to be in an '#ifdef CONFIG_IMA_KEXEC'.
remove_ima_buffer() needs to be defined when CONFIG_HAVE_IMA_KEXEC is
enabled. CONFIG_HAVE_IMA_KEXEC can be enabled even if CONFIG_IMA_KEXEC
is not.
I'll move remove_ima_buffer() under "#ifdef CONFIG_HAVE_IMA_KEXEC" in
this file.
>
>> +
>> /*
>> * of_kexec_setup_new_fdt - modify /chosen and memory reservation for the next kernel
>> *
>> @@ -219,6 +356,10 @@ int of_kexec_setup_new_fdt(const struct kimage *image, void *fdt,
>> }
>>
>> ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0);
>> + if (ret)
>> + goto out;
>> +
>> + ret = setup_ima_buffer(image, fdt, fdt_path_offset(fdt, "/chosen"));
>>
>> out:
>> if (ret)
>> @@ -226,3 +367,60 @@ int of_kexec_setup_new_fdt(const struct kimage *image, void *fdt,
>>
>> return 0;
>> }
>> +
>> +#ifdef CONFIG_IMA_KEXEC
>> +/**
>> + * arch_ima_add_kexec_buffer - do arch-specific steps to add the IMA buffer
>> + *
>> + * @image: kimage struct to set IMA buffer data
>> + * @load_addr: Starting address where IMA buffer is loaded at
>> + * @size: Number of bytes in the IMA buffer
>> + *
>> + * Architectures should use this function to pass on the IMA buffer
>> + * information to the next kernel.
>> + *
>> + * Return: 0 on success, negative errno on error.
>> + */
>> +int arch_ima_add_kexec_buffer(struct kimage *image, unsigned long load_addr,
>> + size_t size)
>
> This should be a static inline in asm/kexec.h.
arch_ima_add_kexec_buffer() is identical for powerpc and arm64.
Would it be better to "static inline" this function in "of.h" instead of
duplicating it in "asm/kexec.h" for powerpc and arm64?
>
>> +{
>> + image->arch.ima_buffer_addr = load_addr;
>> + image->arch.ima_buffer_size = size;
>> +
>> + return 0;
>> +}
>> +
>> +/**
>> + * setup_ima_buffer - add IMA buffer information to the fdt
>> + * @image: kexec image being loaded.
>> + * @fdt: Flattened device tree for the next kernel.
>> + * @chosen_node: Offset to the chosen node.
>> + *
>> + * Return: 0 on success, or negative errno on error.
>> + */
>> +int setup_ima_buffer(const struct kimage *image, void *fdt, int chosen_node)
>
> static
Will update.
>
>> +{
>> + int ret;
>> +
>> + remove_ima_buffer(fdt, chosen_node);
>> + if (!image->arch.ima_buffer_size)
>> + return 0;
>> +
>> + ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
>> + "linux,ima-kexec-buffer",
>> + image->arch.ima_buffer_addr,
>> + image->arch.ima_buffer_size);
>> + if (ret)
>> + return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL);
>> +
>> + ret = fdt_add_mem_rsv(fdt, image->arch.ima_buffer_addr,
>> + image->arch.ima_buffer_size);
>> + if (ret)
>> + return -EINVAL;
>> +
>> + pr_debug("IMA buffer at 0x%llx, size = 0x%zx\n",
>> + image->arch.ima_buffer_addr, image->arch.ima_buffer_size);
>> +
>> + return 0;
>> +}
>> +#endif /* CONFIG_IMA_KEXEC */
>> diff --git a/include/linux/of.h b/include/linux/of.h
>> index 3375f5295875..7477f2266d8f 100644
>> --- a/include/linux/of.h
>> +++ b/include/linux/of.h
>> @@ -562,6 +562,23 @@ struct kimage;
>> int of_kexec_setup_new_fdt(const struct kimage *image, void *fdt,
>> unsigned long initrd_load_addr, unsigned long initrd_len,
>> const char *cmdline);
>> +int ima_get_kexec_buffer(void **addr, size_t *size);
>> +int ima_free_kexec_buffer(void);
>> +void remove_ima_buffer(void *fdt, int chosen_node);
>> +
>> +#ifdef CONFIG_IMA_KEXEC
>> +int arch_ima_add_kexec_buffer(struct kimage *image,
>> + unsigned long load_addr,
>> + size_t size);
>> +int setup_ima_buffer(const struct kimage *image, void *fdt, int chosen_node);
>
> This doesn't need to be public.
Will update.
thanks,
-lakshmi
>
>> +#else
>> +static inline int setup_ima_buffer(const struct kimage *image, void *fdt,
>> + int chosen_node)
>> +{
>> + remove_ima_buffer(fdt, chosen_node);
>> + return 0;
>> +}
>> +#endif /* CONFIG_IMA_KEXEC */
>>
>> #else /* CONFIG_OF */
>>
>> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
>> index 6ebefec616e4..7c3947ad3773 100644
>> --- a/security/integrity/ima/ima.h
>> +++ b/security/integrity/ima/ima.h
>> @@ -24,10 +24,6 @@
>>
>> #include "../integrity.h"
>>
>> -#ifdef CONFIG_HAVE_IMA_KEXEC
>> -#include <asm/ima.h>
>> -#endif
>> -
>> enum ima_show_type { IMA_SHOW_BINARY, IMA_SHOW_BINARY_NO_FIELD_LEN,
>> IMA_SHOW_BINARY_OLD_STRING_FMT, IMA_SHOW_ASCII };
>> enum tpm_pcrs { TPM_PCR0 = 0, TPM_PCR8 = 8, TPM_PCR10 = 10 };
>> diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
>> index 121de3e04af2..3d6a8820e2a5 100644
>> --- a/security/integrity/ima/ima_kexec.c
>> +++ b/security/integrity/ima/ima_kexec.c
>> @@ -9,7 +9,9 @@
>>
>> #include <linux/seq_file.h>
>> #include <linux/vmalloc.h>
>> +#include <linux/of.h>
>> #include <linux/kexec.h>
>> +#include <linux/ima.h>
>> #include "ima.h"
>>
>> #ifdef CONFIG_IMA_KEXEC
>> --
>> 2.29.2
>>
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