diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index debfe857d8f9..a2be556032c9 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -1349,6 +1349,12 @@ mldv2_unsolicited_report_interval - INTEGER MLDv2 report retransmit will take place. Default: 1000 (1 second) +suppress_frag_ndisc - INTEGER + Control RFC 6980 (Security Implications of IPv6 Fragmentation + with IPv6 Neighbor Discovery) behavior: + 1 - (default) discard fragmented neighbor discovery packets + 0 - allow fragmented neighbor discovery packets + icmp/*: ratelimit - INTEGER Limit the maximal rates for sending ICMPv6 packets. diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h index 9ac5047062c8..28ea38439313 100644 --- a/include/linux/ipv6.h +++ b/include/linux/ipv6.h @@ -50,6 +50,7 @@ struct ipv6_devconf { __s32 accept_dad; __s32 force_tllao; __s32 ndisc_notify; + __s32 suppress_frag_ndisc; void *sysctl; }; diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h index d07ac6903e59..593b0e32d956 100644 --- a/include/uapi/linux/ipv6.h +++ b/include/uapi/linux/ipv6.h @@ -162,6 +162,7 @@ enum { DEVCONF_NDISC_NOTIFY, DEVCONF_MLDV1_UNSOLICITED_REPORT_INTERVAL, DEVCONF_MLDV2_UNSOLICITED_REPORT_INTERVAL, + DEVCONF_SUPPRESS_FRAG_NDISC, DEVCONF_MAX }; diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 2d6d1793bbfe..a7183fc9bbc2 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -204,6 +204,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = { .accept_source_route = 0, /* we do not accept RH0 by default. */ .disable_ipv6 = 0, .accept_dad = 1, + .suppress_frag_ndisc = 1, }; static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { @@ -241,6 +242,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { .accept_source_route = 0, /* we do not accept RH0 by default. */ .disable_ipv6 = 0, .accept_dad = 1, + .suppress_frag_ndisc = 1, }; /* IPv6 Wildcard Address and Loopback Address defined by RFC2553 */ @@ -4188,6 +4190,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf, array[DEVCONF_ACCEPT_DAD] = cnf->accept_dad; array[DEVCONF_FORCE_TLLAO] = cnf->force_tllao; array[DEVCONF_NDISC_NOTIFY] = cnf->ndisc_notify; + array[DEVCONF_SUPPRESS_FRAG_NDISC] = cnf->suppress_frag_ndisc; } static inline size_t inet6_ifla6_size(void) @@ -5001,6 +5004,13 @@ static struct addrconf_sysctl_table .mode = 0644, .proc_handler = proc_dointvec }, + { + .procname = "suppress_frag_ndisc", + .data = &ipv6_devconf.suppress_frag_ndisc, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec + }, { /* sentinel */ } diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c index 04d31c2fbef1..41720feeaa64 100644 --- a/net/ipv6/ndisc.c +++ b/net/ipv6/ndisc.c @@ -1519,10 +1519,27 @@ static void pndisc_redo(struct sk_buff *skb) kfree_skb(skb); } +static bool ndisc_suppress_frag_ndisc(struct sk_buff *skb) +{ + struct inet6_dev *idev = __in6_dev_get(skb->dev); + + if (!idev) + return true; + if (IP6CB(skb)->flags & IP6SKB_FRAGMENTED && + idev->cnf.suppress_frag_ndisc) { + net_warn_ratelimited("Received fragmented ndisc packet. Carefully consider disabling suppress_frag_ndisc.\n"); + return true; + } + return false; +} + int ndisc_rcv(struct sk_buff *skb) { struct nd_msg *msg; + if (ndisc_suppress_frag_ndisc(skb)) + return 0; + if (skb_linearize(skb)) return 0;