David Schwartz
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Jeane L. Dixon, world renowned psychic, died Saturday (1/25/97) at age 79.
There was almost universal sadness and lament throughout the world of
celebrity psychics. Contacted at her home, Dionne Warwick's spokeswoman
said that "[Miss] Warwick is beside herself -- none of us expected this to
happen".
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diff -r -u linux-2.0.29/drivers/char/random.c linux/drivers/char/random.c
--- linux-2.0.29/drivers/char/random.c Thu Nov 14 20:21:59 1996
+++ linux/drivers/char/random.c Sun Feb 23 01:42:45 1997
@@ -1345,6 +1345,139 @@
return (seq);
}
+#ifdef CONFIG_RST_COOKIES
+/*
+ * TCP security probe sequence number picking. Losely based upon
+ * secure sequence number algorithm above.
+ */
+__u32 secure_tcp_probe_number(__u32 saddr, __u32 daddr,
+ __u16 sport, __u16 dport, __u32 sseq, int validate)
+{
+ static int is_init = 0;
+ static int valid_secret[2];
+ static __u32 secret_timestamp[2];
+ static __u32 secret[2][16];
+ static int offset = 0;
+ __u32 tmp[16];
+ __u32 seq;
+
+ /*
+ * Pick a random secret the first time we open a TCP
+ * connection, and expire secretes older than 5 minutes.
+ */
+ if (is_init == 0 || jiffies-secret_timestamp[offset] > 600*HZ) {
+ if (is_init == 0) valid_secret[0] = valid_secret[1] = 0;
+ else offset = (offset+1)%2;
+ get_random_bytes(&secret[offset], sizeof(secret[offset]));
+ valid_secret[offset] = 1;
+ secret_timestamp[offset] = jiffies;
+ is_init = 1;
+ }
+
+ memcpy(tmp, secret[offset], sizeof(tmp));
+ /*
+ * Pick a unique starting offset for each
+ * TCP connection endpoints (saddr, daddr, sport, dport)
+ */
+ tmp[8]=saddr;
+ tmp[9]=daddr;
+ tmp[10]=(sport << 16) + dport;
+ HASH_TRANSFORM(tmp, tmp);
+ seq = tmp[1];
+
+ if (!validate) {
+ if (seq == sseq) seq++;
+#if 0
+ printk("init_seq(%lx, %lx, %d, %d, %d) = %d\n",
+ saddr, daddr, sport, dport, sseq, seq);
+#endif
+ return (seq);
+ } else {
+ if (seq == sseq || (seq+1) == sseq) {
+ printk("validated probe(%lx, %lx, %d, %d, %d)\n",
+ saddr, daddr, sport, dport, sseq);
+ return 1;
+ }
+ if (jiffies-secret_timestamp[(offset+1)%2] <= 1200*HZ) {
+ memcpy(tmp, secret[(offset+1)%2], sizeof(tmp));
+ tmp[8]=saddr;
+ tmp[9]=daddr;
+ tmp[10]=(sport << 16) + dport;
+ HASH_TRANSFORM(tmp, tmp);
+ seq = tmp[1];
+ if (seq == sseq || (seq+1) == sseq) {
+#ifdef 0
+ printk("validated probe(%lx, %lx, %d, %d, %d)\n",
+ saddr, daddr, sport, dport, sseq);
+#endif
+ return 1;
+ }
+ }
+#ifdef 0
+ printk("failed validation on probe(%lx, %lx, %d, %d, %d)\n",
+ saddr, daddr, sport, dport, sseq);
+#endif
+ return 0;
+ }
+}
+#endif
+
+#ifdef CONFIG_SYN_COOKIES
+/*
+ * Secure SYN cookie computation. This is the algorithm worked out by
+ * Dan Bernstien and Eric Schenk.
+ *
+ * For linux I implement the 1 minute counter by looking at the jiffies clock.
+ * The count is passed in as a parameter;
+ *
+ */
+__u32 secure_tcp_syn_cookie(__u32 saddr, __u32 daddr,
+ __u16 sport, __u16 dport, __u32 sseq, __u32 count)
+{
+ static int is_init = 0;
+ static __u32 secret[2][16];
+ __u32 tmp[16];
+ __u32 seq;
+
+ /*
+ * Pick two random secret the first time we open a TCP connection.
+ */
+ if (is_init == 0) {
+ get_random_bytes(&secret[0], sizeof(secret[0]));
+ get_random_bytes(&secret[1], sizeof(secret[1]));
+ is_init = 1;
+ }
+
+ /*
+ * Compute the secure sequence number.
+ * The output should be:
+ * MD5(sec1,saddr,sport,daddr,dport,sec1) + their sequence number
+ * + (count * 2^24)
+ * + (MD5(sec2,saddr,sport,daddr,dport,count,sec2) % 2^24).
+ * Where count increases every minute by 1.
+ */
+
+ memcpy(tmp, secret[0], sizeof(tmp));
+ tmp[8]=saddr;
+ tmp[9]=daddr;
+ tmp[10]=(sport << 16) + dport;
+ HASH_TRANSFORM(tmp, tmp);
+ seq = tmp[1];
+
+ memcpy(tmp, secret[1], sizeof(tmp));
+ tmp[8]=saddr;
+ tmp[9]=daddr;
+ tmp[10]=(sport << 16) + dport;
+ tmp[11]=count; /* minute counter */
+ HASH_TRANSFORM(tmp, tmp);
+
+ seq += sseq + (count << 24) + (tmp[1] & 0x00ffffff);
+
+ /* Zap lower 3 bits to leave room for the MSS representation */
+ return (seq & 0xfffff8);
+}
+#endif
+
#ifdef RANDOM_BENCHMARK
/*
* This is so we can do some benchmarking of the random driver, to see
diff -r -u linux-2.0.29/include/linux/random.h linux/include/linux/random.h
--- linux-2.0.29/include/linux/random.h Thu Nov 14 20:02:10 1996
+++ linux/include/linux/random.h Sun Feb 23 01:50:03 1997
@@ -55,6 +55,14 @@
extern __u32 secure_tcp_sequence_number(__u32 saddr, __u32 daddr,
__u16 sport, __u16 dport);
+#ifdef CONFIG_RST_COOKIES
+__u32 secure_tcp_probe_number(__u32 saddr, __u32 daddr,
+ __u16 sport, __u16 dport, __u32 sseq, int validate);
+#endif
+#ifdef CONFIG_SYN_COOKIES
+__u32 secure_tcp_syn_cookie(__u32 saddr, __u32 daddr,
+ __u16 sport, __u16 dport, __u32 sseq, __u32 count);
+#endif
#ifndef MODULE
extern struct file_operations random_fops, urandom_fops;