The Official Radare2 Book

Graph commands

When analyzing data it is usually handy to have different ways to represent it in order to get new perspectives to allow the analyst to understand how different parts of the program interact.

Representing basic block edges, function calls, string references as graphs show a very clear view of this information.

Radare2 supports various types of graph available through commands starting with ag:

[0x00005000]> ag?

|Usage: ag [addr]

| Graph commands:

| aga[format] Data references graph

| agA[format] Global data references graph

| agc[format] Function callgraph

| agC[format] Global callgraph

| agd[format] [fcn addr] Diff graph

| agf[format] Basic blocks function graph

| agi[format] Imports graph

| agr[format] References graph

| agR[format] Global references graph

| agx[format] Cross references graph

| agg[format] Custom graph

| ag- Clear the custom graph

| agn[?] title body Add a node to the custom graph

| age[?] title1 title2 Add an edge to the custom graph

Output formats:

| Ascii art

| * r2 commands

| d Graphviz dot

| g Graph Modelling Language (gml)

| j json ('J' for formatted disassembly)

| k SDB key-value

| t Tiny ascii art

| v Interactive ascii art

| w [path] Write to path or display graph image (see graph.gv.format and graph.web)

The structure of the commands is as follows: ag .

For example, agid displays the imports graph in dot format, while aggj outputs the custom graph in JSON format.

Here's a short description for every output format available:

Ascii Art ** (e.g.

agf

)

Displays the graph directly to stdout using ASCII art to represent blocks and edges.

Warning: displaying large graphs directly to stdout might prove to be computationally expensive and will make r2 not responsive for some time. In case of a doubt, prefer using the interactive view (explained below).

Interactive Ascii Art (e.g.

agfv

)

Displays the ASCII graph in an interactive view similar to VV which allows to move the screen, zoom in / zoom out, ...

Tiny Ascii Art (e.g.

agft

)

Displays the ASCII graph directly to stdout in tiny mode (which is the same as reaching the maximum zoom out level in the interactive view).

Graphviz dot (e.g.

agfd

)

Prints the dot source code representing the graph, which can be interpreted by programs such as graphviz or online viewers like this

JSON (e.g.

agfj

)

Prints a JSON string representing the graph.

• In case of the f format (basic blocks of function), it will have detailed information about the function and will also contain the disassembly of the function (use J format for the formatted disassembly.

• In all other cases, it will only have basic information about the nodes of the graph (id, title, body, and edges).

Graph Modelling Language (e.g.

agfg

)

Prints the GML source code representing the graph, which can be interpreted by programs such as yEd

SDB key-value (e.g.

agfk

)

Prints key-value strings representing the graph that was stored by sdb (radare2's string database).

R2 custom graph commands (e.g.

agf*

)

Prints r2 commands that would recreate the desired graph. The commands to construct the graph are agn [title] [body] to add a node and age [title1] [title2] to add an edge. The [body] field can be expressed in base64 to include special formatting (such as newlines).

To easily execute the printed commands, it is possible to prepend a dot to the command (.agf*).

Web / image (e.g.

agfw

)

Radare2 will convert the graph to dot format, use the dot program to convert it to a .gif image and then try to find an already installed viewer on your system (xdg-open, open, ...) and display the graph there.

The extension of the output image can be set with the graph.extension config variable. Available extensions are png, jpg, gif, pdf, ps.

Note: for particularly large graphs, the most recommended extension is svg as it will produce images of much smaller size

If graph.web config variable is enabled, radare2 will try to display the graph using the browser (this feature is experimental and unfinished, and disabled by default.)

Scripting

Radare2 provides a wide set of a features to automate boring work. It ranges from the simple sequencing of the commands to the calling scripts/another programs via IPC (Inter-Process Communication), called r2pipe.

As mentioned a few times before there is an ability to sequence commands using ; semicolon operator.

[0x00404800]> pd 1 ; ao 1

0x00404800 b827e66100 mov eax, 0x61e627 ; "tab"

address: 0x404800

opcode: mov eax, 0x61e627

prefix: 0

bytes: b827e66100

ptr: 0x0061e627

refptr: 0

size: 5

type: mov

esil: 6415911,rax,=

stack: null

family: cpu

[0x00404800]>

It simply runs the second command after finishing the first one, like in a shell.

The second important way to sequence the commands is with a simple pipe |

ao|grep address

Note, the | pipe only can pipe output of r2 commands to external (shell) commands, like system programs or builtin shell commands. There is a similar way to sequence r2 commands, using the backtick operator `command`. The quoted part will undergo command substitution and the output will be used as an argument of the command line.

For example, we want to see a few bytes of the memory at the address referred to by the 'mov eax, addr' instruction. We can do that without jumping to it, using a sequence of commands:

[0x00404800]> pd 1

0x00404800 b827e66100 mov eax, 0x61e627 ; "tab"

[0x00404800]> ao

address: 0x404800

opcode: mov eax, 0x61e627

prefix: 0

bytes: b827e66100

ptr: 0x0061e627

refptr: 0

size: 5

type: mov

esil: 6415911,rax,=

stack: null

family: cpu

[0x00404800]> ao~ptr[1]

0x0061e627

[0x00404800]> px 10 @ `ao~ptr[1]`

- offset - 0 1 2 3 4 5 6 7 8 9 A B C D E F 0123456789ABCDEF

0x0061e627 7461 6200 2e69 6e74 6572 tab..inter

[0x00404800]>

And of course it's possible to redirect the output of an r2 command into a file, using the > and >> commands

[0x00404800]> px 10 @ `ao~ptr[1]` > example.txt

[0x00404800]> px 10 @ `ao~ptr[1]` >> example.txt

Radare2 also provides quite a few Unix type file processing commands like head, tail, cat, grep and many more. One such command is Uniq, which can be used to filter a file to display only non-duplicate content. So to make a new file with only unique strings, you can do:

[0x00404800]> uniq file > uniq_file

The head command can be used to see the first N number of lines in the file, similarly tail command allows the last N number of lines to be seen.

[0x00404800]> head 3 foodtypes.txt

1 Protein

2 Carbohydrate

3 Fat

[0x00404800]> tail 2 foodtypes.txt

3 Shake

4 Milk

The join command could be used to merge two different files with common first field.

[0x00404800]> cat foodtypes.txt

1 Protein

2 Carbohydrate

3 Fat

[0x00404800]> cat foods.txt

1 Cheese

2 Potato

3 Butter

[0x00404800]> join foodtypes foods.txt

1 Protein Cheese

2 Carbohydrate Potato

3 Fat Butter

Similarly, sorting the content is also possible with the sort command. A typical example could be:

[0x00404800]> sort file

eleven

five

great

one

radare

The ?$? command describes several helpful variables you can use to do similar actions even more easily, like the $v "immediate value" variable, or the $m opcode memory reference variable.