ethtool: Check that reserved fields of struct ethtool_rxfh are 0

We should fail rather than silently ignoring use of these extensions.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

1 files changed, 36 insertions, 53 deletions

diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 8ae452afb545..17cb912793fa 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -681,11 +681,11 @@ static noinline_for_stack int ethtool_get_rxfh(struct net_device *dev,
 {
         int ret;
         const struct ethtool_ops *ops = dev->ethtool_ops;
-        u32 user_indir_size = 0, user_key_size = 0;
+        u32 user_indir_size, user_key_size;
         u32 dev_indir_size = 0, dev_key_size = 0;
+        struct ethtool_rxfh rxfh;
         u32 total_size;
-        u32 indir_offset, indir_bytes;
-        u32 key_offset;
+        u32 indir_bytes;
         u32 *indir = NULL;
         u8 *hkey = NULL;
         u8 *rss_config;
@@ -697,33 +697,24 @@ static noinline_for_stack int ethtool_get_rxfh(struct net_device *dev,
 
         if (ops->get_rxfh_indir_size)
                 dev_indir_size = ops->get_rxfh_indir_size(dev);
-
-        indir_offset = offsetof(struct ethtool_rxfh, indir_size);
-
-        if (copy_from_user(&user_indir_size,
-                           useraddr + indir_offset,
-                           sizeof(user_indir_size)))
-                return -EFAULT;
-
-        if (copy_to_user(useraddr + indir_offset,
-                         &dev_indir_size, sizeof(dev_indir_size)))
-                return -EFAULT;
-
         if (ops->get_rxfh_key_size)
                 dev_key_size = ops->get_rxfh_key_size(dev);
 
         if ((dev_key_size + dev_indir_size) == 0)
                 return -EOPNOTSUPP;
 
-        key_offset = offsetof(struct ethtool_rxfh, key_size);
-
-        if (copy_from_user(&user_key_size,
-                           useraddr + key_offset,
-                           sizeof(user_key_size)))
+        if (copy_from_user(&rxfh, useraddr, sizeof(rxfh)))
                 return -EFAULT;
+        user_indir_size = rxfh.indir_size;
+        user_key_size = rxfh.key_size;
 
-        if (copy_to_user(useraddr + key_offset,
-                         &dev_key_size, sizeof(dev_key_size)))
+        /* Check that reserved fields are 0 for now */
+        if (rxfh.rss_context || rxfh.rsvd[0] || rxfh.rsvd[1])
+                return -EINVAL;
+
+        rxfh.indir_size = dev_indir_size;
+        rxfh.key_size = dev_key_size;
+        if (copy_to_user(useraddr, &rxfh, sizeof(rxfh)))
                 return -EFAULT;
 
         /* If the user buffer size is 0, this is just a query for the
@@ -768,12 +759,11 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
         int ret;
         const struct ethtool_ops *ops = dev->ethtool_ops;
         struct ethtool_rxnfc rx_rings;
-        u32 user_indir_size = 0, dev_indir_size = 0, i;
-        u32 user_key_size = 0, dev_key_size = 0;
+        struct ethtool_rxfh rxfh;
+        u32 dev_indir_size = 0, dev_key_size = 0, i;
         u32 *indir = NULL, indir_bytes = 0;
         u8 *hkey = NULL;
         u8 *rss_config;
-        u32 indir_offset, key_offset;
         u32 rss_cfg_offset = offsetof(struct ethtool_rxfh, rss_config[0]);
 
         if (!(ops->get_rxfh_indir_size || ops->get_rxfh_key_size) ||
@@ -782,40 +772,33 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
 
         if (ops->get_rxfh_indir_size)
                 dev_indir_size = ops->get_rxfh_indir_size(dev);
-
-        indir_offset = offsetof(struct ethtool_rxfh, indir_size);
-        if (copy_from_user(&user_indir_size,
-                           useraddr + indir_offset,
-                           sizeof(user_indir_size)))
-                return -EFAULT;
-
         if (ops->get_rxfh_key_size)
                 dev_key_size = dev->ethtool_ops->get_rxfh_key_size(dev);
-
         if ((dev_key_size + dev_indir_size) == 0)
                 return -EOPNOTSUPP;
 
