Fixes 1654: Fixed win32print.DeviceCapabilities() returning strings with junk in them. #1660
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LincolnPuzey
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@mhammond when you have time, I would appreciate a review of this, thanks. Any suggestions of how I could add a test? |
mhammond
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Feb 1, 2021
win32/src/win32print/win32print.cpp
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| for (bufindex = 0; bufindex < result; bufindex++) { | ||
| if (*(retname + retsize - 1) == 0) | ||
| // check if returned string contains null character | ||
| bool contains_null = false; |
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This could probably be simplified - it looks like retsize_index is always the actual string length (ie, is what we could pass to PyWinObject_FromTCHAR in both cases. So maybe rename it to, say, actual_ret_size and you can kill contains_null and the later if?
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Yep makes sense, will change.
…them. Previously this code would ZeroMemory() the output buffer before passing it to DeviceCapabilities(), and then assume that only characters in each string would be changed, i.e. the characters following the null-terminator would remain null. So it would only check if the last character in each string was null, to check if the string was null-terminated. This assumption is wrong - sometimes DeviceCapabilities() sets the characters after null to junk. Now every character in the returned buffer is checked for being null before falling back to the case where the string takes up all available space. mhammond#1654
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Fixes Issue #1654 |
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Previously this code would
ZeroMemory()the output buffer before passing it toDeviceCapabilities(),and then assume that only characters in each string would be changed, i.e. the characters following
the null-terminator would remain null.
So it would only check if the last character in each string was null, to check if the string was null-terminated.
This assumption is wrong - sometimes
DeviceCapabilities()sets the characters after null to junk.Now every character in the returned buffer is checked for being null before falling back to the case where the
string takes up all available space.