The Official Radare2 Book

Hexadecimal View

Date/Time Formats

Currently supported timestamp output modes are:

[0x00404888]> pt?

|Usage: pt [dn] print timestamps

| pt. print current time

| pt print UNIX time (32 bit `cfg.bigendian`) Since January 1, 1970

| ptd print DOS time (32 bit `cfg.bigendian`) Since January 1, 1980

| pth print HFS time (32 bit `cfg.bigendian`) Since January 1, 1904

| ptn print NTFS time (64 bit `cfg.bigendian`) Since January 1, 1601

For example, you can 'view' the current buffer as timestamps in the ntfs time:

[0x08048000]> e cfg.bigendian = false

[0x08048000]> pt 4

29:04:32948 23:12:36 +0000

[0x08048000]> e cfg.bigendian = true

[0x08048000]> pt 4

20:05:13001 09:29:21 +0000

As you can see, the endianness affects the result. Once you have printed a timestamp, you can grep the output, for example, by year:

[0x08048000]> pt ~1974 | wc -l

15

[0x08048000]> pt ~2022

27:04:2022 16:15:43 +0000

The default date format can be configured using the cfg.datefmt variable. Formatting rules for it follow the well known strftime(3) format. Check the manpage for more details, but these are the most important:

%a The abbreviated name of the day of the week according to the current locale.

%A The full name of the day of the week according to the current locale.

%d The day of the month as a decimal number (range 01 to 31).

%D Equivalent to %m/%d/%y. (Yecch—for Americans only).

%H The hour as a decimal number using a 24-hour clock (range 00 to 23).

%I The hour as a decimal number using a 12-hour clock (range 01 to 12).

%m The month as a decimal number (range 01 to 12).

%M The minute as a decimal number (range 00 to 59).

%p Either "AM" or "PM" according to the given time value.

%s The number of seconds since the Epoch, 1970-01-01 00:00:00 +0000 (UTC). (TZ)

%S The second as a decimal number (range 00 to 60). (The range is up to 60 to allow for occasional leap seconds.)

%T The time in 24-hour notation (%H:%M:%S). (SU)

%y The year as a decimal number without a century (range 00 to 99).

%Y The year as a decimal number including the century.

%z The +hhmm or -hhmm numeric timezone (that is, the hour and minute offset from UTC). (SU)

%Z The timezone name or abbreviation.

Basic Types

There are print modes available for all basic types. If you are interested in a more complex structure, type pf?? for format characters and pf??? for examples:

[0x00499999]> pf??

|pf: pf[.k[.f[=v]]|[v]]|[n]|[0|cnt][fmt] [a0 a1 ...]

| Format:

| b byte (unsigned)

| B resolve enum bitfield (see t?)

| c char (signed byte)

| C byte in decimal

| d 0xHEX value (4 bytes) (see 'i' and 'x')

| D disassemble one opcode

| e temporally swap endian

| E resolve enum name (see t?)

| f float value (4 bytes)

| F double value (8 bytes)

| i signed integer value (4 bytes) (see 'd' and 'x')

| n next char specifies size of signed value (1, 2, 4 or 8 byte(s))

| N next char specifies size of unsigned value (1, 2, 4 or 8 byte(s))

| o octal value (4 byte)

| p pointer reference (2, 4 or 8 bytes)

| q quadword (8 bytes)

| r CPU register `pf r (eax)plop`

| s 32bit pointer to string (4 bytes)

| S 64bit pointer to string (8 bytes)

| t UNIX timestamp (4 bytes)

| T show Ten first bytes of buffer

| u uleb128 (variable length)

| w word (2 bytes unsigned short in hex)

| x 0xHEX value and flag (fd @ addr) (see 'd' and 'i')

| X show formatted hexpairs

| z null terminated string

| Z null terminated wide string

| ? data structure `pf ? (struct_name)example_name`

| * next char is pointer (honors asm.bits)

| + toggle show flags for each offset

| : skip 4 bytes

| . skip 1 byte

| ; rewind 4 bytes

| , rewind 1 byte

Use triple-question-mark pf??? to get some examples using print format strings.

