DynamoRIO / DynamoRIO/dynamorio

Add component test to check eflags settings lookup in decode_fast.

Open
#3,267 6 comments 0 reactions 0 assignees View on GitHub
Component-Tests OpSys-x64 OpSys-x86
Dominant language
C
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Forks
629
Avg merge
2d 18h
Merged PRs (30d)
30

Description

Most likely, even after PR 3265 that fixes byte0/byte1 opcode lookup, the determination for eflags is possibly incorrect for instructions with VEX prefix. We need to check the logic and fix. Also instructions with EVEX prefix will be affected one they will be added to the decoder/encoder.

There is no known failing application/example.

Contributor guide

Open the contributing guide

Research direction

Start at the decode_fast entry point and inspect how eflags settings are looked up after byte0/byte1 opcode handling. Add a component test covering instructions with a VEX prefix, and verify the lookup behavior; keep EVEX impact in mind as described. Done means the test exposes and the fix corrects any incorrect eflags determination.

Written by the indexing model from the issue text.

Assessment

Tech stack
c
Domain
reverse-engineering, testing-qa
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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