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* [PATCH] ALSA: firewire-motu: add bounds check in put_user loop for DSP events
@ 2025-12-09  5:16 Junrui Luo
  2025-12-09  7:09 ` Takashi Iwai
  0 siblings, 1 reply; 2+ messages in thread
From: Junrui Luo @ 2025-12-09  5:16 UTC (permalink / raw)
  To: Clemens Ladisch, Takashi Sakamoto, Jaroslav Kysela, Takashi Iwai
  Cc: Takashi Iwai, linux-sound, linux-kernel, Junrui Luo

In the DSP event handling code, a put_user() loop copies event data.
When the user buffer size is not aligned to 4 bytes, it could overwrite
beyond the buffer boundary.

Fix by adding a bounds check before put_user().

Suggested-by: Takashi Iwai <tiwai@suse.de>
Fixes: 634ec0b2906e ("ALSA: firewire-motu: notify event for parameter change in register DSP model")
Signed-off-by: Junrui Luo <moonafterrain@outlook.com>
---
 sound/firewire/motu/motu-hwdep.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/firewire/motu/motu-hwdep.c b/sound/firewire/motu/motu-hwdep.c
index 6675b23aad69..89dc436a0652 100644
--- a/sound/firewire/motu/motu-hwdep.c
+++ b/sound/firewire/motu/motu-hwdep.c
@@ -75,7 +75,7 @@ static long hwdep_read(struct snd_hwdep *hwdep, char __user *buf, long count,
 		while (consumed < count &&
 		       snd_motu_register_dsp_message_parser_copy_event(motu, &ev)) {
 			ptr = (u32 __user *)(buf + consumed);
-			if (put_user(ev, ptr))
+			if (consumed + sizeof(ev) > count || put_user(ev, ptr))
 				return -EFAULT;
 			consumed += sizeof(ev);
 		}

---
base-commit: 210d77cca3d0494ed30a5c628b20c1d95fa04fb1
change-id: 20251209-fixes-28e18627cc79

Best regards,
-- 
Junrui Luo <moonafterrain@outlook.com>


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] ALSA: firewire-motu: add bounds check in put_user loop for DSP events
  2025-12-09  5:16 [PATCH] ALSA: firewire-motu: add bounds check in put_user loop for DSP events Junrui Luo
@ 2025-12-09  7:09 ` Takashi Iwai
  0 siblings, 0 replies; 2+ messages in thread
From: Takashi Iwai @ 2025-12-09  7:09 UTC (permalink / raw)
  To: Junrui Luo
  Cc: Clemens Ladisch, Takashi Sakamoto, Jaroslav Kysela, Takashi Iwai,
	Takashi Iwai, linux-sound, linux-kernel

On Tue, 09 Dec 2025 06:16:41 +0100,
Junrui Luo wrote:
> 
> In the DSP event handling code, a put_user() loop copies event data.
> When the user buffer size is not aligned to 4 bytes, it could overwrite
> beyond the buffer boundary.
> 
> Fix by adding a bounds check before put_user().
> 
> Suggested-by: Takashi Iwai <tiwai@suse.de>
> Fixes: 634ec0b2906e ("ALSA: firewire-motu: notify event for parameter change in register DSP model")
> Signed-off-by: Junrui Luo <moonafterrain@outlook.com>

Applied now.  Thanks.


Takashi

^ permalink raw reply	[flat|nested] 2+ messages in thread

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