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random: clear new batches when bringing new CPUs online

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The commit that added the new get_random_{u8,u16}() functions neglected
to update the code that clears the batches when bringing up a new CPU.
It also forgot a few comments and helper defines, so add those in too.

Fixes: 585cd5fe9f ("random: add 8-bit and 16-bit batches")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jason A. Donenfeld 2022-10-05 12:54:38 +02:00
parent d687772e6d
commit a890d1c657
2 changed files with 18 additions and 12 deletions
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28
drivers/char/random.c
View File

@ -96,8 +96,8 @@ MODULE_PARM_DESC(ratelimit_disable, "Disable random ratelimit suppression");
/*
* Returns whether or not the input pool has been seeded and thus guaranteed
* to supply cryptographically secure random numbers. This applies to: the
* /dev/urandom device, the get_random_bytes function, and the get_random_{u32,
* ,u64,int,long} family of functions.
* /dev/urandom device, the get_random_bytes function, and the get_random_{u8,
* u16,u32,u64,int,long} family of functions.
*
* Returns: true if the input pool has been seeded.
* false if the input pool has not been seeded.
@ -119,9 +119,9 @@ static void try_to_generate_entropy(void);
/*
* Wait for the input pool to be seeded and thus guaranteed to supply
* cryptographically secure random numbers. This applies to: the /dev/urandom
* device, the get_random_bytes function, and the get_random_{u32,u64,int,long}
* family of functions. Using any of these functions without first calling
* this function forfeits the guarantee of security.
* device, the get_random_bytes function, and the get_random_{u8,u16,u32,u64,
* int,long} family of functions. Using any of these functions without first
* calling this function forfeits the guarantee of security.
*
* Returns: 0 if the input pool has been seeded.
* -ERESTARTSYS if the function was interrupted by a signal.
@ -157,6 +157,8 @@ EXPORT_SYMBOL(wait_for_random_bytes);
* There are a few exported interfaces for use by other drivers:
*
* void get_random_bytes(void *buf, size_t len)
* u8 get_random_u8()
* u16 get_random_u16()
* u32 get_random_u32()
* u64 get_random_u64()
* unsigned int get_random_int()
@ -164,10 +166,10 @@ EXPORT_SYMBOL(wait_for_random_bytes);
*
* These interfaces will return the requested number of random bytes
* into the given buffer or as a return value. This is equivalent to
* a read from /dev/urandom. The u32, u64, int, and long family of
* functions may be higher performance for one-off random integers,
* because they do a bit of buffering and do not invoke reseeding
* until the buffer is emptied.
* a read from /dev/urandom. The u8, u16, u32, u64, int, and long
* family of functions may be higher performance for one-off random
* integers, because they do a bit of buffering and do not invoke
* reseeding until the buffer is emptied.
*
*********************************************************************/
@ -504,10 +506,10 @@ type get_random_ ##type(void) \
} \
EXPORT_SYMBOL(get_random_ ##type);
DEFINE_BATCHED_ENTROPY(u64)
DEFINE_BATCHED_ENTROPY(u32)
DEFINE_BATCHED_ENTROPY(u16)
DEFINE_BATCHED_ENTROPY(u8)
DEFINE_BATCHED_ENTROPY(u16)
DEFINE_BATCHED_ENTROPY(u32)
DEFINE_BATCHED_ENTROPY(u64)
#ifdef CONFIG_SMP
/*
@ -522,6 +524,8 @@ int __cold random_prepare_cpu(unsigned int cpu)
* randomness.
*/
per_cpu_ptr(&crngs, cpu)->generation = ULONG_MAX;
per_cpu_ptr(&batched_entropy_u8, cpu)->position = UINT_MAX;
per_cpu_ptr(&batched_entropy_u16, cpu)->position = UINT_MAX;
per_cpu_ptr(&batched_entropy_u32, cpu)->position = UINT_MAX;
per_cpu_ptr(&batched_entropy_u64, cpu)->position = UINT_MAX;
return 0;

2
include/linux/random.h
View File

@ -96,6 +96,8 @@ static inline int get_random_bytes_wait(void *buf, size_t nbytes)
*out = get_random_ ## name(); \
return 0; \
}
declare_get_random_var_wait(u8, u8)
declare_get_random_var_wait(u16, u16)
declare_get_random_var_wait(u32, u32)
declare_get_random_var_wait(u64, u32)
declare_get_random_var_wait(int, unsigned int)