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random: printk notifications for urandom pool initialization

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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@mit.edu>
This commit is contained in:
Theodore Ts'o 2013-11-03 06:54:51 -05:00
parent 40db23e533
commit 301f0595c0
1 changed files with 11 additions and 1 deletions
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12
drivers/char/random.c
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@ -655,6 +655,9 @@ retry:
r->entropy_total += nbits; r->entropy_total += nbits;
if (!r->initialized && nbits > 0) { if (!r->initialized && nbits > 0) {
if (r->entropy_total > 128) { if (r->entropy_total > 128) {
if (r == &nonblocking_pool)
pr_notice("random: %s pool is initialized\n",
r->name);
r->initialized = 1; r->initialized = 1;
r->entropy_total = 0; r->entropy_total = 0;
} }
@ -1327,7 +1330,14 @@ 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)
{ {
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), trace_urandom_read(8 * nbytes, ENTROPY_BITS(&nonblocking_pool),
ENTROPY_BITS(&input_pool)); ENTROPY_BITS(&input_pool));