[Lldb-commits] [PATCH] D75925: [lldb] reject `.debug_arange` sections with nonzero segment size

[Luke Drummond via Phabricator via lldb-commits]

ldrumm updated this revision to Diff 249663.
ldrumm added a comment.

I found similar unittests for other DWARF entries which allow me to check more about the parser state, so I went with Pavel's suggestion for the testcase


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D75925/new/

https://reviews.llvm.org/D75925

Files:
  lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugArangeSet.cpp
  lldb/unittests/SymbolFile/DWARF/SymbolFileDWARFTests.cpp


Index: lldb/unittests/SymbolFile/DWARF/SymbolFileDWARFTests.cpp
===================================================================
--- lldb/unittests/SymbolFile/DWARF/SymbolFileDWARFTests.cpp
+++ lldb/unittests/SymbolFile/DWARF/SymbolFileDWARFTests.cpp
@@ -18,6 +18,7 @@
 #include "Plugins/SymbolFile/DWARF/DWARFAbbreviationDeclaration.h"
 #include "Plugins/SymbolFile/DWARF/DWARFDataExtractor.h"
 #include "Plugins/SymbolFile/DWARF/DWARFDebugAbbrev.h"
+#include "Plugins/SymbolFile/DWARF/DWARFDebugArangeSet.h"
 #include "Plugins/SymbolFile/DWARF/SymbolFileDWARF.h"
 #include "Plugins/SymbolFile/PDB/SymbolFilePDB.h"
 #include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
@@ -310,3 +311,34 @@
   EXPECT_EQ("abbreviation declaration attribute list not terminated with a "
             "null entry", llvm::toString(std::move(error)));
 }
+
+TEST_F(SymbolFileDWARFTests, ParseArangesNonzeroSegmentSize) {
+  // This `.debug_aranges` table header is a valid 32bit big-endian section
+  // according to the DWARFv5 spec:6.2.1, but contains segment selectors which
+  // are not supported by lldb, and should be gracefully rejected
+  const unsigned char binary_data[] = {
+    0, 0, 0, 41, // unit_length (length field not including this field itself)
+    0, 2, // DWARF version number (half)
+    0, 0, 0, 0, // offset into the .debug_info_table (ignored for the purposes of this test
+    4, // address size
+    1, // segment size
+    // alignment for the first tuple which "begins at an offset that is a
+    // multiple of the size of a single tuple". Tuples are nine bytes in this example.
+    0, 0, 0, 0, 0, 0,
+    // BEGIN TUPLES
+    1, 0, 0, 0, 4, 0, 0, 0, 1, // a 1byte object starting at address 4 in segment 1
+    0, 0, 0, 0, 4, 0, 0, 0, 1, // a 1byte object starting at address 4 in segment 0
+    // END TUPLES
+    0, 0, 0, 0, 0, 0, 0, 0, 0 // terminator
+  };
+  DWARFDataExtractor data;
+  data.SetData(static_cast<const void *>(binary_data), sizeof binary_data,
+               lldb::ByteOrder::eByteOrderBig);
+  DWARFDebugArangeSet debug_aranges;
+  offset_t off = 0;
+  llvm::Error error = debug_aranges.extract(data, &off);
+  EXPECT_TRUE(bool(error));
+  EXPECT_EQ("segmented arange entries are not supported",
+            llvm::toString(std::move(error)));
+  EXPECT_EQ(off, 12); // Parser should read no further than the segment size
+}
Index: lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugArangeSet.cpp
===================================================================
--- lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugArangeSet.cpp
+++ lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugArangeSet.cpp
@@ -63,7 +63,8 @@
   // 1 - the version looks good
   // 2 - the address byte size looks plausible
   // 3 - the length seems to make sense
-  // size looks plausible
+  // 4 - size looks plausible
+  // 5 - the arange tuples do not contain a segment field
   if (m_header.version < 2 || m_header.version > 5)
     return llvm::make_error<llvm::object::GenericBinaryError>(
         "Invalid arange header version");
@@ -81,6 +82,10 @@
     return llvm::make_error<llvm::object::GenericBinaryError>(
         "Invalid arange header length");
 
+  if (m_header.seg_size)
+    return llvm::make_error<llvm::object::GenericBinaryError>(
+        "segmented arange entries are not supported");
+
   // The first tuple following the header in each set begins at an offset
   // that is a multiple of the size of a single tuple (that is, twice the
   // size of an address). The header is padded, if necessary, to the


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