[IB] uverbs: Close some exploitable races
Al Viro pointed out that the current IB userspace verbs interface
allows userspace to cause mischief by closing file descriptors before
we're ready, or issuing the same command twice at the same time. This
patch closes those races, and fixes other obvious problems such as a
module reference leak.
Some other interface bogosities will require an ABI change to fix
properly, so I'm deferring those fixes until 2.6.15.
Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/infiniband/core/uverbs.h b/drivers/infiniband/core/uverbs.h
index b1897be..cc12434 100644
--- a/drivers/infiniband/core/uverbs.h
+++ b/drivers/infiniband/core/uverbs.h
@@ -69,6 +69,7 @@
struct ib_uverbs_file {
struct kref ref;
+ struct semaphore mutex;
struct ib_uverbs_device *device;
struct ib_ucontext *ucontext;
struct ib_event_handler event_handler;
diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index e91ebde..5624451 100644
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -76,8 +76,9 @@
struct ib_uverbs_get_context_resp resp;
struct ib_udata udata;
struct ib_device *ibdev = file->device->ib_dev;
+ struct ib_ucontext *ucontext;
int i;
- int ret = in_len;
+ int ret;
if (out_len < sizeof resp)
return -ENOSPC;
@@ -85,45 +86,56 @@
if (copy_from_user(&cmd, buf, sizeof cmd))
return -EFAULT;
+ down(&file->mutex);
+
+ if (file->ucontext) {
+ ret = -EINVAL;
+ goto err;
+ }
+
INIT_UDATA(&udata, buf + sizeof cmd,
(unsigned long) cmd.response + sizeof resp,
in_len - sizeof cmd, out_len - sizeof resp);
- file->ucontext = ibdev->alloc_ucontext(ibdev, &udata);
- if (IS_ERR(file->ucontext)) {
- ret = PTR_ERR(file->ucontext);
- file->ucontext = NULL;
- return ret;
- }
+ ucontext = ibdev->alloc_ucontext(ibdev, &udata);
+ if (IS_ERR(ucontext))
+ return PTR_ERR(file->ucontext);
- file->ucontext->device = ibdev;
- INIT_LIST_HEAD(&file->ucontext->pd_list);
- INIT_LIST_HEAD(&file->ucontext->mr_list);
- INIT_LIST_HEAD(&file->ucontext->mw_list);
- INIT_LIST_HEAD(&file->ucontext->cq_list);
- INIT_LIST_HEAD(&file->ucontext->qp_list);
- INIT_LIST_HEAD(&file->ucontext->srq_list);
- INIT_LIST_HEAD(&file->ucontext->ah_list);
- spin_lock_init(&file->ucontext->lock);
+ ucontext->device = ibdev;
+ INIT_LIST_HEAD(&ucontext->pd_list);
+ INIT_LIST_HEAD(&ucontext->mr_list);
+ INIT_LIST_HEAD(&ucontext->mw_list);
+ INIT_LIST_HEAD(&ucontext->cq_list);
+ INIT_LIST_HEAD(&ucontext->qp_list);
+ INIT_LIST_HEAD(&ucontext->srq_list);
+ INIT_LIST_HEAD(&ucontext->ah_list);
resp.async_fd = file->async_file.fd;
for (i = 0; i < file->device->num_comp; ++i)
if (copy_to_user((void __user *) (unsigned long) cmd.cq_fd_tab +
i * sizeof (__u32),
- &file->comp_file[i].fd, sizeof (__u32)))
- goto err;
+ &file->comp_file[i].fd, sizeof (__u32))) {
+ ret = -EFAULT;
+ goto err_free;
+ }
if (copy_to_user((void __user *) (unsigned long) cmd.response,
- &resp, sizeof resp))
- goto err;
+ &resp, sizeof resp)) {
+ ret = -EFAULT;
+ goto err_free;
+ }
+
+ file->ucontext = ucontext;
+ up(&file->mutex);
return in_len;
-err:
- ibdev->dealloc_ucontext(file->ucontext);
- file->ucontext = NULL;
+err_free:
