This commit was manufactured by cvs2svn to create branch

[linux-2.6.git] / drivers / char / random.c

diff --git a/drivers/char/random.c b/drivers/char/random.c
index e39179f..a261179 100644 (file)
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -2483,3 +2483,36 @@ __u32 check_tcp_syn_cookie(__u32 cookie, __u32 saddr, __u32 daddr, __u16 sport,
        return (cookie - tmp[17]) & COOKIEMASK; /* Leaving the data behind */
 }
 #endif
+
+/*
+ * Get a random word:
+ */
+unsigned int get_random_int(void)
+{
+       unsigned int val = 0;
+
+       if (!exec_shield_randomize)
+               return 0;
+
+#ifdef CONFIG_X86_HAS_TSC
+       rdtscl(val);
+#endif
+       val += current->pid + jiffies + (int)&val;
+
+       /*
+        * Use IP's RNG. It suits our purpose perfectly: it re-keys itself
+        * every second, from the entropy pool (and thus creates a limited
+        * drain on it), and uses halfMD4Transform within the second. We
+        * also spice it with the TSC (if available), jiffies, PID and the
+        * stack address:
+        */
+       return secure_ip_id(val);
+}
+
+unsigned long randomize_range(unsigned long start, unsigned long end, unsigned long len)
+{
+       unsigned long range = end - len - start;
+       if (end <= start + len)
+               return 0;
+       return PAGE_ALIGN(get_random_int() % range + start);
+}