From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AB8JxZrrb5dfeMX+ZXJy3+Uc3UFbws2wVYILYZOqyo1OucjZLufrr++oKbGq4SH4BKFDzvaHbJR+ ARC-Seal: i=1; a=rsa-sha256; t=1526692424; cv=none; d=google.com; s=arc-20160816; b=lLGyhBGOB0OQg5nw6fEzTLQqJlxRrLQ9T9ZUY6GNtJEG0tbVMk3PNhQtmorNTUye/K QY7L29wLXeoQjef4/5PvzkvJberYLxOBabP4teZi3xIZuuBFG8QbSsAgiPog/x6jlnyP GpTmKRNzHppX3IBA4rooJ/0nKbLagcXJ7LeaNqcu4+5bLvs/L5nfRGkPxIrV6P1Wcdoz PuNHoNKT/R0b52FXvX28xDu+cOa9oZNCb58pQBBVvdA2MnCRO5y3siCUSLJQ+YWbj1q5 8Avt0w3k2HMZEVEbKvy+b9wEeHujeFz3fcttatOqGEpgYzo4+9YnHPAruv3Hk2ty5cHh jSrw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:content-disposition:mime-version:message-id:subject:cc :to:from:date:arc-authentication-results; bh=E/7g7F7Ohbb25kUjdEVKb8HsivEL3/Nqbnpsq/G3BXE=; b=BmL3Tt4jTdXqWMNgeUODn2CQqMI0k4hVpK9o9mg92E9JvUTrz/xomFinLhLBhUAc4x ntQUXD+59lcf9G1YDCr9AovskyuuMYSCRQEb4ALVqOkt38yg01DgeOrorPlK465YZe1o n2HHVO8DPp+07ONIeYM7PpQc0wpn9mzZzUvpyAaH7VFKRyzgEl0u8CVnUGvUTaJ0eWbT 06jBw/L+24zIrd8z1VwAvKDMDLQDOzmGGOd3pCp1Gtlz6x4/X7lu3wiMjcxkjldL3wYN HzegGKAKZuGuSNCWgTeJmXaSoTY4Ze1UERp31Wym5ZaZk0S2Qbljq56ztvWIoBlKG59u TKYw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of gustavo@embeddedor.com designates 192.185.145.1 as permitted sender) smtp.mailfrom=gustavo@embeddedor.com Authentication-Results: mx.google.com; spf=pass (google.com: domain of gustavo@embeddedor.com designates 192.185.145.1 as permitted sender) smtp.mailfrom=gustavo@embeddedor.com X-Authority-Reason: nr=8 Date: Fri, 18 May 2018 20:13:42 -0500 From: "Gustavo A. R. Silva" To: Valentina Manea , Shuah Khan , Greg Kroah-Hartman Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH v3] usbip: vhci_sysfs: fix potential Spectre v1 Message-ID: <20180519011342.GA13962@embeddedgus> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - linuxfoundation.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 187.172.56.86 X-Source-L: No X-Exim-ID: 1fJqRL-004N6K-La X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedgus) [187.172.56.86]:58738 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 3 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1600661041859915107?= X-GMAIL-MSGID: =?utf-8?q?1600853035470472362?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 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 Acked-by: Shuah Khan (Samsung OSG) --- 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); -- 2.7.4