[0x00499999]>

pf???

|pf: pf[.k[.f[=v]]|[v]]|[n]|[0|cnt][fmt] [a0 a1 ...]

| Examples:

| pf 3xi foo bar 3-array of struct, each

with named fields: 'foo' as hex, and 'bar' as int

| pf B (BitFldType)arg_name` bitfield type

| pf E (EnumType)arg_name` enum type

| pf.obj xxdz prev next size name Define the obj format as

xxdz

| pf obj=xxdz prev next size name Same as above

| pf *z*i*w nb name blob Print the pointers with

given labels

| pf iwq foo bar troll Print the iwq format with

foo, bar, troll as the respective names for the fields

| pf 0iwq foo bar troll Same as above, but

considered as a union (all fields at offset 0)

| pf.plop ? (troll)mystruct Use structure troll

previously defined

| pfj.plop @ 0x14 Apply format object at

the given offset

| pf 10xiz pointer length string Print a size 10 array of

the xiz struct with its field names

| pf 5sqw string quad word Print an array with sqw

struct along with its field names

| pf {integer}? (bifc) Print integer times the

following format (bifc)

| pf [4]w[7]i Print an array of 4 words

and then an array of 7 integers

| pf ic...?i foo bar "(pf xw yo foo)troll" yo Print nested anonymous

structures

| pf ;..x Print value located 6

bytes from current offset

| pf [10]z[3]i[10]Zb Print an fixed size str,

widechar, and var

| pfj +F @ 0x14 Print the content at

given offset with flag

| pf n2 print signed short (2

bytes) value. Use N instead of n for printing unsigned values

| pf [2]? (plop)structname @ 0 Prints an array of

structs

| pf eqew bigWord beef Swap endianness and print

with given labels

| pf.foo rr (eax)reg1 (eip)reg2 Create object referencing

to register values

| pf tt troll plop print time stamps with

labels troll and plop

Some examples are below:

[0x4A13B8C0]> pf i

0x00404888 = 837634441

[0x4A13B8C0]> pf

0x00404888 = 837634432.000000

High-level Languages Views

Valid print code formats for human-readable languages are:

• pc C

• pc* print 'wx' r2 commands

• pch C half-words (2 byte)

• pcw C words (4 byte)

• pcd C dwords (8 byte)

• pci C array of bytes with instructions

• pca GAS .byte blob

• pcA .bytes with instructions in comments

• pcs string

• pcS shellscript that reconstructs the bin

• pcj json

• pcJ javascript

• pco Objective-C

• pcp python

• pck kotlin

• pcr rust

• pcv JaVa

• pcV V (vlang.io)

• pcy yara

• pcz Swift

If we need to create a .c file containing a binary blob, use the pc command, that creates this output. The default size is like in many other commands: the block size, which can be changed with the b command.

We can also just temporarily override this block size by expressing it as an argument.

[0xB7F8E810]>

pc 32

#define _BUFFER_SIZE 32

unsigned char buffer[_BUFFER_SIZE] = {

0x89, 0xe0, 0xe8, 0x49, 0x02, 0x00, 0x00, 0x89, 0xc7, 0xe8, 0xe2, 0xff,

0xff, 0xff, 0x81, 0xc3, 0xd6, 0xa7, 0x01, 0x00, 0x8b, 0x83, 0x00, 0xff,

0xff, 0xff, 0x5a, 0x8d, 0x24, 0x84, 0x29, 0xc2 };

That cstring can be used in many programming languages, not just C.

