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| author |   Andy Lutomirski <luto@kernel.org> | 2019-12-23 00:20:45 -0800 |
|---|---|---|
| committer |   Theodore Ts'o <tytso@mit.edu> | 2020-01-07 16:07:00 -0500 |
| commit | c6f1deb158789abba02a7eba600747843eeb3a57 (patch) | |
| tree | 2e8e5715d3dd2705531cf17fa13b0ce7814396df /drivers/char | |
| parent | random: Don't wake crng_init_wait when crng_init == 1 (diff) | |
| download | linux-dev-c6f1deb158789abba02a7eba600747843eeb3a57.tar.xz linux-dev-c6f1deb158789abba02a7eba600747843eeb3a57.zip | |
random: Add a urandom_read_nowait() for random APIs that don't warn
/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@kernel.org>
Link: https://lore.kernel.org/r/c87ab200588de746431d9f916501ef11e5242b13.1577088521.git.luto@kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/random.c | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index 502e37141c72..91954c0091a5 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -2020,11 +2020,22 @@ random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) } 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--; @@ -2036,10 +2047,8 @@ urandom_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) 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 __poll_t @@ -2201,7 +2210,7 @@ SYSCALL_DEFINE3(getrandom, char __user *, buf, size_t, count, if (unlikely(ret)) return ret; } - return urandom_read(NULL, buf, count, NULL); + return urandom_read_nowarn(NULL, buf, count, NULL); } /******************************************************************** |