Messages in this thread | | | Date | Tue, 12 Jan 2021 14:58:47 +0100 | From | Takashi Iwai <> | Subject | Re: [PATCH/RFC 2/2] ALSA: firewire-tascam: Fix integer overflow in midi_port_work() |
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On Mon, 11 Jan 2021 14:02:51 +0100, Geert Uytterhoeven wrote: > > As snd_fw_async_midi_port.consume_bytes is unsigned int, and > NSEC_PER_SEC is 1000000000L, the second multiplication in > > port->consume_bytes * 8 * NSEC_PER_SEC / 31250 > > always overflows on 32-bit platforms, truncating the result. Fix this > by precalculating "NSEC_PER_SEC / 31250", which is an integer constant. > > Note that this assumes port->consume_bytes <= 16777. > > Fixes: 531f471834227d03 ("ALSA: firewire-lib/firewire-tascam: localize async midi port") > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> > --- > Compile-tested only. > > I don't know the maximum transfer length of MIDI, but given it's an old > standard, I guess it's rather small. If it is larger than 16777, the > constant "8" should be replaced by "8ULL", to force 64-bit arithmetic.
Applied now. Thanks.
Takashi
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