+ ibdev->dealloc_ucontext(ucontext);
- return -EFAULT;
+err:
+ up(&file->mutex);
+ return ret;
}
ssize_t ib_uverbs_query_device(struct ib_uverbs_file *file,
@@ -352,9 +364,9 @@
if (ret)
goto err_pd;
- spin_lock_irq(&file->ucontext->lock);
+ down(&file->mutex);
list_add_tail(&uobj->list, &file->ucontext->pd_list);
- spin_unlock_irq(&file->ucontext->lock);
+ up(&file->mutex);
memset(&resp, 0, sizeof resp);
resp.pd_handle = uobj->id;
@@ -368,9 +380,9 @@
return in_len;
err_list:
- spin_lock_irq(&file->ucontext->lock);
+ down(&file->mutex);
list_del(&uobj->list);
- spin_unlock_irq(&file->ucontext->lock);
+ up(&file->mutex);
down(&ib_uverbs_idr_mutex);
idr_remove(&ib_uverbs_pd_idr, uobj->id);
@@ -410,9 +422,9 @@
idr_remove(&ib_uverbs_pd_idr, cmd.pd_handle);
- spin_lock_irq(&file->ucontext->lock);
+ down(&file->mutex);
list_del(&uobj->list);
- spin_unlock_irq(&file->ucontext->lock);
+ up(&file->mutex);
kfree(uobj);
@@ -512,9 +524,9 @@
resp.mr_handle = obj->uobject.id;
- spin_lock_irq(&file->ucontext->lock);
+ down(&file->mutex);
list_add_tail(&obj->uobject.list, &file->ucontext->mr_list);
- spin_unlock_irq(&file->ucontext->lock);
+ up(&file->mutex);
if (copy_to_user((void __user *) (unsigned long) cmd.response,
&resp, sizeof resp)) {
@@ -527,9 +539,9 @@
return in_len;
err_list:
- spin_lock_irq(&file->ucontext->lock);
+ down(&file->mutex);
list_del(&obj->uobject.list);
- spin_unlock_irq(&file->ucontext->lock);
+ up(&file->mutex);
err_unreg:
ib_dereg_mr(mr);
@@ -570,9 +582,9 @@
idr_remove(&ib_uverbs_mr_idr, cmd.mr_handle);
- spin_lock_irq(&file->ucontext->lock);
+ down(&file->mutex);
list_del(&memobj->uobject.list);
- spin_unlock_irq(&file->ucontext->lock);
+ up(&file->mutex);
ib_umem_release(file->device->ib_dev, &memobj->umem);
kfree(memobj);
@@ -647,9 +659,9 @@
if (ret)
goto err_cq;
- spin_lock_irq(&file->ucontext->lock);
+ down(&file->mutex);
list_add_tail(&uobj->uobject.list, &file->ucontext->cq_list);
- spin_unlock_irq(&file->ucontext->lock);
+ up(&file->mutex);
memset(&resp, 0, sizeof resp);
resp.cq_handle = uobj->uobject.id;
@@ -664,9 +676,9 @@
return in_len;
err_list:
- spin_lock_irq(&file->ucontext->lock);
+ down(&file->mutex);
list_del(&uobj->uobject.list);
- spin_unlock_irq(&file->ucontext->lock);
+ up(&file->mutex);
down(&ib_uverbs_idr_mutex);
idr_remove(&ib_uverbs_cq_idr, uobj->uobject.id);
@@ -712,9 +724,9 @@
idr_remove(&ib_uverbs_cq_idr, cmd.cq_handle);
- spin_lock_irq(&file->ucontext->lock);
+ down(&file->mutex);
list_del(&uobj->uobject.list);
- spin_unlock_irq(&file->ucontext->lock);
+ up(&file->mutex);
spin_lock_irq(&file->comp_file[0].lock);
list_for_each_entry_safe(evt, tmp, &uobj->comp_list, obj_list) {
@@ -847,9 +859,9 @@
resp.qp_handle = uobj->uobject.id;
- spin_lock_irq(&file->ucontext->lock);
+ down(&file->mutex);
list_add_tail(&uobj->uobject.list, &file->ucontext->qp_list);
- spin_unlock_irq(&file->ucontext->lock);
+ up(&file->mutex);
if (copy_to_user((void __user *) (unsigned long) cmd.response,
&resp, sizeof resp)) {
@@ -862,9 +874,9 @@
return in_len;
err_list:
- spin_lock_irq(&file->ucontext->lock);
+ down(&file->mutex);
