ipv6: drop fragmented ndisc packets by default (RFC 6980)
This patch implements RFC6980: Drop fragmented ndisc packets by default. If a fragmented ndisc packet is received the user is informed that it is possible to disable the check. Cc: Fernando Gont <fernando@gont.com.ar> Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
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committed by
David S. Miller

parent
a3a975b1df
commit
b800c3b966
@@ -204,6 +204,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = {
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.accept_source_route = 0, /* we do not accept RH0 by default. */
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.disable_ipv6 = 0,
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.accept_dad = 1,
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.suppress_frag_ndisc = 1,
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};
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static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
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@@ -241,6 +242,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
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.accept_source_route = 0, /* we do not accept RH0 by default. */
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.disable_ipv6 = 0,
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.accept_dad = 1,
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.suppress_frag_ndisc = 1,
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};
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/* IPv6 Wildcard Address and Loopback Address defined by RFC2553 */
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@@ -4188,6 +4190,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf,
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array[DEVCONF_ACCEPT_DAD] = cnf->accept_dad;
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array[DEVCONF_FORCE_TLLAO] = cnf->force_tllao;
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array[DEVCONF_NDISC_NOTIFY] = cnf->ndisc_notify;
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array[DEVCONF_SUPPRESS_FRAG_NDISC] = cnf->suppress_frag_ndisc;
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}
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static inline size_t inet6_ifla6_size(void)
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@@ -5001,6 +5004,13 @@ static struct addrconf_sysctl_table
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.mode = 0644,
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.proc_handler = proc_dointvec
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},
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{
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.procname = "suppress_frag_ndisc",
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.data = &ipv6_devconf.suppress_frag_ndisc,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec
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},
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{
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/* sentinel */
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}
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@@ -1519,10 +1519,27 @@ static void pndisc_redo(struct sk_buff *skb)
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kfree_skb(skb);
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}
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static bool ndisc_suppress_frag_ndisc(struct sk_buff *skb)
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{
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struct inet6_dev *idev = __in6_dev_get(skb->dev);
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if (!idev)
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return true;
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if (IP6CB(skb)->flags & IP6SKB_FRAGMENTED &&
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idev->cnf.suppress_frag_ndisc) {
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net_warn_ratelimited("Received fragmented ndisc packet. Carefully consider disabling suppress_frag_ndisc.\n");
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return true;
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}
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return false;
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}
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int ndisc_rcv(struct sk_buff *skb)
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{
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struct nd_msg *msg;
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if (ndisc_suppress_frag_ndisc(skb))
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return 0;
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if (skb_linearize(skb))
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return 0;
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