python/tarfile.cc: LFS: Handle too large file

Handle both file sizes larger than SIZE_MAX and allocation
failures when reading the data of a tarmember.

If using the go() function with a callback, pass None as the data
parameter for files that are too large. For extractdata, raise
a MemoryError if the file too extract is too large.

Also check for an existing error first in extractdata, before
raising a new one.

Test the whole thing on 32-bit platforms with a sample deb that
contains a zeroed file that is 5GB large (compressed using xz
at level 1 to a few kb).

2 files changed, 22 insertions, 0 deletions

diff --git a/tests/data/test_debs/large-package-content_1.0_all.deb b/tests/data/test_debs/large-package-content_1.0_all.deb
new file mode 100644
index 00000000..56bdce3d
--- /dev/null
+++ b/tests/data/test_debs/large-package-content_1.0_all.deb
diff --git a/tests/test_large_file.py b/tests/test_large_file.py
new file mode 100644
index 00000000..2e873131
--- /dev/null
+++ b/tests/test_large_file.py
@@ -0,0 +1,22 @@
+#!/usr/bin/python
+
+import sys
+import unittest
+
+import apt_inst
+
+IS_NOT_32BIT = sys.maxsize > 2**32
+
+@unittest.skipIf(IS_NOT_32BIT, "Large File support is for 32 bit systems")
+class testHashes(unittest.TestCase):
+    " test the hashsum functions against strings and files "
+
+    LARGE_PACKAGE_CONTENT = "data/test_debs/large-package-content_1.0_all.deb"
+
+    def testExtractData(self):
+        deb = apt_inst.DebFile(self.LARGE_PACKAGE_CONTENT)
+
+        self.assertRaises(MemoryError, deb.data.extractdata, "large-file")
+
+if __name__ == "__main__":
+    unittest.main()