IB/core: Better checking of userspace values for receive flow steering

  - Don't allow unsupported comp_mask values, user should check
    ibv_query_device to know which features are supported.
  - Add a check in ib_uverbs_create_flow() to verify the size passed
    from the user space.

Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

2 files changed, 17 insertions, 1 deletions

diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index 6e98df929e29..9112410da11d 100644
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -2652,17 +2652,31 @@ ssize_t ib_uverbs_create_flow(struct ib_uverbs_file *file,
         if (copy_from_user(&cmd, buf, sizeof(cmd)))
                 return -EFAULT;
 
+        if (cmd.comp_mask)
+                return -EINVAL;
+
         if ((cmd.flow_attr.type == IB_FLOW_ATTR_SNIFFER &&
              !capable(CAP_NET_ADMIN)) || !capable(CAP_NET_RAW))
                 return -EPERM;
 
+        if (cmd.flow_attr.num_of_specs < 0 ||
+            cmd.flow_attr.num_of_specs > IB_FLOW_SPEC_SUPPORT_LAYERS)
+                return -EINVAL;
+
+        kern_attr_size = cmd.flow_attr.size - sizeof(cmd) -
+                         sizeof(struct ib_uverbs_cmd_hdr_ex);
+
+        if (cmd.flow_attr.size < 0 || cmd.flow_attr.size > in_len ||
+            kern_attr_size < 0 || kern_attr_size >
+            (cmd.flow_attr.num_of_specs * sizeof(struct ib_kern_spec)))
+                return -EINVAL;
+
         if (cmd.flow_attr.num_of_specs) {
                 kern_flow_attr = kmalloc(cmd.flow_attr.size, GFP_KERNEL);
                 if (!kern_flow_attr)
                         return -ENOMEM;
 
                 memcpy(kern_flow_attr, &cmd.flow_attr, sizeof(*kern_flow_attr));
-                kern_attr_size = cmd.flow_attr.size - sizeof(cmd) - sizeof(struct ib_uverbs_cmd_hdr_ex);
                 if (copy_from_user(kern_flow_attr + 1, buf + sizeof(cmd),
                                    kern_attr_size)) {
                         err = -EFAULT;
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 274205d4df97..bd151eac1e61 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -1098,6 +1098,8 @@ enum ib_flow_spec_type {
         IB_FLOW_SPEC_UDP        = 0x41
 };
 
+#define IB_FLOW_SPEC_SUPPORT_LAYERS 4
+
 /* Flow steering rule priority is set according to it's domain.
  * Lower domain value means higher priority.
  */