Print a notification to the console when the nonblocking pool is
initialized. Also printk a warning when a process tries reading from
/dev/urandom before it is fully initialized.
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
---
drivers/char/random.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/char/random.c b/drivers/char/random.c
index b578c03..f553600 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -655,6 +655,9 @@ retry:
r->entropy_total += nbits;
if (!r->initialized && nbits > 0) {
if (r->entropy_total > 128) {
+ if (r == &nonblocking_pool)
+ pr_notice("random: %s pool is initialized\n",
+ r->name);
r->initialized = 1;
r->entropy_total = 0;
}
@@ -1334,7 +1337,14 @@ random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
static ssize_t
urandom_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
{
- int ret = extract_entropy_user(&nonblocking_pool, buf, nbytes);
+ int ret;
+
+ if (unlikely(nonblocking_pool.initialized == 0))
+ printk_once(KERN_NOTICE "random: %s urandom read "
+ "with %d bits of entropy available\n",
+ current->comm, nonblocking_pool.entropy_total);
+
+ ret = extract_entropy_user(&nonblocking_pool, buf, nbytes);
trace_urandom_read(8 * nbytes, ENTROPY_BITS(&nonblocking_pool),
ENTROPY_BITS(&input_pool));
--
1.7.12.rc0.22.gcdd159b
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