From 63de6fcc826404270c6c576381fd3ad92fd807f9 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Thu, 30 Oct 2014 18:27:17 +0000 Subject: drivers/net, ipv6: Select IPv6 fragment idents for virtio UFO packets [ Upstream commit 5188cd44c55db3e92cd9e77a40b5baa7ed4340f7 ] UFO is now disabled on all drivers that work with virtio net headers, but userland may try to send UFO/IPv6 packets anyway. Instead of sending with ID=0, we should select identifiers on their behalf (as we used to). Signed-off-by: Ben Hutchings Fixes: 916e4cf46d02 ("ipv6: reuse ip6_frag_id from ip6_ufo_append_data") Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv6/output_core.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) (limited to 'net') diff --git a/net/ipv6/output_core.c b/net/ipv6/output_core.c index 798eb0f79078..ae4a06be14df 100644 --- a/net/ipv6/output_core.c +++ b/net/ipv6/output_core.c @@ -3,10 +3,43 @@ * not configured or static. These functions are needed by GSO/GRO implementation. */ #include +#include #include #include #include +/* This function exists only for tap drivers that must support broken + * clients requesting UFO without specifying an IPv6 fragment ID. + * + * This is similar to ipv6_select_ident() but we use an independent hash + * seed to limit information leakage. + * + * The network header must be set before calling this. + */ +void ipv6_proxy_select_ident(struct sk_buff *skb) +{ + static u32 ip6_proxy_idents_hashrnd __read_mostly; + struct in6_addr buf[2]; + struct in6_addr *addrs; + u32 hash, id; + + addrs = skb_header_pointer(skb, + skb_network_offset(skb) + + offsetof(struct ipv6hdr, saddr), + sizeof(buf), buf); + if (!addrs) + return; + + net_get_random_once(&ip6_proxy_idents_hashrnd, + sizeof(ip6_proxy_idents_hashrnd)); + + hash = __ipv6_addr_jhash(&addrs[1], ip6_proxy_idents_hashrnd); + hash = __ipv6_addr_jhash(&addrs[0], hash); + + id = ip_idents_reserve(hash, 1); + skb_shinfo(skb)->ip6_frag_id = htonl(id); +} +EXPORT_SYMBOL_GPL(ipv6_proxy_select_ident); int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr) { -- cgit v1.2.3