From nobody Sun Jun 14 11:29:24 2026 Received: from cstnet.cn (smtp81.cstnet.cn [159.226.251.81]) (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 F25443D649B; Thu, 2 Apr 2026 11:28:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.226.251.81 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775129305; cv=none; b=MLidKPijZifTS+ukEztrYY0Z6hfHUODX8VT0Mf1YQ/HREU2QpX7vx++YUP14GuEs8px5yYmwJOkdlYrHS+TPABZun8PMrr2rpswb9THqc+69+wDZo1e85tuXCt2p9i3zk36VnnlJeYhu90VOvOTdJclc2CMLgAw/2NuEfUoMBcQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775129305; c=relaxed/simple; bh=DUgpiLoTxiYhaUIvk9RbJGb+PTKuUE9jDkMLrPRocFM=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=rVkjvF5NVqtHPH4c0+fwE3tYRbOm4c5CLWJCuuFy3+HdQnW1261Vw8/rDGz5pcDyb5pDWe4URYTDvciEkfhbHpAfuK5DqvQtAsnXeQapPtBAXfbUtnhtKLRoZwBhRsATKCh+oyvaCOFm7X5V9jx7HRMc28jFAvSdy8QwWOFI19k= 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=159.226.251.81 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-03 (Coremail) with SMTP id rQCowACHa+LAUs5pz7WoDA--.7231S2; Thu, 02 Apr 2026 19:28:00 +0800 (CST) From: Pengpeng Hou To: Mauro Carvalho Chehab Cc: Kees Cook , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, pengpeng@iscas.ac.cn Subject: [PATCH] media: ttusb-dec: reject oversized packets before copying them Date: Thu, 2 Apr 2026 19:28:00 +0800 Message-ID: <20260402112800.39716-1-pengpeng@iscas.ac.cn> 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: rQCowACHa+LAUs5pz7WoDA--.7231S2 X-Coremail-Antispam: 1UD129KBjvJXoW7Ar4ftr17Xw4rtF1UGrWUCFg_yoW8uFW3pa 9Yg343tw40qw18tr1fAF1rWr98X3yrAFy2q3y7X3Wj9ws3X3W5K3Wjgw4j9a4UGFy7AayU tws8Z3yrGr42vrJanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUkv14x267AKxVWUJVW8JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26r1I6r4UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4j 6F4UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s 0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xII jxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVW8JVWxJwAm72CE4IkC6x0Yz7v_Jr0_Gr 1lF7xvr2IY64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7MxkF7I0En4kS14v26r126r1D MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr 0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUAVWUtwCIc40Y0x0E wIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxVWUJV W8JwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Gr0_Cr1lIxAI cVC2z280aVCY1x0267AKxVW8Jr0_Cr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUcBMtUUUUU= X-CM-SenderInfo: pshqw1xhqjqxpvfd2hldfou0/ Content-Type: text/plain; charset="utf-8" ttusb_dec_process_urb_frame() derives packet lengths from packet bytes and uses those lengths to drive memcpy() into dec->packet. That staging buffer is fixed at MAX_PVA_LENGTH + 4 bytes, but the parser does not currently verify that a PVA or section packet still fits before it continues copying the rest of the packet. For PVA packets, the parsed payload length is 8 plus a 16-bit field and the parser later appends a 4-byte trailer before processing the packet. For section packets, the parser similarly uses the parsed payload length and then appends a 4-byte trailer plus one padding byte for odd-sized payloads. Reject packets whose advertised total staged length would exceed dec->packet before entering the bulk-copy state. Signed-off-by: Pengpeng Hou --- drivers/media/usb/ttusb-dec/ttusb_dec.c | 19 +++++++++++++++++-- 1 file changed, 17 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..92259ebe59c6 100644 --- a/drivers/media/usb/ttusb-dec/ttusb_dec.c +++ b/drivers/media/usb/ttusb-dec/ttusb_dec.c @@ -703,17 +703,32 @@ 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++; dec->packet_payload_length =3D 8 + (dec->packet[6] << 8) + dec->packet[7]; + if (dec->packet_payload_length + 4 > + sizeof(dec->packet)) { + pr_warn("%s: PVA packet too long - discarding\n", + __func__); + dec->packet_state =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++; dec->packet_payload_length =3D 5 + ((dec->packet[3] & 0x0f) << 8) + dec->packet[4]; + if (dec->packet_payload_length + 4 + + (dec->packet_payload_length % 2) > + sizeof(dec->packet)) { + pr_warn("%s: section packet too long - discarding\n", + __func__); + dec->packet_state =3D 0; + break; + } + dec->packet_state++; } =20 length--; --=20 2.50.1 (Apple Git-155)