Re: [PATCH 1/2] iconvdata: SHIFT_JISX0213 lacks pending character reset (CVE-2026-77117)

* Carlos O'Donell:

> There is another bug present here that results in data loss and should
> probably get it's own bug filed...
>
> What happens if the combining character is the last character?
>
> In such a case loop.c skips calling BODY (because there is no input to
> consume) in that case and returns a success but drops the combining
> character even if there is room, and this leads to a data loss scenario?

As implemented, SHIFT_JISX0213 has shift states due to this pending
character handling.  This means that applications need to flush the
state to drain any pending characters.  I don't think there is a bug.

At the iconv level, where inputs and outputs are opaque byte streams,
SHIFT_JISX0213 could be implemented with shift states.  But this would
preclude use of SHIFT_JISX0213 as a locale character set because the C
interfaces assume that one input character can produce at most one
output character, and glibc (and other implementations) use shift states
to work around that to some extent.

So I think there is no data loss bug here.

Thanks,
Florian