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bitdefender / bddisasm

bddisasm is a fast, lightweight, x86/x64 instruction decoder. The project also features a fast, basic, x86/x64 instruction emulator, designed specifically to detect shellcode-like behavior.
Apache License 2.0
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VPXOR xmm0, xmm0, xmm0 #68

Closed icyfox168168 closed 2 years ago

icyfox168168 commented 2 years ago

Not sure if there is a problem

VPXOR xmm0, xmm0, xmm0 start XMM0 (HI_32) = 0x0000000000000000000000000000000000007ff8000000000000000000000000 start XMM0 (LO_32) = 0x00000000000000f800000000000000f000007ff8000000e800000000000000e0 ture XMM0 (HI_32) = 0x0000000000000000000000000000000000007ff8000000000000000000000000 ture XMM0 (LO_32) = 0x0000000000000000000000000000000000007ff8000000000000000000000000 fuck XMM0 (HI_32) = 0x0000000000000000000000000000000000007ff8000000000000000000000000 fuck XMM0 (LO_32) = 0x00000000000000f800000000000000f000007ff8000000000000000000000000

vlutas commented 2 years ago

Fixed in https://github.com/bitdefender/bddisasm/commit/bf81c647e3a7cf1e84cb968b37c7e7f82d4ecf16.

I would like to point out two things:

  1. Please refrain from using words such as fuck in comments and reports
  2. bdshemu is not intended to be a complete emulator, or an emulator which respects the ISA to the letter (proof that we don't care at all of some of the cases, such as AF or other flags being set in some conditions). bdshemu is intended to be only correct enough so it goes through potential shellcodes, in order to determine if they are malicious or not. I strongly advise against using bdshemu as a general purpose emulator in this regard. Of course, this does not mean that we won't fix bugs - on the contrary - it just means that there are some cases we may already be aware of, and there may be some cases which we do not wish to fix at all (like the AF, for example).

Thanks for reporting this one as well!