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Make note section entries for 64-bit ELF file be the same as for 32-bit file

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There are discrepancies in documentations. SCO documentation
(http://www.sco.com/developers/gabi/latest/ch5.pheader.html#note_section)
requires 8 byte entries alignment for 64-bit ELF file,
but Oracle's definition uses the same structure
for 32-bit and 64-bit formats.
(https://docs.oracle.com/cd/E23824_01/html/819-0690/chapter6-18048.html)

It looks like EM_X86_64 Linux implementation is similar to Oracle's
definition. Therefore, the same alignment works for both formats
This commit is contained in:
Serge Lamikhov-Center 2016-07-10 11:22:53 +03:00
parent e3e0d6dbdb
commit 3c5620d46d
1 changed files with 27 additions and 23 deletions
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50
elfio/elfio_note.hpp
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@ -25,6 +25,18 @@ THE SOFTWARE.
namespace ELFIO {
//------------------------------------------------------------------------------
// There are discrepancies in documentations. SCO documentation
// (http://www.sco.com/developers/gabi/latest/ch5.pheader.html#note_section)
// requires 8 byte entries alignment for 64-bit ELF file,
// but Oracle's definition uses the same structure
// for 32-bit and 64-bit formats.
// (https://docs.oracle.com/cd/E23824_01/html/819-0690/chapter6-18048.html)
//
// It looks like EM_X86_64 Linux implementation is similar to Oracle's
// definition. Therefore, the same alignment works for both formats
//------------------------------------------------------------------------------
//------------------------------------------------------------------------------
class note_section_accessor
{
@ -56,9 +68,10 @@ class note_section_accessor
}
const char* pData = note_section->get_data() + note_start_positions[index];
int align = sizeof( Elf_Word );
const endianess_convertor& convertor = elf_file.get_convertor();
type = convertor( *(Elf_Word*)( pData + 2*sizeof( Elf_Word ) ) );
type = convertor( *(Elf_Word*)( pData + 2*align ) );
Elf_Word namesz = convertor( *(Elf_Word*)( pData ) );
descSize = convertor( *(Elf_Word*)( pData + sizeof( namesz ) ) );
Elf_Word max_name_size = note_section->get_size() - note_start_positions[index];
@ -66,17 +79,13 @@ class note_section_accessor
namesz + descSize > max_name_size ) {
return false;
}
name.assign( pData + 3 * sizeof( Elf_Word ), namesz - 1);
name.assign( pData + 3*align, namesz - 1);
if ( 0 == descSize ) {
desc = 0;
}
else {
int align = sizeof( Elf_Xword );
if ( elf_file.get_class() == ELFCLASS32 ) {
align = sizeof( Elf_Word );
}
desc = const_cast<char*> ( pData + 3*sizeof( Elf_Word ) +
( ( namesz + align - 1 ) / align ) * align );
desc = const_cast<char*> ( pData + 3*align +
( ( namesz + align - 1 )/align )*align );
}
return true;
@ -90,25 +99,24 @@ class note_section_accessor
{
const endianess_convertor& convertor = elf_file.get_convertor();
int align = sizeof( Elf_Word );
Elf_Word nameLen = (Elf_Word)name.size() + 1;
Elf_Word nameLenConv = convertor( nameLen );
std::string buffer( reinterpret_cast<char*>( &nameLenConv ), sizeof( nameLenConv ) );
std::string buffer( reinterpret_cast<char*>( &nameLenConv ), align );
Elf_Word descSizeConv = convertor( descSize );
buffer.append( reinterpret_cast<char*>( &descSizeConv ), sizeof( descSizeConv ) );
buffer.append( reinterpret_cast<char*>( &descSizeConv ), align );
type = convertor( type );
buffer.append( reinterpret_cast<char*>( &type ), sizeof( type ) );
buffer.append( reinterpret_cast<char*>( &type ), align );
buffer.append( name );
buffer.append( 1, '\x00' );
const char pad[] = { '\0', '\0', '\0', '\0' };
if ( nameLen % sizeof( Elf_Word ) != 0 ) {
buffer.append( pad, sizeof( Elf_Word ) -
nameLen % sizeof( Elf_Word ) );
if ( nameLen % align != 0 ) {
buffer.append( pad, align - nameLen % align );
}
if ( desc != 0 && descSize != 0 ) {
buffer.append( reinterpret_cast<const char*>( desc ), descSize );
if ( descSize % sizeof( Elf_Word ) != 0 ) {
buffer.append( pad, sizeof( Elf_Word ) -
descSize % sizeof( Elf_Word ) );
if ( descSize % align != 0 ) {
buffer.append( pad, align - descSize % align );
}
}
@ -132,18 +140,14 @@ class note_section_accessor
return;
}
while ( current + 3*sizeof( Elf_Word ) <= size ) {
int align = sizeof( Elf_Word );
while ( current + 3*align <= size ) {
note_start_positions.push_back( current );
Elf_Word namesz = convertor(
*(Elf_Word*)( data + current ) );
Elf_Word descsz = convertor(
*(Elf_Word*)( data + current + sizeof( namesz ) ) );
int align = sizeof( Elf_Xword );
if ( elf_file.get_class() == ELFCLASS32 ) {
align = sizeof( Elf_Word );
}
current += 3*sizeof( Elf_Word ) +
( ( namesz + align - 1 ) / align ) * align +
( ( descsz + align - 1 ) / align ) * align;