The following commit has been merged into the efi/urgent branch of tip:
Commit-ID: c32ac11da3f83bb42b986702a9b92f0a14ed4182 Gitweb: https://git.kernel.org/tip/c32ac11da3f83bb42b986702a9b92f0a14ed4182 Author: Ard Biesheuvel ardb@kernel.org AuthorDate: Mon, 26 Jul 2021 16:31:44 +02:00 Committer: Ard Biesheuvel ardb@kernel.org CommitterDate: Tue, 03 Aug 2021 07:43:13 +02:00
efi/libstub: arm64: Double check image alignment at entry
On arm64, the stub only moves the kernel image around in memory if needed, which is typically only for KASLR, given that relocatable kernels (which is the default) can run from any 64k aligned address, which is also the minimum alignment communicated to EFI via the PE/COFF header.
Unfortunately, some loaders appear to ignore this header, and load the kernel at some arbitrary offset in memory. We can deal with this, but let's check for this condition anyway, so non-compliant code can be spotted and fixed.
Cc: stable@vger.kernel.org # v5.10+ Signed-off-by: Ard Biesheuvel ardb@kernel.org Tested-by: Benjamin Herrenschmidt benh@kernel.crashing.org --- drivers/firmware/efi/libstub/arm64-stub.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c index 010564f..2363fee 100644 --- a/drivers/firmware/efi/libstub/arm64-stub.c +++ b/drivers/firmware/efi/libstub/arm64-stub.c @@ -119,6 +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;