From 89fb16ed0a2765520658dbfaceb3320617ced6b9 Mon Sep 17 00:00:00 2001
From: jj <john-git@ofjj.net>
Date: Wed, 20 Jul 2022 19:39:11 +0200
Subject: [PATCH] elf_decode: decode notes & coredumps

---
 metasm/exe_format/elf.rb        |  9 +++++---
 metasm/exe_format/elf_decode.rb | 37 ++++++++++++++++++++++++++++++++-
 2 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/metasm/exe_format/elf.rb b/metasm/exe_format/elf.rb
index 5d07a48a9..62ee98d2f 100644
--- a/metasm/exe_format/elf.rb
+++ b/metasm/exe_format/elf.rb
@@ -15,7 +15,9 @@ class ELF < ExeFormat
 	VERSION = { 0 => 'INVALID', 1 => 'CURRENT' }
 	ABI = { 0 => 'SYSV', 1 => 'HPUX', 2 => 'NETBSD', 3 => 'LINUX',
 		6 => 'SOLARIS', 7 => 'AIX', 8 => 'IRIX', 9 => 'FREEBSD',
-		10 => 'TRU64', 11 => 'MODESTO', 12 => 'OPENBSD', 97 => 'ARM',
+		10 => 'TRU64', 11 => 'MODESTO', 12 => 'OPENBSD',
+		13 => 'OPENVMS', 14 => 'NSK', 15 => 'AROS',
+		97 => 'ARM',
 		255 => 'STANDALONE'}
 	TYPE = { 0 => 'NONE', 1 => 'REL', 2 => 'EXEC', 3 => 'DYN', 4 => 'CORE' }
 	TYPE_LOPROC = 0xff00
@@ -196,7 +198,8 @@ class ELF < ExeFormat
 	SYMBOL_TYPE_LOPROC = 13
 	SYMBOL_TYPE_HIPROC = 15
 
-	SYMBOL_VISIBILITY = { 0 => 'DEFAULT', 1 => 'INTERNAL', 2 => 'HIDDEN', 3 => 'PROTECTED' }
+	SYMBOL_VISIBILITY = { 0 => 'DEFAULT', 1 => 'INTERNAL', 2 => 'HIDDEN', 3 => 'PROTECTED',
+		4 => 'EXPORTED', 5 => 'SINGLETON', 6 => 'ELIMINATE' }
 
 	RELOCATION_TYPE = {	# key are in MACHINE.values
 		'386' => { 0 => 'NONE', 1 => '32', 2 => 'PC32', 3 => 'GOT32',
@@ -711,7 +714,7 @@ def self.gnu_hash_symbol_name(name)
 		}
 	end
 
-	attr_accessor :header, :segments, :sections, :tag, :symbols, :relocations, :endianness, :bitsize, :debug, :eh_frame
+	attr_accessor :header, :segments, :sections, :tag, :symbols, :relocations, :endianness, :bitsize, :debug, :eh_frame, :note
 	def initialize(cpu=nil)
 		@header = Header.new
 		@tag = {}
diff --git a/metasm/exe_format/elf_decode.rb b/metasm/exe_format/elf_decode.rb
index b70b3140b..d6d1337b5 100644
--- a/metasm/exe_format/elf_decode.rb
+++ b/metasm/exe_format/elf_decode.rb
@@ -816,6 +816,35 @@ def arch_decode_segments_reloc_aarch64(reloc)
 		Metasm::Relocation.new(Expression[target], :u64, @endianness) if target
 	end
 
+	def decode_notes(off = nil, len = nil)
+		if not off
+			if s = @segments.find { |s_| s_.type == 'NOTE' }
+				# this way it also works with LoadedELF
+				off = addr_to_off(s.vaddr) || s.offset
+				len ||= s.filesz
+			elsif s = @sections.find { |s_| s_.type == 'NOTE' }
+				# if no DYNAMIC segment, assume we decode an ET_REL from file
+				off = s.offset
+				len ||= s.size
+			end
+		end
+		return if not @encoded.ptr = off
+		len ||= @encoded.length - @encoded.ptr
+
+		@note = []
+		while @encoded.ptr < off+len
+			namesz = decode_word
+			descsz = decode_word
+			type = decode_word
+			name = @encoded.read(namesz).chomp(0.chr)
+			@encoded.ptr += 4 - ((namesz-1) % 4) - 1	# name padded to next numeric field alignment
+			descr = @encoded.read(descsz)
+			@encoded.ptr += 4 - ((descsz-1) % 4) - 1	# ^
+
+			@note << [name, type, descr]
+		end
+	end
+
 	class DwarfDebug
 		# decode a DWARF2 'compilation unit'
 		def decode(elf, info, abbrev, str)
@@ -1094,6 +1123,12 @@ def decode_segments_dynamic(decode_relocs=true)
 		decode_segments_relocs_interpret
 	end
 
+	# decode coredump file elements
+	def decode_core
+		decode_segments
+		decode_notes
+	end
+
 	# decodes the dynamic segment, fills segments.encoded
 	def decode_segments
 		decode_segments_dynamic
@@ -1143,7 +1178,7 @@ def decode
 		case @header.type
 		when 'DYN', 'EXEC'; decode_segments
 		when 'REL'; decode_sections
-		when 'CORE'
+		when 'CORE'; decode_core
 		end
 	end