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Commit 9b4d0087 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

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



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.

Cc: stable@kernel.org
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 3371f3da

drivers/char/random.c

+8 −4
Original line number Original line Diff line number Diff line
@@ -1458,12 +1458,16 @@ random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) 
static ssize_t

static ssize_t

urandom_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)

urandom_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)

{

{

	static int maxwarn = 10;

	int ret;

	int ret;





	if (unlikely(nonblocking_pool.initialized == 0))

	if (unlikely(nonblocking_pool.initialized == 0) &&

		printk_once(KERN_NOTICE "random: %s urandom read "

	    maxwarn > 0) {

			    "with %d bits of entropy available\n",

		maxwarn--;

			    current->comm, nonblocking_pool.entropy_total);

		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));

	nbytes = min_t(size_t, nbytes, INT_MAX >> (ENTROPY_SHIFT + 3));

	ret = extract_entropy_user(&nonblocking_pool, buf, nbytes);

	ret = extract_entropy_user(&nonblocking_pool, buf, nbytes);