【BUG】grub2 serial module coredump

[岳远昆]

Hello, I recently discovered a bug.

When using the serial module in the grub shell, there was no response from the grub shell, and it is initially suspected to be a core dump.

Through debugging analysis of grub-core/kern/acpi.c, grub2 crashed after grub_memcmp (tbl ->signature, sig, 4) in grub-acpi_xsdt_find_table().

tbl ->Signature obtained an address that exceeded expectations.

In 64 bit XSDT, perhaps the loop variable s should be more appropriate by dividing by grub_uinit64_t?

For example,

grub-core/kern/acpi.c | 2 +-

 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/grub-core/kern/acpi.c b/grub-core/kern/acpi.c

index 48ded4e2e..8ff0835d5 100644

--- a/grub-core/kern/acpi.c

+++ b/grub-core/kern/acpi.c

@@ -75,7 +75,7 @@ grub_acpi_xsdt_find_table (struct grub_acpi_table_header *xsdt, const char *sig)

     return 0;

   ptr = (grub_unaligned_uint64_t *) (xsdt + 1);

-  s = (xsdt->length - sizeof (*xsdt)) / sizeof (grub_uint32_t);

+  s = (xsdt->length - sizeof (*xsdt)) / sizeof (grub_uint64_t);

   for (; s; s--, ptr++)

     {

       struct grub_acpi_table_header *tbl;

-- 

Hardware platform where the problem occurred: x86_64 UEFI platform, CPU: Haiguang、ZhaoXin

Do you have any better suggestions to solve the current problem?

Thanks!

0001-Fix-tbl-signature-taking-address-beyond-expected-on-.patch
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