From 4e9c93af7279b059faf5bb1897ee90512b258a12 Mon Sep 17 00:00:00 2001 From: Shuah Khan Date: Mon, 29 Mar 2021 19:36:48 -0600 Subject: usbip: add sysfs_lock to synchronize sysfs code paths Fuzzing uncovered race condition between sysfs code paths in usbip drivers. Device connect/disconnect code paths initiated through sysfs interface are prone to races if disconnect happens during connect and vice versa. This problem is common to all drivers while it can be reproduced easily in vhci_hcd. Add a sysfs_lock to usbip_device struct to protect the paths. Use this in vhci_hcd to protect sysfs paths. For a complete fix, usip_host and usip-vudc drivers and the event handler will have to use this lock to protect the paths. These changes will be done in subsequent patches. Cc: stable@vger.kernel.org Reported-and-tested-by: syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com Signed-off-by: Shuah Khan Link: https://lore.kernel.org/r/b6568f7beae702bbc236a545d3c020106ca75eac.1616807117.git.skhan@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman --- drivers/usb/usbip/usbip_common.h | 3 +++ drivers/usb/usbip/vhci_hcd.c | 1 + drivers/usb/usbip/vhci_sysfs.c | 30 +++++++++++++++++++++++++----- 3 files changed, 29 insertions(+), 5 deletions(-) (limited to 'drivers/usb/usbip') diff --git a/drivers/usb/usbip/usbip_common.h b/drivers/usb/usbip/usbip_common.h index d60ce17d3dd2..ea2a20e6d27d 100644 --- a/drivers/usb/usbip/usbip_common.h +++ b/drivers/usb/usbip/usbip_common.h @@ -263,6 +263,9 @@ struct usbip_device { /* lock for status */ spinlock_t lock; + /* mutex for synchronizing sysfs store paths */ + struct mutex sysfs_lock; + int sockfd; struct socket *tcp_socket; diff --git a/drivers/usb/usbip/vhci_hcd.c b/drivers/usb/usbip/vhci_hcd.c index a20a8380ca0c..4ba6bcdaa8e9 100644 --- a/drivers/usb/usbip/vhci_hcd.c +++ b/drivers/usb/usbip/vhci_hcd.c @@ -1101,6 +1101,7 @@ static void vhci_device_init(struct vhci_device *vdev) vdev->ud.side = USBIP_VHCI; vdev->ud.status = VDEV_ST_NULL; spin_lock_init(&vdev->ud.lock); + mutex_init(&vdev->ud.sysfs_lock); INIT_LIST_HEAD(&vdev->priv_rx); INIT_LIST_HEAD(&vdev->priv_tx); diff --git a/drivers/usb/usbip/vhci_sysfs.c b/drivers/usb/usbip/vhci_sysfs.c index c4b4256e5dad..e2847cd3e6e3 100644 --- a/drivers/usb/usbip/vhci_sysfs.c +++ b/drivers/usb/usbip/vhci_sysfs.c @@ -185,6 +185,8 @@ static int vhci_port_disconnect(struct vhci_hcd *vhci_hcd, __u32 rhport) usbip_dbg_vhci_sysfs("enter\n"); + mutex_lock(&vdev->ud.sysfs_lock); + /* lock */ spin_lock_irqsave(&vhci->lock, flags); spin_lock(&vdev->ud.lock); @@ -195,6 +197,7 @@ static int vhci_port_disconnect(struct vhci_hcd *vhci_hcd, __u32 rhport) /* unlock */ spin_unlock(&vdev->ud.lock); spin_unlock_irqrestore(&vhci->lock, flags); + mutex_unlock(&vdev->ud.sysfs_lock); return -EINVAL; } @@ -205,6 +208,8 @@ static int vhci_port_disconnect(struct vhci_hcd *vhci_hcd, __u32 rhport) usbip_event_add(&vdev->ud, VDEV_EVENT_DOWN); + mutex_unlock(&vdev->ud.sysfs_lock); + return 0; } @@ -349,30 +354,36 @@ static ssize_t attach_store(struct device *dev, struct device_attribute *attr, else vdev = &vhci->vhci_hcd_hs->vdev[rhport]; + mutex_lock(&vdev->ud.sysfs_lock); + /* Extract socket from fd. */ socket = sockfd_lookup(sockfd, &err); if (!socket) { dev_err(dev, "failed to lookup sock"); - return -EINVAL; + err = -EINVAL; + goto unlock_mutex; } if (socket->type != SOCK_STREAM) { dev_err(dev, "Expecting SOCK_STREAM - found %d", socket->type); sockfd_put(socket); - return -EINVAL; + err = -EINVAL; + goto unlock_mutex; } /* create threads before locking */ tcp_rx = kthread_create(vhci_rx_loop, &vdev->ud, "vhci_rx"); if (IS_ERR(tcp_rx)) { sockfd_put(socket); - return -EINVAL; + err = -EINVAL; + goto unlock_mutex; } tcp_tx = kthread_create(vhci_tx_loop, &vdev->ud, "vhci_tx"); if (IS_ERR(tcp_tx)) { kthread_stop(tcp_rx); sockfd_put(socket); - return -EINVAL; + err = -EINVAL; + goto unlock_mutex; } /* get task structs now */ @@ -397,7 +408,8 @@ static ssize_t attach_store(struct device *dev, struct device_attribute *attr, * Will be retried from userspace * if there's another free port. */ - return -EBUSY; + err = -EBUSY; + goto unlock_mutex; } dev_info(dev, "pdev(%u) rhport(%u) sockfd(%d)\n", @@ -423,7 +435,15 @@ static ssize_t attach_store(struct device *dev, struct device_attribute *attr, rh_port_connect(vdev, speed); + dev_info(dev, "Device attached\n"); + + mutex_unlock(&vdev->ud.sysfs_lock); + return count; + +unlock_mutex: + mutex_unlock(&vdev->ud.sysfs_lock); + return err; } static DEVICE_ATTR_WO(attach); -- cgit v1.2.3 From 9dbf34a834563dada91366c2ac266f32ff34641a Mon Sep 17 00:00:00 2001 From: Shuah Khan Date: Mon, 29 Mar 2021 19:36:49 -0600 Subject: usbip: stub-dev synchronize sysfs code paths Fuzzing uncovered race condition between sysfs code paths in usbip drivers. Device connect/disconnect code paths initiated through sysfs interface are prone to races if disconnect happens during connect and vice versa. Use sysfs_lock to protect sysfs paths in stub-dev. Cc: stable@vger.kernel.org Reported-and-tested-by: syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com Signed-off-by: Shuah Khan Link: https://lore.kernel.org/r/2b182f3561b4a065bf3bf6dce3b0e9944ba17b3f.1616807117.git.skhan@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman --- drivers/usb/usbip/stub_dev.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'drivers/usb/usbip') diff --git a/drivers/usb/usbip/stub_dev.c b/drivers/usb/usbip/stub_dev.c index 8f1de1fbbeed..d8d3892e5a69 100644 --- a/drivers/usb/usbip/stub_dev.c +++ b/drivers/usb/usbip/stub_dev.c @@ -63,6 +63,7 @@ static ssize_t usbip_sockfd_store(struct device *dev, struct device_attribute *a dev_info(dev, "stub up\n"); + mutex_lock(&sdev->ud.sysfs_lock); spin_lock_irq(&sdev->ud.lock); if (sdev->ud.status != SDEV_ST_AVAILABLE) { @@ -87,13 +88,13 @@ static ssize_t usbip_sockfd_store(struct device *dev, struct device_attribute *a tcp_rx = kthread_create(stub_rx_loop, &sdev->ud, "stub_rx"); if (IS_ERR(tcp_rx)) { sockfd_put(socket); - return -EINVAL; + goto unlock_mutex; } tcp_tx = kthread_create(stub_tx_loop, &sdev->ud, "stub_tx"); if (IS_ERR(tcp_tx)) { kthread_stop(tcp_rx); sockfd_put(socket); - return -EINVAL; + goto unlock_mutex; } /* get task structs now */ @@ -112,6 +113,8 @@ static ssize_t usbip_sockfd_store(struct device *dev, struct device_attribute *a wake_up_process(sdev->ud.tcp_rx); wake_up_process(sdev->ud.tcp_tx); + mutex_unlock(&sdev->ud.sysfs_lock); + } else { dev_info(dev, "stub down\n"); @@ -122,6 +125,7 @@ static ssize_t usbip_sockfd_store(struct device *dev, struct device_attribute *a spin_unlock_irq(&sdev->ud.lock); usbip_event_add(&sdev->ud, SDEV_EVENT_DOWN); + mutex_unlock(&sdev->ud.sysfs_lock); } return count; @@ -130,6 +134,8 @@ sock_err: sockfd_put(socket); err: spin_unlock_irq(&sdev->ud.lock); +unlock_mutex: + mutex_unlock(&sdev->ud.sysfs_lock); return -EINVAL; } static DEVICE_ATTR_WO(usbip_sockfd); @@ -270,6 +276,7 @@ static struct stub_device *stub_device_alloc(struct usb_device *udev) sdev->ud.side = USBIP_STUB; sdev->ud.status = SDEV_ST_AVAILABLE; spin_lock_init(&sdev->ud.lock); + mutex_init(&sdev->ud.sysfs_lock); sdev->ud.tcp_socket = NULL; sdev->ud.sockfd = -1; -- cgit v1.2.3 From bd8b82042269a95db48074b8bb400678dbac1815 Mon Sep 17 00:00:00 2001 From: Shuah Khan Date: Mon, 29 Mar 2021 19:36:50 -0600 