From nobody Sun Apr 5 16:31:08 2026 Received: from cstnet.cn (smtp25.cstnet.cn [159.226.251.25]) (using TLSv1.2 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A78DE14884C; Tue, 24 Mar 2026 01:52:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.226.251.25 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774317152; cv=none; b=kGJUUXD3GJJU7fb1CtRc2gPKGIY5QMQPn0HbPS6+wkB5MY2Hma6iP3yoXPPGzNFHbRXM7i9ryAuq8AxTlwZIOae18WUqw/JSC21dLUlKDDoluhmEie+XdL80oG0gmqWpWIQsLKxzGA4JwiOUIEsqcx7f+xSv2CPqUm38QGFWpWs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774317152; c=relaxed/simple; bh=RwfF5TUs2hlBjtXsNHHVPGVXCi4yNDlBNm4p8KHlt6U=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=C4ZXGcHK2Rq1lWdGJuSH0tQ+JwwzcOreGtpn4X7KbvSuJgQFYg97rYdRvM1zRkvtdfNiWUKkcFcXekzMlKES6Lcm2TMzF6UtlU6WI19399+rIYqL2S9ezJ09EVff80Y+8wgjEfKR+rjaPIQPgBvAgn53J1NuKnHgcdaMDv9Rxw8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn; spf=pass smtp.mailfrom=iscas.ac.cn; arc=none smtp.client-ip=159.226.251.25 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=iscas.ac.cn Received: from localhost.localdomain (unknown [111.196.245.197]) by APP-05 (Coremail) with SMTP id zQCowAD3hAib7MFpzK5JCw--.45024S2; Tue, 24 Mar 2026 09:44:59 +0800 (CST) From: Pengpeng Hou To: mchehab@kernel.org Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, pengpeng@iscas.ac.cn Subject: [PATCH] media: ttusb-dec: reject oversized packet lengths early Date: Tue, 24 Mar 2026 09:44:59 +0800 Message-ID: <20260324014459.93362-1-pengpeng@iscas.ac.cn> X-Mailer: git-send-email 2.50.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: zQCowAD3hAib7MFpzK5JCw--.45024S2 X-Coremail-Antispam: 1UD129KBjvJXoW7uFW7Cw43XrWDXFW7Zw1UWrg_yoW8Zw4kpa 90g343Kw4jqw4rtry3A3WrW3s5C3yxCa4IqrW7X3yqgws3Xa1akF12gw4F9ayUJFy3AayU G3yDZrWrGr12vrJanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUym14x267AKxVWUJVW8JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUXVWUAwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26ryj6F1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4j 6F4UM28EF7xvwVC2z280aVAFwI0_Cr1j6rxdM28EF7xvwVC2z280aVCY1x0267AKxVWxJr 0_GcWle2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E 2Ix0cI8IcVAFwI0_Jrv_JF1lYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbVWUJV W8JwACjcxG0xvY0x0EwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1l42xK82IYc2Ij64vI r41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8Gjc xK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r126r1DMIIYrxkI7VAKI48JMIIF0xvE2Ix0 cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r1j6r4UMIIF0xvE42xK8V AvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv6xkF7I0E 14v26r1j6r4UYxBIdaVFxhVjvjDU0xZFpf9x0JUajgxUUUUU= X-CM-SenderInfo: pshqw1xhqjqxpvfd2hldfou0/ Content-Type: text/plain; charset="utf-8" ttusb_dec_process_urb_frame() derives packet_payload_length directly from bytes in the incoming USB stream and then uses that length to append data into dec->packet[]. The driver only rejects oversized PVA payloads later in ttusb_dec_process_pva(), after the receive state machine has already filled the fixed packet buffer. Reject packet lengths that cannot fit in dec->packet[] before advancing the receive state machine to the bulk copy state. --- drivers/media/usb/ttusb-dec/ttusb_dec.c | 28 +++++++++++++++++++++++-- 1 file changed, 26 insertions(+), 2 deletions(-) diff --git a/drivers/media/usb/ttusb-dec/ttusb_dec.c b/drivers/media/usb/tt= usb-dec/ttusb_dec.c index 825a3875989d..072ce5b09683 100644 --- a/drivers/media/usb/ttusb-dec/ttusb_dec.c +++ b/drivers/media/usb/ttusb-dec/ttusb_dec.c @@ -703,17 +703,41 @@ static void ttusb_dec_process_urb_frame(struct ttusb_= dec *dec, u8 *b, =20 if (dec->packet_type =3D=3D TTUSB_DEC_PACKET_PVA && dec->packet_length =3D=3D 8) { - dec->packet_state++; + unsigned int max_payload_length; + dec->packet_payload_length =3D 8 + (dec->packet[6] << 8) + dec->packet[7]; + max_payload_length =3D sizeof(dec->packet) - 4; + if (dec->packet_payload_length > + max_payload_length) { + printk("%s: packet too long - discarding\n", + __func__); + dec->packet_state =3D 0; + dec->packet_length =3D 0; + break; + } + dec->packet_state++; } else if (dec->packet_type =3D=3D TTUSB_DEC_PACKET_SECTION && dec->packet_length =3D=3D 5) { - dec->packet_state++; + unsigned int max_payload_length; + dec->packet_payload_length =3D 5 + ((dec->packet[3] & 0x0f) << 8) + dec->packet[4]; + max_payload_length =3D sizeof(dec->packet) - 4; + if (dec->packet_payload_length % 2) + max_payload_length--; + if (dec->packet_payload_length > + max_payload_length) { + printk("%s: packet too long - discarding\n", + __func__); + dec->packet_state =3D 0; + dec->packet_length =3D 0; + break; + } + dec->packet_state++; } =20 length--; --=20 2.50.1 (Apple Git-155)