ipv4: Reject routes specifying ECN bits in rtm_tos
Use the new dscp_t type to replace the fc_tos field of fib_config, to
ensure IPv4 routes aren't influenced by ECN bits when configured with
non-zero rtm_tos.
Before this patch, IPv4 routes specifying an rtm_tos with some of the
ECN bits set were accepted. However they wouldn't work (never match) as
IPv4 normally clears the ECN bits with IPTOS_RT_MASK before doing a FIB
lookup (although a few buggy code paths don't).
After this patch, IPv4 routes specifying an rtm_tos with any ECN bit
set is rejected.
Note: IPv6 routes ignore rtm_tos altogether, any rtm_tos is accepted,
but treated as if it were 0.
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 8060524..d937eee 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -61,6 +61,7 @@
#include <linux/vmalloc.h>
#include <linux/notifier.h>
#include <net/net_namespace.h>
+#include <net/inet_dscp.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/route.h>
@@ -1210,9 +1211,9 @@ int fib_table_insert(struct net *net, struct fib_table *tb,
struct fib_info *fi;
u8 plen = cfg->fc_dst_len;
u8 slen = KEYLENGTH - plen;
- u8 tos = cfg->fc_tos;
u32 key;
int err;
+ u8 tos;
key = ntohl(cfg->fc_dst);
@@ -1227,6 +1228,7 @@ int fib_table_insert(struct net *net, struct fib_table *tb,
goto err;
}
+ tos = inet_dscp_to_dsfield(cfg->fc_dscp);
l = fib_find_node(t, &tp, key);
fa = l ? fib_find_alias(&l->leaf, slen, tos, fi->fib_priority,
tb->tb_id, false) : NULL;
@@ -1703,8 +1705,8 @@ int fib_table_delete(struct net *net, struct fib_table *tb,
struct key_vector *l, *tp;
u8 plen = cfg->fc_dst_len;
u8 slen = KEYLENGTH - plen;
- u8 tos = cfg->fc_tos;
u32 key;
+ u8 tos;
key = ntohl(cfg->fc_dst);
@@ -1715,6 +1717,7 @@ int fib_table_delete(struct net *net, struct fib_table *tb,
if (!l)
return -ESRCH;
+ tos = inet_dscp_to_dsfield(cfg->fc_dscp);
fa = fib_find_alias(&l->leaf, slen, tos, 0, tb->tb_id, false);
if (!fa)
return -ESRCH;
