acpi: Fix out of bounds access in grub_acpi_xsdt_find_table()

(cherry picked from commit 3d099f07174b832482b0f627930b802effd7790a)

backport-acpi-Fix-out-of-bounds-access-in-grub_acpi_xsdt_find.patch

@@ -0,0 +1,34 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
+Date: Wed, 16 Oct 2024 16:20:24 +1100
+Subject: [PATCH] acpi: Fix out of bounds access in grub_acpi_xsdt_find_table()
+
+The calculation of the size of the table was incorrect (copy/pasta from
+grub_acpi_rsdt_find_table() I assume...). The entries are 64-bit long.
+
+This causes us to access beyond the end of the table which is causing
+crashes during boot on some systems. Typically this is causing a crash
+on VMWare when using UEFI and enabling serial autodetection, as
+
+grub_acpi_find_table (GRUB_ACPI_SPCR_SIGNATURE);
+
+Will goes past the end of the table (the SPCR table doesn't exits)
+
+Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
+---
+ 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 48ded4e2ea6e..8ff0835d501f 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;

grub.patches

@@ -243,3 +243,4 @@ Patch242:       0001-newfeature-tpcm-add-hygon-tpcm-support.patch
 Patch243:       10_linux-fix-missing-ro-in-kernel-boot-parameters.patch
 Patch244:       0001-cryptodisk-add-OS-provided-secret-support.patch
 Patch245:       0002-efi-Add-API-for-retrieving-the-EFI-secret-for-crypto.patch
+Patch246:       backport-acpi-Fix-out-of-bounds-access-in-grub_acpi_xsdt_find.patch

grub2.spec

@@ -19,7 +19,7 @@
 Name:		grub2
 Epoch:		1
 Version:	2.12
-Release:	26
+Release:	27
 Summary:	Bootloader with support for Linux, Multiboot and more
 License:	GPLv3+
 URL:		http://www.gnu.org/software/grub/
@@ -461,6 +461,12 @@ fi
 %{_datadir}/man/man*
 
 %changelog
+* Wed Nov 13 2024 yueyuankun <yueyuankun@kylinos.cn> - 1:2.12-27
+- Type:bugfix
+- CVE:NA
+- SUG:NA
+- DESC:acpi: Fix out of bounds access in grub_acpi_xsdt_find_table()
+
 * Wed Nov 13 2024 hanliyang <hanliyang@hygon.cn> - 1:2.12-26
 - Type:requirement
 - CVE:NA