net: ethtool: Unify ETHTOOL_{G,S}RXFH rxnfc copy

ETHTOOL_GRXFH correctly copies in the full struct ethtool_rxnfc when
FLOW_RSS is set; ETHTOOL_SRXFH needs a similar code path to handle the
FLOW_RSS case so that ethtool can set the flow hash for custom RSS
contexts (if supported by the driver).

The copy code from ETHTOOL_GRXFH has been pulled out in to a helper so
that it can be called in both ETHTOOL_{G,S}RXFH code paths.

Acked-by: Edward Cree <ecree.xilinx@gmail.com>
Signed-off-by: Joe Damato <jdamato@fastly.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 4a51e0e..7d40e79 100644 (file)
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -907,6 +907,38 @@ static int ethtool_rxnfc_copy_to_compat(void __user *useraddr,
        return 0;
 }
 
+static int ethtool_rxnfc_copy_struct(u32 cmd, struct ethtool_rxnfc *info,
+                                    size_t *info_size, void __user *useraddr)
+{
+       /* struct ethtool_rxnfc was originally defined for
+        * ETHTOOL_{G,S}RXFH with only the cmd, flow_type and data
+        * members.  User-space might still be using that
+        * definition.
+        */
+       if (cmd == ETHTOOL_GRXFH || cmd == ETHTOOL_SRXFH)
+               *info_size = (offsetof(struct ethtool_rxnfc, data) +
+                             sizeof(info->data));
+
+       if (ethtool_rxnfc_copy_from_user(info, useraddr, *info_size))
+               return -EFAULT;
+
+       if ((cmd == ETHTOOL_GRXFH || cmd == ETHTOOL_SRXFH) && info->flow_type & FLOW_RSS) {
+               *info_size = sizeof(*info);
+               if (ethtool_rxnfc_copy_from_user(info, useraddr, *info_size))
+                       return -EFAULT;
+               /* Since malicious users may modify the original data,
+                * we need to check whether FLOW_RSS is still requested.
+                */
+               if (!(info->flow_type & FLOW_RSS))
+                       return -EINVAL;
+       }
+
+       if (info->cmd != cmd)
+               return -EINVAL;
+
+       return 0;
+}
+
 static int ethtool_rxnfc_copy_to_user(void __user *useraddr,
                                      const struct ethtool_rxnfc *rxnfc,
                                      size_t size, const u32 *rule_buf)
@@ -944,16 +976,9 @@ static noinline_for_stack int ethtool_set_rxnfc(struct net_device *dev,
        if (!dev->ethtool_ops->set_rxnfc)
                return -EOPNOTSUPP;
 
-       /* struct ethtool_rxnfc was originally defined for
-        * ETHTOOL_{G,S}RXFH with only the cmd, flow_type and data
-        * members.  User-space might still be using that
-        * definition. */
-       if (cmd == ETHTOOL_SRXFH)
-               info_size = (offsetof(struct ethtool_rxnfc, data) +
-                            sizeof(info.data));
-
-       if (ethtool_rxnfc_copy_from_user(&info, useraddr, info_size))
-               return -EFAULT;
+       rc = ethtool_rxnfc_copy_struct(cmd, &info, &info_size, useraddr);
+       if (rc)
+               return rc;
 
        rc = dev->ethtool_ops->set_rxnfc(dev, &info);
        if (rc)
@@ -978,33 +1003,9 @@ static noinline_for_stack int ethtool_get_rxnfc(struct net_device *dev,
        if (!ops->get_rxnfc)
                return -EOPNOTSUPP;
 
-       /* struct ethtool_rxnfc was originally defined for
-        * ETHTOOL_{G,S}RXFH with only the cmd, flow_type and data
-        * members.  User-space might still be using that
-        * definition. */
-       if (cmd == ETHTOOL_GRXFH)
-               info_size = (offsetof(struct ethtool_rxnfc, data) +
-                            sizeof(info.data));
-
-       if (ethtool_rxnfc_copy_from_user(&info, useraddr, info_size))
-               return -EFAULT;
-
-       /* If FLOW_RSS was requested then user-space must be using the
-        * new definition, as FLOW_RSS is newer.
-        */
-       if (cmd == ETHTOOL_GRXFH && info.flow_type & FLOW_RSS) {
-               info_size = sizeof(info);
-               if (ethtool_rxnfc_copy_from_user(&info, useraddr, info_size))
-                       return -EFAULT;
-               /* Since malicious users may modify the original data,
-                * we need to check whether FLOW_RSS is still requested.
-                */
-               if (!(info.flow_type & FLOW_RSS))
-                       return -EINVAL;
-       }
-
-       if (info.cmd != cmd)
-               return -EINVAL;
+       ret = ethtool_rxnfc_copy_struct(cmd, &info, &info_size, useraddr);
+       if (ret)
+               return ret;
 
        if (info.cmd == ETHTOOL_GRXCLSRLALL) {
                if (info.rule_cnt > 0) {