From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AB8JxZq/QK44YF4tpU6soq5QYdyD+D/ZgpCTCHC2eJNbjyu/av8DHVJdego0S/tTAwmq8cuiGLIf ARC-Seal: i=1; a=rsa-sha256; t=1525116435; cv=none; d=google.com; s=arc-20160816; b=YhXJWXojGbOhZ5lvyvcPh9bveB4rV9KuYLCH0GxCGZeSxbNbqXG2Tda0QOBy7KF0lZ FR71ypxSOBgwQk7AclZmqdSKUkKwQ9/dtjcxM/lPzubJr7xFqYZSH1WPxiulTyosoHAF RFVGj+CLO6+ATWB3XVhVg+dKrde8iWhTx0cdpFhiYT3eDwUkOgdosh2BkRRE/01Lb7Xq 8xuaL3KCOuemVf+X6D9roSvOFgpfXxeJ0osgcuYAIi496Bgcb7w7bMtZDBZlNanQNHIy J4oX8zd/ov/R45xctm1b0k6aFC7b6Y75XAg2G0U3324J/7+DLayUfLlp5tip6x4E4nRO i0NQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:dmarc-filter:arc-authentication-results; bh=x2Acxx5fxy5l34FUSyZAa9juNmuZVMh2jz/9mlnNP5o=; b=AL74J4VjxVSzgDc4HDSBFCr3Tnx+U/6jcLAhVkSLdxRQYKXrPB3MTGLGWB5JR866Pj Io+XWipMsVkC4MwCxZ/HfZwCbNJDeXWbi/cPXAjJbArphLVt/Kj587XxhptQ9ZRhUxAY Mj4o8ICCm4Uv31Fr8hmQ9mrW92iC9UlnfKaJXbNjrgrgrql9LG8aTVzMrsfON712Ubzh +l66rcTGL/EmHP34dgizimXhK9Jhc5j6shADIZaYoljXvUz6XP83UvSaLPTweldsSfDH xBR2MhhMToaUBIRH7ERvwWR35c2W1NyQ3dNvSPC6VL1Xm+ZT06MQ03y3R2Dlm0lc6vlu udPw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of srs0=k66p=ht=linuxfoundation.org=gregkh@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=SRS0=K66P=HT=linuxfoundation.org=gregkh@kernel.org Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of srs0=k66p=ht=linuxfoundation.org=gregkh@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=SRS0=K66P=HT=linuxfoundation.org=gregkh@kernel.org DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AF1FE22DC1 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=fail smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dan Carpenter , Takashi Iwai Subject: [PATCH 4.14 41/91] ALSA: control: Hardening for potential Spectre v1 Date: Mon, 30 Apr 2018 12:24:23 -0700 Message-Id: <20180430184006.315380003@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180430184004.216234025@linuxfoundation.org> References: <20180430184004.216234025@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1599200426740166309?= X-GMAIL-MSGID: =?utf-8?q?1599200491356424869?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Takashi Iwai commit 088e861edffb84879cf0c0d1b02eda078c3a0ffe upstream. As recently Smatch suggested, a few places in ALSA control core codes may expand the array directly from the user-space value with speculation: sound/core/control.c:1003 snd_ctl_elem_lock() warn: potential spectre issue 'kctl->vd' sound/core/control.c:1031 snd_ctl_elem_unlock() warn: potential spectre issue 'kctl->vd' sound/core/control.c:844 snd_ctl_elem_info() warn: potential spectre issue 'kctl->vd' sound/core/control.c:891 snd_ctl_elem_read() warn: potential spectre issue 'kctl->vd' sound/core/control.c:939 snd_ctl_elem_write() warn: potential spectre issue 'kctl->vd' Although all these seem doing only the first load without further reference, we may want to stay in a safer side, so hardening with array_index_nospec() would still make sense. In this patch, we put array_index_nospec() to the common snd_ctl_get_ioff*() helpers instead of each caller. These helpers are also referred from some drivers, too, and basically all usages are to calculate the array index from the user-space value, hence it's better to cover there. BugLink: https://marc.info/?l=linux-kernel&m=152411496503418&w=2 Reported-by: Dan Carpenter Cc: Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- include/sound/control.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/include/sound/control.h +++ b/include/sound/control.h @@ -23,6 +23,7 @@ */ #include +#include #include #define snd_kcontrol_chip(kcontrol) ((kcontrol)->private_data) @@ -148,12 +149,14 @@ int snd_ctl_get_preferred_subdevice(stru static inline unsigned int snd_ctl_get_ioffnum(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id) { - return id->numid - kctl->id.numid; + unsigned int ioff = id->numid - kctl->id.numid; + return array_index_nospec(ioff, kctl->count); } static inline unsigned int snd_ctl_get_ioffidx(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id) { - return id->index - kctl->id.index; + unsigned int ioff = id->index - kctl->id.index; + return array_index_nospec(ioff, kctl->count); } static inline unsigned int snd_ctl_get_ioff(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id)