RDMA/uverbs: check for allocation failure in uapi_add_elm()

If the kzalloc() fails then we should return ERR_PTR(-ENOMEM).  In the
current code it's possible that the kzalloc() fails and the
radix_tree_insert() inserts the NULL pointer successfully and we return
the NULL "elm" pointer to the caller.  That results in a NULL pointer
dereference.

Fixes: 9ed3e5f44772 ("IB/uverbs: Build the specs into a radix tree at runtime")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

diff --git a/drivers/infiniband/core/uverbs_uapi.c b/drivers/infiniband/core/uverbs_uapi.c
index 7a987ac..ccc4be0 100644 (file)
--- a/drivers/infiniband/core/uverbs_uapi.c
+++ b/drivers/infiniband/core/uverbs_uapi.c
@@ -22,6 +22,8 @@ static void *uapi_add_elm(struct uverbs_api *uapi, u32 key, size_t alloc_size)
                return ERR_PTR(-EOVERFLOW);
 
        elm = kzalloc(alloc_size, GFP_KERNEL);
+       if (!elm)
+               return ERR_PTR(-ENOMEM);
        rc = radix_tree_insert(&uapi->radix, key, elm);
        if (rc) {
                kfree(elm);