diff options
Diffstat (limited to 'drivers/char/random.c')
| -rw-r--r-- | drivers/char/random.c | 129 |
1 files changed, 50 insertions, 79 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index 1ef26403bcc8..0ab024918907 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -313,13 +313,6 @@ static int random_read_wakeup_bits = 64; static int random_write_wakeup_bits = 28 * OUTPUT_POOL_WORDS; /* - * The minimum number of seconds between urandom pool reseeding. We - * do this to limit the amount of entropy that can be drained from the - * input pool even if there are heavy demands on /dev/urandom. - */ -static int random_min_urandom_seed = 60; - -/* * Originally, we used a primitive polynomial of degree .poolwords * over GF(2). The taps for various sizes are defined below. They * were chosen to be evenly spaced except for the last tap, which is 1 @@ -409,7 +402,6 @@ static struct poolinfo { */ static DECLARE_WAIT_QUEUE_HEAD(random_read_wait); static DECLARE_WAIT_QUEUE_HEAD(random_write_wait); -static DECLARE_WAIT_QUEUE_HEAD(urandom_init_wait); static struct fasync_struct *fasync; static DEFINE_SPINLOCK(random_ready_list_lock); @@ -467,7 +459,6 @@ struct entropy_store { int entropy_count; int entropy_total; unsigned int initialized:1; - unsigned int limit:1; unsigned int last_data_init:1; __u8 last_data[EXTRACT_SIZE]; }; @@ -485,7 +476,6 @@ static __u32 blocking_pool_data[OUTPUT_POOL_WORDS] __latent_entropy; static struct entropy_store input_pool = { .poolinfo = &poolinfo_table[0], .name = "input", - .limit = 1, .lock = __SPIN_LOCK_UNLOCKED(input_pool.lock), .pool = input_pool_data }; @@ -493,7 +483,6 @@ static struct entropy_store input_pool = { static struct entropy_store blocking_pool = { .poolinfo = &poolinfo_table[1], .name = "blocking", - .limit = 1, .pull = &input_pool, .lock = __SPIN_LOCK_UNLOCKED(blocking_pool.lock), .pool = blocking_pool_data, @@ -855,13 +844,6 @@ static void crng_reseed(struct crng_state *crng, struct entropy_store *r) spin_unlock_irqrestore(&primary_crng.lock, flags); } -static inline void maybe_reseed_primary_crng(void) -{ - if (crng_init > 2 && - time_after(jiffies, primary_crng.init_time + CRNG_RESEED_INTERVAL)) - crng_reseed(&primary_crng, &input_pool); -} - static inline void crng_wait_ready(void) { wait_event_interruptible(crng_init_wait, crng_ready()); @@ -1220,15 +1202,6 @@ static void xfer_secondary_pool(struct entropy_store *r, size_t nbytes) r->entropy_count > r->poolinfo->poolfracbits) return; - if (r->limit == 0 && random_min_urandom_seed) { - unsigned long now = jiffies; - - if (time_before(now, - r->last_pulled + random_min_urandom_seed * HZ)) - return; - r->last_pulled = now; - } - _xfer_secondary_pool(r, nbytes); } @@ -1236,8 +1209,6 @@ static void _xfer_secondary_pool(struct entropy_store *r, size_t nbytes) { __u32 tmp[OUTPUT_POOL_WORDS]; - /* For /dev/random's pool, always leave two wakeups' worth */ - int rsvd_bytes = r->limit ? 0 : random_read_wakeup_bits / 4; int bytes = nbytes; /* pull at least as much as a wakeup */ @@ -1248,7 +1219,7 @@ static void _xfer_secondary_pool(struct entropy_store *r, size_t nbytes) trace_xfer_secondary_pool(r->name, bytes * 8, nbytes * 8, ENTROPY_BITS(r), ENTROPY_BITS(r->pull)); bytes = extract_entropy(r->pull, tmp, bytes, - random_read_wakeup_bits / 8, rsvd_bytes); + random_read_wakeup_bits / 8, 0); mix_pool_bytes(r, tmp, bytes); credit_entropy_bits(r, bytes*8); } @@ -1276,7 +1247,7 @@ static void push_to_pool(struct work_struct *work) static size_t account(struct entropy_store *r, size_t nbytes, int min, int reserved) { - int entropy_count, orig; + int entropy_count, orig, have_bytes; size_t ibytes, nfrac; BUG_ON(r->entropy_count > r->poolinfo->poolfracbits); @@ -1285,14 +1256,12 @@ static size_t account(struct entropy_store *r, size_t nbytes, int min, retry: entropy_count = orig = ACCESS_ONCE(r->entropy_count); ibytes = nbytes; - /* If limited, never pull more than available */ - if (r->limit) { - int have_bytes = entropy_count >> (ENTROPY_SHIFT + 3); + /* never pull more than available */ + have_bytes = entropy_count >> (ENTROPY_SHIFT + 3); - if ((have_bytes -= reserved) < 0) - have_bytes = 0; - ibytes = min_t(size_t, ibytes, have_bytes); - } + if ((have_bytes -= reserved) < 0) + have_bytes = 0; + ibytes = min_t(size_t, ibytes, have_bytes); if (ibytes < min) ibytes = 0; @@ -1912,6 +1881,7 @@ SYSCALL_DEFINE3(getrandom, char __user *, buf, size_t, count, static int min_read_thresh = 8, min_write_thresh; static int max_read_thresh = OUTPUT_POOL_WORDS * 32; static int max_write_thresh = INPUT_POOL_WORDS * 32; +static int random_min_urandom_seed = 60; static char sysctl_bootid[16]; /* @@ -2042,63 +2012,64 @@ struct ctl_table random_table[] = { }; #endif /* CONFIG_SYSCTL */ -static u32 random_int_secret[MD5_MESSAGE_BYTES / 4] ____cacheline_aligned; - -int random_int_secret_init(void) -{ - get_random_bytes(random_int_secret, sizeof(random_int_secret)); - return 0; -} - -static DEFINE_PER_CPU(__u32 [MD5_DIGEST_WORDS], get_random_int_hash) - __aligned(sizeof(unsigned long)); +struct batched_entropy { + union { + u64 entropy_u64[CHACHA20_BLOCK_SIZE / sizeof(u64)]; + u32 entropy_u32[CHACHA20_BLOCK_SIZE / sizeof(u32)]; + }; + unsigned int position; +}; /* - * Get a random word for internal kernel use only. Similar to urandom but - * with the goal of minimal entropy pool depletion. As a result, the random - * value is not cryptographically secure but for several uses the cost of - * depleting entropy is too high + * Get a random word for internal kernel use only. The quality of the random + * number is either as good as RDRAND or as good as /dev/urandom, with the + * goal of being quite fast and not depleting entropy. */ -unsigned int get_random_int(void) +static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_u64); +u64 get_random_u64(void) { - __u32 *hash; - unsigned int ret; + u64 ret; + struct batched_entropy *batch; - if (arch_get_random_int(&ret)) +#if BITS_PER_LONG == 64 + if (arch_get_random_long((unsigned long *)&ret)) return ret; +#else + if (arch_get_random_long((unsigned long *)&ret) && + arch_get_random_long((unsigned long *)&ret + 1)) + return ret; +#endif - hash = get_cpu_var(get_random_int_hash); - - hash[0] += current->pid + jiffies + random_get_entropy(); - md5_transform(hash, random_int_secret); - ret = hash[0]; - put_cpu_var(get_random_int_hash); - + batch = &get_cpu_var(batched_entropy_u64); + if (batch->position % ARRAY_SIZE(batch->entropy_u64) == 0) { + extract_crng((u8 *)batch->entropy_u64); + batch->position = 0; + } + ret = batch->entropy_u64[batch->position++]; + put_cpu_var(batched_entropy_u64); return ret; } -EXPORT_SYMBOL(get_random_int); +EXPORT_SYMBOL(get_random_u64); -/* - * Same as get_random_int(), but returns unsigned long. - */ -unsigned long get_random_long(void) +static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_u32); +u32 get_random_u32(void) { - __u32 *hash; - unsigned long ret; + u32 ret; + struct batched_entropy *batch; - if (arch_get_random_long(&ret)) + if (arch_get_random_int(&ret)) return ret; - hash = get_cpu_var(get_random_int_hash); - - hash[0] += current->pid + jiffies + random_get_entropy(); - md5_transform(hash, random_int_secret); - ret = *(unsigned long *)hash; - put_cpu_var(get_random_int_hash); - + batch = &get_cpu_var(batched_entropy_u32); + if (batch->position % ARRAY_SIZE(batch->entropy_u32) == 0) { + extract_crng((u8 *)batch->entropy_u32); + batch->position = 0; + } + ret = batch->entropy_u32[batch->position++]; + put_cpu_var(batched_entropy_u32); return ret; } -EXPORT_SYMBOL(get_random_long); +EXPORT_SYMBOL(get_random_u32); /** * randomize_page - Generate a random, page aligned address |