[PATCH 3.12 079/100] random: properly align get_random_int_hash

From: Jiri Slaby
Date: Fri Aug 19 2016 - 03:17:26 EST


From: Eric Biggers <ebiggers3@xxxxxxxxx>

3.12-stable review patch. If anyone has any objections, please let me know.

===============

commit b1132deac01c2332d234fa821a70022796b79182 upstream.

get_random_long() reads from the get_random_int_hash array using an
unsigned long pointer. For this code to be guaranteed correct on all
architectures, the array must be aligned to an unsigned long boundary.

Signed-off-by: Eric Biggers <ebiggers3@xxxxxxxxx>
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
drivers/char/random.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index f6b25db16791..85e771c26488 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1465,13 +1465,15 @@ int random_int_secret_init(void)
return 0;
}

+static DEFINE_PER_CPU(__u32 [MD5_DIGEST_WORDS], get_random_int_hash)
+ __aligned(sizeof(unsigned long));
+
/*
* Get a random word for internal kernel use only. Similar to urandom but
* with the goal of minimal entropy pool depletion. As a result, the random
* value is not cryptographically secure but for several uses the cost of
* depleting entropy is too high
*/
-static DEFINE_PER_CPU(__u32 [MD5_DIGEST_WORDS], get_random_int_hash);
unsigned int get_random_int(void)
{
__u32 *hash;
--
2.9.3