ipv4: Convert ip_route_input_mc() to dscp_t.

Pass a dscp_t variable to ip_route_input_mc(), instead of a plain u8,
to prevent accidental setting of ECN bits in ->flowi4_tos.

Only ip_route_input_rcu() actually calls ip_route_input_mc(). Since it
already has a dscp_t variable to pass as parameter, we only need to
remove the inet_dscp_to_dsfield() conversion.

Signed-off-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/0cc653ef59bbc0a28881f706d34896c61eba9e01.1728302212.git.gnault@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 763b8bafd1bf87d6b24848208c59db1d80547104..527121be1ba2cd8cbc80ad64f36734ea4dd243fa 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1697,7 +1697,7 @@ int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 
 /* called in rcu_read_lock() section */
 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
-                            u8 tos, struct net_device *dev, int our)
+                            dscp_t dscp, struct net_device *dev, int our)
 {
        struct in_device *in_dev = __in_dev_get_rcu(dev);
        unsigned int flags = RTCF_MULTICAST;
@@ -1705,7 +1705,9 @@ static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
        u32 itag = 0;
        int err;
 
-       err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag);
+       err = ip_mc_validate_source(skb, daddr, saddr,
+                                   inet_dscp_to_dsfield(dscp), dev, in_dev,
+                                   &itag);
        if (err)
                return err;
 
@@ -2455,9 +2457,8 @@ static int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
                     IN_DEV_MFORWARD(in_dev))
 #endif
                   ) {
-                       err = ip_route_input_mc(skb, daddr, saddr,
-                                               inet_dscp_to_dsfield(dscp),
-                                               dev, our);
+                       err = ip_route_input_mc(skb, daddr, saddr, dscp, dev,
+                                               our);
                }
                return err;
        }