Commit 04ba15aa authored by Lv Zheng's avatar Lv Zheng Committed by Rafael J. Wysocki
Browse files

ACPICA: Tables: Do not validate signature for dynamic table load 

ACPICA commit d3c944f2cdc8c7e847b7942b1864f285189f7bce

Windows seems to allow arbitrary table signatures for Load/load_table
opcodes:
  ACPI BIOS Error (bug): Table has invalid signature [PRAD] (0x44415250)
So this patch removes dynamic load signature checks. However we need to
find a way to avoid table loading against tables like MADT. This is not
covered by this commit.

This Windows behavior has been validated on link #1. An end user bug
report can also be found on link #2.

This patch also includes simple cleanup for static load signature check
code. Reported by Ye Xiaolong, Fixed by Lv Zheng.

Link: https://github.com/acpica/acpica/commit/d3c944f2
Link: https://github.com/acpica/acpica/pull/121 [#1]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=118601

 [#2]
Reported-by: default avatarYe Xiaolong <xiaolong.ye@intel.com>
Reported-by: default avatarOlga Uhina <olga.uhina@gmail.com>
Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
Signed-off-by: default avatarBob Moore <robert.moore@intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 9b019b0f

drivers/acpi/acpica/tbinstal.c

+0 −28
Original line number Diff line number Diff line
@@ -222,34 +222,6 @@ acpi_tb_install_standard_table(acpi_physical_address address, 
	(void)acpi_ut_acquire_mutex(ACPI_MTX_TABLES);



	if (reload) {

		/*

		 * Validate the incoming table signature.

		 *

		 * 1) Originally, we checked the table signature for "SSDT" or "PSDT".

		 * 2) We added support for OEMx tables, signature "OEM".

		 * 3) Valid tables were encountered with a null signature, so we just

		 *    gave up on validating the signature, (05/2008).

		 * 4) We encountered non-AML tables such as the MADT, which caused

		 *    interpreter errors and kernel faults. So now, we once again allow

		 *    only "SSDT", "OEMx", and now, also a null signature. (05/2011).

		 */

		if ((new_table_desc.signature.ascii[0] != 0x00) &&

		    (!ACPI_COMPARE_NAME

		     (&new_table_desc.signature, ACPI_SIG_SSDT))

		    && (strncmp(new_table_desc.signature.ascii, "OEM", 3))) {

			ACPI_BIOS_ERROR((AE_INFO,

					 "Table has invalid signature [%4.4s] (0x%8.8X), "

					 "must be SSDT or OEMx",

					 acpi_ut_valid_nameseg(new_table_desc.

							       signature.

							       ascii) ?

					 new_table_desc.signature.

					 ascii : "????",

					 new_table_desc.signature.integer));



			status = AE_BAD_SIGNATURE;

			goto unlock_and_exit;

		}



		/* Check if table is already registered */

drivers/acpi/acpica/tbxfload.c

+1 −1
Original line number Diff line number Diff line
@@ -206,7 +206,7 @@ acpi_status acpi_tb_load_namespace(void) 
	for (i = 0; i < acpi_gbl_root_table_list.current_table_count; ++i) {

		table = &acpi_gbl_root_table_list.tables[i];



		if (!acpi_gbl_root_table_list.tables[i].address ||

		if (!table->address ||

		    (!ACPI_COMPARE_NAME(table->signature.ascii, ACPI_SIG_SSDT)

		     && !ACPI_COMPARE_NAME(table->signature.ascii,

					   ACPI_SIG_PSDT)

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