From: "H. Peter Anvin" <h...@zytor.com>
-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
If you see a problem with using this for longterm, please comment.
-------------------
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 <h...@linux.intel.com>
Cc: Fenghua Yu <fenghua...@intel.com>
Cc: Matt Mackall <m...@selenic.com>
Cc: Herbert Xu <herb...@gondor.apana.org.au>
Cc: "Theodore Ts'o" <ty...@mit.edu>
[PG: .34 already had "unsigned int ret" in get_random_int, so the
diffstat here is slightly smaller than that of 63d7717. ]
Signed-off-by: Paul Gortmaker <paul.gortma...@windriver.com>
---
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 1e07bbe..6da0696 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -925,7 +925,21 @@ 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);
@@ -1309,9 +1323,14 @@ 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 2948046..0bf2936 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -63,6 +63,19 @@ unsigned long randomize_range(unsigned long start, unsigned
long end, unsigned l
u32 random32(void);
void srandom32(u32 seed);
+#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 */
--
1.7.12.rc2
--
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