On Wed, Jun 12, 2024 at 04:57:08PM +0100, Mate Kukri wrote:
> For NX, we need to set the page access permission attributes for write
> and execute permissions.
>
> This patch adds two new primitives, grub_set_mem_attrs() and
> grub_clear_mem_attrs(), and associated constant definitions, to be used
> for that purpose.
>
> For most platforms, it adds a dummy implementation that returns
> GRUB_ERR_NONE.
>
> On EFI platforms, it implements the primitives using the EFI
> Memory Attribute Protocol (defined in UEFI 2.10 specification).
>
> Original-Author: Peter Jones <pjo...@redhat.com>
Why not Signed-off-by instead?
> Signed-off-by: Mate Kukri <mate.ku...@canonical.com>
> ---
> grub-core/kern/efi/mm.c | 127 ++++++++++++++++++++++++++++++++++++++++
> include/grub/efi/api.h | 25 ++++++++
> include/grub/mm.h | 33 +++++++++++
> 3 files changed, 185 insertions(+)
>
> diff --git a/grub-core/kern/efi/mm.c b/grub-core/kern/efi/mm.c
> index 6a6fba891..9af851e8f 100644
> --- a/grub-core/kern/efi/mm.c
> +++ b/grub-core/kern/efi/mm.c
> @@ -687,3 +687,130 @@ grub_efi_get_ram_base(grub_addr_t *base_addr)
> return GRUB_ERR_NONE;
> }
> #endif
> +
> +static inline grub_uint64_t
You can drop inline from here.
> +grub_mem_attrs_to_uefi_mem_attrs (grub_uint64_t attrs)
> +{
> + grub_uint64_t ret = GRUB_EFI_MEMORY_RP |
> + GRUB_EFI_MEMORY_RO |
> + GRUB_EFI_MEMORY_XP;
I would put this into one line.
> + if (attrs & GRUB_MEM_ATTR_R)
> + ret &= ~GRUB_EFI_MEMORY_RP;
> +
> + if (attrs & GRUB_MEM_ATTR_W)
> + ret &= ~GRUB_EFI_MEMORY_RO;
> +
> + if (attrs & GRUB_MEM_ATTR_X)
> + ret &= ~GRUB_EFI_MEMORY_XP;
All GRUB_EFI_MEMORY_* constants are not defined in this patch. I think
they should be...
> +
> + return ret;
> +}
> +
> +static inline grub_uint64_t
You can drop inline from here.
> +uefi_mem_attrs_to_grub_mem_attrs (grub_uint64_t attrs)
> +{
> + grub_uint64_t ret = GRUB_MEM_ATTR_R |
> + GRUB_MEM_ATTR_W |
> + GRUB_MEM_ATTR_X;
Again, you do need to wrap this line...
> + if (attrs & GRUB_EFI_MEMORY_RP)
> + ret &= ~GRUB_MEM_ATTR_R;
> +
> + if (attrs & GRUB_EFI_MEMORY_RO)
> + ret &= ~GRUB_MEM_ATTR_W;
> +
> + if (attrs & GRUB_EFI_MEMORY_XP)
> + ret &= ~GRUB_MEM_ATTR_X;
> +
> + return ret;
> +}
> +
> +grub_err_t
> +grub_get_mem_attrs (grub_addr_t addr, grub_size_t size, grub_uint64_t *attrs)
> +{
> + grub_efi_memory_attribute_protocol_t *proto;
> + grub_efi_physical_address_t physaddr = addr;
> + grub_guid_t protocol_guid = GRUB_EFI_MEMORY_ATTRIBUTE_PROTOCOL_GUID;
Please add "static" before grub_guid_t initializations.
> + grub_efi_status_t efi_status;
> +
> + if (physaddr & 0xfff || size & 0xfff || size == 0 || attrs == NULL)
Should not 0xfff be defined as a mask (constant)?
> + {
> + return grub_error (GRUB_ERR_BAD_ARGUMENT,
> + N_("grub_get_mem_attrs() called with invalid
> arguments"));
> + }
Please drop redundant curly braces.
