[PATCH] acpica: Fix segfault when disassembling AML (LP: #1050475)

[Colin King]

From: Colin Ian King <colin.king at canonical.com>

Running fwts against a collection of test tables I found a segfault
in source/components/disassembler/dmopcode.c:334, due to Tag being
null. This patch is a fix from Robert Moore at Intel which will land
in the September release of ACPICA/iASL.

Signed-off-by: Colin Ian King <colin.king at canonical.com>
---
 src/acpica/source/common/dmrestag.c                  |    5 +++++
 src/acpica/source/components/disassembler/dmopcode.c |    4 ++++
 2 files changed, 9 insertions(+)

diff --git a/src/acpica/source/common/dmrestag.c b/src/acpica/source/common/dmrestag.c
index 9afaad3..3097f15 100644
--- a/src/acpica/source/common/dmrestag.c
+++ b/src/acpica/source/common/dmrestag.c
@@ -541,6 +541,11 @@ AcpiDmCheckResourceReference (
     /* Get the Index term, must be an integer constant to convert */
 
     IndexOp = BufferNameOp->Common.Next;
+
+    /* Major cheat: The Node field is also used for the Tag ptr. Clear it now */
+
+    IndexOp->Common.Node = NULL;
+
     OpInfo = AcpiPsGetOpcodeInfo (IndexOp->Common.AmlOpcode);
     if (OpInfo->ObjectType != ACPI_TYPE_INTEGER)
     {
diff --git a/src/acpica/source/components/disassembler/dmopcode.c b/src/acpica/source/components/disassembler/dmopcode.c
index 252b1b8..c6fa387 100644
--- a/src/acpica/source/components/disassembler/dmopcode.c
+++ b/src/acpica/source/components/disassembler/dmopcode.c
@@ -326,6 +326,10 @@ AcpiDmFieldPredefinedDescription (
     /* Major cheat: We previously put the Tag ptr in the Node field */
 
     Tag = ACPI_CAST_PTR (char, IndexOp->Common.Node);
+    if (!Tag)
+    {
+        return;
+    }
 
     /* Match the name in the info table */
 
-- 
1.7.10.4