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| author | Theodore Ts'o <tytso@mit.edu> | 2018-04-25 07:12:32 +0200 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2018-04-25 08:41:39 +0200 |
| commit | 4e00b339e264802851aff8e73cde7d24b57b18ce (patch) | |
| tree | c11287bd73bff8a7a119d7fc55c94df2f0b61745 /drivers/char/random.c | |
| parent | random: fix possible sleeping allocation from irq context (diff) | |
| download | linux-4e00b339e264802851aff8e73cde7d24b57b18ce.tar.xz linux-4e00b339e264802851aff8e73cde7d24b57b18ce.zip | |
random: rate limit unseeded randomness warnings
On systems without sufficient boot randomness, no point spamming dmesg.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
Diffstat (limited to 'drivers/char/random.c')
| -rw-r--r-- | drivers/char/random.c | 39 |
1 files changed, 34 insertions, 5 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index 721dca8db9cf..cd888d4ee605 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -261,6 +261,7 @@ #include <linux/ptrace.h> #include <linux/workqueue.h> #include <linux/irq.h> +#include <linux/ratelimit.h> #include <linux/syscalls.h> #include <linux/completion.h> #include <linux/uuid.h> @@ -438,6 +439,16 @@ static void _crng_backtrack_protect(struct crng_state *crng, static void process_random_ready_list(void); static void _get_random_bytes(void *buf, int nbytes); +static struct ratelimit_state unseeded_warning = + RATELIMIT_STATE_INIT("warn_unseeded_randomness", HZ, 3); +static struct ratelimit_state urandom_warning = + RATELIMIT_STATE_INIT("warn_urandom_randomness", HZ, 3); + +static int ratelimit_disable __read_mostly; + +module_param_named(ratelimit_disable, ratelimit_disable, int, 0644); +MODULE_PARM_DESC(ratelimit_disable, "Disable random ratelimit suppression"); + /********************************************************************** * * OS independent entropy store. Here are the functions which handle @@ -932,6 +943,18 @@ static void crng_reseed(struct crng_state *crng, struct entropy_store *r) process_random_ready_list(); wake_up_interruptible(&crng_init_wait); pr_notice("random: crng init done\n"); + if (unseeded_warning.missed) { + pr_notice("random: %d get_random_xx warning(s) missed " + "due to ratelimiting\n", + unseeded_warning.missed); + unseeded_warning.missed = 0; + } + if (urandom_warning.missed) { + pr_notice("random: %d urandom warning(s) missed " + "due to ratelimiting\n", + urandom_warning.missed); + urandom_warning.missed = 0; + } } } @@ -1572,8 +1595,9 @@ static void _warn_unseeded_randomness(const char *func_name, void *caller, #ifndef CONFIG_WARN_ALL_UNSEEDED_RANDOM print_once = true; #endif - pr_notice("random: %s called from %pS with crng_init=%d\n", - func_name, caller, crng_init); + if (__ratelimit(&unseeded_warning)) + pr_notice("random: %s called from %pS with crng_init=%d\n", + func_name, caller, crng_init); } /* @@ -1767,6 +1791,10 @@ static int rand_initialize(void) init_std_data(&blocking_pool); crng_initialize(&primary_crng); crng_global_init_time = jiffies; + if (ratelimit_disable) { + urandom_warning.interval = 0; + unseeded_warning.interval = 0; + } return 0; } early_initcall(rand_initialize); @@ -1834,9 +1862,10 @@ urandom_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) if (!crng_ready() && maxwarn > 0) { maxwarn--; - printk(KERN_NOTICE "random: %s: uninitialized urandom read " - "(%zd bytes read)\n", - current->comm, nbytes); + if (__ratelimit(&urandom_warning)) + printk(KERN_NOTICE "random: %s: uninitialized " + "urandom read (%zd bytes read)\n", + current->comm, nbytes); spin_lock_irqsave(&primary_crng.lock, flags); crng_init_cnt = 0; spin_unlock_irqrestore(&primary_crng.lock, flags); |