3.13.11-ckt19 -stable review patch. If anyone has any objections, please let me know.
------------------ From: Yinghai Lu <[email protected]> commit 7ed620bb343f434f8a85f830020c04988df2a140 upstream. While adding support loading kernel and initrd above 4G to grub2 in legacy mode, I was referring to efi_high_alloc(). That will allocate buffer for kernel and then initrd, and initrd will use kernel buffer start as limit. During testing found two buffers will be overlapped when initrd size is very big like 400M. It turns out efi_high_alloc() boundary checking is not right. end - size will be the new start, and should not compare new start with max, we need to make sure end is smaller than max. [ Basically, with the current efi_high_alloc() code it's possible to allocate memory above 'max', because efi_high_alloc() doesn't check that the tail of the allocation is below 'max'. If you have an EFI memory map with a single entry that looks like so, [0xc0000000-0xc0004000] And want to allocate 0x3000 bytes below 0xc0003000 the current code will allocate [0xc0001000-0xc0004000], not [0xc0000000-0xc0003000] like you would expect. - Matt ] Signed-off-by: Yinghai Lu <[email protected]> Reviewed-by: Ard Biesheuvel <[email protected]> Reviewed-by: Mark Rutland <[email protected]> Tested-by: Mark Rutland <[email protected]> Signed-off-by: Matt Fleming <[email protected]> [ luis: backported to 3.16: - file rename: drivers/firmware/efi/libstub/efi-stub-helper.c -> drivers/firmware/efi/efi-stub-helper.c ] Signed-off-by: Luis Henriques <[email protected]> Signed-off-by: Kamal Mostafa <[email protected]> --- drivers/firmware/efi/efi-stub-helper.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/firmware/efi/efi-stub-helper.c b/drivers/firmware/efi/efi-stub-helper.c index b6bffbf..a7bd9d3 100644 --- a/drivers/firmware/efi/efi-stub-helper.c +++ b/drivers/firmware/efi/efi-stub-helper.c @@ -133,12 +133,12 @@ again: start = desc->phys_addr; end = start + desc->num_pages * (1UL << EFI_PAGE_SHIFT); - if ((start + size) > end || (start + size) > max) - continue; - - if (end - size > max) + if (end > max) end = max; + if ((start + size) > end) + continue; + if (round_down(end - size, align) < start) continue; -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
