Each entry gets param_max_len bytes in the data table, and that's what the
buffer is sized from - but nothing clamped what got written into it.
For VT_UTF8 the length written was s_value.size()+1, and then a terminator was
stored at data_ptr[param_len], one byte beyond that again. The memcpy already
copies the terminator (param_len counts it), so that store was both redundant
and always out of range. It doesn't take a malformed file to hit: several
callers pass the string's own length as max_size - see PSPLoaders.cpp's TITLE,
DISC_ID and DISC_VERSION - so the entry overran by two bytes every time, and a
128-character SAVEDATA_TITLE in a 128-byte slot wrote its terminator into the
next entry's data. VT_UTF8_SPE had the same missing clamp without the
off-by-one.
Both are clamped now and log when they truncate, and a negative max_size no
longer subtracts from the computed buffer size. Bytes written are unchanged for
values that do fit, which is every normal case - the terminator now comes from
the zero-fill instead of an explicit store - so this doesn't change any savedata
the emulator produces.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GZq8ZtJmFY7bkX5FVkr3P9
