Fix out-of-bounds memory accesses#35
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danirod
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Jun 23, 2022
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That is true, good caught, thanks. |
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If
Iends up greater than0xfff, then the memory array can be indexed out-of-bounds (e.g. repeated use of theADD I, Vxinstruction). This is a security vulnerability. A malicious ROM can leverage this to escape the emulator, and execute arbitrary native code on the host system.I noticed this comment in
cpu.h:chip8/src/lib8/cpu.h
Lines 49 to 54 in d952e57
However, this
ADDRESS_MASKconstant is never used anywhere! So, I used it to add masking to all memory reads and writes, fixing the vulnerability.