From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3D9EA34EF19; Fri, 21 Nov 2025 13:57:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763733463; cv=none; b=rEDUG/2ezvyp+Qx4Nbne0MJlaVzIOALjYt+Q0tYbT3ejeBFsKz1hbR6shuS0Do0npueybf/MX1gQxIM1sQPgTBaZ67eIuwinxD7zb90Hg6tdYemgv3yfUdfqtS2JQqfE7nc9z0+fStKss5RQcXnGgJk4wIMgsUKX9VuD3Yy/wys= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763733463; c=relaxed/simple; bh=2Tyvk57FoFnW/rUwimrV7xx+b9aVshDelF0vU1DMcS0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XHUtaPpSKj7789NLflSoekd2Qdl0pxoExPCBaafzZZrBlapY9zvnCa4Iwcl0+KVntXPnhr1AcDS57D0LJin6+Juprd/Az8ODMk1KK8KNic2I7Zf1CkJHVELeQHfM7gK+NDeNvIdnK4j5lNyVHFPWr1+RSsuGk5ak3X5yUXBJfRE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=xCBWn46H; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="xCBWn46H" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BE2EBC4CEF1; Fri, 21 Nov 2025 13:57:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1763733463; bh=2Tyvk57FoFnW/rUwimrV7xx+b9aVshDelF0vU1DMcS0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xCBWn46HB6+GbFGYzou3UMK8mvU+ZvrHCqBVwCiemuoDD85pi8GFBgX5NjIFth9Il N3pohvqdZRMX3N7nLfI/hMTT0E3Yn/vU3/ThCluvnzJ2L0HycPopksBO9fCMGseKVR uFCkI1w+g1EmuRqdgrwLe65caXKpCwt6Z8ihQOlE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+bfd77469c8966de076f7@syzkaller.appspotmail.com, Lizhi Xu , Takashi Iwai Subject: [PATCH 6.6 476/529] ALSA: usb-audio: Fix potential overflow of PCM transfer buffer Date: Fri, 21 Nov 2025 14:12:55 +0100 Message-ID: <20251121130247.946338133@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20251121130230.985163914@linuxfoundation.org> References: <20251121130230.985163914@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Takashi Iwai commit 05a1fc5efdd8560f34a3af39c9cf1e1526cc3ddf upstream. The PCM stream data in USB-audio driver is transferred over USB URB packet buffers, and each packet size is determined dynamically. The packet sizes are limited by some factors such as wMaxPacketSize USB descriptor. OTOH, in the current code, the actually used packet sizes are determined only by the rate and the PPS, which may be bigger than the size limit above. This results in a buffer overflow, as reported by syzbot. Basically when the limit is smaller than the calculated packet size, it implies that something is wrong, most likely a weird USB descriptor. So the best option would be just to return an error at the parameter setup time before doing any further operations. This patch introduces such a sanity check, and returns -EINVAL when the packet size is greater than maxpacksize. The comparison with ep->packsize[1] alone should suffice since it's always equal or greater than ep->packsize[0]. Reported-by: syzbot+bfd77469c8966de076f7@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=bfd77469c8966de076f7 Link: https://lore.kernel.org/690b6b46.050a0220.3d0d33.0054.GAE@google.com Cc: Lizhi Xu Cc: Link: https://patch.msgid.link/20251109091211.12739-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/usb/endpoint.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/sound/usb/endpoint.c +++ b/sound/usb/endpoint.c @@ -1383,6 +1383,11 @@ int snd_usb_endpoint_set_params(struct s 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;