> +
> + proto = grub_efi_locate_protocol (&protocol_guid, 0);
> + if (!proto)
> + {
> + /* No protocol -> do nothing, all memory is RWX in boot services */
> + *attrs = GRUB_MEM_ATTR_R | GRUB_MEM_ATTR_W | GRUB_MEM_ATTR_X;
> + return GRUB_ERR_NONE;
> + }
> +
> + efi_status = proto->get_memory_attributes(proto, physaddr, size, attrs);
> + if (efi_status != GRUB_EFI_SUCCESS)
> + {
> + return grub_error (GRUB_ERR_BAD_ARGUMENT,
> + N_("grub_get_mem_attrs() called with invalid
> arguments"));
> + }
Ditto and in the other places too...
> +
> + *attrs = uefi_mem_attrs_to_grub_mem_attrs (*attrs);
> +
> + grub_dprintf ("nx", "get 0x%"PRIxGRUB_ADDR"-0x%"PRIxGRUB_ADDR":%c%c%c\n",
Missing spaces before and after PRIxGRUB_ADDR.
> + addr, addr + size - 1,
> + (*attrs & GRUB_MEM_ATTR_R) ? 'r' : '-',
> + (*attrs & GRUB_MEM_ATTR_W) ? 'w' : '-',
> + (*attrs & GRUB_MEM_ATTR_X) ? 'x' : '-');
> +
> + return GRUB_ERR_NONE;
> +}
> +
> +grub_err_t
> +grub_update_mem_attrs (grub_addr_t addr, grub_size_t size,
> + grub_uint64_t set_attrs, grub_uint64_t clear_attrs)
> +{
> + grub_efi_memory_attribute_protocol_t *proto;
> + grub_efi_physical_address_t physaddr = addr;
> + grub_guid_t protocol_guid = GRUB_EFI_MEMORY_ATTRIBUTE_PROTOCOL_GUID;
Again, please add "static" to grub_guid_t initializations.
> + grub_efi_status_t efi_status = GRUB_EFI_SUCCESS;
> + grub_uint64_t uefi_set_attrs, uefi_clear_attrs;
s/grub_uint64_t/grub_efi_uint64_t/
> +
> +
Please drop redundant empty line.
> + if (physaddr & 0xfff || size & 0xfff || size == 0)
Certainly 0xfff deserves being a constant...
> + {
> + return grub_error (GRUB_ERR_BAD_ARGUMENT,
> + N_("grub_update_mem_attrs() called with invalid
> arguments"));
> + }
> +
> + proto = grub_efi_locate_protocol (&protocol_guid, 0);
> + if (!proto)
Please use "if (proto == NULL)" in all cases like that one.
> + {
> + /* No protocol -> do nothing, all memory is RWX in boot services */
> + return GRUB_ERR_NONE;
> + }
Again, redundant curly braces. Please fix this everywhere.
> + uefi_set_attrs = grub_mem_attrs_to_uefi_mem_attrs (set_attrs);
> + uefi_clear_attrs = grub_mem_attrs_to_uefi_mem_attrs (clear_attrs);
> + if (uefi_set_attrs)
> + efi_status = proto->set_memory_attributes(proto, physaddr, size,
> uefi_set_attrs);
> + if (efi_status == GRUB_EFI_SUCCESS && uefi_clear_attrs)
> + efi_status = proto->clear_memory_attributes(proto, physaddr, size,
> uefi_clear_attrs);
> +
> + if (efi_status != GRUB_EFI_SUCCESS)
> + {
> + return grub_error (GRUB_ERR_BAD_ARGUMENT,
> + N_("grub_update_mem_attrs() called with invalid
> arguments"));
> + }
> +
> + grub_dprintf ("nx", "set +%s%s%s -%s%s%s on
> 0x%"PRIxGRUB_ADDR"-0x%"PRIxGRUB_ADDR"\n",
> + (set_attrs & GRUB_MEM_ATTR_R) ? "r" : "",
> + (set_attrs & GRUB_MEM_ATTR_W) ? "w" : "",
> + (set_attrs & GRUB_MEM_ATTR_X) ? "x" : "",
> + (clear_attrs & GRUB_MEM_ATTR_R) ? "r" : "",
> + (clear_attrs & GRUB_MEM_ATTR_W) ? "w" : "",
> + (clear_attrs & GRUB_MEM_ATTR_X) ? "x" : "",
> + addr, addr + size - 1);
> +
> + return GRUB_ERR_NONE;
> +}
> diff --git a/include/grub/efi/api.h b/include/grub/efi/api.h
> index d44d00ad7..b686e8afe 100644
> --- a/include/grub/efi/api.h
