Linux Sound subsystem development
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From: Takashi Iwai <tiwai@suse.de>
To: linux-sound@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] ALSA: usb-audio: Avoid potential endless loop in convert_chmap_v3()
Date: Mon, 27 Apr 2026 17:22:15 +0200	[thread overview]
Message-ID: <20260427152224.15276-1-tiwai@suse.de> (raw)

The convert_chmap_v3() has a loop with its increment size of
cs_len->wLength, but we forgot to validate cs_desc->wLength itself,
which may lead to potential endless loop by a malformed descriptor.

Add a proper size check to abort the loop for plugging the hole.

Fixes: ecfd41166b72 ("ALSA: usb-audio: Validate UAC3 cluster segment descriptors")
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/usb/stream.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sound/usb/stream.c b/sound/usb/stream.c
index f8f56ace5652..b2c5c8198281 100644
--- a/sound/usb/stream.c
+++ b/sound/usb/stream.c
@@ -353,6 +353,8 @@ snd_pcm_chmap_elem *convert_chmap_v3(struct uac3_cluster_header_descriptor
 		if (len < sizeof(*cs_desc))
 			break;
 		cs_len = le16_to_cpu(cs_desc->wLength);
+		if (cs_len < sizeof(*cs_desc))
+			break;
 		if (len < cs_len)
 			break;
 		cs_type = cs_desc->bSegmentType;
-- 
2.54.0


                 reply	other threads:[~2026-04-27 15:22 UTC|newest]

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