Questions tagged [arm]
A family of instruction set architectures based on a RISC architecture developed by British company ARM Holdings. Heavily used in embedded devices such as mobile phones, tablets, set-top boxes, ...
219
questions
3
votes
3answers
197 views
ARMv8 (AArch64, ARM64) opcodes list
I'm sorry for such as questions where answer would seem to be easily searched in google...
Some time ago I have seen table/list of ARMv8 instructions with opcodes and it was perfect, but I lost link. ...
2
votes
0answers
34 views
How to proceed after running binwalk on this firmware?
I'm trying to access the firmware from the .bin in this archive: http://mydjiflight.dji.com/file/links/OSMO_ACTION_V17020_20191203_ZIP
So far I've used binwalk and gotten the following output:
...
0
votes
1answer
38 views
Detecting libc function with IDA
I have binary than running on Arm , static and striped.
I don't know which compiler compiled this binary.
How can I identify function like fread sleep printf ioctl
0
votes
1answer
42 views
LDR specifier combination UXTW
Sorry, if this question seems stupid, but I am new in arm64 and next 2 assembly lines seriously damaged my brain:
LDR W0, [X30,W0,UXTW#2]
ADD X30, X30, W0,UXTW
I have readed ...
0
votes
1answer
28 views
Patch Arm binary with Ida
In Ida I can patch binary that run on x86 , but not binary that run on Arm.
How can I simply patch binary , change assembly(not only hex) and save to new binary file
1
vote
1answer
40 views
reverse engineering hi3516ev200
I am new to reverse engineering and will describe my situation thus far. In short, I am looking for some tips on what to do next to gain access to a piece of hardware I am playing with. I bought a ...
1
vote
0answers
50 views
Bin patching Arm7tdmi CRC32?
Ok so I am total noob here. I wanted to play with the bin from an instrument cluster I work on a lot. I was able to pull the bin off the MCU with a J-link. If I erase the chip and flash it with a bin ...
1
vote
1answer
30 views
IDA - ObjC - Meaning of _BYTE and dword_0?
This is my first experience disassembling/reverse engineering, and am having a bit of difficulty keeping up. For reference, I'm trying to uncover the inner workings of a pretty good library in my ...
0
votes
1answer
54 views
How to Modify CBZ Branch in ARM64?
If I want after running the CBZ W0, loc_C5C8 command
Run to the ADRP X8,#selRef_curent_version@PAGE command
regardless of the condition (in picture), what should I do?
2
votes
0answers
86 views
Reversing a firmware update for an LG HTS
I'm trying to reverse a firmware update for an LG Home Theater BH7220, and I've hit a brick wall.
This HTS has a main chip from LG referred to as "BH7000:1165" in the schematics. The chip has the ...
3
votes
3answers
191 views
Strange vtable setup in constructor disassembly
In a program I'm trying to recover data structures I've discovered the following strange (ARM) disassembly code:
ctor_1:
ldr r1, =vtable_base
str r1, [r0] ;r0 always contains ...
0
votes
0answers
14 views
Building firmware.bin from mtd partitions
Working on reversing current router firmware here and I can't find any sources from the manufacturer for their firmware and toolchain.
I wanted to do this approach.
firmware.bin is loaded and ...
1
vote
0answers
28 views
Strange behaviour debugging Android ARM binary with gdbserver
I'm trying to run this armv5 binary from OWASP's mobile security guide (validate) using Android Studio's emulator on my x86_64 machine. I'm seeing very weird behaviour and would appreciate any ...
0
votes
0answers
54 views
Why is U-Boot changing this bit marked as “DO NOT CHANGE”?
While reverse engineering very early hardware initialization code of an old S3C6410 based tablet, I came across an instruction that changes a bit that the user manual (relevant info on pg. 3-50) ...
1
vote
1answer
30 views
Mach-O ARM64 using literal values instead of a frame pointer (BP) register
I'm investigating an iOS app Mach-O binary in IDA and noticed it's using a fixed constant as an offset to the SP to denote the start of the stack frame instead of a register. Is this normal? ARM ...
3
votes
1answer
50 views
What binary value does Thread and Process ID Register contains in Android ARM?
I have following instructions in Android shared library:
MRC p15, 0, R3,c13,c0, 3
LDR R3, [R3,#4]
MOV R0, #0
STR R0, [R3,#0xC]
According to ARM documentation:
Reading or writing the Thread and ...
