random: print a warning for the first ten uninitialized random users

commit 9b4d008787 upstream.

Since systemd is consistently using /dev/urandom before it is
initialized, we can't see the other potentially dangerous users of
/dev/urandom immediately after boot.  So print the first ten such
complaints instead.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Theodore Ts'o
2016-06-13 10:10:51 -04:00
committed by popcornmix
parent e623292b74
commit 08d46758aa

View File

@@ -1460,12 +1460,16 @@ 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)
{
static int maxwarn = 10;
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);
if (unlikely(nonblocking_pool.initialized == 0) &&
maxwarn > 0) {
maxwarn--;
printk(KERN_NOTICE "random: %s: uninitialized urandom read "
"(%zd bytes read, %d bits of entropy available)\n",
current->comm, nbytes, nonblocking_pool.entropy_total);
}
nbytes = min_t(size_t, nbytes, INT_MAX >> (ENTROPY_SHIFT + 3));
ret = extract_entropy_user(&nonblocking_pool, buf, nbytes);