From 63d77173266c1791f1553e9e8ccea65dc87c4485 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Sun, 31 Jul 2011 13:54:50 -0700 Subject: [PATCH] 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: H. Peter Anvin Cc: Fenghua Yu Cc: Matt Mackall Cc: Herbert Xu Cc: "Theodore Ts'o" --- drivers/char/random.c | 25 ++++++++++++++++++++++--- include/linux/random.h | 13 +++++++++++++ 2 files changed, 35 insertions(+), 3 deletions(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index d4ddeba56682..bb587127fb9d 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); @@ -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(); diff --git a/include/linux/random.h b/include/linux/random.h index fb7ab9de5f36..079cbba39a28 100644 --- a/include/linux/random.h +++ b/include/linux/random.h @@ -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 +#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 */ -- 2.39.5