This commit introduces integer underflow mitigation in max_addr calculation
in grub_relocator_alloc_chunk_align() invocation.
It consists of 2 fixes:
1. Introduced grub_relocator_alloc_chunk_align_safe() wrapper function to perform
sanity check for min/max and size values, and to make safe invocation of
grub_relocator_alloc_chunk_align() with validated max_addr value. Replace all
invocations such as grub_relocator_alloc_chunk_align(..., min_addr, max_addr - size, size, ...)
by grub_relocator_alloc_chunk_align_safe(..., min_addr, max_addr, size, ...).
2. Introduced UP_TO_TOP32(s) macro for the cases where max_addr is 32-bit top
address (0xffffffff - size + 1) or similar.
Signed-off-by: Alexey Makhalov <amakhalov@vmware.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
* include/grub/i386/relocator.h (grub_relocator16_state):
New member ebp.
* grub-core/lib/i386/relocator.c (grub_relocator16_ebp): New extern
variable.
(grub_relocator16_boot): Handle %ebp.
* grub-core/lib/i386/relocator16.S: Likewise.
* grub-core/loader/i386/pc/freedos.c:
Load BPB to pass kernel which partition to load from.
Check that kernel file is not too large.
Set register dl to BIOS unit number as well.
* include/grub/i386/pc/int.h (grub_i386_idt): New struct.
(grub_realidt): New var.
* grub-core/lib/i386/relocator16.S (grub_relocator16_idt): New variable
Load idt.
* grub-core/lib/i386/relocator.c (grub_relocator16_idt):
New declaration.
(grub_relocator16_boot): Set grub_relocator16_idt.
* grub-core/kern/i386/realmode.S (realidt): Renamed to ...
(LOCAL(realidt)): ... this.
* grub-core/boot/i386/pc/startup_raw.S: Pass pointer to realidt in eax.
* grub-core/kern/i386/pc/startup.S: Save pointer to realidt.
(grub_realidt): New variable.
part. Instead setup the correct stack in RM.
* grub-core/lib/i386/relocator.c (grub_relocator16_boot): Reserve place
for stack.
* include/grub/i386/relocator_private.h: New file.
required by the boot protocol.
* include/grub/i386/relocator.h (struct grub_relocator32_state): Add
ebp and edi members.
* grub-core/lib/i386/relocator.c (grub_relocator_boot): Handle
state.ebp and state.edi.
* grub-core/lib/i386/relocator32.S (grub_relocator32_start): Set
%ebp and %edi according to grub_relocator32_ebp and
grub_relocator32_edi respectively.
* grub-core/loader/i386/linux.c (grub_linux_boot): Zero state.ebp
and state.edi.