-1
votes
1answer
172 views
What is the following assembly code doing? [closed]
str fp,[sp, -4]!
add fp, sp, #0
sub sp, sp, #12
str r0, [fp, #-8]
str r1 [fp, #-12]
L5:
ldr r3, [fp, #-8]
ldrb r3, [r3]
cmp r3, #0
beq .L2
ldr r3, [fp, #-12]
ldrb r3, [r3]
cmp r3, #0
beq .L2
ldr r3, [...
2
votes
0answers
71 views
When virtual table is not the first element of structure?
Assuming that source code is compiled for ARMv7 architecure using clang (native shared object library for Android, Itanium ABI) what are the cases when virtual table pointer is not the first element ...
2
votes
0answers
217 views
Extracting firmware image from binary
I have firmware file in .bin format, but I need get firmware.img image file and Kernel uImage file for reflashing bricked device. How can I get these parts?
I used Binwalk to extract content, ...
0
votes
1answer
42 views
How is `va_list` implemented in Assembler level on ARMv7 Android?
I need to extract all arguments from CallStaticObjectMethodV JNI call on ARMv7 Android at Assembler level.
Can anyone advice how is va_list implemented on low level in ARMv7 Android?
3
votes
2answers
81 views
Get certain instruction count for multi-architecture binaries
I need to get an ELF binary's total count of
Function call instruction
conditional jump (branch) instruction
The binary could be any CPU architecture, like x64, ARM, MIPS, Motorola 68K, etc.
It ...
3
votes
0answers
116 views
Reverse Engineering Firmware Aether Cone
I have been trying to work out if its possible to reverse engineer the firmware for the Aether Cone. This is a good sound quality WIFI and Bluetooth speaker, but with Aether going bust, there is no ...
0
votes
1answer
45 views
Why does this command crash IDA Android native debugger?
In Android shared library that heavily protected against debugging, I found following code:
CODE32
ldr pc, [pc, #-4]
For me, this instruction looks like NOP; it just jumps to next instruction in ARM ...
1
vote
0answers
71 views
Debugging arbitrary ARM binary image using IDA and QEMU
i'm new to this and still learning a lot. Now i have managed to download the binary image from an Flash memory out of a unit having an OMAP5912 SoC. The SoC has an ARM9 family CPU core running little ...
2
votes
0answers
536 views
Extracting ARM Boot zImage
I'm trying to analyze the firmware of a system running Linux and connecting various home automation and security devices. Every time it boots, the GM8125 processor running ARMv5TE loads a firmware ...
0
votes
0answers
29 views
LLDB Cannot calculate virtual address from ASLR slide
I am trying to set a breakpoint at an Objective-C method in an iOS app (armv7). I create a toy app, dumped the sections to find the loaded address of the __text section, and calculated the mapped ...
0
votes
1answer
101 views
Understand what Ioctl do
I looking in ida on arm linux binary . I can see there that there is ioctl call
ioctl(fd,req,num).
fd is fd to /dev/module. ,req is some 4bytes and num is some number.
How can I understand what ...
0
votes
0answers
83 views
Why decrement a hex value in assembly code?
I am running a disassembly of a firmware image for a Cortex-M4 and the entry point is doing something strange.
EntryPoint:
00001000 db 0x00 ; '.'
00001001 db 0xff ; '.'
00001002 ...
1
vote
1answer
104 views
How to inject some code to ARM .so files permanently?
I am trying to figure out how to solve the following. I have two ARM .SO libraries (32 bit and 64 bit) with the same functions. There is a method which returns const char* , it looks like this in ...
0
votes
0answers
308 views
Disassembling ARM binary
I am trying to disassemble a firmware binary which I am interested in. Yet I don't have much experience in this field, which is why I would like some input from you guys.
My current state is that I ...
1
vote
0answers
120 views
Can you change the architecture in Ghidra after importing?
I've been analyzing an ARMv7 binary for a while and have done a lot of work with it (e.g. labeling functions, creating structs, labeling globals etc.). Unfortunately, I just realized that Ghidra ...
1
vote
1answer
65 views
MEMORY macro in IDA Pro pseudocode
I have a 32-bit ARM Linux kernel module with debug symbols. When it is decompiled, it produces many functions that have a macro called MEMORY in them. Here is an example:
int S_u8init_flag = 0; // ...
1
vote
0answers
151 views
Simplify two 32 bit expressions into one 64 bit expression in decompilation
I am getting started with Ghidra, and am decompiling a simple program of mine. The platform is Linux (ELF) on ARM. I found in the decompiled code things like:
gTime._0_4_ = (undefined4)(time1 >>...
