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relocator: Protect grub_relocator_alloc_chunk_addr() input args against integer underflow/overflow

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Use arithmetic macros from safemath.h to accomplish it. In this commit,
I didn't want to be too paranoid to check every possible math equation
for overflow/underflow. Only obvious places (with non zero chance of
overflow/underflow) were refactored.

Signed-off-by: Alexey Makhalov <amakhalov@vmware.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This commit is contained in:
Alexey Makhalov 2020-07-15 06:42:37 +00:00 • committed by Daniel Kiper
parent 781b3e5efc
commit caea56d1f8
4 changed files with 31 additions and 10 deletions
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9
grub-core/loader/i386/linux.c
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@ -36,6 +36,7 @@
#include <grub/lib/cmdline.h>
#include <grub/linux.h>
#include <grub/machine/kernel.h>
#include <grub/safemath.h>
GRUB_MOD_LICENSE ("GPLv3+");
@ -547,9 +548,13 @@ grub_linux_boot (void)
{
grub_relocator_chunk_t ch;
grub_size_t sz;
if (grub_add (ctx.real_size, efi_mmap_size, &sz))
return GRUB_ERR_OUT_OF_RANGE;
err = grub_relocator_alloc_chunk_addr (relocator, &ch,
ctx.real_mode_target,
(ctx.real_size + efi_mmap_size));
ctx.real_mode_target, sz);
if (err)
return err;
real_mode_mem = get_virtual_current_address (ch);