IB/core: clarify overflow/underflow checks on ib_create/destroy_flow

This patch fixes the following issues:

1. Unneeded checks were removed

2. Removed the fixed size out of flow_attr.size, thus simplifying the checks.

3. Remove a 32bit hole on 64bit systems with strict alignment in
   struct ib_kern_flow_att by adding a reserved field.

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

diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index 2f0f01b..26ee2d2 100644 (file)
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -2657,7 +2657,6 @@ ssize_t ib_uverbs_create_flow(struct ib_uverbs_file *file,
        void *kern_spec;
        void *ib_spec;
        int i;
-       int kern_attr_size;
 
        if (out_len < sizeof(resp))
                return -ENOSPC;
@@ -2672,32 +2671,28 @@ ssize_t ib_uverbs_create_flow(struct ib_uverbs_file *file,
             !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)
+       if (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 >
+       if (cmd.flow_attr.size > (in_len - sizeof(cmd)) ||
+           cmd.flow_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);
+               kern_flow_attr = kmalloc(sizeof(*kern_flow_attr) + cmd.flow_attr.size,
+                                        GFP_KERNEL);
                if (!kern_flow_attr)
                        return -ENOMEM;
 
                memcpy(kern_flow_attr, &cmd.flow_attr, sizeof(*kern_flow_attr));
                if (copy_from_user(kern_flow_attr + 1, buf + sizeof(cmd),
-                                  kern_attr_size)) {
+                                  cmd.flow_attr.size)) {
                        err = -EFAULT;
                        goto err_free_attr;
                }
        } else {
                kern_flow_attr = &cmd.flow_attr;
-               kern_attr_size = sizeof(cmd.flow_attr);
        }
 
        uobj = kmalloc(sizeof(*uobj), GFP_KERNEL);
@@ -2714,7 +2709,7 @@ ssize_t ib_uverbs_create_flow(struct ib_uverbs_file *file,
                goto err_uobj;
        }
 
-       flow_attr = kmalloc(cmd.flow_attr.size, GFP_KERNEL);
+       flow_attr = kmalloc(sizeof(*flow_attr) + cmd.flow_attr.size, GFP_KERNEL);
        if (!flow_attr) {
                err = -ENOMEM;
                goto err_put;
@@ -2729,19 +2724,22 @@ ssize_t ib_uverbs_create_flow(struct ib_uverbs_file *file,
 
        kern_spec = kern_flow_attr + 1;
        ib_spec = flow_attr + 1;
-       for (i = 0; i < flow_attr->num_of_specs && kern_attr_size > 0; i++) {
+       for (i = 0; i < flow_attr->num_of_specs &&
+            cmd.flow_attr.size > offsetof(struct ib_kern_spec, reserved) &&
+            cmd.flow_attr.size >=
+            ((struct ib_kern_spec *)kern_spec)->size; i++) {
                err = kern_spec_to_ib_spec(kern_spec, ib_spec);
                if (err)
                        goto err_free;
                flow_attr->size +=
                        ((union ib_flow_spec *) ib_spec)->size;
-               kern_attr_size -= ((struct ib_kern_spec *) kern_spec)->size;
+               cmd.flow_attr.size -= ((struct ib_kern_spec *)kern_spec)->size;
                kern_spec += ((struct ib_kern_spec *) kern_spec)->size;
                ib_spec += ((union ib_flow_spec *) ib_spec)->size;
        }
-       if (kern_attr_size) {
-               pr_warn("create flow failed, %d bytes left from uverb cmd\n",
-                       kern_attr_size);
+       if (cmd.flow_attr.size || (i != flow_attr->num_of_specs)) {
+               pr_warn("create flow failed, flow %d: %d bytes left from uverb cmd\n",
+                       i, cmd.flow_attr.size);
                goto err_free;
        }
        flow_id = ib_create_flow(qp, flow_attr, IB_FLOW_DOMAIN_USER);

diff --git a/include/uapi/rdma/ib_user_verbs.h b/include/uapi/rdma/ib_user_verbs.h
index e3ddd86..99a58bd 100644 (file)
--- a/include/uapi/rdma/ib_user_verbs.h
+++ b/include/uapi/rdma/ib_user_verbs.h
@@ -771,6 +771,7 @@ struct ib_kern_flow_attr {
 
 struct ib_uverbs_create_flow  {
        __u32 comp_mask;
+       __u32 reserved;
        __u64 response;
        __u32 qp_handle;
        struct ib_kern_flow_attr flow_attr;