From 6e237576f0e3a409e04c3bf9f131421b5c0912e2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pierre=20B=C3=A9lissent?=
<belissent@users.noreply.github.com>
Date: Sat, 6 Jun 2020 21:16:44 +0200
Subject: [PATCH] Issue serge1/ELFIO#19: Test case to reproduce, and correction
---
ELFIOTest/ELFIOTest1.cpp | 123 ++++++++++++++++++++++++++++++---------
elfio/elfio.hpp | 4 +-
2 files changed, 97 insertions(+), 30 deletions(-)
diff --git a/ELFIOTest/ELFIOTest1.cpp b/ELFIOTest/ELFIOTest1.cpp
index efb49e0..8a254ba 100644
--- a/ELFIOTest/ELFIOTest1.cpp
+++ b/ELFIOTest/ELFIOTest1.cpp
@@ -26,15 +26,15 @@ bool write_obj_i386( bool is64bit )
text_sec->set_type( SHT_PROGBITS );
text_sec->set_flags( SHF_ALLOC | SHF_EXECINSTR );
text_sec->set_addr_align( 0x10 );
-
+
// Add data into it
- char text[] = { '\xB8', '\x04', '\x00', '\x00', '\x00', // mov eax, 4
- '\xBB', '\x01', '\x00', '\x00', '\x00', // mov ebx, 1
- '\xB9', '\x00', '\x00', '\x00', '\x00', // mov ecx, msg
- '\xBA', '\x0E', '\x00', '\x00', '\x00', // mov edx, 14
- '\xCD', '\x80', // int 0x80
- '\xB8', '\x01', '\x00', '\x00', '\x00', // mov eax, 1
- '\xCD', '\x80' // int 0x80
+ char text[] = { '\xB8', '\x04', '\x00', '\x00', '\x00', // mov eax, 4
+ '\xBB', '\x01', '\x00', '\x00', '\x00', // mov ebx, 1
+ '\xB9', '\x00', '\x00', '\x00', '\x00', // mov ecx, msg
+ '\xBA', '\x0E', '\x00', '\x00', '\x00', // mov edx, 14
+ '\xCD', '\x80', // int 0x80
+ '\xB8', '\x01', '\x00', '\x00', '\x00', // mov eax, 1
+ '\xCD', '\x80' // int 0x80
};
text_sec->set_data( text, sizeof( text ) );
@@ -43,7 +43,7 @@ bool write_obj_i386( bool is64bit )
data_sec->set_type( SHT_PROGBITS );
data_sec->set_flags( SHF_ALLOC | SHF_WRITE );
data_sec->set_addr_align( 4 );
-
+
char data[] = { '\x48', '\x65', '\x6C', '\x6C', '\x6F', // msg: db 'Hello, World!', 10
'\x2C', '\x20', '\x57', '\x6F', '\x72',
'\x6C', '\x64', '\x21', '\x0A'
@@ -63,7 +63,7 @@ bool write_obj_i386( bool is64bit )
sym_sec->set_link( str_sec->get_index() );
sym_sec->set_addr_align( 4 );
sym_sec->set_entry_size( writer.get_default_entry_size( SHT_SYMTAB ) );
-
+
symbol_section_accessor symbol_writer( writer, sym_sec );
Elf_Word nSymIndex = symbol_writer.add_symbol( nStrIndex, 0, 0,
STB_LOCAL, STT_NOTYPE, 0,
@@ -96,13 +96,13 @@ bool write_obj_i386( bool is64bit )
section* note_sec = writer.sections.add( ".note" );
note_sec->set_type( SHT_NOTE );
note_sec->set_addr_align( 1 );
-
+
// Create notes writer
note_section_accessor note_writer( writer, note_sec );
note_writer.add_note( 0x77, "Created by ELFIO", 0, 0 );
// Create ELF file
- writer.save(
+ writer.save(
is64bit ?
