From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Jens Axboe <axboe@kernel.dk>,
Al Viro <viro@zeniv.linux.org.uk>,
"Jason A. Donenfeld" <Jason@zx2c4.com>
Subject: [PATCH 5.18 42/47] random: convert to using fops->read_iter()
Date: Fri, 27 May 2022 10:50:22 +0200 [thread overview]
Message-ID: <20220527084808.267747499@linuxfoundation.org> (raw)
In-Reply-To: <20220527084801.223648383@linuxfoundation.org>
From: Jens Axboe <axboe@kernel.dk>
commit 1b388e7765f2eaa137cf5d92b47ef5925ad83ced upstream.
This is a pre-requisite to wiring up splice() again for the random
and urandom drivers. It also allows us to remove the INT_MAX check in
getrandom(), because import_single_range() applies capping internally.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
[Jason: rewrote get_random_bytes_user() to simplify and also incorporate
additional suggestions from Al.]
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/char/random.c | 65 ++++++++++++++++++++++----------------------------
1 file changed, 29 insertions(+), 36 deletions(-)
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -446,13 +446,13 @@ void get_random_bytes(void *buf, size_t
}
EXPORT_SYMBOL(get_random_bytes);
-static ssize_t get_random_bytes_user(void __user *ubuf, size_t len)
+static ssize_t get_random_bytes_user(struct iov_iter *iter)
{
- size_t block_len, left, ret = 0;
u32 chacha_state[CHACHA_STATE_WORDS];
- u8 output[CHACHA_BLOCK_SIZE];
+ u8 block[CHACHA_BLOCK_SIZE];
+ size_t ret = 0, copied;
- if (!len)
+ if (unlikely(!iov_iter_count(iter)))
return 0;
/*
@@ -466,30 +466,22 @@ static ssize_t get_random_bytes_user(voi
* use chacha_state after, so we can simply return those bytes to
* the user directly.
*/
- if (len <= CHACHA_KEY_SIZE) {
- ret = len - copy_to_user(ubuf, &chacha_state[4], len);
+ if (iov_iter_count(iter) <= CHACHA_KEY_SIZE) {
+ ret = copy_to_iter(&chacha_state[4], CHACHA_KEY_SIZE, iter);
goto out_zero_chacha;
}
for (;;) {
- chacha20_block(chacha_state, output);
+ chacha20_block(chacha_state, block);
if (unlikely(chacha_state[12] == 0))
++chacha_state[13];
- block_len = min_t(size_t, len, CHACHA_BLOCK_SIZE);
- left = copy_to_user(ubuf, output, block_len);
- if (left) {
- ret += block_len - left;
+ copied = copy_to_iter(block, sizeof(block), iter);
+ ret += copied;
+ if (!iov_iter_count(iter) || copied != sizeof(block))
break;
- }
- ubuf += block_len;
- ret += block_len;
- len -= block_len;
- if (!len)
- break;
-
- BUILD_BUG_ON(PAGE_SIZE % CHACHA_BLOCK_SIZE != 0);
+ BUILD_BUG_ON(PAGE_SIZE % sizeof(block) != 0);
if (ret % PAGE_SIZE == 0) {
if (signal_pending(current))
break;
@@ -497,7 +489,7 @@ static ssize_t get_random_bytes_user(voi
}
}
- memzero_explicit(output, sizeof(output));
+ memzero_explicit(block, sizeof(block));
out_zero_chacha:
memzero_explicit(chacha_state, sizeof(chacha_state));
return ret ? ret : -EFAULT;
@@ -1265,6 +1257,10 @@ static void __cold try_to_generate_entro
SYSCALL_DEFINE3(getrandom, char __user *, ubuf, size_t, len, unsigned int, flags)
{
+ struct iov_iter iter;
+ struct iovec iov;
+ int ret;
+
if (flags & ~(GRND_NONBLOCK | GRND_RANDOM | GRND_INSECURE))
return -EINVAL;
@@ -1275,19 +1271,18 @@ SYSCALL_DEFINE3(getrandom, char __user *
if ((flags & (GRND_INSECURE | GRND_RANDOM)) == (GRND_INSECURE | GRND_RANDOM))
return -EINVAL;
- if (len > INT_MAX)
- len = INT_MAX;
-
if (!crng_ready() && !(flags & GRND_INSECURE)) {
- int ret;
-
if (flags & GRND_NONBLOCK)
return -EAGAIN;
ret = wait_for_random_bytes();
if (unlikely(ret))
return ret;
}
