diff mbox series

[v2,net,1/7] secure_seq: use the 64 bits of the siphash for port offset calculation

Message ID 20220428124001.7428-2-w@1wt.eu (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series insufficient TCP source port randomness | expand

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Context Check Description
netdev/tree_selection success Clearly marked for net
netdev/fixes_present fail Series targets non-next tree, but doesn't contain any Fixes tags
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1112 this patch: 1112
netdev/cc_maintainers warning 3 maintainers not CCed: yoshfuji@linux-ipv6.org dsahern@kernel.org pabeni@redhat.com
netdev/build_clang success Errors and warnings before: 139 this patch: 139
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1117 this patch: 1117
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 84 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Willy Tarreau April 28, 2022, 12:39 p.m. UTC 
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>
---
 include/net/inet_hashtables.h |  2 +-
 include/net/secure_seq.h      |  4 ++--
 net/core/secure_seq.c         |  4 ++--
 net/ipv4/inet_hashtables.c    | 10 ++++++----
 net/ipv6/inet6_hashtables.c   |  4 ++--
 5 files changed, 13 insertions(+), 11 deletions(-)

Comments

Jason A. Donenfeld April 29, 2022, 2:38 p.m. UTC | #1 
Hi Willy,

On Thu, Apr 28, 2022 at 02:39:55PM +0200, Willy Tarreau wrote:
> 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>
> ---
>  include/net/inet_hashtables.h |  2 +-
>  include/net/secure_seq.h      |  4 ++--
>  net/core/secure_seq.c         |  4 ++--
>  net/ipv4/inet_hashtables.c    | 10 ++++++----
>  net/ipv6/inet6_hashtables.c   |  4 ++--
>  5 files changed, 13 insertions(+), 11 deletions(-)

For the secure_seq parts:

Acked-by: Jason A. Donenfeld <Jason@zx2c4.com> # For secure_seq.[ch]

Thanks,
Jason
diff mbox series

Patch

diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index f72ec113ae56..98e1ec1a14f0 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -425,7 +425,7 @@  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 d7d2495f83c2..dac91aa38c5a 100644
--- a/include/net/secure_seq.h
+++ b/include/net/secure_seq.h
@@ -4,8 +4,8 @@ 
 
 #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_seq(__be32 saddr, __be32 daddr,
 		   __be16 sport, __be16 dport);
diff --git a/net/core/secure_seq.c b/net/core/secure_seq.c
index 9b8443774449..55aa5cc258e3 100644
--- a/net/core/secure_seq.c
+++ b/net/core/secure_seq.c
@@ -94,7 +94,7 @@  u32 secure_tcpv6_seq(const __be32 *saddr, const __be32 *daddr,
 }
 EXPORT_SYMBOL(secure_tcpv6_seq);
 
-u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
+u64 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
 			       __be16 dport)
 {
 	const struct {
@@ -142,7 +142,7 @@  u32 secure_tcp_seq(__be32 saddr, __be32 daddr,
 }
 EXPORT_SYMBOL_GPL(secure_tcp_seq);
 
-u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport)
+u64 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport)
 {
 	net_secret_init();
 	return siphash_3u32((__force u32)saddr, (__force u32)daddr,
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 17440840a791..9d24d9319f3d 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -504,7 +504,7 @@  static int __inet_check_established(struct inet_timewait_death_row *death_row,
 	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);
 
@@ -734,7 +734,7 @@  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 **))
 {
@@ -777,7 +777,9 @@  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.
 	 */
@@ -859,7 +861,7 @@  int __inet_hash_connect(struct inet_timewait_death_row *death_row,
 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 4740afecf7c6..32ccac10bd62 100644
--- a/net/ipv6/inet6_hashtables.c
+++ b/net/ipv6/inet6_hashtables.c
@@ -308,7 +308,7 @@  static int __inet6_check_established(struct inet_timewait_death_row *death_row,
 	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);
 
@@ -320,7 +320,7 @@  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);