secure_seq: use the 64 bits of the siphash for port offset calculation

commit b2d057560b8107c633b39aabe517ff9d93f285e3 upstream.

SipHash replaced MD5 in secure_ipv{4,6}_port_ephemeral() via commit
7cd23e5300c1 ("secure_seq: use SipHash in place of MD5"), but the output
remained truncated to 32-bit only. In order to exploit more bits from the
hash, let's make the functions return the full 64-bit of siphash_3u32().
We also make sure the port offset calculation in __inet_hash_connect()
remains done on 32-bit to avoid the need for div_u64_rem() and an extra
cost on 32-bit systems.

Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Moshe Kol <moshe.kol@mail.huji.ac.il>
Cc: Yossi Gilad <yossi.gilad@mail.huji.ac.il>
Cc: Amit Klein <aksecurity@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index fc445e7ccadf4466743f42a85cbd6bbd43512e99..c3cf2021bb3b3cb2f662e13a3d63f4ca5cbbadff 100644 (file)
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -382,7 +382,7 @@ static inline void sk_rcv_saddr_set(struct sock *sk, __be32 addr)
 }
 
 int __inet_hash_connect(struct inet_timewait_death_row *death_row,
-                       struct sock *sk, u32 port_offset,
+                       struct sock *sk, u64 port_offset,
                        int (*check_established)(struct inet_timewait_death_row *,
                                                 struct sock *, __u16,
                                                 struct inet_timewait_sock **));

diff --git a/include/net/secure_seq.h b/include/net/secure_seq.h
index 3f36d45b714a4ba295fe253dbca56e54e0dd0b32..542a80c05107441f4b685de9dd0274ea05130b19 100644 (file)
--- a/include/net/secure_seq.h
+++ b/include/net/secure_seq.h
@@ -3,8 +3,8 @@
 
 #include <linux/types.h>
 
-u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport);
-u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
+u64 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport);
+u64 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
                               __be16 dport);
 __u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr,
                                 __be16 sport, __be16 dport);

diff --git a/net/core/secure_seq.c b/net/core/secure_seq.c
index fd3ce461fbe6210ab95fbcbb4b5e6c862a262898..ed05b8277aa40466710f4aea48b9332347094bad 100644 (file)
--- a/net/core/secure_seq.c
+++ b/net/core/secure_seq.c
@@ -62,7 +62,7 @@ __u32 secure_tcpv6_sequence_number(const __be32 *saddr, const __be32 *daddr,
 }
 EXPORT_SYMBOL(secure_tcpv6_sequence_number);
 
-u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
+u64 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
                               __be16 dport)
 {
        u32 secret[MD5_MESSAGE_BYTES / 4];
@@ -102,7 +102,7 @@ __u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr,
        return seq_scale(hash[0]);
 }
 
-u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport)
+u64 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport)
 {
        u32 hash[MD5_DIGEST_WORDS];
 

diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 6dc2afaa330f9d22d32516c390c96d6df681467f..025e87ed97a2d00e368ebc62501ade8a3512657a 100644 (file)
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -382,7 +382,7 @@ not_unique:
        return -EADDRNOTAVAIL;
 }
 
-static u32 inet_sk_port_offset(const struct sock *sk)
+static u64 inet_sk_port_offset(const struct sock *sk)
 {
        const struct inet_sock *inet = inet_sk(sk);
 
@@ -549,7 +549,7 @@ EXPORT_SYMBOL_GPL(inet_unhash);
 static u32 table_perturb[1 << INET_TABLE_PERTURB_SHIFT];
 
 int __inet_hash_connect(struct inet_timewait_death_row *death_row,
-               struct sock *sk, u32 port_offset,
+               struct sock *sk, u64 port_offset,
                int (*check_established)(struct inet_timewait_death_row *,
                        struct sock *, __u16, struct inet_timewait_sock **))
 {
@@ -589,7 +589,9 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row,
        net_get_random_once(table_perturb, sizeof(table_perturb));
        index = hash_32(port_offset, INET_TABLE_PERTURB_SHIFT);
 
-       offset = (READ_ONCE(table_perturb[index]) + port_offset) % remaining;
+       offset = READ_ONCE(table_perturb[index]) + port_offset;
+       offset %= remaining;
+
        /* In first pass we try ports of @low parity.
         * inet_csk_get_port() does the opposite choice.
         */
@@ -670,7 +672,7 @@ ok:
 int inet_hash_connect(struct inet_timewait_death_row *death_row,
                      struct sock *sk)
 {
-       u32 port_offset = 0;
+       u64 port_offset = 0;
 
        if (!inet_sk(sk)->inet_num)
                port_offset = inet_sk_port_offset(sk);

diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c
index d47cab6d7c6de1afc1a69fcf186cbad76025a504..8223ac61a9fd38545257c08cf3a8780035b6a760 100644 (file)
--- a/net/ipv6/inet6_hashtables.c
+++ b/net/ipv6/inet6_hashtables.c
@@ -242,7 +242,7 @@ not_unique:
        return -EADDRNOTAVAIL;
 }
 
-static u32 inet6_sk_port_offset(const struct sock *sk)
+static u64 inet6_sk_port_offset(const struct sock *sk)
 {
        const struct inet_sock *inet = inet_sk(sk);
 
@@ -254,7 +254,7 @@ static u32 inet6_sk_port_offset(const struct sock *sk)
 int inet6_hash_connect(struct inet_timewait_death_row *death_row,
                       struct sock *sk)
 {
-       u32 port_offset = 0;
+       u64 port_offset = 0;
 
        if (!inet_sk(sk)->inet_num)
                port_offset = inet6_sk_port_offset(sk);