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Date:   Fri, 29 Sep 2023 17:59:22 +0200
From:   "Gustavo A. R. Silva" <gustavoars@kernel.org>
To:     Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>,
        Jussi Kivilinna <jussi.kivilinna@iki.fi>
Cc:     alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org,
        "Gustavo A. R. Silva" <gustavoars@kernel.org>,
        linux-hardening@vger.kernel.org
Subject: [PATCH][next] ALSA: 6fire: Fix undefined behavior bug in struct
 comm_runtime
Message-ID: <ZRb0WiViajjqcyKT@work>
MIME-Version: 1.0
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Precedence: bulk

`struct urb` is a flexible structure, which means that it contains a
flexible-array member at the bottom. This could potentially lead to an
overwrite of the objects following `receiver` in `struct comm_runtime`,
among them some function pointers.

Fix this by placing the declaration of object `receiver` at the end of
`struct comm_runtime`.

Fixes: ddb6b5a96437 ("ALSA: 6fire: fix DMA issues with URB transfer_buffer usage")
Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 sound/usb/6fire/comm.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/usb/6fire/comm.h b/sound/usb/6fire/comm.h
index 2447d7ecf179..ee81572a4eec 100644
--- a/sound/usb/6fire/comm.h
+++ b/sound/usb/6fire/comm.h
@@ -19,7 +19,6 @@ enum /* settings for comm */
 struct comm_runtime {
 	struct sfire_chip *chip;
 
-	struct urb receiver;
 	u8 *receiver_buffer;
 
 	u8 serial; /* urb serial */
@@ -30,6 +29,7 @@ struct comm_runtime {
 	int (*write8)(struct comm_runtime *rt, u8 request, u8 reg, u8 value);
 	int (*write16)(struct comm_runtime *rt, u8 request, u8 reg,
 			u8 vh, u8 vl);
+	struct urb receiver;
 };
 
 int usb6fire_comm_init(struct sfire_chip *chip);
-- 
2.34.1