ERESI(1)
NAME
ERESI - The ERESI Reverse Engineering Software Interface
SYNOPSIS
elfsh [OPTIONS] etrace [OPTIONS] e2dbg programtodebug kernsh
DESCRIPTION
The ERESI Reverse Engineering Software Interface is a unified reverse
engineering framework for UNIX operating systems based on the Executable & Linking Format (ELF) such as Linux, BSD, Solaris, IRIX, and
BeOS. It has a command line interface that make it useful remotely, and
can generate graph images from code analysis on demand. It has a real
dedicated reverse engineering language that makes it scriptable and
adaptable to the precise needs of the users. ERESI contains more than
10 innovative and exclusive features that turns it into an environment
of choice for the instrumentation, analysis, debugging, tracing, hooking, or simply integrity checking and events logging of binary programs. ERESI is composed of ELFsh (the ELF shell), E2dbg (The Embedded
ELF debugger) and Etrace (The Embedded ELF tracer). This documentation
applies on all of the components.
OPTIONS
The ELF shell (part of ERESI) can take the following command line
parameters:
-f input file
- -w output file
- Note that the command line is slightly different for E2dbg and Etrace which do NOT take those parameters.
COMMANDS
E2dbg and Etrace have to be executed using a unique command line parameter (the program file to be debugged or traced). The following primitives can be used interactively in E2dbg, Etrace, and ELFsh, but also
on command line when preceded by a - (ELFsh only) at the UNIX shell
command prompt.
- General purpose commands
- cat edit exec exit help info list load lscripts nocolor profile quit sdir setcolor switch unload workspace
- cat print the file argument
- edit Edit the file given in parameter
- exec Fork and execute parameter command (with args)
- help Print the help screen
- info Print the extra details help screen
- list List the loaded files and their ID
- load filename
- Load input file filename
- lscripts
- List macro commands
- nocolor
- Toggle color status
- profile (enable | disable) (traces | warns | alloc | debug | all)
Change the ELFsh profiling behavior. Traces profiling print all the internal function calls done by the framework. Warning profiling prints all the (fatal and non-fatal) warnings reported by the internal API : it very useful for tracking bugs and it should be used when reporting issues on the bugtracking system. Allocation and debug profiling are experimental and should only be used by experienced ERESI developers.- quit Quit the shell without saving
- sdir Change the script directory. This allows to make precise the
- location of complete ERESI library and bind script files on command names in the shell.
- setcolor Associates data types to colors
setcolor type [bg,fg] color- setcolor type [underline,bold] (1=on,0=off)
- Available types : address, number, string, endstring, warnstring typestring, fieldstring, instr, pspecial, psname pspecial, pversion, prelease, pedition
- Available colors : black red green yellow blue magenta cyan white
- switch (filename | fileID)
- Change the current file to work on to filename or fileID
- unload (filename | fileID)
- Unload file filename or fileID without saving
- workspace [wname]
- When executed without parameter, this command list existing workspaces. When given an existing workspace name, this command switch to that workspace. If given a non-existing workspace name, this command creates a new workspace and switch to it.
- tables [regex]
- If given without parameter, list all the existing hash tables in the ERESI framework. If given with a parameter, print the content of hash tables whoose name match the regular expression.
- vectors [vname[:idx1:...:idxN]] [symbol|addr]
- If given without parameter, list all the existing vectors in the ERESI framework. If given with a parameter, print the content of this vector. If given one long parameter, print the content of a given vector entry. If given 2 parameters, modify the vector entry with a user provided address or resolved symbol address.
- ========================================================================
- Ondisk/Memory ELF commands
Those commands works in all components of the ERESI framework (ELFsh, E2dbg, and Etrace).- add cmp ctors disasm div dtors dyn dynsym elf findrel get got hexa interp mod mul notes pht print redir rel reladd set sht sub write test
- add Add the 2 parameters and put the result in variable $_
- cmp Compare 2 parameters. The difference is put in variable $_
- ct ctors [Regex]
- Print .ctors section entries matching Regex
- D disasm [Regex]
- Disassemble matching binary objects in current file
- disasm parameter
- Allowed parameter format : regx regx:rva regx:rva%size regx%size
- regx : Regular expression (mandatory)
- rva : Byte offset from the beginning (optional)
- size : Bytes number limit (optional) - div Divide first param by second one and put the result in the first
- one
- dt dtors [Regex]
- Print .dtors section entries matching Regex
- dyn Print the ELF dynamic section
- ds dynsym [Regex]
- Print dynamic symtab (.dynsym) entries matching Regex
- e elf Print the ELF header
- findrel
- Try to find back stripped relocation information. Note: retreiving this information in a very exact manner is very difficult, this command only gives you an approximative list of pointer accesses in the binary code. It does not deal either with constructed addresses using multiple arithmetic and logic instructions, or with false positives that appear to be valid mapped pointers but are not in reality (ex: Hashed data)
- get Print parameter object value. The parameter can be a constant or
- defined value, a variable or any ELF object that is part of any file loaded in the shell, provided you give its id at the beginning of the object path. See info command for the exact grammar of object paths.
