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Date: Tue, 24 Sep 2013 06:19:57 -0700
From: Eric Dumazet <eric.dumazet@...il.com>
To: Hannes Frederic Sowa <hannes@...essinduktion.org>
Cc: Tom Herbert <therbert@...gle.com>, davem@...emloft.net,
netdev@...r.kernel.org, jesse.brandeburg@...el.com
Subject: [PATCH] net: net_secret should not depend on TCP
From: Eric Dumazet <edumazet@...gle.com>
A host might need net_secret[] and never open a single socket.
Problem added in commit aebda156a570782
("net: defer net_secret[] initialization")
Based on prior patch from Hannes Frederic Sowa.
Reported-by: Hannes Frederic Sowa <hannes@...essinduktion.org>
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
include/net/secure_seq.h | 1 -
net/core/secure_seq.c | 27 ++++++++++++++++++++++++---
net/ipv4/af_inet.c | 4 +---
3 files changed, 25 insertions(+), 7 deletions(-)
diff --git a/include/net/secure_seq.h b/include/net/secure_seq.h
index 6ca975b..c2e542b 100644
--- a/include/net/secure_seq.h
+++ b/include/net/secure_seq.h
@@ -3,7 +3,6 @@
#include <linux/types.h>
-extern void net_secret_init(void);
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);
diff --git a/net/core/secure_seq.c b/net/core/secure_seq.c
index 6a2f13c..3f1ec15 100644
--- a/net/core/secure_seq.c
+++ b/net/core/secure_seq.c
@@ -10,11 +10,24 @@
#include <net/secure_seq.h>
-static u32 net_secret[MD5_MESSAGE_BYTES / 4] ____cacheline_aligned;
+#define NET_SECRET_SIZE (MD5_MESSAGE_BYTES / 4)
-void net_secret_init(void)
+static u32 net_secret[NET_SECRET_SIZE] ____cacheline_aligned;
+
+static void net_secret_init(void)
{
- get_random_bytes(net_secret, sizeof(net_secret));
+ u32 tmp;
+ int i;
+
+ if (likely(net_secret[0]))
+ return;
+
+ for (i = NET_SECRET_SIZE; i > 0;) {
+ do {
+ get_random_bytes(&tmp, sizeof(tmp));
+ } while (!tmp);
+ cmpxchg(&net_secret[--i], 0, tmp);
+ }
}
#ifdef CONFIG_INET
@@ -42,6 +55,7 @@ __u32 secure_tcpv6_sequence_number(const __be32 *saddr, const __be32 *daddr,
u32 hash[MD5_DIGEST_WORDS];
u32 i;
+ net_secret_init();
memcpy(hash, saddr, 16);
for (i = 0; i < 4; i++)
secret[i] = net_secret[i] + (__force u32)daddr[i];
@@ -63,6 +77,7 @@ u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
u32 hash[MD5_DIGEST_WORDS];
u32 i;
+ net_secret_init();
memcpy(hash, saddr, 16);
for (i = 0; i < 4; i++)
secret[i] = net_secret[i] + (__force u32) daddr[i];
@@ -82,6 +97,7 @@ __u32 secure_ip_id(__be32 daddr)
{
u32 hash[MD5_DIGEST_WORDS];
+ net_secret_init();
hash[0] = (__force __u32) daddr;
hash[1] = net_secret[13];
hash[2] = net_secret[14];
@@ -96,6 +112,7 @@ __u32 secure_ipv6_id(const __be32 daddr[4])
{
__u32 hash[4];
+ net_secret_init();
memcpy(hash, daddr, 16);
md5_transform(hash, net_secret);
@@ -107,6 +124,7 @@ __u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr,
{
u32 hash[MD5_DIGEST_WORDS];
+ net_secret_init();
hash[0] = (__force u32)saddr;
hash[1] = (__force u32)daddr;
hash[2] = ((__force u16)sport << 16) + (__force u16)dport;
@@ -121,6 +139,7 @@ u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport)
{
u32 hash[MD5_DIGEST_WORDS];
+ net_secret_init();
hash[0] = (__force u32)saddr;
hash[1] = (__force u32)daddr;
hash[2] = (__force u32)dport ^ net_secret[14];
@@ -140,6 +159,7 @@ u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr,
u32 hash[MD5_DIGEST_WORDS];
u64 seq;
+ net_secret_init();
hash[0] = (__force u32)saddr;
hash[1] = (__force u32)daddr;
hash[2] = ((__force u16)sport << 16) + (__force u16)dport;
@@ -164,6 +184,7 @@ u64 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr,
u64 seq;
u32 i;
+ net_secret_init();
memcpy(hash, saddr, 16);
for (i = 0; i < 4; i++)
secret[i] = net_secret[i] + daddr[i];
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 7a1874b..cfeb85c 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -263,10 +263,8 @@ void build_ehash_secret(void)
get_random_bytes(&rnd, sizeof(rnd));
} while (rnd == 0);
- if (cmpxchg(&inet_ehash_secret, 0, rnd) == 0) {
+ if (cmpxchg(&inet_ehash_secret, 0, rnd) == 0)
get_random_bytes(&ipv6_hash_secret, sizeof(ipv6_hash_secret));
- net_secret_init();
- }
}
EXPORT_SYMBOL(build_ehash_secret);
--
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