From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: ADUXVKI/2j54xledtkXgjEPms9m1Fr7elJi4D5y9Fz8xDF898qmBeIpz0q85rMbPeFg86FqKUDGA ARC-Seal: i=1; a=rsa-sha256; t=1527004617; cv=none; d=google.com; s=arc-20160816; b=T/IqEAm63OuOV4dVsguDe3iW3OZ07479ZMB8pnskGR8ehc/MfPHhSLq/fXUETo9WyC dQztRUwkzdx16oXlFffXKwunoBvreHb/nWE9zEcV534kkrqGnER/r1nAsmpdDL7wHPun i4xhAijW08Hg9Cn7kw/nbCKjHo+CT7JjpeYo3SwiZ4O4Z/yKDBsRZe1pF49aLYWDkLSh IkmdTeAjX7ELYFTFHz7aqwMrtrpaz6IRpse7W9GTZm0dRIIDy90NvoN4ifNCi3Jjs8yl 1x0bjEdPzfwHuPWgNNoKpH3hNuF2W22/ILTmoLBLOUt6xV8ArGjaBPhV6yfzkwrPJuF2 kzbQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:from:references:cc:to:subject :arc-authentication-results; bh=DOmo6gwUs+DJcp0d5gPixSKPZX8XRDIGioKcMWtAAOQ=; b=PjQ7OA/+ClY/PAfmDoaVdGOk6aoHpI+NDcua1vJOGevZjhjRg5B8ThuGfseyY98rKF TIB+pvpUlvtq/u8bI1iKS5bhfJ1yMtymkAcroP9CdCsN5qd6duhJyl+qw4MiHYTAtDhR vbRC4n0CWb+EUCoSe8FDpAJLbeZfklcFAcYR9nlUYQwyKpMJ749ygtCmqsm/kcVXB+8A RcLfYz/qJVdvT/g64VTSRU5CrMPKARJyEciXZz4mGCvNcdddKHLfqM+G5WDIqrDcoU4h 2hVgIh83HNyDq5NRTdAevQHzVGKW3t5om15rmUmqeOCkqRp3CKnDJHLbxbcTO62olFoQ 3PNw== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning shuah@kernel.org does not designate 64.68.200.34 as permitted sender) smtp.mailfrom=shuah@kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning shuah@kernel.org does not designate 64.68.200.34 as permitted sender) smtp.mailfrom=shuah@kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org Subject: Re: [PATCH v3] usbip: vhci_sysfs: fix potential Spectre v1 To: "Gustavo A. R. Silva" , Valentina Manea , Greg Kroah-Hartman Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Shuah Khan References: <20180519011342.GA13962@embeddedgus> From: Shuah Khan Message-ID: <8d36b487-4187-4aef-1796-af6d10f357d7@kernel.org> Date: Tue, 22 May 2018 09:56:47 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20180519011342.GA13962@embeddedgus> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1600661041859915107?= X-GMAIL-MSGID: =?utf-8?q?1601180393207967260?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 05/18/2018 07:13 PM, Gustavo A. R. Silva wrote: > pdev_nr and rhport can be controlled by user-space, hence leading to > a potential exploitation of the Spectre variant 1 vulnerability. > > This issue was detected with the help of Smatch: > drivers/usb/usbip/vhci_sysfs.c:238 detach_store() warn: potential spectre issue 'vhcis' > drivers/usb/usbip/vhci_sysfs.c:328 attach_store() warn: potential spectre issue 'vhcis' > drivers/usb/usbip/vhci_sysfs.c:338 attach_store() warn: potential spectre issue 'vhci->vhci_hcd_ss->vdev' > drivers/usb/usbip/vhci_sysfs.c:340 attach_store() warn: potential spectre issue 'vhci->vhci_hcd_hs->vdev' > > Fix this by sanitizing pdev_nr and rhport before using them to index > vhcis and vhci->vhci_hcd_ss->vdev respectively. > > Notice that given that speculation windows are large, the policy is > to kill the speculation on the first load and not worry if it can be > completed with a dependent load/store [1]. > > [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2 > > Cc: stable@vger.kernel.org > Signed-off-by: Gustavo A. R. Silva > --- > Changes in v3: > - Pass the addresses of pdev_nr and rhport into valid_port and > valid_args. > > Changes in v2: > - Place the barriers into valid_port. > > drivers/usb/usbip/vhci_sysfs.c | 24 ++++++++++++++++-------- > 1 file changed, 16 insertions(+), 8 deletions(-) > > diff --git a/drivers/usb/usbip/vhci_sysfs.c b/drivers/usb/usbip/vhci_sysfs.c > index 4880838..be37aec 100644 > --- a/drivers/usb/usbip/vhci_sysfs.c > +++ b/drivers/usb/usbip/vhci_sysfs.c > @@ -10,6 +10,9 @@ > #include > #include > > +/* Hardening for Spectre-v1 */ > +#include > + > #include "usbip_common.h" > #include "vhci.h" > > @@ -205,16 +208,20 @@ static int vhci_port_disconnect(struct vhci_hcd *vhci_hcd, __u32 rhport) > return 0; > } > > -static int valid_port(__u32 pdev_nr, __u32 rhport) > +static int valid_port(__u32 *pdev_nr, __u32 *rhport) > { > - if (pdev_nr >= vhci_num_controllers) { > - pr_err("pdev %u\n", pdev_nr); > + if (*pdev_nr >= vhci_num_controllers) { > + pr_err("pdev %u\n", *pdev_nr); > return 0; > } > - if (rhport >= VHCI_HC_PORTS) { > - pr_err("rhport %u\n", rhport); > + *pdev_nr = array_index_nospec(*pdev_nr, vhci_num_controllers); > + > + if (*rhport >= VHCI_HC_PORTS) { > + pr_err("rhport %u\n", *rhport); > return 0; > } > + *rhport = array_index_nospec(*rhport, VHCI_HC_PORTS); > + > return 1; > } > > @@ -232,7 +239,7 @@ static ssize_t detach_store(struct device *dev, struct device_attribute *attr, > pdev_nr = port_to_pdev_nr(port); > rhport = port_to_rhport(port); > > - if (!valid_port(pdev_nr, rhport)) > + if (!valid_port(&pdev_nr, &rhport)) > return -EINVAL; > > hcd = platform_get_drvdata(vhcis[pdev_nr].pdev); > @@ -258,7 +265,8 @@ static ssize_t detach_store(struct device *dev, struct device_attribute *attr, > } > static DEVICE_ATTR_WO(detach); > > -static int valid_args(__u32 pdev_nr, __u32 rhport, enum usb_device_speed speed) > +static int valid_args(__u32 *pdev_nr, __u32 *rhport, > + enum usb_device_speed speed) > { > if (!valid_port(pdev_nr, rhport)) { > return 0; > @@ -322,7 +330,7 @@ static ssize_t attach_store(struct device *dev, struct device_attribute *attr, > sockfd, devid, speed); > > /* check received parameters */ > - if (!valid_args(pdev_nr, rhport, speed)) > + if (!valid_args(&pdev_nr, &rhport, speed)) > return -EINVAL; > > hcd = platform_get_drvdata(vhcis[pdev_nr].pdev); > Looks good to me. Thanks for taking care of this. Acked-by: Shuah Khan (Samsung OSG) -- Shuah