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| author |   Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2016-01-11 10:43:16 +0100 |
|---|---|---|
| committer |   Catalin Marinas <catalin.marinas@arm.com> | 2016-02-24 14:57:28 +0000 |
| commit | 2ddbfc81eac84a299cb4747a8764bc43f23e9008 (patch) | |
| tree | 958da4ff15f5fc23a4d65a427a41537a6a747cfb /drivers/firmware/efi/libstub/efistub.h | |
| parent | efi: stub: implement efi_get_random_bytes() based on EFI_RNG_PROTOCOL (diff) | |
| download | linux-dev-2ddbfc81eac84a299cb4747a8764bc43f23e9008.tar.xz linux-dev-2ddbfc81eac84a299cb4747a8764bc43f23e9008.zip | |
efi: stub: add implementation of efi_random_alloc()
This implements efi_random_alloc(), which allocates a chunk of memory of
a certain size at a certain alignment, and uses the random_seed argument
it receives to randomize the address of the allocation.
This is implemented by iterating over the UEFI memory map, counting the
number of suitable slots (aligned offsets) within each region, and picking
a random number between 0 and 'number of slots - 1' to select the slot,
This should guarantee that each possible offset is chosen equally likely.
Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'drivers/firmware/efi/libstub/efistub.h')
| -rw-r--r-- | drivers/firmware/efi/libstub/efistub.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h index 206b7252b9d1..5ed3d3f38166 100644 --- a/drivers/firmware/efi/libstub/efistub.h +++ b/drivers/firmware/efi/libstub/efistub.h @@ -46,4 +46,8 @@ void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size, efi_status_t efi_get_random_bytes(efi_system_table_t *sys_table, unsigned long size, u8 *out); +efi_status_t efi_random_alloc(efi_system_table_t *sys_table_arg, + unsigned long size, unsigned long align, + unsigned long *addr, unsigned long random_seed); + #endif |