list_del(&uobj->uobject.list);
- spin_unlock_irq(&file->ucontext->lock);
+ up(&file->mutex);
err_destroy:
ib_destroy_qp(qp);
@@ -989,9 +1001,9 @@
idr_remove(&ib_uverbs_qp_idr, cmd.qp_handle);
- spin_lock_irq(&file->ucontext->lock);
+ down(&file->mutex);
list_del(&uobj->uobject.list);
- spin_unlock_irq(&file->ucontext->lock);
+ up(&file->mutex);
spin_lock_irq(&file->async_file.lock);
list_for_each_entry_safe(evt, tmp, &uobj->event_list, obj_list) {
@@ -1136,9 +1148,9 @@
resp.srq_handle = uobj->uobject.id;
- spin_lock_irq(&file->ucontext->lock);
+ down(&file->mutex);
list_add_tail(&uobj->uobject.list, &file->ucontext->srq_list);
- spin_unlock_irq(&file->ucontext->lock);
+ up(&file->mutex);
if (copy_to_user((void __user *) (unsigned long) cmd.response,
&resp, sizeof resp)) {
@@ -1151,9 +1163,9 @@
return in_len;
err_list:
- spin_lock_irq(&file->ucontext->lock);
+ down(&file->mutex);
list_del(&uobj->uobject.list);
- spin_unlock_irq(&file->ucontext->lock);
+ up(&file->mutex);
err_destroy:
ib_destroy_srq(srq);
@@ -1227,9 +1239,9 @@
idr_remove(&ib_uverbs_srq_idr, cmd.srq_handle);
- spin_lock_irq(&file->ucontext->lock);
+ down(&file->mutex);
list_del(&uobj->uobject.list);
- spin_unlock_irq(&file->ucontext->lock);
+ up(&file->mutex);
spin_lock_irq(&file->async_file.lock);
list_for_each_entry_safe(evt, tmp, &uobj->event_list, obj_list) {
diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c
index ce5bdb7..1251180 100644
--- a/drivers/infiniband/core/uverbs_main.c
+++ b/drivers/infiniband/core/uverbs_main.c
@@ -448,7 +448,9 @@
if (hdr.in_words * 4 != count)
return -EINVAL;
- if (hdr.command < 0 || hdr.command >= ARRAY_SIZE(uverbs_cmd_table))
+ if (hdr.command < 0 ||
+ hdr.command >= ARRAY_SIZE(uverbs_cmd_table) ||
+ !uverbs_cmd_table[hdr.command])
return -EINVAL;
if (!file->ucontext &&
@@ -484,27 +486,29 @@
file = kmalloc(sizeof *file +
(dev->num_comp - 1) * sizeof (struct ib_uverbs_event_file),
GFP_KERNEL);
- if (!file)
- return -ENOMEM;
+ if (!file) {
+ ret = -ENOMEM;
+ goto err;
+ }
file->device = dev;
kref_init(&file->ref);
+ init_MUTEX(&file->mutex);
file->ucontext = NULL;
+ kref_get(&file->ref);
ret = ib_uverbs_event_init(&file->async_file, file);
if (ret)
- goto err;
+ goto err_kref;
file->async_file.is_async = 1;
- kref_get(&file->ref);
-
for (i = 0; i < dev->num_comp; ++i) {
+ kref_get(&file->ref);
ret = ib_uverbs_event_init(&file->comp_file[i], file);
if (ret)
goto err_async;
- kref_get(&file->ref);
file->comp_file[i].is_async = 0;
}
@@ -524,9 +528,16 @@
ib_uverbs_event_release(&file->async_file);
-err:
+err_kref:
+ /*
+ * One extra kref_put() because we took a reference before the
+ * event file creation that failed and got us here.
+ */
+ kref_put(&file->ref, ib_uverbs_release_file);
kref_put(&file->ref, ib_uverbs_release_file);
+err:
+ module_put(dev->ib_dev->owner);
return ret;
}
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index e16cf94..e6f4c9e 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -665,7 +665,6 @@
struct list_head qp_list;
struct list_head srq_list;
struct list_head ah_list;
- spinlock_t lock;
};
struct ib_uobject {