[-] PROGRAM ABORT : Repeatedly failed to deliver sample

[symeonp]

Hi Ivan,

Unfortunately am facing this issue where after 2 days of fuzzing am getting the following error with Jackalope exiting and
not saving the crash test case!

Exception at address 0000000076A39AFB
Exception in instrumented module xxx.dll
Code before:
99 2b c2 8b c8 d1 f9 8b c6 99
Code after:
f7 f9 8b b5 28 fd ff ff e9 38 00 00 00 8b 85 48
[!] WARNING: Error delivering sample, retrying with a clean target
[-] PROGRAM ABORT : Repeatedly failed to deliver sample         Location : Fuzzer::TryReproduceCrash(), C:\Users\symeon\Desktop\Jackalope\fuzzer.cpp:300

Interesting enough, I was able to reproduce this issue with different samples where before exiting it did save
the crash and I can confirm it was a valid crash!

What's the best way to help you reproduce it? Any ideas why is this happening?

Thanks!

Edit: Yes can confirm if I load the input_1 from the output folder (last fuzzed file) will indeed crash my harness.

Edit2: Am able to reproduce this issue within seconds, perhaps I could send you my repro privately..

[ifratric]

Hi Symeon,
Having some kind of a repo would definitely help. I guess you are using file sample delivery (as opposed to shared memory sample delivery which is faster and isn't susceptible to these problems). My guess would be that when your target crashes the OS still thinks the file is opened and can't be rewritten (what happens if you try to delete input_1 manually?). Either that or something else gains a reference to the file.