Revision 4969c1192d15afa3389e7ae3302096ff684ba655 authored by Andrea Arcangeli on 09 September 2010, 23:37:52 UTC, committed by Linus Torvalds on 10 September 2010, 01:57:24 UTC
The pte_same check is reliable only if the swap entry remains pinned (by the page lock on swapcache). We've also to ensure the swapcache isn't removed before we take the lock as try_to_free_swap won't care about the page pin. One of the possible impacts of this patch is that a KSM-shared page can point to the anon_vma of another process, which could exit before the page is freed. This can leave a page with a pointer to a recycled anon_vma object, or worse, a pointer to something that is no longer an anon_vma. [riel@redhat.com: changelog help] Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Hugh Dickins <hughd@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 7c5367f
ctr.c
/*
* CTR: Counter mode
*
* (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
*/
#include <crypto/algapi.h>
#include <crypto/ctr.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
struct crypto_ctr_ctx {
struct crypto_cipher *child;
};
struct crypto_rfc3686_ctx {
struct crypto_blkcipher *child;
u8 nonce[CTR_RFC3686_NONCE_SIZE];
};
static int crypto_ctr_setkey(struct crypto_tfm *parent, const u8 *key,
unsigned int keylen)
{
struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(parent);
struct crypto_cipher *child = ctx->child;
int err;
crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
CRYPTO_TFM_REQ_MASK);
err = crypto_cipher_setkey(child, key, keylen);
crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
CRYPTO_TFM_RES_MASK);
return err;
}
static void crypto_ctr_crypt_final(struct blkcipher_walk *walk,
struct crypto_cipher *tfm)
{
unsigned int bsize = crypto_cipher_blocksize(tfm);
unsigned long alignmask = crypto_cipher_alignmask(tfm);
u8 *ctrblk = walk->iv;
u8 tmp[bsize + alignmask];
u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1);
u8 *src = walk->src.virt.addr;
u8 *dst = walk->dst.virt.addr;
unsigned int nbytes = walk->nbytes;
crypto_cipher_encrypt_one(tfm, keystream, ctrblk);
crypto_xor(keystream, src, nbytes);
memcpy(dst, keystream, nbytes);
crypto_inc(ctrblk, bsize);
}
static int crypto_ctr_crypt_segment(struct blkcipher_walk *walk,
struct crypto_cipher *tfm)
{
void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
crypto_cipher_alg(tfm)->cia_encrypt;
unsigned int bsize = crypto_cipher_blocksize(tfm);
u8 *ctrblk = walk->iv;
u8 *src = walk->src.virt.addr;
u8 *dst = walk->dst.virt.addr;
unsigned int nbytes = walk->nbytes;
do {
/* create keystream */
fn(crypto_cipher_tfm(tfm), dst, ctrblk);
crypto_xor(dst, src, bsize);
/* increment counter in counterblock */
crypto_inc(ctrblk, bsize);
src += bsize;
dst += bsize;
} while ((nbytes -= bsize) >= bsize);
return nbytes;
}
static int crypto_ctr_crypt_inplace(struct blkcipher_walk *walk,
struct crypto_cipher *tfm)
{
void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
crypto_cipher_alg(tfm)->cia_encrypt;
unsigned int bsize = crypto_cipher_blocksize(tfm);
unsigned long alignmask = crypto_cipher_alignmask(tfm);
unsigned int nbytes = walk->nbytes;
u8 *ctrblk = walk->iv;
u8 *src = walk->src.virt.addr;
u8 tmp[bsize + alignmask];
u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1);
do {
/* create keystream */
fn(crypto_cipher_tfm(tfm), keystream, ctrblk);
crypto_xor(src, keystream, bsize);
/* increment counter in counterblock */
crypto_inc(ctrblk, bsize);
src += bsize;
} while ((nbytes -= bsize) >= bsize);
return nbytes;
}
static int crypto_ctr_crypt(struct blkcipher_desc *desc,
struct scatterlist *dst, struct scatterlist *src,
unsigned int nbytes)
{
