From: Andy Lutomirski <luto@xxxxxxxxxx> commit c6f1deb158789abba02a7eba600747843eeb3a57 upstream. /dev/random and getrandom() never warn. Split the meat of urandom_read() into urandom_read_nowarn() and leave the warning code in urandom_read(). This has no effect on kernel behavior, but it makes subsequent patches more straightforward. It also makes the fact that getrandom() never warns more obvious. Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx> Link: https://lore.kernel.org/r/c87ab200588de746431d9f916501ef11e5242b13.1577088521.git.luto@xxxxxxxxxx Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/char/random.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1962,11 +1962,22 @@ random_read(struct file *file, char __us } static ssize_t +urandom_read_nowarn(struct file *file, char __user *buf, size_t nbytes, + loff_t *ppos) +{ + int ret; + + nbytes = min_t(size_t, nbytes, INT_MAX >> (ENTROPY_SHIFT + 3)); + ret = extract_crng_user(buf, nbytes); + trace_urandom_read(8 * nbytes, 0, ENTROPY_BITS(&input_pool)); + return ret; +} + +static ssize_t urandom_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) { unsigned long flags; static int maxwarn = 10; - int ret; if (!crng_ready() && maxwarn > 0) { maxwarn--; @@ -1978,10 +1989,8 @@ urandom_read(struct file *file, char __u crng_init_cnt = 0; spin_unlock_irqrestore(&primary_crng.lock, flags); } - nbytes = min_t(size_t, nbytes, INT_MAX >> (ENTROPY_SHIFT + 3)); - ret = extract_crng_user(buf, nbytes); - trace_urandom_read(8 * nbytes, 0, ENTROPY_BITS(&input_pool)); - return ret; + + return urandom_read_nowarn(file, buf, nbytes, ppos); } static unsigned int @@ -2141,7 +2150,7 @@ SYSCALL_DEFINE3(getrandom, char __user * if (unlikely(ret)) return ret; } - return urandom_read(NULL, buf, count, NULL); + return urandom_read_nowarn(NULL, buf, count, NULL); } /********************************************************************
