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Be more restrictive about VEX prefix combinations

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Alexis Engelke
2019-11-02 15:53:00 +01:00
parent 5613adda25
commit c4a4df458d
1 changed files with 4 additions and 0 deletions
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4
decode.c
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@@ -131,6 +131,10 @@ decode_prefixes(const uint8_t* buffer, int len, DecodeMode mode,
if (mode == DECODE_32 && (byte & 0xc0) != 0xc0) if (mode == DECODE_32 && (byte & 0xc0) != 0xc0)
goto out; goto out;
// VEX + REX/66/F2/F3/LOCK will #UD.
if (prefixes & (PREFIX_REX|PREFIX_REP|PREFIX_REPNZ|PREFIX_LOCK))
return -1;
prefixes |= PREFIX_VEX; prefixes |= PREFIX_VEX;
prefixes |= byte & 0x80 ? 0 : PREFIX_REXR; prefixes |= byte & 0x80 ? 0 : PREFIX_REXR;
if (prefix == 0xc4) // 3-byte VEX if (prefix == 0xc4) // 3-byte VEX