From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:59700 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728002AbeJHWkG (ORCPT ); Mon, 8 Oct 2018 18:40:06 -0400 From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Jozef Balga , Mauro Carvalho Chehab , Sasha Levin Subject: [PATCH AUTOSEL 3.18 1/4] media: af9035: prevent buffer overflow on write Date: Mon, 8 Oct 2018 11:27:46 -0400 Message-Id: <20181008152749.71018-1-sashal@kernel.org> Sender: stable-owner@vger.kernel.org List-ID: From: Jozef Balga [ Upstream commit 312f73b648626a0526a3aceebb0a3192aaba05ce ] When less than 3 bytes are written to the device, memcpy is called with negative array size which leads to buffer overflow and kernel panic. This patch adds a condition and returns -EOPNOTSUPP instead. Fixes bugzilla issue 64871 [mchehab+samsung@kernel.org: fix a merge conflict and changed the condition to match the patch's comment, e. g. len == 3 could also be valid] Signed-off-by: Jozef Balga Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Sasha Levin --- drivers/media/usb/dvb-usb-v2/af9035.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/media/usb/dvb-usb-v2/af9035.c b/drivers/media/usb/dvb-usb-v2/af9035.c index 1896ab218b11..efc1545bf29e 100644 --- a/drivers/media/usb/dvb-usb-v2/af9035.c +++ b/drivers/media/usb/dvb-usb-v2/af9035.c @@ -389,8 +389,10 @@ static int af9035_i2c_master_xfer(struct i2c_adapter *adap, msg[0].addr == (state->af9033_i2c_addr[1] >> 1)) reg |= 0x100000; - ret = af9035_wr_regs(d, reg, &msg[0].buf[3], - msg[0].len - 3); + ret = (msg[0].len >= 3) ? af9035_wr_regs(d, reg, + &msg[0].buf[3], + msg[0].len - 3) + : -EOPNOTSUPP; } else { /* I2C write */ u8 buf[MAX_XFER_SIZE]; -- 2.17.1