Subject: usbip: vudc synchronize sysfs code paths Fuzzing uncovered race condition between sysfs code paths in usbip drivers. Device connect/disconnect code paths initiated through sysfs interface are prone to races if disconnect happens during connect and vice versa. Use sysfs_lock to protect sysfs paths in vudc. Cc: stable@vger.kernel.org Reported-and-tested-by: syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com Signed-off-by: Shuah Khan Link: https://lore.kernel.org/r/caabcf3fc87bdae970509b5ff32d05bb7ce2fb15.1616807117.git.skhan@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman --- drivers/usb/usbip/vudc_dev.c | 1 + drivers/usb/usbip/vudc_sysfs.c | 5 +++++ 2 files changed, 6 insertions(+) (limited to 'drivers/usb/usbip') diff --git a/drivers/usb/usbip/vudc_dev.c b/drivers/usb/usbip/vudc_dev.c index c8eeabdd9b56..2bc428f2e261 100644 --- a/drivers/usb/usbip/vudc_dev.c +++ b/drivers/usb/usbip/vudc_dev.c @@ -572,6 +572,7 @@ static int init_vudc_hw(struct vudc *udc) init_waitqueue_head(&udc->tx_waitq); spin_lock_init(&ud->lock); + mutex_init(&ud->sysfs_lock); ud->status = SDEV_ST_AVAILABLE; ud->side = USBIP_VUDC; diff --git a/drivers/usb/usbip/vudc_sysfs.c b/drivers/usb/usbip/vudc_sysfs.c index 7383a543c6d1..f7633ee655a1 100644 --- a/drivers/usb/usbip/vudc_sysfs.c +++ b/drivers/usb/usbip/vudc_sysfs.c @@ -112,6 +112,7 @@ static ssize_t usbip_sockfd_store(struct device *dev, dev_err(dev, "no device"); return -ENODEV; } + mutex_lock(&udc->ud.sysfs_lock); spin_lock_irqsave(&udc->lock, flags); /* Don't export what we don't have */ if (!udc->driver || !udc->pullup) { @@ -187,6 +188,8 @@ static ssize_t usbip_sockfd_store(struct device *dev, wake_up_process(udc->ud.tcp_rx); wake_up_process(udc->ud.tcp_tx); + + mutex_unlock(&udc->ud.sysfs_lock); return count; } else { @@ -207,6 +210,7 @@ static ssize_t usbip_sockfd_store(struct device *dev, } spin_unlock_irqrestore(&udc->lock, flags); + mutex_unlock(&udc->ud.sysfs_lock); return count; @@ -216,6 +220,7 @@ unlock_ud: spin_unlock_irq(&udc->ud.lock); unlock: spin_unlock_irqrestore(&udc->lock, flags); + mutex_unlock(&udc->ud.sysfs_lock); return ret; } -- cgit v1.2.3 From 363eaa3a450abb4e63bd6e3ad79d1f7a0f717814 Mon Sep 17 00:00:00 2001 From: Shuah Khan Date: Mon, 29 Mar 2021 19:36:51 -0600 Subject: usbip: synchronize event handler with sysfs code paths Fuzzing uncovered race condition between sysfs code paths in usbip drivers. Device connect/disconnect code paths initiated through sysfs interface are prone to races if disconnect happens during connect and vice versa. Use sysfs_lock to synchronize event handler with sysfs paths in usbip drivers. Cc: stable@vger.kernel.org Reported-and-tested-by: syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com Signed-off-by: Shuah Khan Link: https://lore.kernel.org/r/c5c8723d3f29dfe3d759cfaafa7dd16b0dfe2918.1616807117.git.skhan@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman --- drivers/usb/usbip/usbip_event.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/usb/usbip') diff --git a/drivers/usb/usbip/usbip_event.c b/drivers/usb/usbip/usbip_event.c index 5d88917c9631..086ca76dd053 100644 --- a/drivers/usb/usbip/usbip_event.c +++ b/drivers/usb/usbip/usbip_event.c @@ -70,6 +70,7 @@ static void event_handler(struct work_struct *work) while ((ud = get_event()) != NULL) { usbip_dbg_eh("pending event %lx\n", ud->event); + mutex_lock(&ud->sysfs_lock); /* * NOTE: shutdown must come first. * Shutdown the device. @@ -90,6 +91,7 @@ static void event_handler(struct work_struct *work) ud->eh_ops.unusable(ud); unset_event(ud, USBIP_EH_UNUSABLE); } + mutex_unlock(&ud->sysfs_lock); wake_up(&ud->eh_waitq); } -- cgit v1.2.3