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>

5 files changed, 5 insertions, 0 deletions

diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 3c0369a3a663..984ec656b03b 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -21,6 +21,7 @@
 
 #include <net/inet_connection_sock.h>
 #include <net/inet_hashtables.h>
+#include <net/secure_seq.h>
 #include <net/ip.h>
 
 /*
diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c
index e38213817d0a..86f13c67ea85 100644
--- a/net/ipv4/inetpeer.c
+++ b/net/ipv4/inetpeer.c
@@ -19,6 +19,7 @@
 #include <linux/net.h>
 #include <net/ip.h>
 #include <net/inetpeer.h>
+#include <net/secure_seq.h>
 
 /*
  *  Theory of operations.
diff --git a/net/ipv4/netfilter/nf_nat_proto_common.c b/net/ipv4/netfilter/nf_nat_proto_common.c
index 3e61faf23a9a..f52d41ea0690 100644
--- a/net/ipv4/netfilter/nf_nat_proto_common.c
+++ b/net/ipv4/netfilter/nf_nat_proto_common.c
@@ -12,6 +12,7 @@
 #include <linux/ip.h>
 
 #include <linux/netfilter.h>
+#include <net/secure_seq.h>
 #include <net/netfilter/nf_nat.h>
 #include <net/netfilter/nf_nat_core.h>
 #include <net/netfilter/nf_nat_rule.h>
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 6afc4eb50591..e3dec1c9f09d 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -109,6 +109,7 @@
 #include <linux/sysctl.h>
 #endif
 #include <net/atmclip.h>
+#include <net/secure_seq.h>
 
 #define RT_FL_TOS(oldflp4) \
     ((u32)(oldflp4->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK)))
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 955b8e65b69e..1c12b8ec849d 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -72,6 +72,7 @@
 #include <net/timewait_sock.h>
 #include <net/xfrm.h>
 #include <net/netdma.h>
+#include <net/secure_seq.h>
 
 #include <linux/inet.h>
 #include <linux/ipv6.h>