s390/crypto: fix stckf loop

The store-clock-fast loop in generate_entropy() mixes (exors)
only the first 64 bytes of the initial page before doing the
first SHA256. Fix the loop to mix the store-clock-fast values
all over the page.

Signed-off-by: Harald Freudenberger <freude@linux.vnet.ibm.com>
Reported-by: David Binderman <dcb314@hotmail.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/crypto/prng.c b/arch/s390/crypto/prng.c
index 1f374b3..9d5192c 100644 (file)
--- a/arch/s390/crypto/prng.c
+++ b/arch/s390/crypto/prng.c
@@ -125,7 +125,7 @@ static int generate_entropy(u8 *ebuf, size_t nbytes)
                /* fill page with urandom bytes */
                get_random_bytes(pg, PAGE_SIZE);
                /* exor page with stckf values */
-               for (n = 0; n < sizeof(PAGE_SIZE/sizeof(u64)); n++) {
+               for (n = 0; n < PAGE_SIZE / sizeof(u64); n++) {
                        u64 *p = ((u64 *)pg) + n;
                        *p ^= get_tod_clock_fast();
                }