icmp: avoid allocating large struct on stack

struct icmp_bxm is a large struct, reduce stack usage
by allocating it on heap.

Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Joe Perches <joe@perches.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 23 insertions, 17 deletions

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 2864ca33bedc..5f7d11a45871 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -482,7 +482,7 @@ void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
 {
         struct iphdr *iph;
         int room;
-        struct icmp_bxm icmp_param;
+        struct icmp_bxm *icmp_param;
         struct rtable *rt = skb_rtable(skb_in);
         struct ipcm_cookie ipc;
         struct flowi4 fl4;
@@ -558,9 +558,13 @@ void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
                 }
         }
 
+        icmp_param = kmalloc(sizeof(*icmp_param), GFP_ATOMIC);
+        if (!icmp_param)
+                return;
+
         sk = icmp_xmit_lock(net);
         if (sk == NULL)
-                return;
+                goto out_free;
 
         /*
          *      Construct source address and options.
@@ -586,7 +590,7 @@ void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
                                            IPTOS_PREC_INTERNETCONTROL) :
                                           iph->tos;
 
-        if (ip_options_echo(&icmp_param.replyopts.opt.opt, skb_in))
+        if (ip_options_echo(&icmp_param->replyopts.opt.opt, skb_in))
                 goto out_unlock;
 
 
@@ -594,19 +598,19 @@ void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
          *      Prepare data for ICMP header.
          */
 
-        icmp_param.data.icmph.type       = type;
-        icmp_param.data.icmph.code       = code;
-        icmp_param.data.icmph.un.gateway = info;
-        icmp_param.data.icmph.checksum   = 0;
-        icmp_param.skb    = skb_in;
-        icmp_param.offset = skb_network_offset(skb_in);
+        icmp_param->data.icmph.type      = type;
+        icmp_param->data.icmph.code      = code;
+        icmp_param->data.icmph.un.gateway = info;
+        icmp_param->data.icmph.checksum  = 0;
+        icmp_param->skb   = skb_in;
+        icmp_param->offset = skb_network_offset(skb_in);
         inet_sk(sk)->tos = tos;
         ipc.addr = iph->saddr;
-        ipc.opt = &icmp_param.replyopts.opt;
+        ipc.opt = &icmp_param->replyopts.opt;
         ipc.tx_flags = 0;
 
         rt = icmp_route_lookup(net, &fl4, skb_in, iph, saddr, tos,
-                               type, code, &icmp_param);
+                               type, code, icmp_param);
         if (IS_ERR(rt))
                 goto out_unlock;
 
@@ -618,19 +622,21 @@ void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
         room = dst_mtu(&rt->dst);
         if (room > 576)
                 room = 576;
-        room -= sizeof(struct iphdr) + icmp_param.replyopts.opt.opt.optlen;
+        room -= sizeof(struct iphdr) + icmp_param->replyopts.opt.opt.optlen;
         room -= sizeof(struct icmphdr);
 
-        icmp_param.data_len = skb_in->len - icmp_param.offset;
-        if (icmp_param.data_len > room)
-                icmp_param.data_len = room;
-        icmp_param.head_len = sizeof(struct icmphdr);
+        icmp_param->data_len = skb_in->len - icmp_param->offset;
+        if (icmp_param->data_len > room)
+                icmp_param->data_len = room;
+        icmp_param->head_len = sizeof(struct icmphdr);
 
-        icmp_push_reply(&icmp_param, &fl4, &ipc, &rt);
+        icmp_push_reply(icmp_param, &fl4, &ipc, &rt);
 ende:
         ip_rt_put(rt);
 out_unlock:
         icmp_xmit_unlock(sk);
+out_free:
+        kfree(icmp_param);
 out:;
 }
 EXPORT_SYMBOL(icmp_send);