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ip: ip_options_compile() resilient to NULL skb route

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Scot Doyle demonstrated ip_options_compile() could be called with an skb
without an attached route, using a setup involving a bridge, netfilter,
and forged IP packets.

Let's make ip_options_compile() and ip_options_rcv_srr() a bit more
robust, instead of changing bridge/netfilter code.

With help from Hiroaki SHIMODA.

Reported-by: Scot Doyle <lkml@scotdoyle.com>
Tested-by: Scot Doyle <lkml@scotdoyle.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Hiroaki SHIMODA <shimoda.hiroaki@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2011-04-14 05:55:37 +00:00 committed by David S. Miller
parent 49b4947aae
commit c65353daf1
1 changed files with 3 additions and 3 deletions
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6
net/ipv4/ip_options.c
View file

@ -329,7 +329,7 @@ int ip_options_compile(struct net *net,
pp_ptr = optptr + 2; pp_ptr = optptr + 2;
goto error; goto error;
} }
if (skb) { if (rt) {
memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4); memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4);
opt->is_changed = 1; opt->is_changed = 1;
} }
@ -371,7 +371,7 @@ int ip_options_compile(struct net *net,
goto error; goto error;
} }
opt->ts = optptr - iph; opt->ts = optptr - iph;
if (skb) { if (rt) {
memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4); memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4);
timeptr = (__be32*)&optptr[optptr[2]+3]; timeptr = (__be32*)&optptr[optptr[2]+3];
} }
@ -603,7 +603,7 @@ int ip_options_rcv_srr(struct sk_buff *skb)
unsigned long orefdst; unsigned long orefdst;
int err; int err;
if (!opt->srr) if (!opt->srr || !rt)
return 0; return 0;
if (skb->pkt_type != PACKET_HOST) if (skb->pkt_type != PACKET_HOST)