- g got [Regex]
- Print the entries of the Global Offset Table (GOT) matching Regex. The regex can apply on either an address, an entry index, or a resolved symbol from the entry address (or contained address).
- X hexa [Regex]
- Dump matching binary objects in current file. This has the same syntax than D/disasm command.
- X parameter
- ParamFormat : regx regx:rva regx:rva%size regx%size
- regx : Regular expression (mandatory)
- rva : Byte offset from the beginning (optional)
- size : Bytes number limit (optional) - interp Print ELF interpreter path standing in .interp section.
- mod Modulo operation between 2 parameters. The result is put in the
- destination variable.
- mul Multiply the 2 parameters. The result is put in the destination
- variable.
- n notes [Regex]
- Print the Notes sections entries matching Regex
- p pht Print the Program Header Table (PHT)
- print [ObjectPath1 ObjectPath2 ... ObjectPathN]
- Print the values of objects ObjectPath1 ObjectPath2 ... ObjectPathN. Objects can be constant strings, ELF objects, variables, defined values, and so on.
- redir func (func2 | addr)
- Redirect calls to function func to func2 or address addr. If the original function has a PLT entry, the ALTPLT technique is used to perform the redirection. If the function is internal (or if we are in a static binary) the CFLOW technique is used to perform the redirection. ALTPLT technique is available on INTEL, SPARC, MIPS, and ALPHA architectures. CFLOW technique is currently not available on the SPARC architecture. The hook (second) function is usually an injected C code provided by the user and injected using the reladd primitive. In case the provided hook function calls other function which are not in the host binary, ERESI will use the EXTPLT technique (or EXTSTATIC technique on static binaries) to relink the host binary in order to add new relocation entries, dynamic symbols with their names, symbol versions, extra GOT and PLT entries (using additionally the ALTGOT technique on RISC architectures), and will fixup the .dynamic section to reflect those changes on the section list.
- r rel [Regex]
- Print the relocation entries matching Regex
- reladd (DestFilePath | DestfileID) (RelocFilePath | RelocFileID)
- Inject the ELF relocatable object RelocFileID into the ELF executable object DestFileID. This command is used for injecting plain C compiled code linked into a .o file into a host ET_EXEC (executable) or ET_DYN (shared library) ELF file.
- set DestObjectPath SourceObjectPath
- Set the value of object DestObjectPath to SourceObjectPath. The $_ variable gets modified depending on the result. See the info command for a list of all accessible objects using the set command.
- s sht [Regex]
- Print the sections in the Section Header Table (SHT) matching Regex
- sub Substract 2nd parameter to the first one. The $_ variable is
- modified depending on the result.
- write DestObjectPath SourceObjectPath
- Copy data from SourceObjectPath to DestObjectPath. The destination object has to be of type RAW (the data field of a section) and the source object has to be of type RAW or STRING. See the info command for more detail about this.
- ========================================================================
- Debugger commands
backtrace break continue dbgstack delete dumpregs linkmap stack step display threads itrace- backtrace
- Print backtrace (needs frame pointer).
- break (BPsymbol | 0xaddress)
- Put a breakpoint on symbol or address. Print all breakpoints if given without parameter.
- step
Enable or disable stepping of debuggee program. Use continue for singlestepping.- continue
Continue executing debuggee program after breakpoint or singlestep.- delete (BPID | BPsymbol | 0xaddress)
Delete breakpoint by symbol, address, or ID.- dbgstack WordsNBR
Dump N words (N given as first parameter) from the debugger stack. We can do that because the debugger is embedded into the debuggee process.- stack WordsNBR
Dump WordsNBR words on debuggee stack.- dumpregs
Dump registers of debuggee at breakpoint or step.- linkmap
Print Linkmap list for the debuggee process.- display BPid Full_ERESI_command
- Set a command to be executed on event. The first parameter must be the breakpoint id that correspond to the event. The ERESI command can be any valid ERESI command, including the sourcing of an ERESI script.
- threads [ThreadID]
- If called without parameter, this command list existing threads in the debuggee process. If called with a thread ID parameter, the current thread is switched to the thread indicated by the ID.
