random: Add optional continuous repetition test to entropy store based rngs

[net-next-2.6.git] / drivers / char / random.c

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 8c7444857a4b97a7ec6d2a636710f12936081e68..d8a9255e1a3f1ed757d2066a528108cf033e1760 100644 (file)
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -240,6 +240,7 @@
 #include <linux/spinlock.h>
 #include <linux/percpu.h>
 #include <linux/cryptohash.h>
+#include <linux/fips.h>
 
 #ifdef CONFIG_GENERIC_HARDIRQS
 # include <linux/irq.h>
@@ -413,6 +414,7 @@ struct entropy_store {
        unsigned add_ptr;
        int entropy_count;
        int input_rotate;
+       __u8 *last_data;
 };
 
 static __u32 input_pool_data[INPUT_POOL_WORDS];
@@ -852,12 +854,21 @@ static ssize_t extract_entropy(struct entropy_store *r, void *buf,
 {
        ssize_t ret = 0, i;
        __u8 tmp[EXTRACT_SIZE];
+       unsigned long flags;
 
        xfer_secondary_pool(r, nbytes);
        nbytes = account(r, nbytes, min, reserved);
 
        while (nbytes) {
                extract_buf(r, tmp);
+
+               if (r->last_data) {
+                       spin_lock_irqsave(&r->lock, flags);
+                       if (!memcmp(tmp, r->last_data, EXTRACT_SIZE))
+                               panic("Hardware RNG duplicated output!\n");
+                       memcpy(r->last_data, tmp, EXTRACT_SIZE);
+                       spin_unlock_irqrestore(&r->lock, flags);
+               }
                i = min_t(int, nbytes, EXTRACT_SIZE);
                memcpy(buf, tmp, i);
                nbytes -= i;
@@ -940,6 +951,9 @@ static void init_std_data(struct entropy_store *r)
        now = ktime_get_real();
        mix_pool_bytes(r, &now, sizeof(now));
        mix_pool_bytes(r, utsname(), sizeof(*(utsname())));
+       /* Enable continuous test in fips mode */
+       if (fips_enabled)
+               r->last_data = kmalloc(EXTRACT_SIZE, GFP_KERNEL);
 }
 
 static int rand_initialize(void)