Add support for large-address aware applications #21
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May 5, 2022
src/wow64ext.h
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| @@ -351,6 +351,10 @@ struct _CONTEXT64 | |||
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| #pragma pack(pop) | |||
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| // Without the double casting, the pointer is sign extended, not zero extended, | |||
| // which leads to invalid addresses with /LARGEADDRESSAWARE. | |||
| #define PTR_TO_DWORD64(p) ((DWORD64)(DWORD)(p)) | |||
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If this is ever called from x64 code, it will truncate the pointer
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Yes, wow64ext is an x32-only library, but PTR_TO_DWORD64 might be helpful in generic code outside of the library. I changed the macro, should be fine now, thanks.
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for me its ok, @rwfpl can you merge this PR?
rwfpl
approved these changes
Jun 19, 2022
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PTR_TO_DWORD64 not applicable to hProcess |
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Large-address aware applications linked with the
/LARGEADDRESSAWAREflag can have a user-mode address with its upper bit set. The current code sign-extends the pointer, e.g.87aaeb58toffffffff87aaeb58, leading to an invalid pointer and likely to a crash.I discovered this due to a bug report for Windhawk:
ramensoftware/windhawk#3
I came up with a small program which triggers the bug most of the time:
https://gist.github.com/m417z/7177d820252ab42f4d86c905589b6f05
Also, a similar notice regarding 32-bit to 64-bit pointer casting can be found here: