6.1-stable review patch. If anyone has any objections, please let me know.
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From: Ard Biesheuvel ardb+git@google.com
From: Ard Biesheuvel ardb@kernel.org
[ Commit a37dac5c5dcfe0f1fd58513c16cdbc280a47f628 upstream ]
The UEFI spec does not mention or reason about the configured size of the virtual address space at all, but it does mention that all memory should be identity mapped using a page size of 4 KiB.
This means that a LPA2 capable system that has any system memory outside of the 48-bit addressable physical range and follows the spec to the letter may serve page allocation requests from regions of memory that the kernel cannot access unless it was built with LPA2 support and enables it at runtime.
So let's ensure that all page allocations are limited to the 48-bit range.
Signed-off-by: Ard Biesheuvel ardb@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/include/asm/efi.h | 1 + drivers/firmware/efi/libstub/alignedmem.c | 2 ++ drivers/firmware/efi/libstub/arm64-stub.c | 5 +++-- drivers/firmware/efi/libstub/efistub.h | 4 ++++ drivers/firmware/efi/libstub/mem.c | 2 ++ drivers/firmware/efi/libstub/randomalloc.c | 2 +- 6 files changed, 13 insertions(+), 3 deletions(-)
--- a/arch/arm64/include/asm/efi.h +++ b/arch/arm64/include/asm/efi.h @@ -103,6 +103,7 @@ static inline void free_screen_info(stru }
#define EFI_ALLOC_ALIGN SZ_64K +#define EFI_ALLOC_LIMIT ((1UL << 48) - 1)
/* * On ARM systems, virtually remapped UEFI runtime services are set up in two --- a/drivers/firmware/efi/libstub/alignedmem.c +++ b/drivers/firmware/efi/libstub/alignedmem.c @@ -29,6 +29,8 @@ efi_status_t efi_allocate_pages_aligned( efi_status_t status; int slack;
+ max = min(max, EFI_ALLOC_LIMIT); + if (align < EFI_ALLOC_ALIGN) align = EFI_ALLOC_ALIGN;
--- a/drivers/firmware/efi/libstub/arm64-stub.c +++ b/drivers/firmware/efi/libstub/arm64-stub.c @@ -191,10 +191,11 @@ efi_status_t handle_kernel_image(unsigne if (status != EFI_SUCCESS) { if (!check_image_region((u64)_text, kernel_memsize)) { efi_err("FIRMWARE BUG: Image BSS overlaps adjacent EFI memory region\n"); - } else if (IS_ALIGNED((u64)_text, min_kimg_align)) { + } else if (IS_ALIGNED((u64)_text, min_kimg_align) && + (u64)_end < EFI_ALLOC_LIMIT) { /* * Just execute from wherever we were loaded by the - * UEFI PE/COFF loader if the alignment is suitable. + * UEFI PE/COFF loader if the placement is suitable. */ *image_addr = (u64)_text; *reserve_size = 0; --- a/drivers/firmware/efi/libstub/efistub.h +++ b/drivers/firmware/efi/libstub/efistub.h @@ -29,6 +29,10 @@ #define EFI_ALLOC_ALIGN EFI_PAGE_SIZE #endif
+#ifndef EFI_ALLOC_LIMIT +#define EFI_ALLOC_LIMIT ULONG_MAX +#endif + extern bool efi_nochunk; extern bool efi_nokaslr; extern int efi_loglevel; --- a/drivers/firmware/efi/libstub/mem.c +++ b/drivers/firmware/efi/libstub/mem.c @@ -89,6 +89,8 @@ efi_status_t efi_allocate_pages(unsigned efi_physical_addr_t alloc_addr; efi_status_t status;
+ max = min(max, EFI_ALLOC_LIMIT); + if (EFI_ALLOC_ALIGN > EFI_PAGE_SIZE) return efi_allocate_pages_aligned(size, addr, max, EFI_ALLOC_ALIGN, --- a/drivers/firmware/efi/libstub/randomalloc.c +++ b/drivers/firmware/efi/libstub/randomalloc.c @@ -29,7 +29,7 @@ static unsigned long get_entry_num_slots return 0;
region_end = min(md->phys_addr + md->num_pages * EFI_PAGE_SIZE - 1, - (u64)ULONG_MAX); + (u64)EFI_ALLOC_LIMIT); if (region_end < size) return 0;