From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AB8JxZr9SZndqflfYYOfhN1nfTwf6WFVYrcSm7wkdAqURspa80V6yLNeGS97ydIf6ED9ZnknqiDY ARC-Seal: i=1; a=rsa-sha256; t=1525116373; cv=none; d=google.com; s=arc-20160816; b=VCYd6YY1olWWk4xvQYNHdjMYVXqE/60BotUmcJ6KnRxtVUUUuLmojDLNE8OiAbQShL X+X7yhMPaXdRg8uBpsP/OekLdpO30Z8YNFZmi65e3np8WOcqOaUo61rnvabkTpOjQqBx flz7e7s+/TM1qzfnOOav0hj28Nc7sAPa9y6Vc0WfIr1+VUSwv/0XOvcDirYVWbrxPwRt XjfOjnH+PIETVNEJnEI4bRmpl+PFZbfsB5kaaIDw20xL3p1IgQwdazKzhopg0E4PC/ju Ldpib3QM7XW9uiD+kC1mwthxgonEvJscyMaMmlDJp6iSRAJCg98kkxe9JGzKb6hOAPaq CKBA== 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=u6F57In1LyIer2815VCuKURPVZ9wOUPkbSH+qHVWi+8=; b=Hf6MDV6+tjZJhkt18UkhjAzz6El4LLmJWntdmDK1iTg2S9RfBaUvhDZdLqY0fbX3sB EcoHgkEP7GkFOkyX2iMhbbxMdBuageGoHKmcCuMQGok7B8RvhKFptHUhgh94hD8nlzaO 7QQrbOY/vOJ55GkcJ/a+2YaclG/l2a/FOoaKe377KnlOozzPALA12jQNjbWfzjG1G5Hw Ob4Azbr5EK0k72K+SlXeokeDz0OzR9v27tyMn1VokZBD0I/MVG7XmmrqLKHpFLVtnCR6 FublmYEDqU+MdwUj2we6e5ysqvot/P4nRbSyH6JDG/gEOvBAJhVN8jyv6Xg3SCBFJV24 H2+A== 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 431AC22DBE 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 4.4 24/44] ALSA: control: Hardening for potential Spectre v1 Date: Mon, 30 Apr 2018 12:24:35 -0700 Message-Id: <20180430190947.309464317@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180430190946.093694747@linuxfoundation.org> References: <20180430190946.093694747@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?1599200426740166309?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.4-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 @@ -22,6 +22,7 @@ * */ +#include #include #define snd_kcontrol_chip(kcontrol) ((kcontrol)->private_data) @@ -147,12 +148,14 @@ 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)