Commit be612f5e authored by Guillaume Nault's avatar Guillaume Nault Committed by Jakub Kicinski
Browse files

ipv4: Convert ip_route_input_rcu() to dscp_t. 



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

Callers of ip_route_input_rcu() to consider are:

  * ip_route_input_noref(), which already has a dscp_t variable to pass
    as parameter. We just need to remove the inet_dscp_to_dsfield()
    conversion.

  * inet_rtm_getroute(), which receives a u8 from user space and needs
    to convert it with inet_dsfield_to_dscp().

Signed-off-by: default avatarGuillaume Nault <gnault@redhat.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/c4dbb5aa9cbc79c4fcb317abbffa7c7156bc56a7.1727807926.git.gnault@redhat.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 66fb6386

net/ipv4/route.c

+9 −7
Original line number Diff line number Diff line
@@ -2415,7 +2415,8 @@ out: return err; 


/* called with rcu_read_lock held */

static int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,

			      u8 tos, struct net_device *dev, struct fib_result *res)

			      dscp_t dscp, struct net_device *dev,

			      struct fib_result *res)

{

	/* Multicast recognition logic is moved from route cache to here.

	 * The problem was that too many Ethernet cards have broken/missing
@@ -2456,12 +2457,14 @@ static int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr, 
#endif

		   ) {

			err = ip_route_input_mc(skb, daddr, saddr,

						tos, dev, our);

						inet_dscp_to_dsfield(dscp),

						dev, our);

		}

		return err;

	}



	return ip_route_input_slow(skb, daddr, saddr, tos, dev, res);

	return ip_route_input_slow(skb, daddr, saddr,

				   inet_dscp_to_dsfield(dscp), dev, res);

}



int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
@@ -2471,8 +2474,7 @@ int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 
	int err;



	rcu_read_lock();

	err = ip_route_input_rcu(skb, daddr, saddr, inet_dscp_to_dsfield(dscp),

				 dev, &res);

	err = ip_route_input_rcu(skb, daddr, saddr, dscp, dev, &res);

	rcu_read_unlock();



	return err;
@@ -3286,8 +3288,8 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 
		skb->dev	= dev;

		skb->mark	= mark;

		err = ip_route_input_rcu(skb, dst, src,

					 rtm->rtm_tos & INET_DSCP_MASK, dev,

					 &res);

					 inet_dsfield_to_dscp(rtm->rtm_tos),

					 dev, &res);



		rt = skb_rtable(skb);

		if (err == 0 && rt->dst.error)