struct blkcipher_walk walk;
struct crypto_blkcipher *tfm = desc->tfm;
struct crypto_ctr_ctx *ctx = crypto_blkcipher_ctx(tfm);
struct crypto_cipher *child = ctx->child;
unsigned int bsize = crypto_cipher_blocksize(child);
int err;
blkcipher_walk_init(&walk, dst, src, nbytes);
err = blkcipher_walk_virt_block(desc, &walk, bsize);
while (walk.nbytes >= bsize) {
if (walk.src.virt.addr == walk.dst.virt.addr)
nbytes = crypto_ctr_crypt_inplace(&walk, child);
else
nbytes = crypto_ctr_crypt_segment(&walk, child);
err = blkcipher_walk_done(desc, &walk, nbytes);
}
if (walk.nbytes) {
crypto_ctr_crypt_final(&walk, child);
err = blkcipher_walk_done(desc, &walk, 0);
}
return err;
}
static int crypto_ctr_init_tfm(struct crypto_tfm *tfm)
{
struct crypto_instance *inst = (void *)tfm->__crt_alg;
struct crypto_spawn *spawn = crypto_instance_ctx(inst);
struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
struct crypto_cipher *cipher;
cipher = crypto_spawn_cipher(spawn);
if (IS_ERR(cipher))
return PTR_ERR(cipher);
ctx->child = cipher;
return 0;
}
static void crypto_ctr_exit_tfm(struct crypto_tfm *tfm)
{
struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
crypto_free_cipher(ctx->child);
}
static struct crypto_instance *crypto_ctr_alloc(struct rtattr **tb)
{
struct crypto_instance *inst;
struct crypto_alg *alg;
int err;
err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
if (err)
return ERR_PTR(err);
alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER,
CRYPTO_ALG_TYPE_MASK);
if (IS_ERR(alg))
return ERR_CAST(alg);
/* Block size must be >= 4 bytes. */
err = -EINVAL;
if (alg->cra_blocksize < 4)
goto out_put_alg;
/* If this is false we'd fail the alignment of crypto_inc. */
if (alg->cra_blocksize % 4)
goto out_put_alg;
inst = crypto_alloc_instance("ctr", alg);
if (IS_ERR(inst))
goto out;
inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
inst->alg.cra_priority = alg->cra_priority;
inst->alg.cra_blocksize = 1;
inst->alg.cra_alignmask = alg->cra_alignmask | (__alignof__(u32) - 1);
inst->alg.cra_type = &crypto_blkcipher_type;
inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
inst->alg.cra_ctxsize = sizeof(struct crypto_ctr_ctx);
inst->alg.cra_init = crypto_ctr_init_tfm;
inst->alg.cra_exit = crypto_ctr_exit_tfm;
inst->alg.cra_blkcipher.setkey = crypto_ctr_setkey;
inst->alg.cra_blkcipher.encrypt = crypto_ctr_crypt;
inst->alg.cra_blkcipher.decrypt = crypto_ctr_crypt;
inst->alg.cra_blkcipher.geniv = "chainiv";
out:
crypto_mod_put(alg);
return inst;
out_put_alg:
inst = ERR_PTR(err);
goto out;
}
static void crypto_ctr_free(struct crypto_instance *inst)
{
crypto_drop_spawn(crypto_instance_ctx(inst));
kfree(inst);
}
static struct crypto_template crypto_ctr_tmpl = {
.name = "ctr",
.alloc = crypto_ctr_alloc,
.free = crypto_ctr_free,
.module = THIS_MODULE,
};
static int crypto_rfc3686_setkey(struct crypto_tfm *parent, const u8 *key,
unsigned int keylen)
{
struct crypto_rfc3686_ctx *ctx = crypto_tfm_ctx(parent);
struct crypto_blkcipher *child = ctx->child;
int err;
/* the nonce is stored in bytes at end of key */
if (keylen < CTR_RFC3686_NONCE_SIZE)
return -EINVAL;
memcpy(ctx->nonce, key + (keylen - CTR_RFC3686_NONCE_SIZE),
CTR_RFC3686_NONCE_SIZE);
keylen -= CTR_RFC3686_NONCE_SIZE;
crypto_blkcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
crypto_blkcipher_set_flags(child, crypto_tfm_get_flags(parent) &
CRYPTO_TFM_REQ_MASK);
err = crypto_blkcipher_setkey(child, key, keylen);
crypto_tfm_set_flags(parent, crypto_blkcipher_get_flags(child) &
CRYPTO_TFM_RES_MASK);
return err;
}
static int crypto_rfc3686_crypt(struct blkcipher_desc *desc,
struct scatterlist *dst,
struct scatterlist *src, unsigned int nbytes)
{
