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Commit 63d77173 authored by H. Peter Anvin's avatar H. Peter Anvin
Browse files

random: Add support for architectural random hooks 



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: default avatarH. 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>
parent 02f8c6ae

drivers/char/random.c

+22 −3
Original line number Diff line number Diff line
@@ -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);
@@ -1635,8 +1649,13 @@ DEFINE_PER_CPU(__u32 [4], get_random_int_hash); 
unsigned int get_random_int(void)

{

	struct keydata *keyptr;

	__u32 *hash = get_cpu_var(get_random_int_hash);

	int ret;

	__u32 *hash;

	unsigned int ret;



	if (arch_get_random_int(&ret))

		return ret;



	hash = get_cpu_var(get_random_int_hash);



	keyptr = get_keyptr();

	hash[0] += current->pid + jiffies + get_cycles();

include/linux/random.h

+13 −0
Original line number Diff line number Diff line
@@ -102,6 +102,19 @@ 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 */