[AIX][BigArchive] Treat the archive is empty if the first child member offset is...

If the archive contains free list and contains no member file, the buffer length doesn't equal to length of the header.

Reviewed By: Esme, DiggerLin, #powerpc

Differential Revision: https://reviews.llvm.org/D138986

diff --git a/llvm/include/llvm/Object/Archive.h b/llvm/include/llvm/Object/Archive.h
index fbacee9..b77c853 100644 (file)
--- a/llvm/include/llvm/Object/Archive.h
+++ b/llvm/include/llvm/Object/Archive.h
@@ -410,9 +410,7 @@ public:
   BigArchive(MemoryBufferRef Source, Error &Err);
   uint64_t getFirstChildOffset() const override { return FirstChildOffset; }
   uint64_t getLastChildOffset() const { return LastChildOffset; }
-  bool isEmpty() const override {
-    return Data.getBufferSize() == sizeof(FixLenHdr);
-  };
+  bool isEmpty() const override { return getFirstChildOffset() == 0; }
 };
 
 } // end namespace object

diff --git a/llvm/lib/Object/Archive.cpp b/llvm/lib/Object/Archive.cpp
index 2cf9241..046bcb3 100644 (file)
--- a/llvm/lib/Object/Archive.cpp
+++ b/llvm/lib/Object/Archive.cpp
@@ -949,7 +949,15 @@ Archive::child_iterator Archive::child_begin(Error &Err,
     return child_iterator::itr(
         Child(this, FirstRegularData, FirstRegularStartOfFile), Err);
 
-  const char *Loc = Data.getBufferStart() + getFirstChildOffset();
+  uint64_t FirstChildOffset = getFirstChildOffset();
+  const char *Loc = Data.getBufferStart() + FirstChildOffset;
+  if (Loc >= Data.getBufferEnd()) {
+    Err = malformedError("First member offset " + Twine(FirstChildOffset) +
+                         " is beyond the data buffer which has size of " +
+                         Twine(Data.getBufferSize()));
+    return child_end();
+  }
+
   Child C(this, Loc, &Err);
   if (Err)
     return child_end();

diff --git a/llvm/test/Object/archive-big-malformed-first-member.test b/llvm/test/Object/archive-big-malformed-first-member.test
new file mode 100644 (file)
index 0000000..08ae37b
--- /dev/null
+++ b/llvm/test/Object/archive-big-malformed-first-member.test
@@ -0,0 +1,7 @@
+# Test reading an empty archive with first member's offset is not zero.
+# RUN: echo    "<bigaf>" > %t.a
+# RUN: echo -n "0                   0                   0                   128                 0                   0                   " >> %t.a
+# RUN: not llvm-ar tv %t.a 2>&1 | grep 'truncated or malformed archive'
+# RUN: echo    "<bigaf>" > %t.a
+# RUN: echo -n "0                   0                   0                   28                  0                   0                   " >> %t.a
+# RUN: not llvm-ar tv %t.a 2>&1 | grep 'truncated or malformed archive'

diff --git a/llvm/test/Object/archive-big-read-empty-with-freelist.test b/llvm/test/Object/archive-big-read-empty-with-freelist.test
index 2ac3253..05e45ca 100644 (file)
--- a/llvm/test/Object/archive-big-read-empty-with-freelist.test
+++ b/llvm/test/Object/archive-big-read-empty-with-freelist.test
@@ -1,3 +1,3 @@
 # Test reading an empty archive with free list in it.
-# RUN: not llvm-ar tv %p/Inputs/aix-empty-big-archive-with-freelist.a 2>&1 \
-# RUN:   | grep 'truncated or malformed archive'
+# RUN: llvm-ar tv %p/Inputs/aix-empty-big-archive-with-freelist.a 2>&1 \
+# RUN:   | not grep 'truncated or malformed archive'