Revision e700898fa075c69b3ae02b702ab57fb75e1a82ec authored by Mike Kravetz on 12 December 2022, 23:50:41 UTC, committed by Andrew Morton on 21 December 2022, 22:31:52 UTC
Commit bbff39cc6cbc ("hugetlb: allocate vma lock for all sharable vmas") removed the pmd sharable checks in the vma lock helper routines. However, it left the functional version of helper routines behind #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE. Therefore, the vma lock is not being used for sharable vmas on architectures that do not support pmd sharing. On these architectures, a potential fault/truncation race is exposed that could leave pages in a hugetlb file past i_size until the file is removed. Move the functional vma lock helpers outside the ifdef, and remove the non-functional stubs. Since the vma lock is not just for pmd sharing, rename the routine __vma_shareable_flags_pmd. Link: https://lkml.kernel.org/r/20221212235042.178355-1-mike.kravetz@oracle.com Fixes: bbff39cc6cbc ("hugetlb: allocate vma lock for all sharable vmas") Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: David Hildenbrand <david@redhat.com> Cc: James Houghton <jthoughton@google.com> Cc: Mina Almasry <almasrymina@google.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev> Cc: Peter Xu <peterx@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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jitterentropy-kcapi.c
/*
* Non-physical true random number generator based on timing jitter --
* Linux Kernel Crypto API specific code
*
* Copyright Stephan Mueller <smueller@chronox.de>, 2015
*
* 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/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <crypto/internal/rng.h>
#include "jitterentropy.h"
/***************************************************************************
* Helper function
***************************************************************************/
void *jent_zalloc(unsigned int len)
{
return kzalloc(len, GFP_KERNEL);
}
void jent_zfree(void *ptr)
{
kfree_sensitive(ptr);
}
void jent_panic(char *s)
{
panic("%s", s);
}
void jent_memcpy(void *dest, const void *src, unsigned int n)
{
memcpy(dest, src, n);
}
/*
* Obtain a high-resolution time stamp value. The time stamp is used to measure
* the execution time of a given code path and its variations. Hence, the time
* stamp must have a sufficiently high resolution.
*
* Note, if the function returns zero because a given architecture does not
* implement a high-resolution time stamp, the RNG code's runtime test
* will detect it and will not produce output.
*/
void jent_get_nstime(__u64 *out)
{
__u64 tmp = 0;
tmp = random_get_entropy();
/*
* If random_get_entropy does not return a value, i.e. it is not
* implemented for a given architecture, use a clock source.
* hoping that there are timers we can work with.
*/
if (tmp == 0)
tmp = ktime_get_ns();
*out = tmp;
}
/***************************************************************************
* Kernel crypto API interface
***************************************************************************/
struct jitterentropy {
spinlock_t jent_lock;
struct rand_data *entropy_collector;
unsigned int reset_cnt;
};
static int jent_kcapi_init(struct crypto_tfm *tfm)
{
struct jitterentropy *rng = crypto_tfm_ctx(tfm);
int ret = 0;
rng->entropy_collector = jent_entropy_collector_alloc(1, 0);
if (!rng->entropy_collector)
ret = -ENOMEM;
spin_lock_init(&rng->jent_lock);
return ret;
}
static void jent_kcapi_cleanup(struct crypto_tfm *tfm)
{
struct jitterentropy *rng = crypto_tfm_ctx(tfm);
spin_lock(&rng->jent_lock);
if (rng->entropy_collector)
jent_entropy_collector_free(rng->entropy_collector);
rng->entropy_collector = NULL;
spin_unlock(&rng->jent_lock);
}
static int jent_kcapi_random(struct crypto_rng *tfm,
const u8 *src, unsigned int slen,
u8 *rdata, unsigned int dlen)
{
struct jitterentropy *rng = crypto_rng_ctx(tfm);
int ret = 0;
spin_lock(&rng->jent_lock);
/* Return a permanent error in case we had too many resets in a row. */
if (rng->reset_cnt > (1<<10)) {
ret = -EFAULT;
goto out;
}
ret = jent_read_entropy(rng->entropy_collector, rdata, dlen);
/* Reset RNG in case of health failures */
if (ret < -1) {
pr_warn_ratelimited("Reset Jitter RNG due to health test failure: %s failure\n",
(ret == -2) ? "Repetition Count Test" :
"Adaptive Proportion Test");
rng->reset_cnt++;
ret = -EAGAIN;
} else {
rng->reset_cnt = 0;
/* Convert the Jitter RNG error into a usable error code */
if (ret == -1)
ret = -EINVAL;
}
out:
spin_unlock(&rng->jent_lock);
return ret;
}
static int jent_kcapi_reset(struct crypto_rng *tfm,
const u8 *seed, unsigned int slen)
{
return 0;
}
static struct rng_alg jent_alg = {
.generate = jent_kcapi_random,
.seed = jent_kcapi_reset,
.seedsize = 0,
.base = {
.cra_name = "jitterentropy_rng",
.cra_driver_name = "jitterentropy_rng",
.cra_priority = 100,
.cra_ctxsize = sizeof(struct jitterentropy),
.cra_module = THIS_MODULE,
.cra_init = jent_kcapi_init,
.cra_exit = jent_kcapi_cleanup,
}
};
static int __init jent_mod_init(void)
{
int ret = 0;
ret = jent_entropy_init();
if (ret) {
pr_info("jitterentropy: Initialization failed with host not compliant with requirements: %d\n", ret);
return -EFAULT;
}
return crypto_register_rng(&jent_alg);
}
static void __exit jent_mod_exit(void)
{
crypto_unregister_rng(&jent_alg);
}
module_init(jent_mod_init);
module_exit(jent_mod_exit);
MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
MODULE_DESCRIPTION("Non-physical True Random Number Generator based on CPU Jitter");
MODULE_ALIAS_CRYPTO("jitterentropy_rng");
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