Help/Support Code injection - add extra instruction inbetween

[QuasaR 4 iPhone 7 Plus 12.1.1]

Hi Guys,

In IDA I have the following code:

__text:00000001002E4330                 MOV             X1, #0
__text:00000001002E4334                 BL              Inventory$$get_size
__text:00000001002E4338                 MOV             X1, X0
__text:00000001002E433C                 CBZ             X21, loc_1002E44B0

What I want is to add an extra instruction before the MOV X1,X0 with something like MOV X0,#50.

So it will look like this:

__text:00000001002E4330                 MOV             X1, #0
__text:00000001002E4334                 BL              Inventory$$get_size
__text:0000000XXXXXXXXX                 MOV             X0, #50
__text:00000001002E4338                 MOV             X1, X0
__text:00000001002E433C                 CBZ             X21, loc_1002E44B0

How can I do that with code injection without overwriting the rest of the instructions or losing instructions ?

[iDavie 2.9k iPhone 6 9.3.3]

I'm not sure, just learning this myself 

Updated October 6, 2017 by iDavie

[xiaov 6.6k iPhone 6 8.3]

6 minutes ago, QuasaR said:

Hi Guys,

In IDA I have the following code:

__text:00000001002E4330                 MOV             X1, #0
__text:00000001002E4334                 BL              Inventory$$get_size
__text:00000001002E4338                 MOV             X1, X0
__text:00000001002E433C                 CBZ             X21, loc_1002E44B0

What I want is to add an extra instruction before the MOV X1,X0 with something like MOV X0,#50.

So it will look like this:

__text:00000001002E4330                 MOV             X1, #0
__text:00000001002E4334                 BL              Inventory$$get_size
__text:0000000XXXXXXXXX                 MOV             X0, #50
__text:00000001002E4338                 MOV             X1, X0
__text:00000001002E433C                 CBZ             X21, loc_1002E44B0

How can I do that with code injection without overwriting the rest of the instructions or losing instructions ?

 

replace

1002E4334                 BL              Inventory$$get_size

to mov x0, #50 your own code.

[QuasaR 4 iPhone 7 Plus 12.1.1]

Ah, ofcourse... instead of getting the size I already set it myself :+