Linux Sound subsystem development
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From: Takashi Iwai <tiwai@suse.de>
To: Jiaming Zhang <r772577952@gmail.com>
Cc: tiwai@suse.de, g@b4.vu, linux-kernel@vger.kernel.org,
	linux-sound@vger.kernel.org, perex@perex.cz,
	syzkaller@googlegroups.com, tiwai@suse.com
Subject: Re: [PATCH] ALSA: FCP: Fix NULL pointer dereference in interface lookup
Date: Fri, 26 Jun 2026 07:47:35 +0200	[thread overview]
Message-ID: <87mrwhua2w.wl-tiwai@suse.de> (raw)
In-Reply-To: <20260625134933.425785-1-r772577952@gmail.com>

On Thu, 25 Jun 2026 15:49:33 +0200,
Jiaming Zhang wrote:
> 
> A malformed USB device can provide a vendor-specific interface without
> any endpoint descriptors. fcp_find_fc_interface() currently selects the
> first vendor-specific interface and reads endpoint 0 from it, without
> checking whether the interface actually has any endpoints.
> 
> When bNumEndpoints is zero, no endpoint array is allocated for the parsed
> alternate setting, so get_endpoint(..., 0) yields an invalid endpoint
> descriptor pointer. Dereferencing it through usb_endpoint_num() then
> triggers a NULL pointer dereference.
> 
> Skip vendor-specific interfaces that do not have any endpoints.
> 
> Fixes: 46757a3e7d50 ("ALSA: FCP: Add Focusrite Control Protocol driver")
> Reported-by: Jiaming Zhang <r772577952@gmail.com>
> Closes: https://lore.kernel.org/lkml/CANypQFb1EHj0xX8bA1WxSOSK-5xca6ZNKzOQcp12=s=puY7VFw@mail.gmail.com/
> Signed-off-by: Jiaming Zhang <r772577952@gmail.com>

Applied now.  Thanks.


Takashi

      reply	other threads:[~2026-06-26  5:47 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-25 10:24 [Linux Kernel Bug] general protection fault in snd_fcp_init Jiaming Zhang
2026-06-25 11:44 ` Takashi Iwai
2026-06-25 13:49   ` [PATCH] ALSA: FCP: Fix NULL pointer dereference in interface lookup Jiaming Zhang
2026-06-26  5:47     ` Takashi Iwai [this message]

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