[0x7fcd6a891630]>

pcs

"\x48\x89\xe7\xe8\x68\x39\x00\x00\x49\x89\xc4\x8b\x05\xef\x16\x22\x00\x5a\x48\x8d\x24\xc4\x29\xc2\x52\x48\x89\xd6\x49\x89\xe5\x48\x83\xe4\xf0\x48\x8b\x3d\x06\x1a

Strings

Strings are probably one of the most important entry points when starting to reverse engineer a program because they usually reference information about functions' actions (asserts, debug or info messages...). Therefore, radare supports various string formats:

[0x00000000]> ps?

|Usage: ps[bijqpsuwWxz+] [N] Print String

| ps print string

| ps+[j] print libc++ std::string (same-endian, ascii, zero-terminated)

| psb print strings in current block

| psi print string inside curseek

| psj print string in JSON format

| psp[j] print pascal string

| psq alias for pqs

| pss print string in screen (wrap width)

| psu[zj] print utf16 unicode (json)

| psw[j] print 16bit wide string

| psW[j] print 32bit wide string

| psx show string with escaped chars

| psz[j] print zero-terminated string

Most strings are zero-terminated. Below there is an example using the debugger to continue the execution of a program until it executes the 'open' syscall. When we recover the control over the process, we get the arguments passed to the syscall, pointed by %ebx. In the case of the 'open' call, it is a zero terminated string which we can inspect using psz.

[0x4A13B8C0]> dcs open

0x4a14fc24 syscall(5) open ( 0x4a151c91 0x00000000 0x00000000 ) = 0xffffffda

[0x4A13B8C0]> dr

eax 0xffffffda esi 0xffffffff eip 0x4a14fc24

ebx 0x4a151c91 edi 0x4a151be1 oeax 0x00000005

ecx 0x00000000 esp 0xbfbedb1c eflags 0x200246

edx 0x00000000 ebp 0xbfbedbb0 cPaZstIdor0 (PZI)

[0x4A13B8C0]>

[0x4A13B8C0]> psz @ 0x4a151c91

/etc/ld.so.cache

Print Memory Contents

It is also possible to print various packed data types using the pf command:

[0xB7F08810]> pf xxS @ rsp

0x7fff0d29da30 = 0x00000001

0x7fff0d29da34 = 0x00000000

0x7fff0d29da38 = 0x7fff0d29da38 -> 0x0d29f7ee /bin/ls

This can be used to look at the arguments passed to a function. To achieve this, simply pass a 'format memory string' as an argument to pf, and temporally change the current seek position/offset using @. It is also possible to define arrays of structures with pf. To do this, prefix the format string with a numeric value. You can also define a name for each field of the structure by appending them as a space-separated arguments list.

[0x4A13B8C0]> pf 2*xw pointer type @ esp

0x00404888 [0] {

pointer :

(*0xffffffff8949ed31) type : 0x00404888 = 0x8949ed31

0x00404890 = 0x48e2

}

0x00404892 [1] {

(*0x50f0e483) pointer : 0x00404892 = 0x50f0e483

type : 0x0040489a = 0x2440

}

A practical example for using pf on a binary of a GStreamer plugin:

$ radare2 /usr/lib/gstreamer-1.0/libgstflv.so

[0x00006020]> aa; pdf @ sym.gst_plugin_flv_get_desc

[x] Analyze all flags starting with sym. and entry0 (aa)

sym.gst_plugin_flv_get_desc ();

[...]

0x00013830 488d0549db0000 lea rax, section..data.rel.ro ; 0x21380

0x00013837 c3 ret

[0x00006020]> s section..data.rel.ro

[0x00021380]> pf ii*z*zp*z*z*z*z*z*z major minor name desc init version license source package origin release_datetime

major : 0x00021380 = 1

minor : 0x00021384 = 18

name : (*0x19cf2)0x00021388 = "flv"

desc : (*0x1b358)0x00021390 = "FLV muxing and demuxing plugin"

init : 0x00021398 = (qword)0x0000000000013460

version : (*0x19cae)0x000213a0 = "1.18.2"

license : (*0x19ce1)0x000213a8 = "LGPL"

source : (*0x19cd0)0x000213b0 = "gst-plugins-good"

package : (*0x1b378)0x000213b8 = "GStreamer Good Plugins (Arch Linux)"

origin : (*0x19cb5)0x000213c0 = "https://www.archlinux.org/"

release_datetime : (*0x19cf6)0x000213c8 = "2020-12-06"

Disassembly

The pd command is used to disassemble code. It accepts a numeric value to specify how many instructions should be disassembled. The pD command is similar but instead of a number of instructions, it decompiles a given number of bytes.

