Revision 9c29bcd189f4ab1644b7125713602532d0aefdb7 authored by Eric Dumazet on 21 September 2018, 22:27:48 UTC, committed by David S. Miller on 24 September 2018, 04:55:25 UTC
As diagnosed by Song Liu, ndo_poll_controller() can be very dangerous on loaded hosts, since the cpu calling ndo_poll_controller() might steal all NAPI contexts (for all RX/TX queues of the NIC). This capture can last for unlimited amount of time, since one cpu is generally not able to drain all the queues under load. mlx5 uses NAPI for TX completions, so we better let core networking stack call the napi->poll() to avoid the capture. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Saeed Mahameed <saeedm@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent a24b66c
algif_rng.c
/*
* algif_rng: User-space interface for random number generators
*
* This file provides the user-space API for random number generators.
*
* Copyright (C) 2014, Stephan Mueller <smueller@chronox.de>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, and the entire permission notice in its entirety,
* including the disclaimer of warranties.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* ALTERNATIVELY, this product may be distributed under the terms of
* the GNU General Public License, in which case the provisions of the GPL2
* are required INSTEAD OF the above restrictions. (This clause is
* necessary due to a potential bad interaction between the GPL and
* the restrictions contained in a BSD-style copyright.)
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
* WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
* USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*/
#include <linux/module.h>
#include <crypto/rng.h>
#include <linux/random.h>
#include <crypto/if_alg.h>
#include <linux/net.h>
#include <net/sock.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
MODULE_DESCRIPTION("User-space interface for random number generators");
struct rng_ctx {
#define MAXSIZE 128
unsigned int len;
struct crypto_rng *drng;
};
static int rng_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
int flags)
{
struct sock *sk = sock->sk;
struct alg_sock *ask = alg_sk(sk);
struct rng_ctx *ctx = ask->private;
int err = -EFAULT;
int genlen = 0;
u8 result[MAXSIZE];
if (len == 0)
return 0;
if (len > MAXSIZE)
len = MAXSIZE;
/*
* although not strictly needed, this is a precaution against coding
* errors
*/
memset(result, 0, len);
/*
* The enforcement of a proper seeding of an RNG is done within an
* RNG implementation. Some RNGs (DRBG, krng) do not need specific
* seeding as they automatically seed. The X9.31 DRNG will return
* an error if it was not seeded properly.
*/
genlen = crypto_rng_get_bytes(ctx->drng, result, len);
if (genlen < 0)
return genlen;
err = memcpy_to_msg(msg, result, len);
memzero_explicit(result, len);
return err ? err : len;
}
static struct proto_ops algif_rng_ops = {
.family = PF_ALG,
.connect = sock_no_connect,
.socketpair = sock_no_socketpair,
.getname = sock_no_getname,
.ioctl = sock_no_ioctl,
.listen = sock_no_listen,
.shutdown = sock_no_shutdown,
.getsockopt = sock_no_getsockopt,
.mmap = sock_no_mmap,
.bind = sock_no_bind,
.accept = sock_no_accept,
.setsockopt = sock_no_setsockopt,
.sendmsg = sock_no_sendmsg,
.sendpage = sock_no_sendpage,
.release = af_alg_release,
.recvmsg = rng_recvmsg,
};
static void *rng_bind(const char *name, u32 type, u32 mask)
{
return crypto_alloc_rng(name, type, mask);
}
static void rng_release(void *private)
{
crypto_free_rng(private);
}
static void rng_sock_destruct(struct sock *sk)
{
struct alg_sock *ask = alg_sk(sk);
struct rng_ctx *ctx = ask->private;
sock_kfree_s(sk, ctx, ctx->len);
af_alg_release_parent(sk);
}
static int rng_accept_parent(void *private, struct sock *sk)
{
struct rng_ctx *ctx;
struct alg_sock *ask = alg_sk(sk);
unsigned int len = sizeof(*ctx);
ctx = sock_kmalloc(sk, len, GFP_KERNEL);
if (!ctx)
return -ENOMEM;
ctx->len = len;
/*
* No seeding done at that point -- if multiple accepts are
* done on one RNG instance, each resulting FD points to the same
* state of the RNG.
*/
ctx->drng = private;
ask->private = ctx;
sk->sk_destruct = rng_sock_destruct;
return 0;
}
static int rng_setkey(void *private, const u8 *seed, unsigned int seedlen)
{
/*
* Check whether seedlen is of sufficient size is done in RNG
* implementations.
*/
return crypto_rng_reset(private, seed, seedlen);
}
static const struct af_alg_type algif_type_rng = {
.bind = rng_bind,
.release = rng_release,
.accept = rng_accept_parent,
.setkey = rng_setkey,
.ops = &algif_rng_ops,
.name = "rng",
.owner = THIS_MODULE
};
static int __init rng_init(void)
{
return af_alg_register_type(&algif_type_rng);
}
static void __exit rng_exit(void)
{
int err = af_alg_unregister_type(&algif_type_rng);
BUG_ON(err);
}
module_init(rng_init);
module_exit(rng_exit);
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