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authorEric Dumazet <eric.dumazet@gmail.com>2011-07-21 21:25:58 -0700
committerDavid S. Miller <davem@davemloft.net>2011-07-21 21:25:58 -0700
commit87c48fa3b4630905f98268dde838ee43626a060c (patch)
tree1374b52ed0514682f836cfa0a6a683eb549c9613 /include
parent21efcfa0ff27776902a8a15e810147be4d937d69 (diff)
ipv6: make fragment identifications less predictable
IPv6 fragment identification generation is way beyond what we use for IPv4 : It uses a single generator. Its not scalable and allows DOS attacks. Now inetpeer is IPv6 aware, we can use it to provide a more secure and scalable frag ident generator (per destination, instead of system wide) This patch : 1) defines a new secure_ipv6_id() helper 2) extends inet_getid() to provide 32bit results 3) extends ipv6_select_ident() with a new dest parameter Reported-by: Fernando Gont <fernando@gont.com.ar> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
-rw-r--r--include/linux/random.h1
-rw-r--r--include/net/inetpeer.h13
-rw-r--r--include/net/ipv6.h12
3 files changed, 12 insertions, 14 deletions
diff --git a/include/linux/random.h b/include/linux/random.h
index fb7ab9de5f3..ce29a040c8d 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -58,6 +58,7 @@ extern void get_random_bytes(void *buf, int nbytes);
void generate_random_uuid(unsigned char uuid_out[16]);
extern __u32 secure_ip_id(__be32 daddr);
+extern __u32 secure_ipv6_id(const __be32 daddr[4]);
extern u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport);
extern u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
__be16 dport);
diff --git a/include/net/inetpeer.h b/include/net/inetpeer.h
index 39d123081e7..4233e6f9841 100644
--- a/include/net/inetpeer.h
+++ b/include/net/inetpeer.h
@@ -71,7 +71,7 @@ static inline bool inet_metrics_new(const struct inet_peer *p)
}
/* can be called with or without local BH being disabled */
-struct inet_peer *inet_getpeer(struct inetpeer_addr *daddr, int create);
+struct inet_peer *inet_getpeer(const struct inetpeer_addr *daddr, int create);
static inline struct inet_peer *inet_getpeer_v4(__be32 v4daddr, int create)
{
@@ -106,11 +106,18 @@ static inline void inet_peer_refcheck(const struct inet_peer *p)
/* can be called with or without local BH being disabled */
-static inline __u16 inet_getid(struct inet_peer *p, int more)
+static inline int inet_getid(struct inet_peer *p, int more)
{
+ int old, new;
more++;
inet_peer_refcheck(p);
- return atomic_add_return(more, &p->ip_id_count) - more;
+ do {
+ old = atomic_read(&p->ip_id_count);
+ new = old + more;
+ if (!new)
+ new = 1;
+ } while (atomic_cmpxchg(&p->ip_id_count, old, new) != old);
+ return new;
}
#endif /* _NET_INETPEER_H */
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index c033ed00df7..3b5ac1fbff3 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -463,17 +463,7 @@ static inline int ipv6_addr_diff(const struct in6_addr *a1, const struct in6_add
return __ipv6_addr_diff(a1, a2, sizeof(struct in6_addr));
}
-static __inline__ void ipv6_select_ident(struct frag_hdr *fhdr)
-{
- static u32 ipv6_fragmentation_id = 1;
- static DEFINE_SPINLOCK(ip6_id_lock);
-
- spin_lock_bh(&ip6_id_lock);
- fhdr->identification = htonl(ipv6_fragmentation_id);
- if (++ipv6_fragmentation_id == 0)
- ipv6_fragmentation_id = 1;
- spin_unlock_bh(&ip6_id_lock);
-}
+extern void ipv6_select_ident(struct frag_hdr *fhdr, struct rt6_info *rt);
/*
* Prototypes exported by ipv6