CWorldServer::RandNumber (and three inlined copies of the same pattern
in worldpackets.cpp's item-refine code) computed "range*rand()" in
integer arithmetic before dividing by (RAND_MAX + 1.0). On Windows
RAND_MAX is 32767 (15-bit), so this never overflowed. On Linux/glibc
RAND_MAX is 2147483647 (2^31-1), so "range*rand()" overflows a 32-bit
UINT for the vast majority of rand() outputs, wrapping to a small
value -- the division by ~2^31 then collapses the result to ~0 or 1
almost always, regardless of the requested range. This made every
percentage-based roll in the game (item drop selection, refine
durability/stats, and anything else using RandNumber) behave as if
called with range 1-2 instead of the real range, which is why item
drops effectively never triggered post-port. Cast to double before
the multiply so it can't overflow.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
