[PATCH 5.4 303/320] libcxgb: Dont accidentally set RTO_ONLINK in cxgb_find_route()

Greg Kroah-Hartman
2022-01-24T19:42:00Z

From: Guillaume Nault <gnault@redhat.com>

commit a915deaa9abe4fb3a440312c954253a6a733608e upstream.

Mask the ECN bits before calling ip_route_output_ports(). The tos
variable might be passed directly from an IPv4 header, so it may have
the last ECN bit set. This interferes with the route lookup process as
ip_route_output_key_hash() interpretes this bit specially (to restrict
the route scope).

Found by code inspection, compile tested only.

Fixes: 804c2f3e36ef ("libcxgb,iw_cxgb4,cxgbit: add cxgb_find_route()")
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/chelsio/libcxgb/libcxgb_cm.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/chelsio/libcxgb/libcxgb_cm.c
+++ b/drivers/net/ethernet/chelsio/libcxgb/libcxgb_cm.c
@@ -32,6 +32,7 @@

#include <linux/tcp.h>
#include <linux/ipv6.h>
+#include <net/inet_ecn.h>
#include <net/route.h>
#include <net/ip6_route.h>

@@ -99,7 +100,7 @@ cxgb_find_route(struct cxgb4_lld_info *l

rt = ip_route_output_ports(&init_net, &fl4, NULL, peer_ip, local_ip,
peer_port, local_port, IPPROTO_TCP,
- tos, 0);
+ tos & ~INET_ECN_MASK, 0);
if (IS_ERR(rt))
return NULL;
n = dst_neigh_lookup(&rt->dst, &peer_ip);