- itrace Singlestep the debuggee program until next breakpoint event,
- printing all executed instructions until it stops.
- ========================================================================
- ELFsh modules commands
modhelp modload modunload- modhelp ModuleFilePath
- Print help for a loaded ERESI module.
- modload ModuleFilePath
- Load an ERESI module. The path has to be absolute or relative to the registered module path.
- modunload ModuleFilePath
- Unload an ERESI module. The path has to be absolute or relative to the registered module path.
- ========================================================================
- ELF objects flags
fixup shtrm sstrip- fixup Mark BSS section to be included in disk file. The BSS gets imme
- diately fixed in the ELFsh internal descriptor of the object.
- shtrm Mark Section Header Table as removed. The SHT will be removed
- only when the file is saved.
- sstrip Mark the Section Header Table (SHT) and Symbol Table (.symtab)
- as stripped. They will be removed only when the file is saved.
- ========================================================================
- Ondisk only ELF commands
Those commands only works in ELFsh, or in E2dbg when switched to the static mode using the mode command.- append extend flush insert remove save stab sym
- append SectionName SourceObjectPath
- Append the data of object SourceObjectPath to section SectionName
- extend SectionName length
- Extend section SectionName with length zero bytes
- flush Flush all injected .o files from current file.
- insert Inject new object (section, symbol, or program header) in cur
- rent working file.
- insert sect name code|data|unmap [sz] [align]
sym name value [sz]
phdr type vaddr [sz] - remove Remove ELF object (section, symbol, or program header) from cur
- rent working file
- remove sect name
sym name
phdr index - save filename
- Dump current selected file to output file filename. This command writes a file on disk.
- debug Print unified debug format information for the current file.
- st sym [Regex]
- Print the symtab (.symtab) entries matching Regex.
- ========================================================================
- Kernsh modules commands
Those commands only works in Kernsh.- openmem
- Open kernel memory and static kernel
- closemem
- Close kernel memory and static kernel
- sct Display the syscall table
- idt Display the interrupt descriptor table
- gdt Display the global descriptor table
- alloc Alloc contiguous kernel memory
- free Free contiguous kernel memory
- alloc_nc
- Alloc non contiguous kernel memory
- free_nc
- Free non contiguous kernel memory
- kmodule
- Handle kernel module
- kmodule -l module : load a lkm
- kmodule -u module : unload a lkm
- kmodule -r module1 module2 moduleout : link module with another
- kmodule -i module original_name evil_name : change lkm init (original_name) with another function (evil_name)
- ksym Get an address of a kernel symbol
- kmd5 sa output | sa:rva output | sa%rva%size output | sa%size output
- Make a md5sum.
- sa : Symbol or addr
- rva : Byte offset form the beginning (optional)
- size : Bytes number limit (optional) (if size is 0 or not put, we search the end of the function)
- output : file output (optional)
- kcmd5 format | file
- Check a md5.
- format : addr:mode:size:off:md5
- file : filename
- ========================================================================
- Type related primitives
Those primitives allow to define and habitate types in the ERESI meta-language:- type [regex]
Print list of types (only those matching the regular expression if given in parameter).- type name = field1:type1 ... fieldN:typeN
Define a new type in the ERESI meta-language. Predefined types include byte, short, int, caddr, daddr, long, hash, vector, string, and raw.- typedef tname tname2
Copy and rename a type. Any modification on one of the types will not affect the other.- inform type [name | address]
Make type name habitated by the variable standing at address name. If called with a single type name parameter, the command list all variables that habitate this type. If given 2 parameters, the name is interpreted as a symbol pointing on a variable. Its address is resolved and the type is informed about this variable. If only an address is given, its symbol is looked up and the variable corresponding to the symbol is informed. If no symbol corresponds to this address, a new one is created that points on the address, and the newly symbolic variable is informed.- uninform type [name]
Uninform a given variable from a type. If no variable name is given, all variables previously informed are removed from the type habitation.- ========================================================================
- Network commands
connect disconnect net netkill netlist peerslist rcmd- connect
- Add a DUMP connection to given host
- disconnect
- Kill the DUMP connection from IP
- net Activate networking capabilities
- netkill
- Kill a network client by IP
- netlist
- List connected network clients
- peerslist
- List connected DUMP peers
- rcmd Execute a command on a remote machine
- ========================================================================
- Available prefixes
alert all quiet sort verb- alert Alert prefix : change alert regular expression
- a all regex
- Set a global regular expression. All commands which take a regular expression as a parameter will default to use this global regular expression.
