From 4e8fb957a349558648d5cddb80a89460bc97439e Mon Sep 17 00:00:00 2001
From: Jon Maloy <jmaloy@redhat.com>
Date: Wed, 30 Mar 2022 14:52:34 -0400
Subject: [PATCH 09/18] acpi: fix QEMU crash when started with SLIC table
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RH-Author: Jon Maloy <jmaloy@redhat.com>
RH-MergeRequest: 141: acpi: fix QEMU crash when started with SLIC table
RH-Commit: [1/10] 0c34e80346c33da4f220d9c486b120c35005144e (jmaloy/qemu-kvm)
RH-Bugzilla: 2062611
RH-Acked-by: Igor Mammedov <imammedo@redhat.com>

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2062611
Upstream: Merged

commit 8cdb99af45365727ac17f45239a9b8c1d5155c6d)
Author: Igor Mammedov <imammedo@redhat.com>
Date:   Mon Dec 27 14:31:17 2021 -0500

    acpi: fix QEMU crash when started with SLIC table

    if QEMU is started with used provided SLIC table blob,

      -acpitable sig=SLIC,oem_id='CRASH ',oem_table_id="ME",oem_rev=00002210,asl_compiler_id="",asl_compiler_rev=00000000,data=/dev/null
    it will assert with:

      hw/acpi/aml-build.c:61:build_append_padded_str: assertion failed: (len <= maxlen)

    and following backtrace:

      ...
      build_append_padded_str (array=0x555556afe320, str=0x555556afdb2e "CRASH ME", maxlen=0x6, pad=0x20) at hw/acpi/aml-build.c:61
      acpi_table_begin (desc=0x7fffffffd1b0, array=0x555556afe320) at hw/acpi/aml-build.c:1727
      build_fadt (tbl=0x555556afe320, linker=0x555557ca3830, f=0x7fffffffd318, oem_id=0x555556afdb2e "CRASH ME", oem_table_id=0x555556afdb34 "ME") at hw/acpi/aml-build.c:2064
      ...

    which happens due to acpi_table_begin() expecting NULL terminated
    oem_id and oem_table_id strings, which is normally the case, but
    in case of user provided SLIC table, oem_id points to table's blob
    directly and as result oem_id became longer than expected.

    Fix issue by handling oem_id consistently and make acpi_get_slic_oem()
    return NULL terminated strings.

    PS:
    After [1] refactoring, oem_id semantics became inconsistent, where
    NULL terminated string was coming from machine and old way pointer
    into byte array coming from -acpitable option. That used to work
    since build_header() wasn't expecting NULL terminated string and
    blindly copied the 1st 6 bytes only.

    However commit [2] broke that by replacing build_header() with
    acpi_table_begin(), which was expecting NULL terminated string
    and was checking oem_id size.

    1) 602b45820 ("acpi: Permit OEM ID and OEM table ID fields to be changed")
    2)
    Fixes: 4b56e1e4eb08 ("acpi: build_fadt: use acpi_table_begin()/acpi_table_end() instead of build_header()")
    Resolves: https://gitlab.com/qemu-project/qemu/-/issues/786
    Signed-off-by: Igor Mammedov <imammedo@redhat.com>
    Message-Id: <20211227193120.1084176-2-imammedo@redhat.com>
    Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
    Tested-by: Denis Lisov <dennis.lissov@gmail.com>
    Tested-by: Alexander Tsoy <alexander@tsoy.me>
    Cc: qemu-stable@nongnu.org
    Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
    Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

(cherry picked from commit 8cdb99af45365727ac17f45239a9b8c1d5155c6d)
Signed-off-by: Jon Maloy <jmaloy@redhat.com>
---
 hw/acpi/core.c       | 4 ++--
 hw/i386/acpi-build.c | 2 ++
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/hw/acpi/core.c b/hw/acpi/core.c
index 1e004d0078..3e811bf03c 100644
--- a/hw/acpi/core.c
+++ b/hw/acpi/core.c
@@ -345,8 +345,8 @@ int acpi_get_slic_oem(AcpiSlicOem *oem)
         struct acpi_table_header *hdr = (void *)(u - sizeof(hdr->_length));
 
         if (memcmp(hdr->sig, "SLIC", 4) == 0) {
-            oem->id = hdr->oem_id;
-            oem->table_id = hdr->oem_table_id;
+            oem->id = g_strndup(hdr->oem_id, 6);
+            oem->table_id = g_strndup(hdr->oem_table_id, 8);
             return 0;
         }
     }
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index a4478e77b7..acc4869db0 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -2726,6 +2726,8 @@ void acpi_build(AcpiBuildTables *tables, MachineState *machine)
 
     /* Cleanup memory that's no longer used. */
     g_array_free(table_offsets, true);
+    g_free(slic_oem.id);
+    g_free(slic_oem.table_id);
 }
 
 static void acpi_ram_update(MemoryRegion *mr, GArray *data)
-- 
2.27.0