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loader/i386/linux: Fix initrd maximum address overflow

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The current i386 initrd is limited under 1 GiB memory and it works with
most compressed initrds (also initrd_addr_max case reported by kernel).

addr = (addr_max - aligned_size) & ~0xFFF;

Above line is used to calculate the reasonable address to store the initrd.

However, if initrd size is greater than 1 GiB or initrd_addr_max, then it
will get overflow, especially on x86_64 arch.

Therefore, add a check point to prevent it overflows as well as having
a debug log for complex story of initrd addresses.

Signed-off-by: Jeremy Szu <jeremy.szu@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This commit is contained in:
Jeremy Szu 2022-12-04 20:25:09 +08:00 committed by Daniel Kiper
parent ef562269bc
commit 012fe7f055
1 changed files with 13 additions and 0 deletions
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13
grub-core/loader/i386/linux.c
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@ -1085,9 +1085,22 @@ grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),
addr_min = (grub_addr_t) prot_mode_target + prot_init_space;
/* Make sure the maximum address is able to store the initrd. */
if (addr_max < aligned_size)
{
grub_error (GRUB_ERR_OUT_OF_RANGE,
N_("the size of initrd is bigger than addr_max"));
goto fail;
}
/* Put the initrd as high as possible, 4KiB aligned. */
addr = (addr_max - aligned_size) & ~0xFFF;
grub_dprintf ("linux",
"Initrd at addr 0x%" PRIxGRUB_ADDR " which is expected in"
" ranger 0x%" PRIxGRUB_ADDR " ~ 0x%" PRIxGRUB_ADDR "\n",
addr, addr_min, addr_max);
if (addr < addr_min)
{
grub_error (GRUB_ERR_OUT_OF_RANGE, "the initrd is too big");