From: Andy Lutomirski <luto@kernel.org>
To: Ted Ts'o <tytso@mit.edu>
Cc: LKML <linux-kernel@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>,
Kees Cook <keescook@chromium.org>,
"Jason A. Donenfeld" <Jason@zx2c4.com>,
"Ahmed S. Darwish" <darwish.07@gmail.com>,
Lennart Poettering <mzxreary@0pointer.de>,
"Eric W. Biederman" <ebiederm@xmission.com>,
"Alexander E. Patrakov" <patrakov@gmail.com>,
Michael Kerrisk <mtk.manpages@gmail.com>,
Willy Tarreau <w@1wt.eu>, Matthew Garrett <mjg59@srcf.ucam.org>,
Ext4 Developers List <linux-ext4@vger.kernel.org>,
linux-man <linux-man@vger.kernel.org>,
Stephan Mueller <smueller@chronox.de>,
Andy Lutomirski <luto@kernel.org>
Subject: [PATCH v3 2/8] random: Add a urandom_read_nowait() for random APIs that don't warn
Date: Mon, 23 Dec 2019 00:20:45 -0800 [thread overview]
Message-ID: <c87ab200588de746431d9f916501ef11e5242b13.1577088521.git.luto@kernel.org> (raw)
In-Reply-To: <cover.1577088521.git.luto@kernel.org>
/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>
---
drivers/char/random.c | 21 +++++++++++++++------
1 file changed, 15 insertions(+), 6 deletions(-)
diff --git a/drivers/char/random.c b/drivers/char/random.c
index c6252a3a4aec..7b46751772e5 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -2018,12 +2018,23 @@ random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
return _random_read(file->f_flags & O_NONBLOCK, buf, nbytes);
}
+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--;
@@ -2035,10 +2046,8 @@ 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
@@ -2200,7 +2209,7 @@ 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);
}
/********************************************************************
--
2.23.0
next prev parent reply other threads:[~2019-12-23 8:20 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-23 8:20 [PATCH v3 0/8] Rework random blocking Andy Lutomirski
2019-12-23 8:20 ` [PATCH v3 1/8] random: Don't wake crng_init_wait when crng_init == 1 Andy Lutomirski
2020-01-07 20:42 ` Theodore Y. Ts'o
2019-12-23 8:20 ` Andy Lutomirski [this message]
2020-01-07 20:43 ` [PATCH v3 2/8] random: Add a urandom_read_nowait() for random APIs that don't warn Theodore Y. Ts'o
2019-12-23 8:20 ` [PATCH v3 3/8] random: Add GRND_INSECURE to return best-effort non-cryptographic bytes Andy Lutomirski
2020-01-07 20:44 ` Theodore Y. Ts'o
2019-12-23 8:20 ` [PATCH v3 4/8] random: Ignore GRND_RANDOM in getentropy(2) Andy Lutomirski
2020-01-07 20:44 ` Theodore Y. Ts'o
2019-12-23 8:20 ` [PATCH v3 5/8] random: Make /dev/random be almost like /dev/urandom Andy Lutomirski
2020-01-07 21:02 ` Theodore Y. Ts'o
2019-12-23 8:20 ` [PATCH v3 6/8] random: Remove the blocking pool Andy Lutomirski
2020-01-07 21:03 ` Theodore Y. Ts'o
2019-12-23 8:20 ` [PATCH v3 7/8] random: Delete code to pull data into pools Andy Lutomirski
2020-01-07 21:03 ` Theodore Y. Ts'o
2019-12-23 8:20 ` [PATCH v3 8/8] random: Remove kernel.random.read_wakeup_threshold Andy Lutomirski
2020-01-07 21:04 ` Theodore Y. Ts'o
2019-12-26 9:29 ` [PATCH v3 0/8] Rework random blocking Stephan Müller
2019-12-26 10:03 ` Matthew Garrett
2019-12-26 11:40 ` Stephan Mueller
2019-12-26 11:12 ` Andy Lutomirski
2019-12-26 12:03 ` Stephan Mueller
2019-12-26 12:46 ` Andy Lutomirski
2019-12-27 9:55 ` Stephan Mueller
2019-12-26 14:04 ` Theodore Y. Ts'o
2019-12-26 23:29 ` Andy Lutomirski
2019-12-27 10:29 ` Stephan Mueller
2019-12-27 13:04 ` Theodore Y. Ts'o
2019-12-27 21:22 ` Stephan Mueller
2019-12-27 22:08 ` Theodore Y. Ts'o
2019-12-28 2:06 ` Andy Lutomirski
2019-12-29 14:49 ` Theodore Y. Ts'o
2019-12-29 15:08 ` Andy Lutomirski
2019-12-28 7:01 ` Willy Tarreau
[not found] ` <20191227220857.GD70060-3s7WtUTddSA@public.gmane.org>
2020-01-09 22:02 ` Kurt Roeckx
[not found] ` <20200109220230.GA39185-burXGKnpAKGzQB+pC5nmwQ@public.gmane.org>
2020-01-09 22:40 ` Theodore Y. Ts'o
[not found] ` <20200109224011.GD41242-3s7WtUTddSA@public.gmane.org>
2020-01-09 23:02 ` Kurt Roeckx
[not found] ` <20200109230237.GA2992-burXGKnpAKGzQB+pC5nmwQ@public.gmane.org>
2020-01-10 7:53 ` Stephan Mueller
2020-01-10 0:30 ` Andy Lutomirski
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