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Code Issues Releases Wiki Activity

random: make consistent usage of crng_ready()

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Rather than sometimes checking `crng_init < 2`, we should always use the
crng_ready() macro, so that should we change anything later, it's
consistent. Additionally, that macro already has a likely() around it,
which means we don't need to open code our own likely() and unlikely()
annotations.

Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jason A. Donenfeld 2022-03-08 11:20:17 -07:00
parent f5eab0e2db
commit a96cfe2d42
1 changed files with 7 additions and 12 deletions
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19
drivers/char/random.c
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@ -122,18 +122,13 @@ static void try_to_generate_entropy(void);
*/ */
int wait_for_random_bytes(void) int wait_for_random_bytes(void)
{ {
if (likely(crng_ready())) while (!crng_ready()) {
return 0;
do {
int ret; int ret;
ret = wait_event_interruptible_timeout(crng_init_wait, crng_ready(), HZ); ret = wait_event_interruptible_timeout(crng_init_wait, crng_ready(), HZ);
if (ret) if (ret)
return ret > 0 ? 0 : ret; return ret > 0 ? 0 : ret;
try_to_generate_entropy(); try_to_generate_entropy();
} while (!crng_ready()); }
return 0; return 0;
} }
EXPORT_SYMBOL(wait_for_random_bytes); EXPORT_SYMBOL(wait_for_random_bytes);
@ -288,7 +283,7 @@ static void crng_reseed(bool force)
++next_gen; ++next_gen;
WRITE_ONCE(base_crng.generation, next_gen); WRITE_ONCE(base_crng.generation, next_gen);
WRITE_ONCE(base_crng.birth, jiffies); WRITE_ONCE(base_crng.birth, jiffies);
if (crng_init < 2) { if (!crng_ready()) {
crng_init = 2; crng_init = 2;
finalize_init = true; finalize_init = true;
} }
@ -351,7 +346,7 @@ static void crng_make_state(u32 chacha_state[CHACHA_STATE_WORDS],
* ready, we do fast key erasure with the base_crng directly, because * ready, we do fast key erasure with the base_crng directly, because
* this is what crng_pre_init_inject() mutates during early init. * this is what crng_pre_init_inject() mutates during early init.
*/ */
if (unlikely(!crng_ready())) { if (!crng_ready()) {
bool ready; bool ready;
spin_lock_irqsave(&base_crng.lock, flags); spin_lock_irqsave(&base_crng.lock, flags);
@ -794,7 +789,7 @@ static void credit_entropy_bits(size_t nbits)
entropy_count = min_t(unsigned int, POOL_BITS, orig + add); entropy_count = min_t(unsigned int, POOL_BITS, orig + add);
} while (cmpxchg(&input_pool.entropy_count, orig, entropy_count) != orig); } while (cmpxchg(&input_pool.entropy_count, orig, entropy_count) != orig);
if (crng_init < 2 && entropy_count >= POOL_MIN_BITS) if (!crng_ready() && entropy_count >= POOL_MIN_BITS)
crng_reseed(false); crng_reseed(false);
} }
@ -956,7 +951,7 @@ int __init rand_initialize(void)
extract_entropy(base_crng.key, sizeof(base_crng.key)); extract_entropy(base_crng.key, sizeof(base_crng.key));
++base_crng.generation; ++base_crng.generation;
if (arch_init && trust_cpu && crng_init < 2) { if (arch_init && trust_cpu && !crng_ready()) {
crng_init = 2; crng_init = 2;
pr_notice("crng init done (trusting CPU's manufacturer)\n"); pr_notice("crng init done (trusting CPU's manufacturer)\n");
} }
@ -1558,7 +1553,7 @@ static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
case RNDRESEEDCRNG: case RNDRESEEDCRNG:
if (!capable(CAP_SYS_ADMIN)) if (!capable(CAP_SYS_ADMIN))
return -EPERM; return -EPERM;
if (crng_init < 2) if (!crng_ready())
return -ENODATA; return -ENODATA;
crng_reseed(false); crng_reseed(false);
return 0; return 0;