From patchwork Fri Jun 14 15:22:25 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chi Zhiling X-Patchwork-Id: 13698834 Received: from m16.mail.163.com (m16.mail.163.com [117.135.210.5]) by smtp.subspace.kernel.org (Postfix) with ESMTP id EE60915CD64; Fri, 14 Jun 2024 15:23:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=117.135.210.5 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718378584; cv=none; b=NJlQZWVu2sG0X/QTzq3l3PO+nNNXuSqrscEGRNQuzOlu/+6zbhcV8ICQGJKIe7h0x7Ed+buc7h+4f9ZSucVgCIZWNk2LCnF6UzXjlPFenAJ0MwA4jtNARa87nL8mP1FplZdQNNu7k+EcWZofi42phs2trAvjhYHLL6dcA4GVy4o= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718378584; c=relaxed/simple; bh=ceHwlhkQOv5Wkvy5F61fCWlYXHLEh5xGfP6+3SG6EDs=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=C4o71iNwZnPrnMbbnMDeQyYs6CRFXkVKz3qAM5a4SBlaxYPBPYTu97H6J1tjhjCh93KwLumTKWP18wNFuG1k8mTkXdcjtqoiIzvr2m4Uf6yRFISGg5Uhrkh3BbLs48+RVWV8YT3nbr9rSLQI3sQpn//MIj+a6e17u2dQrNXvLHQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=H6sZ+JFk; arc=none smtp.client-ip=117.135.210.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="H6sZ+JFk" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id:MIME-Version; bh=yAGhS Ow2NI85cih3XGIkfc/UtZ8P/eczFTAfdvqLy8o=; b=H6sZ+JFkVQTNUzqKHaUah N/CJydLUMiy1B8fj/9SITomrvG2oIcTQqUvOqpbyfYKo0b4Fw1wbGoz4q0ggrmNV raLZVoLLy4Fv3ELXa5C4qFpv2e9FqCUagUsIzscZsTSa35D/w7hfT9Q7+YrbO3vI 4CGTNj8l6l5IQcmYARwGKw= Received: from ubuntu.localdomain (unknown [120.228.117.74]) by gzga-smtp-mta-g1-0 (Coremail) with SMTP id _____wD3n6tCYGxmSah9Cg--.3328S2; Fri, 14 Jun 2024 23:22:42 +0800 (CST) From: Chi Zhiling To: mchehab@kernel.org Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Chi Zhiling Subject: [PATCH v2] media: xc2028: avoid use-after-free in load_firmware_cb() Date: Fri, 14 Jun 2024 08:22:25 -0700 Message-Id: <20240614152225.3943-1-chizhiling@163.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20240531091026.3094284-1-chizhiling@163.com> References: <20240531091026.3094284-1-chizhiling@163.com> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: _____wD3n6tCYGxmSah9Cg--.3328S2 X-Coremail-Antispam: 1Uf129KBjvJXoWxXF47KrWDJr43Ar1UJr4fKrg_yoWrWw43pF nxZFWfCrW8Jry3Jr47Jr4UJr1FqrW5Aa10kr4xA34agr13WrZ8tryUtFWUXr1UWr45Aa47 JF15JrWrtF4qyw7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07UsFxUUUUUU= X-CM-SenderInfo: hfkl6xxlol0wi6rwjhhfrp/xtbBLwr9nWXAk3F1ZQABsT From: Chi Zhiling syzkaller reported use-after-free in load_firmware_cb() [1]. The reason is because the module allocated a struct tuner in tuner_probe(), and then the module initialization failed, the struct tuner was released. A worker which created during module initialization accesses this struct tuner later, it caused use-after-free. The process is as follows: task-6504 worker_thread tuner_probe <= alloc dvb_frontend [2] ... request_firmware_nowait <= create a worker ... tuner_remove <= free dvb_frontend ... request_firmware_work_func <= the firmware is ready load_firmware_cb <= but now the dvb_frontend has been freed To fix the issue, check the dvd_frontend in load_firmware_cb(), if it is null, report a warning and just return. [1]: ================================================================== BUG: KASAN: use-after-free in load_firmware_cb+0x1310/0x17a0 Read of size 8 at addr ffff8000d7ca2308 by task kworker/2:3/6504 Call trace: load_firmware_cb+0x1310/0x17a0 request_firmware_work_func+0x128/0x220 process_one_work+0x770/0x1824 worker_thread+0x488/0xea0 kthread+0x300/0x430 ret_from_fork+0x10/0x20 Allocated by task 6504: kzalloc tuner_probe+0xb0/0x1430 i2c_device_probe+0x92c/0xaf0 really_probe+0x678/0xcd0 driver_probe_device+0x280/0x370 __device_attach_driver+0x220/0x330 bus_for_each_drv+0x134/0x1c0 __device_attach+0x1f4/0x410 device_initial_probe+0x20/0x30 bus_probe_device+0x184/0x200 device_add+0x924/0x12c0 device_register+0x24/0x30 i2c_new_device+0x4e0/0xc44 v4l2_i2c_new_subdev_board+0xbc/0x290 v4l2_i2c_new_subdev+0xc8/0x104 em28xx_v4l2_init+0x1dd0/0x3770 Freed by task 6504: kfree+0x238/0x4e4 tuner_remove+0x144/0x1c0 i2c_device_remove+0xc8/0x290 __device_release_driver+0x314/0x5fc device_release_driver+0x30/0x44 bus_remove_device+0x244/0x490 device_del+0x350/0x900 device_unregister+0x28/0xd0 i2c_unregister_device+0x174/0x1d0 v4l2_device_unregister+0x224/0x380 em28xx_v4l2_init+0x1d90/0x3770 The buggy address belongs to the object at ffff8000d7ca2000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 776 bytes inside of 2048-byte region [ffff8000d7ca2000, ffff8000d7ca2800) The buggy address belongs to the page: page:ffff7fe00035f280 count:1 mapcount:0 mapping:ffff8000c001f000 index:0x0 flags: 0x7ff800000000100(slab) raw: 07ff800000000100 ffff7fe00049d880 0000000300000003 ffff8000c001f000 raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8000d7ca2200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8000d7ca2280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8000d7ca2300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8000d7ca2380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8000d7ca2400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== [2] Actually, it is allocated for struct tuner, and dvb_frontend is inside. Signed-off-by: Chi Zhiling --- drivers/media/tuners/xc2028.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/media/tuners/xc2028.c b/drivers/media/tuners/xc2028.c index 5a967edceca9..352b8a3679b7 100644 --- a/drivers/media/tuners/xc2028.c +++ b/drivers/media/tuners/xc2028.c @@ -1361,9 +1361,16 @@ static void load_firmware_cb(const struct firmware *fw, void *context) { struct dvb_frontend *fe = context; - struct xc2028_data *priv = fe->tuner_priv; + struct xc2028_data *priv; int rc; + if (!fe) { + pr_warn("xc2028: No frontend in %s\n", __func__); + return; + } + + priv = fe->tuner_priv; + tuner_dbg("request_firmware_nowait(): %s\n", fw ? "OK" : "error"); if (!fw) { tuner_err("Could not load firmware %s.\n", priv->fname);