Add function to apply a permutation on the dynamic symbols

api/python/ELF/objects/pyBinary.cpp

@@ -198,6 +198,10 @@ void init_ELF_Binary_class(py::module& m) {
         &Binary::strip,
         "Strip the binary")
 
+    .def("permute_dynamic_symbols",
+        &Binary::permute_dynamic_symbols,
+        "Apply the given permutation on the dynamic symbols table")
+
     .def("write",
         &Binary::write,
         "Rebuild the binary and write it in a file",

include/LIEF/ELF/Binary.hpp

@@ -97,7 +97,6 @@ class DLL_PUBLIC Binary : public LIEF::Binary {
     it_symbols                             get_dynamic_symbols(void);
     it_const_symbols                       get_dynamic_symbols(void) const;
 
-
     //! @brief Return symbols which are exported by the binary
     it_exported_symbols                    get_exported_symbols(void);
     it_const_exported_symbols              get_exported_symbols(void) const;
@@ -346,6 +345,12 @@ class DLL_PUBLIC Binary : public LIEF::Binary {
     //! @brief Method so that the ``visitor`` can visit us
     virtual void accept(LIEF::Visitor& visitor) const override;
 
+    //! @brief Apply the given permutation on the dynamic symbols table
+    //!
+    //! To avoid override by the ELF::Builder, one should set ELF::Builder::empties_gnuhash
+    //! to ``true``
+    void permute_dynamic_symbols(const std::vector<size_t>& permutation);
+
     size_t hash(const std::string& name);
 
     virtual ~Binary(void);

src/ELF/Binary.cpp

@@ -1391,6 +1391,23 @@ bool Binary::has_dynamic_entry(DYNAMIC_TAGS tag) const {
   return true;
 }
 
+
+void Binary::permute_dynamic_symbols(const std::vector<size_t>& permutation) {
+  for (size_t i = 0; i < permutation.size(); ++i) {
+    if (this->dynamic_symbols_[i]->has_version() and this->dynamic_symbols_[permutation[i]]->has_version()) {
+      std::swap(this->symbol_version_table_[i], this->symbol_version_table_[permutation[i]]);
+      std::swap(this->dynamic_symbols_[i], this->dynamic_symbols_[permutation[i]]);
+    } else if (not this->dynamic_symbols_[i]->has_version() and not this->dynamic_symbols_[permutation[i]]->has_version()) {
+      std::swap(this->dynamic_symbols_[i], this->dynamic_symbols_[permutation[i]]);
+    } else if (permutation[i] == i) {
+      continue;
+    } else {
+      LOG(ERROR) << "Can't apply permutation at index " << std::dec << i;
+    }
+
+  }
+}
+
 LIEF::Header Binary::get_abstract_header(void) const {
   LIEF::Header header;
   const std::pair<ARCHITECTURES, std::set<MODES>>& am = this->get_header().abstract_architecture();
@@ -1403,6 +1420,8 @@ LIEF::Header Binary::get_abstract_header(void) const {
 }
 
 
+
+
 void Binary::accept(LIEF::Visitor&) const {
 }
 

tests/elf/elf_test.py

@@ -1,12 +1,25 @@
 #!/usr/bin/env python
 import unittest
 import lief
+import tempfile
+import sys
+import subprocess
+import stat
+import os
+import logging
+import random
+
+
+from subprocess import Popen
 
 from unittest import TestCase
 from utils import get_sample
 
 class TestELF(TestCase):
 
+    def setUp(self):
+        self.logger = logging.getLogger(__name__)
+
     def test_rpath(self):
         etterlog = lief.parse(get_sample('ELF/ELF64_x86-64_binary_etterlog.bin'))
 
@@ -59,6 +72,41 @@ class TestELF(TestCase):
                 0x12F7C433, 0xEB01FAB6, 0xECD54543, 0xAD3C9892, 0x72632CCF, 0x12F7A2B3, 0x7C92E3BB, 0x7C96F087]
         self.assertEqual(hash_values, hash_values_test)
 
+    def test_permutation(self):
+        samples = [
+                "ELF/ELF64_x86-64_binary_ls.bin",
+                "ELF/ELF64_x86-64_binary_gcc.bin",
+                "ELF/ELF64_x86-64_binary_openssl.bin",
+        ]
+        tmp_dir = tempfile.mkdtemp(suffix='_lief_test_permutation')
+        for sample in samples:
+            binary = lief.parse(get_sample(sample))
+            dynamic_symbols = binary.dynamic_symbols
+
+            gnu_hash_table = binary.gnu_hash
+
+            idx = gnu_hash_table.symbol_index
+
+            permutation = [i for i in range(1, len(dynamic_symbols))]
+            random.shuffle(permutation)
+            permutation = [0] + permutation
+
+            builder = lief.ELF.Builder(binary)
+            builder.empties_gnuhash(True)
+            builder.build()
+            output = os.path.join(tmp_dir, "{}.permutated".format(binary.name))
+            binary.write(output)
+            if not sys.platform.startswith("linux"):
+                return
+
+            st = os.stat(output)
+            os.chmod(output, st.st_mode | stat.S_IEXEC)
+
+            p = Popen([output, "--help"], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+            stdout, _ = p.communicate()
+            self.logger.debug(stdout.decode("utf8"))
+            self.assertEqual(p.returncode, 0)
+
 
 
 
@@ -68,5 +116,13 @@ class TestELF(TestCase):
 
 
 if __name__ == '__main__':
-    unittest.main(verbosity = 2)
+
+    root_logger = logging.getLogger()
+    root_logger.setLevel(logging.DEBUG)
+
+    ch = logging.StreamHandler()
+    ch.setLevel(logging.DEBUG)
+    root_logger.addHandler(ch)
+
+    unittest.main(verbosity=2)