[PATCH net-next 6/7] ipv4: Convert fib_validate_source() to dscp_t.

[Guillaume Nault <gnault@redhat.com>]

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

All callers of fib_validate_source() already have a dscp_t variable to
pass as parameter. We just need to remove the inet_dscp_to_dsfield()
conversions.

Signed-off-by: Guillaume Nault <gnault@redhat.com>
---
 include/net/ip_fib.h    |  3 ++-
 net/ipv4/fib_frontend.c |  5 +++--
 net/ipv4/route.c        | 21 +++++++++------------
 3 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index 967e4dc555fa..06130933542d 100644
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -449,8 +449,9 @@ int fib_gw_from_via(struct fib_config *cfg, struct nlattr *nla,
 __be32 fib_compute_spec_dst(struct sk_buff *skb);
 bool fib_info_nh_uses_dev(struct fib_info *fi, const struct net_device *dev);
 int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
-			u8 tos, int oif, struct net_device *dev,
+			dscp_t dscp, int oif, struct net_device *dev,
 			struct in_device *idev, u32 *itag);
+
 #ifdef CONFIG_IP_ROUTE_CLASSID
 static inline int fib_num_tclassid_users(struct net *net)
 {
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 793e6781399a..d0fbc8c8c5e6 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -419,7 +419,7 @@ static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 
 /* Ignore rp_filter for packets protected by IPsec. */
 int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
-			u8 tos, int oif, struct net_device *dev,
+			dscp_t dscp, int oif, struct net_device *dev,
 			struct in_device *idev, u32 *itag)
 {
 	int r = secpath_exists(skb) ? 0 : IN_DEV_RPFILTER(idev);
@@ -448,7 +448,8 @@ int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 	}
 
 full_check:
-	return __fib_validate_source(skb, src, dst, tos, oif, dev, r, idev, itag);
+	return __fib_validate_source(skb, src, dst, inet_dscp_to_dsfield(dscp),
+				     oif, dev, r, idev, itag);
 }
 
 static inline __be32 sk_extract_addr(struct sockaddr *addr)
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 1efb65e647c1..a0b091a7df87 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1687,9 +1687,8 @@ int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 		    ip_hdr(skb)->protocol != IPPROTO_IGMP)
 			return -EINVAL;
 	} else {
-		err = fib_validate_source(skb, saddr, 0,
-					  inet_dscp_to_dsfield(dscp), 0, dev,
-					  in_dev, itag);
+		err = fib_validate_source(skb, saddr, 0, dscp, 0, dev, in_dev,
+					  itag);
 		if (err < 0)
 			return err;
 	}
@@ -1786,8 +1785,8 @@ static int __mkroute_input(struct sk_buff *skb, const struct fib_result *res,
 		return -EINVAL;
 	}
 
-	err = fib_validate_source(skb, saddr, daddr, inet_dscp_to_dsfield(dscp),
-				  FIB_RES_OIF(*res), in_dev->dev, in_dev, &itag);
+	err = fib_validate_source(skb, saddr, daddr, dscp, FIB_RES_OIF(*res),
+				  in_dev->dev, in_dev, &itag);
 	if (err < 0) {
 		ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
 					 saddr);
@@ -2159,8 +2158,8 @@ int ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 	if (rt->rt_type != RTN_LOCAL)
 		goto skip_validate_source;
 
-	err = fib_validate_source(skb, saddr, daddr, inet_dscp_to_dsfield(dscp),
-				  0, dev, in_dev, &tag);
+	err = fib_validate_source(skb, saddr, daddr, dscp, 0, dev, in_dev,
+				  &tag);
 	if (err < 0)
 		goto martian_source;
 
@@ -2298,8 +2297,7 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 	}
 
 	if (res->type == RTN_LOCAL) {
-		err = fib_validate_source(skb, saddr, daddr,
-					  inet_dscp_to_dsfield(dscp), 0, dev,
+		err = fib_validate_source(skb, saddr, daddr, dscp, 0, dev,
 					  in_dev, &itag);
 		if (err < 0)
 			goto martian_source;
@@ -2322,9 +2320,8 @@ out:	return err;
 		goto e_inval;
 
 	if (!ipv4_is_zeronet(saddr)) {
-		err = fib_validate_source(skb, saddr, 0,
-					  inet_dscp_to_dsfield(dscp), 0, dev,
-					  in_dev, &itag);
+		err = fib_validate_source(skb, saddr, 0, dscp, 0, dev, in_dev,
+					  &itag);
 		if (err < 0)
 			goto martian_source;
 	}
-- 
2.39.2