devlink: validate length of param values

DEVLINK_ATTR_PARAM_VALUE_DATA may have different types
so it's not checked by the normal netlink policy. Make
sure the attribute length is what we expect.

Fixes: e3b7ca18ad7b ("devlink: Add param set command")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/devlink.c b/net/core/devlink.c
index 5e220809844c81c539d5e7506bc4095bd9a48ff4..8e44dc5cde7344353b9c5114ddabd8826f1b9adc 100644 (file)
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -3352,34 +3352,41 @@ devlink_param_value_get_from_info(const struct devlink_param *param,
                                  struct genl_info *info,
                                  union devlink_param_value *value)
 {
+       struct nlattr *param_data;
        int len;
 
-       if (param->type != DEVLINK_PARAM_TYPE_BOOL &&
-           !info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA])
+       param_data = info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA];
+
+       if (param->type != DEVLINK_PARAM_TYPE_BOOL && !param_data)
                return -EINVAL;
 
        switch (param->type) {
        case DEVLINK_PARAM_TYPE_U8:
-               value->vu8 = nla_get_u8(info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA]);
+               if (nla_len(param_data) != sizeof(u8))
+                       return -EINVAL;
+               value->vu8 = nla_get_u8(param_data);
                break;
        case DEVLINK_PARAM_TYPE_U16:
-               value->vu16 = nla_get_u16(info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA]);
+               if (nla_len(param_data) != sizeof(u16))
+                       return -EINVAL;
+               value->vu16 = nla_get_u16(param_data);
                break;
        case DEVLINK_PARAM_TYPE_U32:
-               value->vu32 = nla_get_u32(info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA]);
+               if (nla_len(param_data) != sizeof(u32))
+                       return -EINVAL;
+               value->vu32 = nla_get_u32(param_data);
                break;
        case DEVLINK_PARAM_TYPE_STRING:
-               len = strnlen(nla_data(info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA]),
-                             nla_len(info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA]));
-               if (len == nla_len(info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA]) ||
+               len = strnlen(nla_data(param_data), nla_len(param_data));
+               if (len == nla_len(param_data) ||
                    len >= __DEVLINK_PARAM_MAX_STRING_VALUE)
                        return -EINVAL;
-               strcpy(value->vstr,
-                      nla_data(info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA]));
+               strcpy(value->vstr, nla_data(param_data));
                break;
        case DEVLINK_PARAM_TYPE_BOOL:
-               value->vbool = info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA] ?
-                              true : false;
+               if (param_data && nla_len(param_data))
+                       return -EINVAL;
+               value->vbool = nla_get_flag(param_data);
                break;
        }
        return 0;