> +++ b/include/grub/efi/api.h
> @@ -379,6 +379,11 @@
> {0xb6, 0xc7, 0x44, 0x0b, 0x29, 0xbb, 0x8c, 0x4f } \
> }
>
> +#define GRUB_EFI_MEMORY_ATTRIBUTE_PROTOCOL_GUID \
> + { 0xf4560cf6, 0x40ec, 0x4b4a, \
> + { 0xa1, 0x92, 0xbf, 0x1d, 0x57, 0xd0, 0xb1, 0x89 } \
> + }
> +
> struct grub_efi_sal_system_table
> {
> grub_uint32_t signature;
> @@ -1815,4 +1820,24 @@ struct initrd_media_device_path {
> } GRUB_PACKED;
> typedef struct initrd_media_device_path initrd_media_device_path_t;
>
> +struct grub_efi_memory_attribute_protocol
> +{
> + grub_efi_status_t (__grub_efi_api *get_memory_attributes) (
> + struct grub_efi_memory_attribute_protocol *this,
> + grub_efi_physical_address_t base_address,
> + grub_efi_uint64_t length,
> + grub_efi_uint64_t *attributes);
> + grub_efi_status_t (__grub_efi_api *set_memory_attributes) (
> + struct grub_efi_memory_attribute_protocol *this,
> + grub_efi_physical_address_t base_address,
> + grub_efi_uint64_t length,
> + grub_efi_uint64_t attributes);
> + grub_efi_status_t (__grub_efi_api *clear_memory_attributes) (
> + struct grub_efi_memory_attribute_protocol *this,
> + grub_efi_physical_address_t base_address,
> + grub_efi_uint64_t length,
> + grub_efi_uint64_t attributes);
> +};
> +typedef struct grub_efi_memory_attribute_protocol
> grub_efi_memory_attribute_protocol_t;
> +
> #endif /* ! GRUB_EFI_API_HEADER */
> diff --git a/include/grub/mm.h b/include/grub/mm.h
> index f3bf87fa0..dcccfe395 100644
> --- a/include/grub/mm.h
> +++ b/include/grub/mm.h
> @@ -23,6 +23,7 @@
> #include <grub/err.h>
> #include <grub/types.h>
> #include <grub/symbol.h>
> +#include <grub/err.h>
> #include <config.h>
>
> #ifndef NULL
> @@ -56,6 +57,38 @@ void *EXPORT_FUNC(grub_realloc) (void *ptr, grub_size_t
> size);
> void *EXPORT_FUNC(grub_memalign) (grub_size_t align, grub_size_t size);
> #endif
>
> +#define GRUB_MEM_ATTR_R 0x0000000000000004LLU
> +#define GRUB_MEM_ATTR_W 0x0000000000000002LLU
> +#define GRUB_MEM_ATTR_X 0x0000000000000001LLU
I think we should define a mem attr type and cast to it here.
The LLU may not always be grub_uint64_t as you expect.
> +
> +#ifdef GRUB_MACHINE_EFI
> +grub_err_t EXPORT_FUNC(grub_get_mem_attrs) (grub_addr_t addr,
> + grub_size_t size,
> + grub_uint64_t *attrs);
> +grub_err_t EXPORT_FUNC(grub_update_mem_attrs) (grub_addr_t addr,
> + grub_size_t size,
> + grub_uint64_t set_attrs,
> + grub_uint64_t clear_attrs);
> +#else /* !GRUB_MACHINE_EFI */
> +static inline grub_err_t
> +grub_get_mem_attrs (grub_addr_t addr __attribute__((__unused__)),
> + grub_size_t size __attribute__((__unused__)),
> + grub_uint64_t *attrs __attribute__((__unused__)))
You mark attrs as unused and then use it below...
> +{
> + *attrs = GRUB_MEM_ATTR_R | GRUB_MEM_ATTR_W | GRUB_MEM_ATTR_X;
> + return GRUB_ERR_NONE;
> +}
> +
> +static inline grub_err_t
> +grub_update_mem_attrs (grub_addr_t addr __attribute__((__unused__)),
> + grub_size_t size __attribute__((__unused__)),
> + grub_uint64_t set_attrs __attribute__((__unused__)),
> + grub_uint64_t clear_attrs __attribute__((__unused__)))
... but here it is correct...
> +{
> + return GRUB_ERR_NONE;
> +}
Daniel
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