- return get_random_bytes_user(ubuf, len);
+
+ ret = import_single_range(READ, ubuf, len, &iov, &iter);
+ if (unlikely(ret))
+ return ret;
+ return get_random_bytes_user(&iter);
}
static __poll_t random_poll(struct file *file, poll_table *wait)
@@ -1331,8 +1326,7 @@ static ssize_t random_write(struct file
return (ssize_t)len;
}
-static ssize_t urandom_read(struct file *file, char __user *ubuf,
- size_t len, loff_t *ppos)
+static ssize_t urandom_read_iter(struct kiocb *kiocb, struct iov_iter *iter)
{
static int maxwarn = 10;
@@ -1348,23 +1342,22 @@ static ssize_t urandom_read(struct file
++urandom_warning.missed;
else if (ratelimit_disable || __ratelimit(&urandom_warning)) {
--maxwarn;
- pr_notice("%s: uninitialized urandom read (%zd bytes read)\n",
- current->comm, len);
+ pr_notice("%s: uninitialized urandom read (%zu bytes read)\n",
+ current->comm, iov_iter_count(iter));
}
}
- return get_random_bytes_user(ubuf, len);
+ return get_random_bytes_user(iter);
}
-static ssize_t random_read(struct file *file, char __user *ubuf,
- size_t len, loff_t *ppos)
+static ssize_t random_read_iter(struct kiocb *kiocb, struct iov_iter *iter)
{
int ret;
ret = wait_for_random_bytes();
if (ret != 0)
return ret;
- return get_random_bytes_user(ubuf, len);
+ return get_random_bytes_user(iter);
}
static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
@@ -1426,7 +1419,7 @@ static int random_fasync(int fd, struct
}
const struct file_operations random_fops = {
- .read = random_read,
+ .read_iter = random_read_iter,
.write = random_write,
.poll = random_poll,
.unlocked_ioctl = random_ioctl,
@@ -1436,7 +1429,7 @@ const struct file_operations random_fops
};
const struct file_operations urandom_fops = {
- .read = urandom_read,
+ .read_iter = urandom_read_iter,
.write = random_write,
.unlocked_ioctl = random_ioctl,
.compat_ioctl = compat_ptr_ioctl,
next prev parent reply other threads:[~2022-05-27 8:58 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-27 8:49 [PATCH 5.18 00/47] 5.18.1-rc1 review Greg Kroah-Hartman
2022-05-27 8:49 ` [PATCH 5.18 01/47] lockdown: also lock down previous kgdb use Greg Kroah-Hartman
2022-05-27 8:49 ` [PATCH 5.18 02/47] HID: amd_sfh: Add support for sensor discovery Greg Kroah-Hartman
2022-05-27 8:49 ` [PATCH 5.18 03/47] random: fix sysctl documentation nits Greg Kroah-Hartman
2022-05-27 8:49 ` [PATCH 5.18 04/47] init: call time_init() before rand_initialize() Greg Kroah-Hartman
2022-05-27 8:49 ` [PATCH 5.18 05/47] ia64: define get_cycles macro for arch-override Greg Kroah-Hartman
2022-05-27 8:49 ` [PATCH 5.18 06/47] s390: " Greg Kroah-Hartman
2022-05-27 8:49 ` [PATCH 5.18 07/47] parisc: " Greg Kroah-Hartman
2022-05-27 8:49 ` [PATCH 5.18 08/47] alpha: " Greg Kroah-Hartman
2022-05-27 8:49 ` [PATCH 5.18 09/47] powerpc: " Greg Kroah-Hartman
2022-05-27 8:49 ` [PATCH 5.18 10/47] timekeeping: Add raw clock fallback for random_get_entropy() Greg Kroah-Hartman
2022-05-27 8:49 ` [PATCH 5.18 11/47] m68k: use fallback for random_get_entropy() instead of zero Greg Kroah-Hartman
2022-05-27 8:49 ` [PATCH 5.18 12/47] riscv: " Greg Kroah-Hartman
2022-05-27 8:49 ` [PATCH 5.18 13/47] mips: use fallback for random_get_entropy() instead of just c0 random Greg Kroah-Hartman
2022-05-27 8:49 ` [PATCH 5.18 14/47] arm: use fallback for random_get_entropy() instead of zero Greg Kroah-Hartman
2022-05-27 8:49 ` [PATCH 5.18 15/47] nios2: " Greg Kroah-Hartman
2022-05-27 8:49 ` [PATCH 5.18 16/47] x86/tsc: Use " Greg Kroah-Hartman
2022-05-27 8:49 ` [PATCH 5.18 17/47] um: use " Greg Kroah-Hartman
2022-05-27 8:49 ` [PATCH 5.18 18/47] sparc: " Greg Kroah-Hartman
2022-05-27 8:49 ` [PATCH 5.18 19/47] xtensa: " Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 20/47] random: insist on random_get_entropy() existing in order to simplify Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 21/47] random: do not use batches when !crng_ready() Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 22/47] random: use first 128 bits of input as fast init Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 23/47] random: do not pretend to handle premature next security model Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 24/47] random: order timer entropy functions below interrupt functions Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 25/47] random: do not use input pool from hard IRQs Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 26/47] random: help compiler out with fast_mix() by using simpler arguments Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 27/47] siphash: use one source of truth for siphash permutations Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 28/47] random: use symbolic constants for crng_init states Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 29/47] random: avoid initializing twice in credit race Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 30/47] random: move initialization out of reseeding hot path Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 31/47] random: remove ratelimiting for in-kernel unseeded randomness Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 32/47] random: use proper jiffies comparison macro Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 33/47] random: handle latent entropy and command line from random_init() Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 34/47] random: credit architectural init the exact amount Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 35/47] random: use static branch for crng_ready() Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 36/47] random: remove extern from functions in header Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 37/47] random: use proper return types on get_random_{int,long}_wait() Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 38/47] random: make consistent use of buf and len Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 39/47] random: move initialization functions out of hot pages Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 40/47] random: move randomize_page() into mm where it belongs Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 41/47] random: unify batched entropy implementations Greg Kroah-Hartman
2022-05-27 8:50 ` Greg Kroah-Hartman [this message]
2022-05-27 8:50 ` [PATCH 5.18 43/47] random: convert to using fops->write_iter() Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 44/47] random: wire up fops->splice_{read,write}_iter() Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 45/47] random: check for signals after page of pool writes Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 46/47] ACPI: sysfs: Fix BERT error region memory mapping Greg Kroah-Hartman
2022-05-27 8:50 ` [PATCH 5.18 47/47] ALSA: ctxfi: Add SB046x PCI ID Greg Kroah-Hartman
2022-05-27 22:40 ` [PATCH 5.18 00/47] 5.18.1-rc1 review Guenter Roeck
2022-05-28 1:53 ` Justin Forbes
2022-05-28 2:24 ` Ron Economos
2022-05-28 2:50 ` Bagas Sanjaya
2022-05-28 11:16 ` Naresh Kamboju
2022-05-28 13:39 ` Rudi Heitbaum
2022-05-29 2:48 ` Fox Chen
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