"../elf_examples/write_obj_i386_64.o" :
"../elf_examples/write_obj_i386_32.o"
@@ -150,15 +150,15 @@ bool write_exe_i386( const std::string& filename, bool is64bit, bool set_addr =
if ( set_addr ) {
text_sec->set_address( addr );
}
-
+
// Add data into it
- char text[] = { '\xB8', '\x04', '\x00', '\x00', '\x00', // mov eax, 4
- '\xBB', '\x01', '\x00', '\x00', '\x00', // mov ebx, 1
- '\xB9', '\x20', '\x80', '\x04', '\x08', // mov ecx, msg
- '\xBA', '\x0E', '\x00', '\x00', '\x00', // mov edx, 14
- '\xCD', '\x80', // int 0x80
- '\xB8', '\x01', '\x00', '\x00', '\x00', // mov eax, 1
- '\xCD', '\x80' // int 0x80
+ char text[] = { '\xB8', '\x04', '\x00', '\x00', '\x00', // mov eax, 4
+ '\xBB', '\x01', '\x00', '\x00', '\x00', // mov ebx, 1
+ '\xB9', '\x20', '\x80', '\x04', '\x08', // mov ecx, msg
+ '\xBA', '\x0E', '\x00', '\x00', '\x00', // mov edx, 14
+ '\xCD', '\x80', // int 0x80
+ '\xB8', '\x01', '\x00', '\x00', '\x00', // mov eax, 1
+ '\xCD', '\x80' // int 0x80
};
text_sec->set_data( text, sizeof( text ) );
@@ -229,7 +229,7 @@ void checkObjestsAreEqual( std::string file_name1, std::string file_name2 )
BOOST_CHECK_EQUAL( file1.save( file_name2 ), true );
BOOST_REQUIRE_EQUAL( file1.load( file_name1 ), true );
BOOST_REQUIRE_EQUAL( file2.load( file_name2 ), true );
-
+
for (int i = 0; i < file1.sections.size(); ++i ) {
BOOST_CHECK_EQUAL( file1.sections[i]->get_address(),
file2.sections[i]->get_address() );
@@ -262,7 +262,7 @@ void checkObjestsAreEqual( std::string file_name1, std::string file_name2 )
BOOST_REQUIRE_NE( file1.sections[i]->get_data(), (const char*)0 );
BOOST_REQUIRE_NE( file2.sections[i]->get_data(), (const char*)0 );
std::string pdata1( file1.sections[i]->get_data(),
- file1.sections[i]->get_data() +
+ file1.sections[i]->get_data() +
file1.sections[i]->get_size() );
std::string pdata2( file2.sections[i]->get_data(),
file2.sections[i]->get_data() +
@@ -282,7 +282,7 @@ void checkObjestsAreEqual( std::string file_name1, std::string file_name2 )
void checkExeAreEqual( std::string file_name1, std::string file_name2, int skipTests = 0 )
{
checkObjestsAreEqual( file_name1, file_name2 );
-
+
elfio file1;
elfio file2;
@@ -357,7 +357,7 @@ BOOST_AUTO_TEST_CASE( section_header_address_update )
BOOST_REQUIRE_NE( sec, (section*)0 );
BOOST_CHECK_EQUAL( sec->get_address(), 0x08048100 );
-
+
const std::string file_wo_addr ( "../elf_examples/write_exe_i386_32_wo_addr" );
write_exe_i386( file_wo_addr, false, false, 0 );
reader.load( file_wo_addr );
@@ -377,7 +377,7 @@ BOOST_AUTO_TEST_CASE( elfio_copy )
e.load( filename );
Elf_Half num = e.sections.size();
- //section* new_sec =
+ //section* new_sec =
e.sections.add( "new" );
e.save( filename );
BOOST_CHECK_EQUAL( num + 1, e.sections.size() );
@@ -452,7 +452,7 @@ BOOST_AUTO_TEST_CASE( get_symbol_32 )
section* psymsec = elf.sections[ ".symtab" ];
const symbol_section_accessor symbols( elf, psymsec );
- BOOST_CHECK_EQUAL( true,
+ BOOST_CHECK_EQUAL( true,
symbols.get_symbol( 0x08048478, name, size, bind,
type, section_index, other) );
BOOST_CHECK_EQUAL( "_IO_stdin_used", name );
@@ -476,10 +476,79 @@ BOOST_AUTO_TEST_CASE( get_symbol_64 )
section* psymsec = elf.sections[ ".symtab" ];
const symbol_section_accessor symbols( elf, psymsec );
- BOOST_CHECK_EQUAL( true,
+ BOOST_CHECK_EQUAL( true,
symbols.get_symbol(0x00400498, name, size, bind,
type, section_index, other) );
BOOST_CHECK_EQUAL( "main", name );
BOOST_CHECK_EQUAL( 12, section_index );
BOOST_CHECK_EQUAL( 21, size );
}
+
+////////////////////////////////////////////////////////////////////////////////
+BOOST_AUTO_TEST_CASE( null_section_inside_segment )
