Create EscapedFrameIntervalsFinder and ComplexStackVariableTransformer #1157
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`EscapedFrameIntervalsFinder` finds intervals in the `[[-12, -4], (struct ""str"" 0008 (0 int32 dw0000) (4 real32 r0004))]` form. Then `ComplexStackVariableTransformer` rewrites expressions like `fp - <offset>` if offset is inside of one of the intervals collected by `EscapedFrameIntervalsFinder`. Current implementation works only if user or environment procedure signature is defined.
ptomin
added
enhancement
uxmal
reviewed
Feb 18, 2022
| @@ -7,7 +7,7 @@ | |||
| // 10001000: Register (ptr32 Eq_n) sum_wrapper(Stack (ptr32 Eq_n) ptrArg04, Stack (ptr32 Eq_n) ptrArg08) | |||
| PyObject * sum_wrapper(PyObject * ptrArg04, PyObject * ptrArg08) | |||
| { | |||
| PyObject * eax_n = PyArg_ParseTuple(ptrArg08, "ii:sum", fp - 0x04, fp - 0x08); | |||
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As discussed earlier, the declarations of the two new variables can be done in a future commit.
| QueryPerformanceCounter(fp - 0x14); | ||
| ui32 esi_n = esi_n ^ (dwLoc10 ^ dwLoc14); | ||
| QueryPerformanceCounter(&tLoc14); | ||
| ui32 esi_n = esi_n ^ (tLoc14.dw0004 ^ tLoc14); |
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What happened here? tLoc14 seems to have sub-structure?
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The type of tLoc14 is LARGE_INTEGER union.
typedef union _LARGE_INTEGER {
struct {
DWORD LowPart;
LONG HighPart;
} DUMMYSTRUCTNAME;
struct {
DWORD LowPart;
LONG HighPart;
} u;
LONGLONG QuadPart;
} LARGE_INTEGER;
The result should be
ui32 esi_n = esi_n ^ (tLoc14.HighPart ^ tLoc14.LowPart);
It looks like later phase (TypeAnalysis/ComplexExpressionRewiter) can't transform correctly accesses to such unions.
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Can we make an issue to track this then?
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There are two phases.
EscapedFrameIntervalsFinderfinds intervals in the[[-12, -4], (struct ""str"" 0008 (0 int32 dw0000) (4 real32 r0004))]form. Then
ComplexStackVariableTransformerrewrites expressions likefp - <offset>if offset is inside of one of the intervals collected byEscapedFrameIntervalsFinder.Current implementation works only if user or environment procedure
signature is defined.