1 files changed, 26 insertions, 3 deletions

diff --git a/net/core/secure_seq.c b/net/core/secure_seq.c
index 6a2f13cee86a..8d9d05edd2eb 100644
--- a/net/core/secure_seq.c
+++ b/net/core/secure_seq.c
@@ -10,12 +10,27 @@
 
 #include <net/secure_seq.h>
 
-static u32 net_secret[MD5_MESSAGE_BYTES / 4] ____cacheline_aligned;
+#if IS_ENABLED(CONFIG_IPV6) || IS_ENABLED(CONFIG_INET)
+#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);
+        }
 }
+#endif
 
 #ifdef CONFIG_INET
 static u32 seq_scale(u32 seq)
@@ -42,6 +57,7 @@ __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 +79,7 @@ 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 +99,7 @@ __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 +114,7 @@ __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 +126,7 @@ __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 +141,7 @@ 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 +161,7 @@ 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 +186,7 @@ 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];