[PATCH net-next v2 4/6] net: mpls: Limit memory allocation for mpls_route

[David Ahern]

Limit memory allocation size for mpls_route to 4096.

Signed-off-by: David Ahern <d...@cumulusnetworks.com>
---
v2
- new patch in v2 of set

 net/mpls/af_mpls.c | 31 +++++++++++++++++++++----------
 1 file changed, 21 insertions(+), 10 deletions(-)

diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index 1863b94133e4..f84c52b6eafc 100644
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -26,6 +26,9 @@
 
 #define MAX_NEW_LABELS 2
 
+/* max memory we will use for mpls_route */
+#define MAX_MPLS_ROUTE_MEM     4096
+
 /* Maximum number of labels to look ahead at when selecting a path of
  * a multipath route
  */
@@ -477,14 +480,20 @@ static struct mpls_route *mpls_rt_alloc(u8 num_nh, u8 
max_alen, u8 max_labels)
 {
        u8 nh_size = MPLS_NH_SIZE(max_labels, max_alen);
        struct mpls_route *rt;
+       size_t size;
 
-       rt = kzalloc(sizeof(*rt) + num_nh * nh_size, GFP_KERNEL);
-       if (rt) {
-               rt->rt_nhn = num_nh;
-               rt->rt_nhn_alive = num_nh;
-               rt->rt_nh_size = nh_size;
-               rt->rt_via_offset = MPLS_NH_VIA_OFF(max_labels);
-       }
+       size = sizeof(*rt) + num_nh * nh_size;
+       if (size > MAX_MPLS_ROUTE_MEM)
+               return ERR_PTR(-EINVAL);
+
+       rt = kzalloc(size, GFP_KERNEL);
+       if (!rt)
+               return ERR_PTR(-ENOMEM);
+
+       rt->rt_nhn = num_nh;
+       rt->rt_nhn_alive = num_nh;
+       rt->rt_nh_size = nh_size;
+       rt->rt_via_offset = MPLS_NH_VIA_OFF(max_labels);
 
        return rt;
 }
@@ -898,8 +907,10 @@ static int mpls_route_add(struct mpls_route_config *cfg)
 
        err = -ENOMEM;
        rt = mpls_rt_alloc(nhs, max_via_alen, MAX_NEW_LABELS);
-       if (!rt)
+       if (IS_ERR(rt)) {
+               err = PTR_ERR(rt);
                goto errout;
+       }
 
        rt->rt_protocol = cfg->rc_protocol;
        rt->rt_payload_type = cfg->rc_payload_type;
@@ -1970,7 +1981,7 @@ static int resize_platform_label_table(struct net *net, 
size_t limit)
        if (limit > MPLS_LABEL_IPV4NULL) {
                struct net_device *lo = net->loopback_dev;
                rt0 = mpls_rt_alloc(1, lo->addr_len, MAX_NEW_LABELS);
-               if (!rt0)
+               if (IS_ERR(rt0))
                        goto nort0;
                RCU_INIT_POINTER(rt0->rt_nh->nh_dev, lo);
                rt0->rt_protocol = RTPROT_KERNEL;
@@ -1984,7 +1995,7 @@ static int resize_platform_label_table(struct net *net, 
size_t limit)
        if (limit > MPLS_LABEL_IPV6NULL) {
                struct net_device *lo = net->loopback_dev;
                rt2 = mpls_rt_alloc(1, lo->addr_len, MAX_NEW_LABELS);
-               if (!rt2)
+               if (IS_ERR(rt2))
                        goto nort2;
                RCU_INIT_POINTER(rt2->rt_nh->nh_dev, lo);
                rt2->rt_protocol = RTPROT_KERNEL;
-- 
2.1.4