From 9f65df9c589f249435255da37a5dd11f1bc86f4d Mon Sep 17 00:00:00 2001
From: Geert Uytterhoeven <geert+renesas@glider.be>
Date: Mon, 11 Jan 2021 14:02:51 +0100
Subject: [PATCH] ALSA: firewire-tascam: Fix integer overflow in midi_port_work()
Git-commit: 9f65df9c589f249435255da37a5dd11f1bc86f4d
Patch-mainline: v5.11-rc4
References: git-fixes
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 <o-takashi@sakamocchi.jp>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20210111130251.361335-3-geert+renesas@glider.be
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
sound/firewire/tascam/tascam-transaction.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/firewire/tascam/tascam-transaction.c b/sound/firewire/tascam/tascam-transaction.c
index 90288b4b4637..a073cece4a7d 100644
--- a/sound/firewire/tascam/tascam-transaction.c
+++ b/sound/firewire/tascam/tascam-transaction.c
@@ -209,7 +209,7 @@ 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;
--
2.26.2