-        key_offset = offsetof(struct ethtool_rxfh, key_size);
-        if (copy_from_user(&user_key_size,
-                           useraddr + key_offset,
-                           sizeof(user_key_size)))
+        if (copy_from_user(&rxfh, useraddr, sizeof(rxfh)))
                 return -EFAULT;
 
+        /* Check that reserved fields are 0 for now */
+        if (rxfh.rss_context || rxfh.rsvd[0] || rxfh.rsvd[1])
+                return -EINVAL;
+
         /* If either indir or hash key is valid, proceed further.
          * It is not valid to request that both be unchanged.
          */
-        if ((user_indir_size &&
-             user_indir_size != ETH_RXFH_INDIR_NO_CHANGE &&
-             user_indir_size != dev_indir_size) ||
-            (user_key_size && (user_key_size != dev_key_size)) ||
-            (user_indir_size == ETH_RXFH_INDIR_NO_CHANGE &&
-             user_key_size == 0))
+        if ((rxfh.indir_size &&
+             rxfh.indir_size != ETH_RXFH_INDIR_NO_CHANGE &&
+             rxfh.indir_size != dev_indir_size) ||
+            (rxfh.key_size && (rxfh.key_size != dev_key_size)) ||
+            (rxfh.indir_size == ETH_RXFH_INDIR_NO_CHANGE &&
+             rxfh.key_size == 0))
                 return -EINVAL;
 
-        if (user_indir_size != ETH_RXFH_INDIR_NO_CHANGE)
+        if (rxfh.indir_size != ETH_RXFH_INDIR_NO_CHANGE)
                 indir_bytes = dev_indir_size * sizeof(indir[0]);
 
-        rss_config = kzalloc(indir_bytes + user_key_size, GFP_USER);
+        rss_config = kzalloc(indir_bytes + rxfh.key_size, GFP_USER);
         if (!rss_config)
                 return -ENOMEM;
 
@@ -824,29 +807,29 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
         if (ret)
                 goto out;
 
-        /* user_indir_size == 0 means reset the indir table to default.
-         * user_indir_size == ETH_RXFH_INDIR_NO_CHANGE means leave it unchanged.
+        /* rxfh.indir_size == 0 means reset the indir table to default.
+         * rxfh.indir_size == ETH_RXFH_INDIR_NO_CHANGE means leave it unchanged.
          */
-        if (user_indir_size &&
-            user_indir_size != ETH_RXFH_INDIR_NO_CHANGE) {
+        if (rxfh.indir_size &&
+            rxfh.indir_size != ETH_RXFH_INDIR_NO_CHANGE) {
                 indir = (u32 *)rss_config;
                 ret = ethtool_copy_validate_indir(indir,
                                                   useraddr + rss_cfg_offset,
                                                   &rx_rings,
-                                                  user_indir_size);
+                                                  rxfh.indir_size);
                 if (ret)
                         goto out;
-        } else if (user_indir_size == 0) {
+        } else if (rxfh.indir_size == 0) {
                 indir = (u32 *)rss_config;
                 for (i = 0; i < dev_indir_size; i++)
                         indir[i] = ethtool_rxfh_indir_default(i, rx_rings.data);
         }
 
-        if (user_key_size) {
+        if (rxfh.key_size) {
                 hkey = rss_config + indir_bytes;
                 if (copy_from_user(hkey,
                                    useraddr + rss_cfg_offset + indir_bytes,
-                                   user_key_size)) {
+                                   rxfh.key_size)) {
                         ret = -EFAULT;
                         goto out;
                 }