From 60e1751cb52cc6d1ae04b6bd3c2b96e770b5823f Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Fri, 6 Jun 2014 18:25:04 +0200 Subject: [PATCH] IB/umad: Fix use-after-free on close Avoid that closing /dev/infiniband/umad or /dev/infiniband/issm triggers a use-after-free. __fput() invokes f_op->release() before it invokes cdev_put(). Make sure that the ib_umad_device structure is freed by the cdev_put() call instead of f_op->release(). This avoids that changing the port mode from IB into Ethernet and back to IB followed by restarting opensmd triggers the following kernel oops: general protection fault: 0000 [#1] PREEMPT SMP RIP: 0010:[] [] module_put+0x2c/0x170 Call Trace: [] cdev_put+0x20/0x30 [] __fput+0x1ae/0x1f0 [] ____fput+0xe/0x10 [] task_work_run+0xac/0xe0 [] do_notify_resume+0x9f/0xc0 [] int_signal+0x12/0x17 Reference: https://bugzilla.kernel.org/show_bug.cgi?id=75051 Signed-off-by: Bart Van Assche Reviewed-by: Yann Droneaud Cc: # 3.x: 8ec0a0e6b58: IB/umad: Fix error handling Signed-off-by: Roland Dreier --- drivers/infiniband/core/user_mad.c | 30 +++++++++++++++++++----------- 1 file changed, 19 insertions(+), 11 deletions(-) diff --git a/drivers/infiniband/core/user_mad.c b/drivers/infiniband/core/user_mad.c index 9bdf576cd4ab..1acb99100556 100644 --- a/drivers/infiniband/core/user_mad.c +++ b/drivers/infiniband/core/user_mad.c @@ -98,7 +98,7 @@ struct ib_umad_port { struct ib_umad_device { int start_port, end_port; - struct kref ref; + struct kobject kobj; struct ib_umad_port port[0]; }; @@ -134,14 +134,18 @@ static DECLARE_BITMAP(dev_map, IB_UMAD_MAX_PORTS); static void ib_umad_add_one(struct ib_device *device); static void ib_umad_remove_one(struct ib_device *device); -static void ib_umad_release_dev(struct kref *ref) +static void ib_umad_release_dev(struct kobject *kobj) { struct ib_umad_device *dev = - container_of(ref, struct ib_umad_device, ref); + container_of(kobj, struct ib_umad_device, kobj); kfree(dev); } +static struct kobj_type ib_umad_dev_ktype = { + .release = ib_umad_release_dev, +}; + static int hdr_size(struct ib_umad_file *file) { return file->use_pkey_index ? sizeof (struct ib_user_mad_hdr) : @@ -812,7 +816,7 @@ static int ib_umad_open(struct inode *inode, struct file *filp) goto out; } - kref_get(&port->umad_dev->ref); + kobject_get(&port->umad_dev->kobj); out: mutex_unlock(&port->file_mutex); @@ -851,7 +855,7 @@ static int ib_umad_close(struct inode *inode, struct file *filp) mutex_unlock(&file->port->file_mutex); kfree(file); - kref_put(&dev->ref, ib_umad_release_dev); + kobject_put(&dev->kobj); return 0; } @@ -902,7 +906,7 @@ static int ib_umad_sm_open(struct inode *inode, struct file *filp) if (ret) goto err_clr_sm_cap; - kref_get(&port->umad_dev->ref); + kobject_get(&port->umad_dev->kobj); return 0; @@ -932,7 +936,7 @@ static int ib_umad_sm_close(struct inode *inode, struct file *filp) up(&port->sm_sem); - kref_put(&port->umad_dev->ref, ib_umad_release_dev); + kobject_put(&port->umad_dev->kobj); return ret; } @@ -1000,6 +1004,7 @@ static int find_overflow_devnum(void) } static int ib_umad_init_port(struct ib_device *device, int port_num, + struct ib_umad_device *umad_dev, struct ib_umad_port *port) { int devnum; @@ -1032,6 +1037,7 @@ static int ib_umad_init_port(struct ib_device *device, int port_num, cdev_init(&port->cdev, &umad_fops); port->cdev.owner = THIS_MODULE; + port->cdev.kobj.parent = &umad_dev->kobj; kobject_set_name(&port->cdev.kobj, "umad%d", port->dev_num); if (cdev_add(&port->cdev, base, 1)) goto err_cdev; @@ -1050,6 +1056,7 @@ static int ib_umad_init_port(struct ib_device *device, int port_num, base += IB_UMAD_MAX_PORTS; cdev_init(&port->sm_cdev, &umad_sm_fops); port->sm_cdev.owner = THIS_MODULE; + port->sm_cdev.kobj.parent = &umad_dev->kobj; kobject_set_name(&port->sm_cdev.kobj, "issm%d", port->dev_num); if (cdev_add(&port->sm_cdev, base, 1)) goto err_sm_cdev; @@ -1143,7 +1150,7 @@ static void ib_umad_add_one(struct ib_device *device) if (!umad_dev) return; - kref_init(&umad_dev->ref); + kobject_init(&umad_dev->kobj, &ib_umad_dev_ktype); umad_dev->start_port = s; umad_dev->end_port = e; @@ -1151,7 +1158,8 @@ static void ib_umad_add_one(struct ib_device *device) for (i = s; i <= e; ++i) { umad_dev->port[i - s].umad_dev = umad_dev; - if (ib_umad_init_port(device, i, &umad_dev->port[i - s])) + if (ib_umad_init_port(device, i, umad_dev, + &umad_dev->port[i - s])) goto err; } @@ -1163,7 +1171,7 @@ err: while (--i >= s) ib_umad_kill_port(&umad_dev->port[i - s]); - kref_put(&umad_dev->ref, ib_umad_release_dev); + kobject_put(&umad_dev->kobj); } static void ib_umad_remove_one(struct ib_device *device) @@ -1177,7 +1185,7 @@ static void ib_umad_remove_one(struct ib_device *device) for (i = 0; i <= umad_dev->end_port - umad_dev->start_port; ++i) ib_umad_kill_port(&umad_dev->port[i]); - kref_put(&umad_dev->ref, ib_umad_release_dev); + kobject_put(&umad_dev->kobj); } static char *umad_devnode(struct device *dev, umode_t *mode) -- 2.20.1