net: Compute protocol sequence numbers and fragment IDs using MD5.

Computers have become a lot faster since we compromised on the
partial MD4 hash which we use currently for performance reasons.

MD5 is a much safer choice, and is inline with both RFC1948 and
other ISS generators (OpenBSD, Solaris, etc.)

Furthermore, only having 24-bits of the sequence number be truly
unpredictable is a very serious limitation.  So the periodic
regeneration and 8-bit counter have been removed.  We compute and
use a full 32-bit sequence number.

For ipv6, DCCP was found to use a 32-bit truncated initial sequence
number (it needs 43-bits) and that is fixed here as well.

Reported-by: Dan Kaminsky <dan@doxpara.com>
Tested-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller
2011-08-03 20:50:44 -07:00
parent bc0b96b54a
commit 6e5714eaf7
14 changed files with 223 additions and 361 deletions

View File

@@ -29,6 +29,7 @@
#include <net/transp_v6.h>
#include <net/ip6_checksum.h>
#include <net/xfrm.h>
#include <net/secure_seq.h>
#include "dccp.h"
#include "ipv6.h"
@@ -69,13 +70,7 @@ static inline void dccp_v6_send_check(struct sock *sk, struct sk_buff *skb)
dh->dccph_checksum = dccp_v6_csum_finish(skb, &np->saddr, &np->daddr);
}
static inline __u32 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr,
__be16 sport, __be16 dport )
{
return secure_tcpv6_sequence_number(saddr, daddr, sport, dport);
}
static inline __u32 dccp_v6_init_sequence(struct sk_buff *skb)
static inline __u64 dccp_v6_init_sequence(struct sk_buff *skb)
{
return secure_dccpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
ipv6_hdr(skb)->saddr.s6_addr32,