4
votes
1answer
796 views
In Ghidra what do I need to set so disassembler is in Thumb mode instead of ARM
In IDA I would press Alt+G and set the T register to 1 to first the code to be Thumb, but in Ghidra am not not sure how to force it.
The context is I have some functions pointed to by a data ...
0
votes
1answer
172 views
How to split ARM code/data from binary in Inmarsat Isatphone Pro?
I'm analyzing the 3 binaries for updating firmware to the Inmarsat Isatphone Pro phone. Additionally, I'm following the Groundworks Technologies paper, and attempting to recreate their work as a ...
0
votes
1answer
105 views
Finding function at offset loaded with ADRP/ADD
I have this assembly:
ADRP X8, #off_FFFFFFF006F1E960@PAGE
ADD X8, X8, #off_FFFFFFF006F1E960@PAGEOFF
LDR X0, [X8] ; qword_FFFFFFF0077F08A8
LDR X8, [X0]
...
4
votes
1answer
155 views
Reverse engineering a compression algorithm to decompress ASCII text (LZ-variant?)
Reposted from StackOverflow as is.
I'm trying to decompress a very long text block from an ARMv5t powered Gameboy Advance ROM, which was compressed using some kind of custom LZ-esque compression ...
1
vote
1answer
57 views
How is thumb branch calculated
I have the instruction which is:
5ff1aed4 bl sub_5ff171d0
which assembles to:
FCF77CF9
This appears to mean that the program is branching backwards, However I can't seem to find ...
0
votes
0answers
77 views
Dumping flash from a running Cortex-M
I have a working device with a STM32F405ZGT6 in it. I want to dump the software it runs.
As far as I can tell, there's no external flash on the device, so it must be running off of the internal flash....
0
votes
3answers
307 views
Firmware reverse engineering
this question is a follow-up from this previous post: Flash dump binwalk blank, low entropy
I need to reverse engineer a firmware from a very secure device. I was able to reverse engineer the PCB ...
2
votes
1answer
79 views
Process Immediately Killed
I'm trying to reverse an ARM executable. It's for an embedded system, but I don't have any details about the normally targeted environment.
Here's what file shows: ELF 32-bit LSB executable, ARM, ...
1
vote
0answers
72 views
Help understanding ARM Assembly example code - loops, set flags and code mnemonics
This is the example code:
_start:
LDR r0, =n
LDR r0, [r0]
LDR r1, =array1
MOV r2, #0
LDR r4, =array2
loop:
LDR r3, [r1], #4
CMP r3, #58
BGT a_point
CMP r3, #47
BLT a_point
SUB r3, r3, #0x30
STR r3, [...
-1
votes
1answer
2k views
how should i change an instruction to NOP in IDA?
I am new with IDA assembler and i used to work with hopper app.
the problem is i can't change instruction in IDA from something like CBNZ to NOP.
is there any button to do this? i can't find anything ...
0
votes
1answer
192 views
Confused about a firmware binary
I'm trying to reverse engineer an ARM Thumb2 firmware binary, and I've come across a few oddities. Parts of the file when treated as RGB binary data form perfect images, which seems unusual for a ...
5
votes
1answer
805 views
Find function in a stripped dynamic ELF library
Im currently reverse engineering an android app and this app calls a function named "getUserInfo" in an ARM 32bit ELF library called "libcms.so" (from TikTok) via the Java Native Interface.
My ...
3
votes
1answer
103 views
Enumerating (name, addresses) in PLT of an ELF file without elf.h
I want to show users imported symbols of a given ELF file like this(#1) in a disassembler project.(Android app)
1d21a: f7fa e8e8 blx 173ec ; __android_log_print@plt ...
Currently, I can only show ...
5
votes
1answer
427 views
How does API call work on Android (NDK)?
In windows platform, an application usually references its IAT(Import Access Table) to get the address of the APIs it wants, then call it. Then some mechanisms are done as demonstrated here nicely.
...
1
vote
1answer
131 views
Bp on memory access in arm deb
I'm using idapro for arm native debugging (with androidseever) . I'd like to check when a memory data is read by code (what instruction and where). Hardware bp is not possible. How can i do? How to ...
2
votes
0answers
77 views
Understanding ESIL
I cross-compiled a simple program with the aarch-linux-gnu-gcc compiler for ARM. So the machine is "ARM aarch64". I want to understand a single instruction and it's realization in ESIL. The opcode of ...
2
votes
1answer
100 views
How are ARMv7 assembly opcodes and operands stored in bytes?
I've been trying to analyze an ARM binary but cannot figure out how the operators and operands are stored in the bytes of a program.
For example, by looking at the disassembly listing of an ARMv7 ...
