On Sun, 7 Apr 2024 at 03:39, Andres Freund <and...@anarazel.de> wrote: > Changing the global vars to size_t seems mildly bogus to me. All it's > achieving is to use slightly more memory. It also just seems unrelated to the > change.
I took a closer look at this. I agree that changing PqSendBufferSize to size_t is unnecessary: given the locations that it is used I see no risk of overflow anywhere. Changing the type of PqSendPointer and PqSendStart is needed though, because (as described by Heiki and David upthread) the argument type of internal_flush_buffer is size_t*. So if you actually pass int* there, and the sizes are not the same then you will start writing out of bounds. And because internal_flush_buffer is introduced in this patch, it is related to this change. This is what David just committed too. However, the "required" var actually should be of size_t to avoid overflow if len is larger than int even without this change. So attached is a tiny patch that does that.
v7-0001-Avoid-possible-overflow-in-socket_putmessage_nonb.patch
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