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author | 2021-08-15 06:38:26 -1000 | |
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committer | 2021-08-15 06:38:26 -1000 | |
commit | 12aef8acf0991e8a4a5fe892067e2c8fc6760ace (patch) | |
tree | 91d9d818664806cd6c1e7b7096d51434aa4d8404 /drivers/firmware/efi | |
parent | Merge tag 'x86_urgent_for_v5.14_rc6' of git://git.kernel.org/pub/scm/linux/ke... (diff) | |
parent | Merge tag 'efi-urgent-for-v5.14-rc4' of git://git.kernel.org/pub/scm/linux/ke... (diff) | |
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Merge tag 'efi_urgent_for_v5.14_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull EFI fixes from Borislav Petkov:
"A batch of fixes for the arm64 stub image loader:
- fix a logic bug that can make the random page allocator fail
spuriously
- force reallocation of the Image when it overlaps with firmware
reserved memory regions
- fix an oversight that defeated on optimization introduced earlier
where images loaded at a suitable offset are never moved if booting
without randomization
- complain about images that were not loaded at the right offset by
the firmware image loader"
* tag 'efi_urgent_for_v5.14_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
efi/libstub: arm64: Double check image alignment at entry
efi/libstub: arm64: Warn when efi_random_alloc() fails
efi/libstub: arm64: Relax 2M alignment again for relocatable kernels
efi/libstub: arm64: Force Image reallocation if BSS was not reserved
arm64: efi: kaslr: Fix occasional random alloc (and boot) failure
Diffstat (limited to 'drivers/firmware/efi')
-rw-r--r-- | drivers/firmware/efi/libstub/arm64-stub.c | 71 | ||||
-rw-r--r-- | drivers/firmware/efi/libstub/randomalloc.c | 2 |
2 files changed, 63 insertions, 10 deletions
diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c index 7bf0a7acae5e..2363fee9211c 100644 --- a/drivers/firmware/efi/libstub/arm64-stub.c +++ b/drivers/firmware/efi/libstub/arm64-stub.c @@ -35,15 +35,48 @@ efi_status_t check_platform_features(void) } /* - * Although relocatable kernels can fix up the misalignment with respect to - * MIN_KIMG_ALIGN, the resulting virtual text addresses are subtly out of - * sync with those recorded in the vmlinux when kaslr is disabled but the - * image required relocation anyway. Therefore retain 2M alignment unless - * KASLR is in use. + * Distro versions of GRUB may ignore the BSS allocation entirely (i.e., fail + * to provide space, and fail to zero it). Check for this condition by double + * checking that the first and the last byte of the image are covered by the + * same EFI memory map entry. */ -static u64 min_kimg_align(void) +static bool check_image_region(u64 base, u64 size) { - return efi_nokaslr ? MIN_KIMG_ALIGN : EFI_KIMG_ALIGN; + unsigned long map_size, desc_size, buff_size; + efi_memory_desc_t *memory_map; + struct efi_boot_memmap map; + efi_status_t status; + bool ret = false; + int map_offset; + + map.map = &memory_map; + map.map_size = &map_size; + map.desc_size = &desc_size; + map.desc_ver = NULL; + map.key_ptr = NULL; + map.buff_size = &buff_size; + + status = efi_get_memory_map(&map); + if (status != EFI_SUCCESS) + return false; + + for (map_offset = 0; map_offset < map_size; map_offset += desc_size) { + efi_memory_desc_t *md = (void *)memory_map + map_offset; + u64 end = md->phys_addr + md->num_pages * EFI_PAGE_SIZE; + + /* + * Find the region that covers base, and return whether + * it covers base+size bytes. + */ + if (base >= md->phys_addr && base < end) { + ret = (base + size) <= end; + break; + } + } + + efi_bs_call(free_pool, memory_map); + + return ret; } efi_status_t handle_kernel_image(unsigned long *image_addr, @@ -56,6 +89,16 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, unsigned long kernel_size, kernel_memsize = 0; u32 phys_seed = 0; + /* + * Although relocatable kernels can fix up the misalignment with + * respect to MIN_KIMG_ALIGN, the resulting virtual text addresses are + * subtly out of sync with those recorded in the vmlinux when kaslr is + * disabled but the image required relocation anyway. Therefore retain + * 2M alignment if KASLR was explicitly disabled, even if it was not + * going to be activated to begin with. + */ + u64 min_kimg_align = efi_nokaslr ? MIN_KIMG_ALIGN : EFI_KIMG_ALIGN; + if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { if (!efi_nokaslr) { status = efi_get_random_bytes(sizeof(phys_seed), @@ -76,6 +119,10 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, if (image->image_base != _text) efi_err("FIRMWARE BUG: efi_loaded_image_t::image_base has bogus value\n"); + if (!IS_ALIGNED((u64)_text, EFI_KIMG_ALIGN)) + efi_err("FIRMWARE BUG: kernel image not aligned on %ldk boundary\n", + EFI_KIMG_ALIGN >> 10); + kernel_size = _edata - _text; kernel_memsize = kernel_size + (_end - _edata); *reserve_size = kernel_memsize; @@ -85,14 +132,18 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, * If KASLR is enabled, and we have some randomness available, * locate the kernel at a randomized offset in physical memory. */ - status = efi_random_alloc(*reserve_size, min_kimg_align(), + status = efi_random_alloc(*reserve_size, min_kimg_align, reserve_addr, phys_seed); + if (status != EFI_SUCCESS) + efi_warn("efi_random_alloc() failed: 0x%lx\n", status); } else { status = EFI_OUT_OF_RESOURCES; } if (status != EFI_SUCCESS) { - if (IS_ALIGNED((u64)_text, min_kimg_align())) { + 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)) { /* * Just execute from wherever we were loaded by the * UEFI PE/COFF loader if the alignment is suitable. @@ -103,7 +154,7 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, } status = efi_allocate_pages_aligned(*reserve_size, reserve_addr, - ULONG_MAX, min_kimg_align()); + ULONG_MAX, min_kimg_align); if (status != EFI_SUCCESS) { efi_err("Failed to relocate kernel\n"); diff --git a/drivers/firmware/efi/libstub/randomalloc.c b/drivers/firmware/efi/libstub/randomalloc.c index a408df474d83..724155b9e10d 100644 --- a/drivers/firmware/efi/libstub/randomalloc.c +++ b/drivers/firmware/efi/libstub/randomalloc.c @@ -30,6 +30,8 @@ static unsigned long get_entry_num_slots(efi_memory_desc_t *md, region_end = min(md->phys_addr + md->num_pages * EFI_PAGE_SIZE - 1, (u64)ULONG_MAX); + if (region_end < size) + return 0; first_slot = round_up(md->phys_addr, align); last_slot = round_down(region_end - size + 1, align); |