From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from exchange.fintech.ru (exchange.fintech.ru [195.54.195.159]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 72E9D14A4E1; Mon, 26 Aug 2024 10:40:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.54.195.159 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724668856; cv=none; b=Wyxcj8EZDjqy4KR8ccCLd2ylN+x8DVUJortQgG+wgAUwAYpF7HHlfMSM/esbmFPEg0DFdWzCZkP74adONvj/DvgzVdfHAr7QRorR4JgwEefkgPBA+xKQbRZx+GbtD/lkKVY+JJsEalW+isRzNmV8UyAd3ZPBk38DW793DVuAkaI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724668856; c=relaxed/simple; bh=afyYNouRafrI1PVLHdus6keUfhP3xJW8Q5A0kSWXOIo=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=NiS/U7mDPB1PfkOpitr+KcDpnj+wSrtdwzTGHiuHu5it0BJCqqqVqDU2Fz8PvFP21f0KRDzZWafOcrtG1lNwD5E5kaTglajQ1gQ+Exq2qqWWx1v2D5bQJ/BLTMoYJ7wvnaoTx86b34rOVsPcjO9U27SYf2zd5OV1fb6+D30mAYw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=fintech.ru; spf=pass smtp.mailfrom=fintech.ru; arc=none smtp.client-ip=195.54.195.159 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=fintech.ru Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=fintech.ru Received: from Ex16-01.fintech.ru (10.0.10.18) by exchange.fintech.ru (195.54.195.159) with Microsoft SMTP Server (TLS) id 14.3.498.0; Mon, 26 Aug 2024 13:39:39 +0300 Received: from [192.168.211.130] (10.0.253.138) by Ex16-01.fintech.ru (10.0.10.18) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2242.4; Mon, 26 Aug 2024 13:39:38 +0300 Message-ID: <2417bf98-424b-4d37-ae36-8f5affaffb24@fintech.ru> Date: Mon, 26 Aug 2024 03:39:35 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] media: dvb-frontends: dib3000mb: fix uninit-value in dib3000_write_reg To: Mauro Carvalho Chehab , Hans Verkuil CC: Luis Chamberlain , Greg Kroah-Hartman , Patrick Boettcher , , , , References: <20240517155800.9881-1-n.zhandarovich@fintech.ru> Content-Language: en-US From: Nikita Zhandarovich In-Reply-To: <20240517155800.9881-1-n.zhandarovich@fintech.ru> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: Ex16-02.fintech.ru (10.0.10.19) To Ex16-01.fintech.ru (10.0.10.18) Hi, On 5/17/24 08:58, Nikita Zhandarovich wrote: > Syzbot reports [1] an uninitialized value issue found by KMSAN in > dib3000_read_reg(). > > Local u8 rb[2] is used in i2c_transfer() as a read buffer; in case > that call fails, the buffer may end up with some undefined values. > > Since no elaborate error handling is expected in dib3000_write_reg(), > simply zero out rb buffer to mitigate the problem. > > [1] Syzkaller report > dvb-usb: bulk message failed: -22 (6/0) > ===================================================== > BUG: KMSAN: uninit-value in dib3000mb_attach+0x2d8/0x3c0 drivers/media/dvb-frontends/dib3000mb.c:758 > dib3000mb_attach+0x2d8/0x3c0 drivers/media/dvb-frontends/dib3000mb.c:758 > dibusb_dib3000mb_frontend_attach+0x155/0x2f0 drivers/media/usb/dvb-usb/dibusb-mb.c:31 > dvb_usb_adapter_frontend_init+0xed/0x9a0 drivers/media/usb/dvb-usb/dvb-usb-dvb.c:290 > dvb_usb_adapter_init drivers/media/usb/dvb-usb/dvb-usb-init.c:90 [inline] > dvb_usb_init drivers/media/usb/dvb-usb/dvb-usb-init.c:186 [inline] > dvb_usb_device_init+0x25a8/0x3760 drivers/media/usb/dvb-usb/dvb-usb-init.c:310 > dibusb_probe+0x46/0x250 drivers/media/usb/dvb-usb/dibusb-mb.c:110 > ... > Local variable rb created at: > dib3000_read_reg+0x86/0x4e0 drivers/media/dvb-frontends/dib3000mb.c:54 > dib3000mb_attach+0x123/0x3c0 drivers/media/dvb-frontends/dib3000mb.c:758 > ... > > Fixes: 74340b0a8bc6 ("V4L/DVB (4457): Remove dib3000-common-module") > Reported-by: syzbot+c88fc0ebe0d5935c70da@syzkaller.appspotmail.com > Signed-off-by: Nikita Zhandarovich > --- > drivers/media/dvb-frontends/dib3000mb.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/media/dvb-frontends/dib3000mb.c b/drivers/media/dvb-frontends/dib3000mb.c > index c598b2a63325..7c452ddd9e40 100644 > --- a/drivers/media/dvb-frontends/dib3000mb.c > +++ b/drivers/media/dvb-frontends/dib3000mb.c > @@ -51,7 +51,7 @@ MODULE_PARM_DESC(debug, "set debugging level (1=info,2=xfer,4=setfe,8=getfe (|-a > static int dib3000_read_reg(struct dib3000_state *state, u16 reg) > { > u8 wb[] = { ((reg >> 8) | 0x80) & 0xff, reg & 0xff }; > - u8 rb[2]; > + u8 rb[2] = {}; > struct i2c_msg msg[] = { > { .addr = state->config.demod_address, .flags = 0, .buf = wb, .len = 2 }, > { .addr = state->config.demod_address, .flags = I2C_M_RD, .buf = rb, .len = 2 }, Gentle ping... Regards, Nikita