- quiet Toggle quiet flag (do not print executed commands)
- sort Sorting prefix (use a -addr- or s -size-)
- verb Toggle verbose flag (undo the quiet flag)
- ========================================================================
- Available Script jumps
A certain number of jumps construct are available:- je jg jge jl jle jmp jne
- je Jump on label if equal (use last cmp result)
- jg Jump on label if greater (use last cmp result)
- jge Jump on label if greater or equal (use last cmp result)
- jl Jump on label if lower (use last cmp result)
- jle Jump on label if lower or equal (use last cmp result)
- jmp Unconditional jump to script label
- jne Jump on label if nont equal (use last cmp result)
You might also consider using a foreach construct, which is not described in this manual page.- ========================================================================
- Available modules
modflow modremap modtest- modflow
- Modflow is an ELFsh module designed to perform control flow analysis on ELF binaries for detailed examples and usage see README in ELFsh/modules/modflow
- modremap
- Modflow is an ELFsh module designed to perform remapping sections in Elf binaries see ELFsh/modules/modremap for further details
- modtest
- Modtest is a ElFsh module designed to show the usage of adding new commands to ELFsh see ELFsh/modules/modtest for further details
- ========================================================================
OBJECT PATH FORMAT
This section explains how to access different objects in an ELF file.
For most commands the object can also be a decimal or hexadecimal numbers. In this case the ObjectPath is the number.
- ELF Header
- filename.hdrfield
- ELF header fields are :
- magic Magic number
- class File class
- type Object file type
- machine
- Architecture
- version
- Object file version
- entry Entry point virtual address
- phoff Program header table file offset
- shoff Section header table file offset
- flags Processor-specific Flags
- ehsize Size of the ELF header in bytes
- phentsize
- Size of the program headers
- shentsize
- Size of the section headers
- phnum Number of program headers
- shnum Number of section headers
- shstrndx
- Section header string table index
- pax_pageexec
- PAX use paging based non-executable pages
- pax_emultramp
- PAX emulate trampolines
- pax_mprotect
- PAX restrict mmap
- pax_randmmap
- PAX randomize mmap
- pax_randexec
- PAX randomly map executable address
- pax_segmexec
- PAX use segmentation based non-executable pages
- got/ctors/dtors tables
- (filename | fileID).(got|ctors|dtors)[index]
- In this command, the index can also be a symbol name that corresponds to the requested GOT, CTORS, OR DTORS entry.
- Program segment header table
- (filename | fileID).pht[index].fi eld
- Program segment header table entry fields are :
- type Segment type
- offset Segment file offset
- paddr Segment physical address
- vaddr Segment virtual address
- filesz Segment size in file
- memsz Segment size in memory
- flags Segment flags
- align Segment alignment
- Symbol/Dynamic symbol tables
- (filename | fileID).(symtab|dynsym)[index].fi eld
- Symbol/Dynamic symbol table entry fields are :
- name Symbol name
- value Symbol value
- size Symbol size
- bind Symbol binding
- type Symbol type
- other Symbol visibility
- Dynamic section
- (filename | fileID).dynamic[index].fi eld
- The .dynamic section entry fields are :
- val Integer or address value
- tag Dynamic entry type
- Section header table
- (filename | fileID).sht[index].fi eld
- The index can be the name of the section. Section Header Table entries fields are :
- type Section type
- offset Section Offset in ELF file
- addr Section Address
- size Section Size in bytes
- link Link to another section
- info Additional Info
- align Section Alignment
- entsize
- Entry size if section holds table
- flags
- a Section occupies memory during execution
- w Section is Writeable
- x Section is Executable
- s Contains nul-terminated strings
- m Section might be merged
- l Preserve order after combining
- o OS specific
- Relocation table
- (filename | fileID).rel[indextable][indexentry].fi eld
- Relocation entry fields are :
- type Relocation Type
- sym Relocation symbol index
- offset Address
- Additional sections information
- (filename | fileID).section[sectionindex].fi eld
- The section object is not a real object of the binary, but a kind of virtual one. It holds all the information about a section that do not stand in the sectoin header table entries. Section fields are :
- name Section name
- raw Section Raw data
To access use following path format :- filename.section[index[:offset[%elemsize]]].raw
AUTHOR
- ERESI was created by Julien Vanegue and developed by the ERESI team
- <team at eresi-project dot antispam org>
- The complete list of ERESI contributors can be found on the website:
http://www.eresi-project.org- This manual page was created by Julien Vanegue, from previous work on the ELFsh man page by Peter De Schrijver for the Debian GNU/Linux system. Additional improvements were made by stingduk for version 0.7.