From: Geert Uytterhoeven Date: Mon, 11 Jan 2021 13:02:51 +0000 (+0100) Subject: ALSA: firewire-tascam: Fix integer overflow in midi_port_work() X-Git-Tag: v4.19.169~5 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=ab2c8bb6615b604a79b4ccadce654d2081998201;p=users%2Fdwmw2%2Flinux.git ALSA: firewire-tascam: Fix integer overflow in midi_port_work() commit 9f65df9c589f249435255da37a5dd11f1bc86f4d upstream. 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") Reviewed-by: Takashi Sakamoto Signed-off-by: Geert Uytterhoeven Link: https://lore.kernel.org/r/20210111130251.361335-3-geert+renesas@glider.be Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- diff --git a/sound/firewire/tascam/tascam-transaction.c b/sound/firewire/tascam/tascam-transaction.c index 2ad692dd4b137..92f7e74d58478 100644 --- a/sound/firewire/tascam/tascam-transaction.c +++ b/sound/firewire/tascam/tascam-transaction.c @@ -210,7 +210,7 @@ static void midi_port_work(struct work_struct *work) /* Set interval to next transaction. */ port->next_ktime = ktime_add_ns(ktime_get(), - port->consume_bytes * 8 * NSEC_PER_SEC / 31250); + port->consume_bytes * 8 * (NSEC_PER_SEC / 31250)); /* Start this transaction. */ port->idling = false;