GRAPHICS: Handle seek-only case in TTFLibrary readCallback#6324
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bluegr merged 2 commits intoscummvm:masterfrom Dec 19, 2024
Merged
GRAPHICS: Handle seek-only case in TTFLibrary readCallback#6324bluegr merged 2 commits intoscummvm:masterfrom
bluegr merged 2 commits intoscummvm:masterfrom
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As documented in FreeType API Reference. This avoids passing a null buffer to ttfFile->read().
Even with dataSize=0, this is undefined behaviour. What caller would pass in nullptr? UBSan caught this happening in a FreeType callback, for example.
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Thanks! |
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Shoot, I've just noticed the code formatting is not good, sorry! I guess it can simply be fixed in a janitorial pass in the future. |
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Thanks, fixed! |
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The FreeType API Reference explains that a FT_Stream_IoFunc such as our
TTFLibrary::readCallbackshould simply perform a seek ifcountis 0 and return a status.In that case,
buffercan be nullptr; previously, that was passed to a stream's read(), which in turn gave it to memcpy(). Some argue that memcpy(null, ..., 0) is acceptable, but it's undeniably undefined behaviour.This PR includes a commit which checks nullptr in
MemoryReadStream::read. I guess that ought never to be the case, so it may be dropped, but it has happened:...sheesh, I'm switching to plain
-O0...