| Date | Tue, 02 Oct 2012 00:54:36 +0200 | From | Willy Tarreau <> | Subject | [ 159/180] random: Add support for architectural random hooks |
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2.6.32-longterm review patch. If anyone has any objections, please let me know.
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From: H. Peter Anvin <hpa@zytor.com>
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> [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.gortmaker@windriver.com> Signed-off-by: Willy Tarreau <w@1wt.eu> --- 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 0adb8c8..93b3c29 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); @@ -1360,9 +1374,14 @@ 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 */ -- 1.7.2.1.45.g54fbc
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