From 6133313b3bcbd0473feac85c8a8d7ef704ff2279 Mon Sep 17 00:00:00 2001
From: "H. Peter Anvin" <hpa@zytor.com>
Date: Sun, 31 Jul 2011 13:54:50 -0700
Subject: [PATCH] random: Add support for architectural random hooks
commit 63d77173266c1791f1553e9e8ccea65dc87c4485 upstream.
Add support for architecture-specific hooks into the kernel-directed
random number generator interfaces. This patchset does not use the
architecture random number generator interfaces for the
userspace-directed interfaces (/dev/random and /dev/urandom), thus
eliminating the need to distinguish between them based on a pool
pointer.
Changes in version 3:
- Moved the hooks from extract_entropy() to get_random_bytes().
- Changes the hooks to inlines.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/char/random.c | 23 +++++++++++++++++++++--
include/linux/random.h | 13 +++++++++++++
2 files changed, 34 insertions(+), 2 deletions(-)
diff --git a/drivers/char/random.c b/drivers/char/random.c
index c35a785005b0..154eeda26db5 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -932,7 +932,21 @@ static ssize_t extract_entropy_user(struct entropy_store *r, void __user *buf,
*/
void get_random_bytes(void *buf, int nbytes)
{
- extract_entropy(&nonblocking_pool, buf, nbytes, 0, 0);
+ char *p = buf;
+
+ while (nbytes) {
+ unsigned long v;
+ int chunk = min(nbytes, (int)sizeof(unsigned long));
+
+ if (!arch_get_random_long(&v))
+ break;
+
+ memcpy(buf, &v, chunk);
+ p += chunk;
+ nbytes -= chunk;
+ }
+
+ extract_entropy(&nonblocking_pool, p, nbytes, 0, 0);
}
EXPORT_SYMBOL(get_random_bytes);
@@ -1318,9 +1332,14 @@ late_initcall(random_int_secret_init);
DEFINE_PER_CPU(__u32 [MD5_DIGEST_WORDS], get_random_int_hash);
unsigned int get_random_int(void)
{
- __u32 *hash = get_cpu_var(get_random_int_hash);
+ __u32 *hash;
unsigned int ret;
+ if (arch_get_random_int(&ret))
+ return ret;
+
+ hash = get_cpu_var(get_random_int_hash);
+
hash[0] += current->pid + jiffies + get_cycles();
md5_transform(hash, random_int_secret);
ret = hash[0];
diff --git a/include/linux/random.h b/include/linux/random.h
index d13059f3ea32..8f74538c96db 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -91,6 +91,19 @@ static inline void prandom32_seed(struct rnd_state *state, u64 seed)
state->s3 = __seed(i, 15);
}
+#ifdef CONFIG_ARCH_RANDOM
+# include <asm/archrandom.h>
+#else
+static inline int arch_get_random_long(unsigned long *v)
+{
+ return 0;
+}
+static inline int arch_get_random_int(unsigned int *v)
+{
+ return 0;
+}
+#endif
+
#endif /* __KERNEL___ */
#endif /* _LINUX_RANDOM_H */
--
2.30.9