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authorTheodore Ts'o <tytso@mit.edu>2016-06-13 10:10:51 -0400
committerTheodore Ts'o <tytso@mit.edu>2016-06-13 11:54:26 -0400
commit9b4d008787f864f17d008c9c15bbe8a0f7e2fc24 (patch)
tree95ed8d9865986a90511e583f7f163434e09860d2 /drivers/char/random.c
parent3371f3da08cff4b75c1f2dce742d460539d6566d (diff)
downloadblackbird-op-linux-9b4d008787f864f17d008c9c15bbe8a0f7e2fc24.tar.gz
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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: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'drivers/char/random.c')
-rw-r--r--drivers/char/random.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 4e2627a8d226..d057438266bb 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1458,12 +1458,16 @@ 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);
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