From 748c030f360a940fe0c9382c8ca1649096c3a80d Mon Sep 17 00:00:00 2001 From: Igor Mammedov Date: Wed, 12 Jan 2022 08:03:31 -0500 Subject: acpi: fix OEM ID/OEM Table ID padding Commit [2] broke original '\0' padding of OEM ID and OEM Table ID fields in headers of ACPI tables. While it doesn't have impact on default values since QEMU uses 6 and 8 characters long values respectively, it broke usecase where IDs are provided on QEMU CLI. It shouldn't affect guest (but may cause licensing verification issues in guest OS). One of the broken usecases is user supplied SLIC table with IDs shorter than max possible length, where [2] mangles IDs with extra spaces in RSDT and FADT tables whereas guest OS expects those to mirror the respective values of the used SLIC table. Fix it by replacing whitespace padding with '\0' padding in accordance with [1] and expectations of guest OS 1) ACPI spec, v2.0b 17.2 AML Grammar Definition ... //OEM ID of up to 6 characters. If the OEM ID is //shorter than 6 characters, it can be terminated //with a NULL character. 2) Fixes: 602b458201 ("acpi: Permit OEM ID and OEM table ID fields to be changed") Resolves: https://gitlab.com/qemu-project/qemu/-/issues/707 Reported-by: Dmitry V. Orekhov Signed-off-by: Igor Mammedov Cc: qemu-stable@nongnu.org Message-Id: <20220112130332.1648664-4-imammedo@redhat.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Reviewed-by: Ani Sinha Tested-by: Dmitry V. Orekhov dima.orekhov@gmail.com --- hw/acpi/aml-build.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c index bb2cad6..8966e16 100644 --- a/hw/acpi/aml-build.c +++ b/hw/acpi/aml-build.c @@ -1724,9 +1724,9 @@ void acpi_table_begin(AcpiTable *desc, GArray *array) build_append_int_noprefix(array, 0, 4); /* Length */ build_append_int_noprefix(array, desc->rev, 1); /* Revision */ build_append_int_noprefix(array, 0, 1); /* Checksum */ - build_append_padded_str(array, desc->oem_id, 6, ' '); /* OEMID */ + build_append_padded_str(array, desc->oem_id, 6, '\0'); /* OEMID */ /* OEM Table ID */ - build_append_padded_str(array, desc->oem_table_id, 8, ' '); + build_append_padded_str(array, desc->oem_table_id, 8, '\0'); build_append_int_noprefix(array, 1, 4); /* OEM Revision */ g_array_append_vals(array, ACPI_BUILD_APPNAME8, 4); /* Creator ID */ build_append_int_noprefix(array, 1, 4); /* Creator Revision */ -- cgit v1.1