struct crypto_blkcipher *tfm = desc->tfm;
struct crypto_rfc3686_ctx *ctx = crypto_blkcipher_ctx(tfm);
struct crypto_blkcipher *child = ctx->child;
unsigned long alignmask = crypto_blkcipher_alignmask(tfm);
u8 ivblk[CTR_RFC3686_BLOCK_SIZE + alignmask];
u8 *iv = PTR_ALIGN(ivblk + 0, alignmask + 1);
u8 *info = desc->info;
int err;
/* set up counter block */
memcpy(iv, ctx->nonce, CTR_RFC3686_NONCE_SIZE);
memcpy(iv + CTR_RFC3686_NONCE_SIZE, info, CTR_RFC3686_IV_SIZE);
/* initialize counter portion of counter block */
*(__be32 *)(iv + CTR_RFC3686_NONCE_SIZE + CTR_RFC3686_IV_SIZE) =
cpu_to_be32(1);
desc->tfm = child;
desc->info = iv;
err = crypto_blkcipher_encrypt_iv(desc, dst, src, nbytes);
desc->tfm = tfm;
desc->info = info;
return err;
}
static int crypto_rfc3686_init_tfm(struct crypto_tfm *tfm)
{
struct crypto_instance *inst = (void *)tfm->__crt_alg;
struct crypto_spawn *spawn = crypto_instance_ctx(inst);
struct crypto_rfc3686_ctx *ctx = crypto_tfm_ctx(tfm);
struct crypto_blkcipher *cipher;
cipher = crypto_spawn_blkcipher(spawn);
if (IS_ERR(cipher))
return PTR_ERR(cipher);
ctx->child = cipher;
return 0;
}
static void crypto_rfc3686_exit_tfm(struct crypto_tfm *tfm)
{
struct crypto_rfc3686_ctx *ctx = crypto_tfm_ctx(tfm);
crypto_free_blkcipher(ctx->child);
}
static struct crypto_instance *crypto_rfc3686_alloc(struct rtattr **tb)
{
struct crypto_instance *inst;
struct crypto_alg *alg;
int err;
err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
if (err)
return ERR_PTR(err);
alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_BLKCIPHER,
CRYPTO_ALG_TYPE_MASK);
err = PTR_ERR(alg);
if (IS_ERR(alg))
return ERR_PTR(err);
/* We only support 16-byte blocks. */
err = -EINVAL;
if (alg->cra_blkcipher.ivsize != CTR_RFC3686_BLOCK_SIZE)
goto out_put_alg;
/* Not a stream cipher? */
if (alg->cra_blocksize != 1)
goto out_put_alg;
inst = crypto_alloc_instance("rfc3686", alg);
if (IS_ERR(inst))
goto out;
inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
inst->alg.cra_priority = alg->cra_priority;
inst->alg.cra_blocksize = 1;
inst->alg.cra_alignmask = alg->cra_alignmask;
inst->alg.cra_type = &crypto_blkcipher_type;
inst->alg.cra_blkcipher.ivsize = CTR_RFC3686_IV_SIZE;
inst->alg.cra_blkcipher.min_keysize = alg->cra_blkcipher.min_keysize
+ CTR_RFC3686_NONCE_SIZE;
inst->alg.cra_blkcipher.max_keysize = alg->cra_blkcipher.max_keysize
+ CTR_RFC3686_NONCE_SIZE;
inst->alg.cra_blkcipher.geniv = "seqiv";
inst->alg.cra_ctxsize = sizeof(struct crypto_rfc3686_ctx);
inst->alg.cra_init = crypto_rfc3686_init_tfm;
inst->alg.cra_exit = crypto_rfc3686_exit_tfm;
inst->alg.cra_blkcipher.setkey = crypto_rfc3686_setkey;
inst->alg.cra_blkcipher.encrypt = crypto_rfc3686_crypt;
inst->alg.cra_blkcipher.decrypt = crypto_rfc3686_crypt;
out:
crypto_mod_put(alg);
return inst;
out_put_alg:
inst = ERR_PTR(err);
goto out;
}
static struct crypto_template crypto_rfc3686_tmpl = {
.name = "rfc3686",
.alloc = crypto_rfc3686_alloc,
.free = crypto_ctr_free,
.module = THIS_MODULE,
};
static int __init crypto_ctr_module_init(void)
{
int err;
err = crypto_register_template(&crypto_ctr_tmpl);
if (err)
goto out;
err = crypto_register_template(&crypto_rfc3686_tmpl);
if (err)
goto out_drop_ctr;
out:
return err;
out_drop_ctr:
crypto_unregister_template(&crypto_ctr_tmpl);
goto out;
}
static void __exit crypto_ctr_module_exit(void)
{
crypto_unregister_template(&crypto_rfc3686_tmpl);
crypto_unregister_template(&crypto_ctr_tmpl);
}
module_init(crypto_ctr_module_init);
module_exit(crypto_ctr_module_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("CTR Counter block mode");
MODULE_ALIAS("rfc3686");
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