• d : disassembly N opcodes count of opcodes

• D : asm.arch disassembler bsize bytes

[0x00404888]> pd 1

;-- entry0:

0x00404888 31ed xor ebp, ebp

Selecting Target Architecture

The architecture flavor for the disassembler is defined by the asm.arch eval variable. You can use e asm.arch=?? to list all available architectures.

[0x00005310]> e asm.arch=??

_dAe _8_16 6502 LGPL3 6502/NES/C64/Tamagotchi/T-1000 CPU

_dAe _8 8051 PD 8051 Intel CPU

_dA_ _16_32 arc GPL3 Argonaut RISC Core

a___ _16_32_64 arm.as LGPL3 as ARM Assembler (use ARM_AS environment)

adAe _16_32_64 arm BSD Capstone ARM disassembler

_dA_ _16_32_64 arm.gnu GPL3 Acorn RISC Machine CPU

_d__ _16_32 arm.winedbg LGPL2 WineDBG's ARM disassembler

adAe _8_16 avr GPL AVR Atmel

adAe _16_32_64 bf LGPL3 Brainfuck

_dA_ _32 chip8 LGPL3 Chip8 disassembler

_dA_ _16 cr16 LGPL3 cr16 disassembly plugin

_dA_ _32 cris GPL3 Axis Communications 32-bit embedded processor

adA_ _32_64 dalvik LGPL3 AndroidVM Dalvik

ad__ _16 dcpu16 PD Mojang's DCPU-16

_dA_ _32_64 ebc LGPL3 EFI Bytecode

adAe _16 gb LGPL3 GameBoy(TM) (z80-like)

_dAe _16 h8300 LGPL3 H8/300 disassembly plugin

_dAe _32 hexagon LGPL3 Qualcomm Hexagon (QDSP6) V6

_d__ _32 hppa GPL3 HP PA-RISC

_dAe _0 i4004 LGPL3 Intel 4004 microprocessor

_dA_ _8 i8080 BSD Intel 8080 CPU

adA_ _32 java Apache Java bytecode

_d__ _32 lanai GPL3 LANAI

...

Configuring the Disassembler

There are multiple options which can be used to configure the output of the disassembler. All these options are described in e? asm.

[0x00005310]> e? asm.

asm.anal: Analyze code and refs while disassembling (see anal.strings)

asm.arch: Set the arch to be used by asm

asm.assembler: Set the plugin name to use when assembling

asm.bbline: Show empty line after every basic block

asm.bits: Word size in bits at assembler

asm.bytes: Display the bytes of each instruction

asm.bytespace: Separate hexadecimal bytes with a whitespace

asm.calls: Show callee function related info as comments in disasm

asm.capitalize: Use camelcase at disassembly

asm.cmt.col: Column to align comments

asm.cmt.flgrefs: Show comment flags associated to branch reference

asm.cmt.fold: Fold comments, toggle with Vz

...

Currently there are 136 asm. configuration variables so we do not list them all.

Disassembly Syntax

The asm.syntax variable is used to change the flavor of the assembly syntax used by a disassembler engine. To switch between Intel and AT&T representations:

e asm.syntax = intel

e asm.syntax = att

You can also check asm.pseudo, which is an experimental pseudocode view, and asm.esil which outputs ESIL ('Evaluable Strings Intermediate Language'). ESIL's goal is to have a human-readable representation of every opcode semantics. Such representations can be evaluated (interpreted) to emulate effects of individual instructions.

Flags are conceptually similar to bookmarks. They associate a name with a given offset in a file. Flags can be grouped into 'flag spaces'. A flag space is a namespace for flags, grouping together flags of similar characteristics or type. Examples for flag spaces: sections, registers, symbols.

