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From: Hillf Danton <hdanton@sina.com>
To: Takashi Iwai <tiwai@suse.de>
Cc: Lizhi Xu <lizhi.xu@windriver.com>,
	linux-kernel@vger.kernel.org, linux-sound@vger.kernel.org,
	linux-usb@vger.kernel.org, perex@perex.cz,
	syzbot+bfd77469c8966de076f7@syzkaller.appspotmail.com,
	syzkaller-bugs@googlegroups.com, tiwai@suse.com
Subject: Re: [PATCH] ALSA: usb-audio: Prevent urb from writing out of bounds
Date: Fri,  7 Nov 2025 07:51:26 +0800	[thread overview]
Message-ID: <20251106235128.8908-1-hdanton@sina.com> (raw)
In-Reply-To: <87h5v7ru58.wl-tiwai@suse.de>

On Thu, 06 Nov 2025 17:41:07 +0100 Takashi Iwai wrote:
> OK, then a fix like below would work?

Test Takashi's fix.

#syz test

--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -1362,6 +1362,11 @@ int snd_usb_endpoint_set_params(struct snd_usb_audio *chip,
 	ep->sample_rem = ep->cur_rate % ep->pps;
 	ep->packsize[0] = ep->cur_rate / ep->pps;
 	ep->packsize[1] = (ep->cur_rate + (ep->pps - 1)) / ep->pps;
+	if (ep->packsize[1] > ep->maxpacksize) {
+		usb_audio_dbg(chip, "Too small maxpacksize %u for rate %u / pps %u\n",
+			      ep->maxpacksize, ep->cur_rate, ep->pps);
+		return -EINVAL;
+	}
 
 	/* calculate the frequency in 16.16 format */
 	ep->freqm = ep->freqn;
--

  reply	other threads:[~2025-11-06 23:52 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-11-05 15:20 [syzbot] [sound?] [usb?] KASAN: slab-out-of-bounds Write in copy_to_urb syzbot
2025-11-06  2:10 ` Hillf Danton
2025-11-06  2:32   ` syzbot
2025-11-06  7:50 ` Forwarded: " syzbot
2025-11-06  8:33 ` [PATCH] ALSA: usb-audio: Prevent urb from writing out of bounds Lizhi Xu
2025-11-06 10:02   ` Takashi Iwai
2025-11-06 11:31     ` Lizhi Xu
2025-11-06 11:49       ` Takashi Iwai
2025-11-06 14:35         ` Lizhi Xu
2025-11-06 16:41           ` Takashi Iwai
2025-11-06 23:51             ` Hillf Danton [this message]
2025-11-07  0:12               ` [syzbot] [sound?] [usb?] KASAN: slab-out-of-bounds Write in copy_to_urb syzbot
2025-11-07  0:54             ` [PATCH] ALSA: usb-audio: Prevent urb from writing out of bounds Lizhi Xu
2025-11-07  1:13               ` Lizhi Xu
2025-11-08  7:54                 ` Takashi Iwai

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