[PATCH 5.4 72/76] ALSA: fireface: Fix integer overflow in transmit_midi_msg()
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2021-01-18 18:54:01
Also in:
lkml
From: Geert Uytterhoeven <geert+renesas@glider.be>
commit e7c22eeaff8565d9a8374f320238c251ca31480b upstream.
As snd_ff.rx_bytes[] is unsigned int, and NSEC_PER_SEC is 1000000000L,
the second multiplication in
ff->rx_bytes[port] * 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 ff->rx_bytes[port] <= 16777.
Fixes: 19174295788de77d ("ALSA: fireface: add transaction support")
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20210111130251.361335-2-geert+renesas@glider.be (local)
Signed-off-by: Takashi Iwai <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
sound/firewire/fireface/ff-transaction.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/sound/firewire/fireface/ff-transaction.c
+++ b/sound/firewire/fireface/ff-transaction.c@@ -88,7 +88,7 @@ static void transmit_midi_msg(struct snd /* Set interval to next transaction. */ ff->next_ktime[port] = ktime_add_ns(ktime_get(), - ff->rx_bytes[port] * 8 * NSEC_PER_SEC / 31250); + ff->rx_bytes[port] * 8 * (NSEC_PER_SEC / 31250)); if (quad_count == 1) tcode = TCODE_WRITE_QUADLET_REQUEST;