To create a flag:

[0x4A13B8C0]> f flag_name @ offset

You can remove a flag by appending the - character to command. Most commands accept - as argument-prefix as an indication to delete something.

[0x4A13B8C0]> f-flag_name

To switch between or create new flagspaces use the fs command:

[0x00005310]> fs?

|Usage: fs [*] [+-][flagspace|addr] # Manage flagspaces

| fs display flagspaces

| fs* display flagspaces as r2 commands

| fsj display flagspaces in JSON

| fs * select all flagspaces

| fs flagspace select flagspace or create if it doesn't exist

| fs-flagspace remove flagspace

| fs-* remove all flagspaces

| fs+foo push previous flagspace and set

| fs- pop to the previous flagspace

| fs-. remove the current flagspace

| fsq list flagspaces in quiet mode

| fsm [addr] move flags at given address to the current flagspace

| fss display flagspaces stack

| fss* display flagspaces stack in r2 commands

| fssj display flagspaces stack in JSON

| fsr newname rename selected flagspace

[0x00005310]> fs

0 439 * strings

1 17 * symbols

2 54 * sections

3 20 * segments

4 115 * relocs

5 109 * imports

[0x00005310]>

Here there are some command examples:

[0x4A13B8C0]> fs symbols ; select only flags in symbols flagspace

[0x4A13B8C0]> f ; list only flags in symbols flagspace

[0x4A13B8C0]> fs * ; select all flagspaces

[0x4A13B8C0]> f myflag ; create a new flag called 'myflag'

[0x4A13B8C0]> f-myflag ; delete the flag called 'myflag'

You can rename flags with fr.

Local flags

Every flag name should be unique for addressing reasons. But it is quite a common need to have the flags, for example inside the functions, with simple and ubiquitous names like loop or return. For this purpose you can use so called "local" flags, which are tied to the function where they reside. It is possible to add them using f. command:

[0x00003a04]> pd 10

│ 0x00003a04 48c705c9cc21. mov qword [0x002206d8], 0xffffffffffffffff ;

[0x2206d8:8]=0

│ 0x00003a0f c60522cc2100. mov byte [0x00220638], 0 ; [0x220638:1]=0

│ 0x00003a16 83f802 cmp eax, 2

│ .─< 0x00003a19 0f84880d0000 je 0x47a7

│ │ 0x00003a1f 83f803 cmp eax, 3

│ .──< 0x00003a22 740e je 0x3a32

│ ││ 0x00003a24 83e801 sub eax, 1

│.───< 0x00003a27 0f84ed080000 je 0x431a

││││ 0x00003a2d e8fef8ffff call sym.imp.abort ; void abort(void)

││││ ; CODE XREF from main (0x3a22)

││╰──> 0x00003a32 be07000000 mov esi, 7

[0x00003a04]> f. localflag @ 0x3a32

[0x00003a04]> f.

0x00003a32 localflag [main + 210]

[0x00003a04]> pd 10

│ 0x00003a04 48c705c9cc21. mov qword [0x002206d8], 0xffffffffffffffff ;

[0x2206d8:8]=0

│ 0x00003a0f c60522cc2100. mov byte [0x00220638], 0 ; [0x220638:1]=0

│ 0x00003a16 83f802 cmp eax, 2

│ .─< 0x00003a19 0f84880d0000 je 0x47a7

│ │ 0x00003a1f 83f803 cmp eax, 3

│ .──< 0x00003a22 740e je 0x3a32 ; main.localflag

│ ││ 0x00003a24 83e801 sub eax, 1

│.───< 0x00003a27 0f84ed080000 je 0x431a

││││ 0x00003a2d e8fef8ffff call sym.imp.abort ; void abort(void)

││││ ; CODE XREF from main (0x3a22)

││`──> .localflag:

││││ ; CODE XREF from main (0x3a22)

││`──> 0x00003a32 be07000000 mov esi, 7

[0x00003a04]>

Flag Zones

radare2 offers flag zones, which lets you label different offsets on the scrollbar, for making it easier to navigate through large binaries. You can set a flag zone on the current seek using: