Revision 6b7339f4c31ad69c8e9c0b2859276e22cf72176d authored by Kirill A. Shutemov on 06 July 2015, 20:18:37 UTC, committed by Linus Torvalds on 09 July 2015, 18:12:48 UTC
Reading page fault handler code I've noticed that under right circumstances kernel would map anonymous pages into file mappings: if the VMA doesn't have vm_ops->fault() and the VMA wasn't fully populated on ->mmap(), kernel would handle page fault to not populated pte with do_anonymous_page(). Let's change page fault handler to use do_anonymous_page() only on anonymous VMA (->vm_ops == NULL) and make sure that the VMA is not shared. For file mappings without vm_ops->fault() or shred VMA without vm_ops, page fault on pte_none() entry would lead to SIGBUS. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Willy Tarreau <w@1wt.eu> Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 883a2df
lz4hc.c
/*
* Cryptographic API.
*
* Copyright (c) 2013 Chanho Min <chanho.min@lge.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 51
* Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/crypto.h>
#include <linux/vmalloc.h>
#include <linux/lz4.h>
struct lz4hc_ctx {
void *lz4hc_comp_mem;
};
static int lz4hc_init(struct crypto_tfm *tfm)
{
struct lz4hc_ctx *ctx = crypto_tfm_ctx(tfm);
ctx->lz4hc_comp_mem = vmalloc(LZ4HC_MEM_COMPRESS);
if (!ctx->lz4hc_comp_mem)
return -ENOMEM;
return 0;
}
static void lz4hc_exit(struct crypto_tfm *tfm)
{
struct lz4hc_ctx *ctx = crypto_tfm_ctx(tfm);
vfree(ctx->lz4hc_comp_mem);
}
static int lz4hc_compress_crypto(struct crypto_tfm *tfm, const u8 *src,
unsigned int slen, u8 *dst, unsigned int *dlen)
{
struct lz4hc_ctx *ctx = crypto_tfm_ctx(tfm);
size_t tmp_len = *dlen;
int err;
err = lz4hc_compress(src, slen, dst, &tmp_len, ctx->lz4hc_comp_mem);
if (err < 0)
return -EINVAL;
*dlen = tmp_len;
return 0;
}
static int lz4hc_decompress_crypto(struct crypto_tfm *tfm, const u8 *src,
unsigned int slen, u8 *dst, unsigned int *dlen)
{
int err;
size_t tmp_len = *dlen;
size_t __slen = slen;
err = lz4_decompress_unknownoutputsize(src, __slen, dst, &tmp_len);
if (err < 0)
return -EINVAL;
*dlen = tmp_len;
return err;
}
static struct crypto_alg alg_lz4hc = {
.cra_name = "lz4hc",
.cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
.cra_ctxsize = sizeof(struct lz4hc_ctx),
.cra_module = THIS_MODULE,
.cra_list = LIST_HEAD_INIT(alg_lz4hc.cra_list),
.cra_init = lz4hc_init,
.cra_exit = lz4hc_exit,
.cra_u = { .compress = {
.coa_compress = lz4hc_compress_crypto,
.coa_decompress = lz4hc_decompress_crypto } }
};
static int __init lz4hc_mod_init(void)
{
return crypto_register_alg(&alg_lz4hc);
}
static void __exit lz4hc_mod_fini(void)
{
crypto_unregister_alg(&alg_lz4hc);
}
module_init(lz4hc_mod_init);
module_exit(lz4hc_mod_fini);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("LZ4HC Compression Algorithm");
MODULE_ALIAS_CRYPTO("lz4hc");
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