+{
+ // This test case checks the load/save of SHT_NULL sections in a segment
+ // See https://github.com/serge1/ELFIO/issues/19
+ //
+ // Note: The test case checking the load/save of a segment containing no section
+ // is covered by elf_object_copy_32: ../elf_examples/hello_32 has empty segments
+
+ // Create an ELF file with SHT_NULL sections at the beginning/middle/end of a segment
+ elfio writer;
+ writer.create( ELFCLASS32, ELFDATA2LSB );
+ writer.set_os_abi( ELFOSABI_LINUX );
+ writer.set_type( ET_EXEC );
+ writer.set_machine( EM_386 );
+ // Create code section 1
+ section* text_sec1 = writer.sections.add( ".text1" );
+ text_sec1->set_type( SHT_PROGBITS );
+ text_sec1->set_flags( SHF_ALLOC | SHF_EXECINSTR );
+ text_sec1->set_addr_align( 0x10 );
+ text_sec1->set_address( 0x08048000 );
+ char text[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
+ text_sec1->set_data( text, sizeof( text ) );
+ // Create code section 2
+ section* text_sec2 = writer.sections.add( ".text2" );
+ text_sec2->set_type( SHT_PROGBITS );
+ text_sec2->set_flags( SHF_ALLOC | SHF_EXECINSTR );
+ text_sec2->set_addr_align( 0x10 );
+ text_sec2->set_address( 0x08048010 );
+ text_sec2->set_data( text, sizeof( text ) );
+ // Create null sections
+ section* null_sec1 = writer.sections.add( "null" );
+ null_sec1->set_type( SHT_NULL );
+ null_sec1->set_flags( SHF_ALLOC | SHF_EXECINSTR );
+ null_sec1->set_address( 0x08048000 );
+ section* null_sec2 = writer.sections.add( "null" );
+ null_sec2->set_type( SHT_NULL );
+ null_sec2->set_flags( SHF_ALLOC | SHF_EXECINSTR );
+ null_sec2->set_address( 0x08048010 );
+ section* null_sec3 = writer.sections.add( "null" );
+ null_sec3->set_type( SHT_NULL );
+ null_sec3->set_flags( SHF_ALLOC | SHF_EXECINSTR );
+ null_sec3->set_address( 0x08048020 );
+ // Create a loadable segment
+ segment* text_seg = writer.segments.add();
+ text_seg->set_type( PT_LOAD );
+ text_seg->set_virtual_address( 0x08048000 );
+ text_seg->set_physical_address( 0x08048000 );
+ text_seg->set_flags( PF_X | PF_R );
+ text_seg->set_align( 0x1000 );
+ // Add sections into the loadable segment
+ text_seg->add_section_index( null_sec1->get_index(), null_sec1->get_addr_align() );
+ text_seg->add_section_index( text_sec1->get_index(), text_sec1->get_addr_align() );
+ text_seg->add_section_index( null_sec2->get_index(), null_sec2->get_addr_align() );
+ text_seg->add_section_index( text_sec2->get_index(), text_sec2->get_addr_align() );
+ text_seg->add_section_index( null_sec3->get_index(), null_sec3->get_addr_align() );
+ // Setup entry point
+ writer.set_entry( 0x08048000 );
+ // Create ELF file
+ std::string f1 = "../elf_examples/null_section_inside_segment1";
+ std::string f2 = "../elf_examples/null_section_inside_segment2";
+ BOOST_CHECK_EQUAL( writer.save(f1), true );
+
+ // Load and check the ELF file created above
+ elfio elf;
+ BOOST_CHECK_EQUAL( elf.load(f1), true );
+ BOOST_CHECK_EQUAL( elf.save(f2), true );
+}
diff --git a/elfio/elfio.hpp b/elfio/elfio.hpp
index 0ab8552..c92ba62 100644
--- a/elfio/elfio.hpp
+++ b/elfio/elfio.hpp
@@ -666,9 +666,7 @@ class elfio
header->get_segment_entry_size() * header->get_segments_num();
}
// Special case:
- // Segments which start with the NULL section and have further sections
- else if ( seg->get_sections_num() > 1
- && sections[seg->get_section_index_at( 0 )]->get_type() == SHT_NULL ) {
+ else if ( seg->is_offset_initialized() && seg->get_offset() == 0 ) {
seg_start_pos = 0;
if ( seg->get_sections_num() ) {
segment_memory = segment_filesize = current_file_pos;
--
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