linux-stable/crypto/pcrypt.c
Daniel Jordan 71ec65c700 crypto: pcrypt - Delay write to padata->info
[ Upstream commit 68b6dea802 ]

These three events can race when pcrypt is used multiple times in a
template ("pcrypt(pcrypt(...))"):

  1.  [taskA] The caller makes the crypto request via crypto_aead_encrypt()
  2.  [kworkerB] padata serializes the inner pcrypt request
  3.  [kworkerC] padata serializes the outer pcrypt request

3 might finish before the call to crypto_aead_encrypt() returns in 1,
resulting in two possible issues.

First, a use-after-free of the crypto request's memory when, for
example, taskA writes to the outer pcrypt request's padata->info in
pcrypt_aead_enc() after kworkerC completes the request.

Second, the outer pcrypt request overwrites the inner pcrypt request's
return code with -EINPROGRESS, making a successful request appear to
fail.  For instance, kworkerB writes the outer pcrypt request's
padata->info in pcrypt_aead_done() and then taskA overwrites it
in pcrypt_aead_enc().

Avoid both situations by delaying the write of padata->info until after
the inner crypto request's return code is checked.  This prevents the
use-after-free by not touching the crypto request's memory after the
next-inner crypto request is made, and stops padata->info from being
overwritten.

Fixes: 5068c7a883 ("crypto: pcrypt - Add pcrypt crypto parallelization wrapper")
Reported-by: syzbot+b187b77c8474f9648fae@syzkaller.appspotmail.com
Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-11-18 14:04:12 +01:00

382 lines
9.2 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* pcrypt - Parallel crypto wrapper.
*
* Copyright (C) 2009 secunet Security Networks AG
* Copyright (C) 2009 Steffen Klassert <steffen.klassert@secunet.com>
*/
#include <crypto/algapi.h>
#include <crypto/internal/aead.h>
#include <linux/atomic.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/kobject.h>
#include <linux/cpu.h>
#include <crypto/pcrypt.h>
static struct padata_instance *pencrypt;
static struct padata_instance *pdecrypt;
static struct kset *pcrypt_kset;
struct pcrypt_instance_ctx {
struct crypto_aead_spawn spawn;
struct padata_shell *psenc;
struct padata_shell *psdec;
atomic_t tfm_count;
};
struct pcrypt_aead_ctx {
struct crypto_aead *child;
unsigned int cb_cpu;
};
static inline struct pcrypt_instance_ctx *pcrypt_tfm_ictx(
struct crypto_aead *tfm)
{
return aead_instance_ctx(aead_alg_instance(tfm));
}
static int pcrypt_aead_setkey(struct crypto_aead *parent,
const u8 *key, unsigned int keylen)
{
struct pcrypt_aead_ctx *ctx = crypto_aead_ctx(parent);
return crypto_aead_setkey(ctx->child, key, keylen);
}
static int pcrypt_aead_setauthsize(struct crypto_aead *parent,
unsigned int authsize)
{
struct pcrypt_aead_ctx *ctx = crypto_aead_ctx(parent);
return crypto_aead_setauthsize(ctx->child, authsize);
}
static void pcrypt_aead_serial(struct padata_priv *padata)
{
struct pcrypt_request *preq = pcrypt_padata_request(padata);
struct aead_request *req = pcrypt_request_ctx(preq);
aead_request_complete(req->base.data, padata->info);
}
static void pcrypt_aead_done(struct crypto_async_request *areq, int err)
{
struct aead_request *req = areq->data;
struct pcrypt_request *preq = aead_request_ctx(req);
struct padata_priv *padata = pcrypt_request_padata(preq);
padata->info = err;
padata_do_serial(padata);
}
static void pcrypt_aead_enc(struct padata_priv *padata)
{
struct pcrypt_request *preq = pcrypt_padata_request(padata);
struct aead_request *req = pcrypt_request_ctx(preq);
int ret;
ret = crypto_aead_encrypt(req);
if (ret == -EINPROGRESS)
return;
padata->info = ret;
padata_do_serial(padata);
}
static int pcrypt_aead_encrypt(struct aead_request *req)
{
int err;
struct pcrypt_request *preq = aead_request_ctx(req);
struct aead_request *creq = pcrypt_request_ctx(preq);
struct padata_priv *padata = pcrypt_request_padata(preq);
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct pcrypt_aead_ctx *ctx = crypto_aead_ctx(aead);
u32 flags = aead_request_flags(req);
struct pcrypt_instance_ctx *ictx;
ictx = pcrypt_tfm_ictx(aead);
memset(padata, 0, sizeof(struct padata_priv));
padata->parallel = pcrypt_aead_enc;
padata->serial = pcrypt_aead_serial;
aead_request_set_tfm(creq, ctx->child);
aead_request_set_callback(creq, flags & ~CRYPTO_TFM_REQ_MAY_SLEEP,
pcrypt_aead_done, req);
aead_request_set_crypt(creq, req->src, req->dst,
req->cryptlen, req->iv);
aead_request_set_ad(creq, req->assoclen);
err = padata_do_parallel(ictx->psenc, padata, &ctx->cb_cpu);
if (!err)
return -EINPROGRESS;
return err;
}
static void pcrypt_aead_dec(struct padata_priv *padata)
{
struct pcrypt_request *preq = pcrypt_padata_request(padata);
struct aead_request *req = pcrypt_request_ctx(preq);
int ret;
ret = crypto_aead_decrypt(req);
if (ret == -EINPROGRESS)
return;
padata->info = ret;
padata_do_serial(padata);
}
static int pcrypt_aead_decrypt(struct aead_request *req)
{
int err;
struct pcrypt_request *preq = aead_request_ctx(req);
struct aead_request *creq = pcrypt_request_ctx(preq);
struct padata_priv *padata = pcrypt_request_padata(preq);
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct pcrypt_aead_ctx *ctx = crypto_aead_ctx(aead);
u32 flags = aead_request_flags(req);
struct pcrypt_instance_ctx *ictx;
ictx = pcrypt_tfm_ictx(aead);
memset(padata, 0, sizeof(struct padata_priv));
padata->parallel = pcrypt_aead_dec;
padata->serial = pcrypt_aead_serial;
aead_request_set_tfm(creq, ctx->child);
aead_request_set_callback(creq, flags & ~CRYPTO_TFM_REQ_MAY_SLEEP,
pcrypt_aead_done, req);
aead_request_set_crypt(creq, req->src, req->dst,
req->cryptlen, req->iv);
aead_request_set_ad(creq, req->assoclen);
err = padata_do_parallel(ictx->psdec, padata, &ctx->cb_cpu);
if (!err)
return -EINPROGRESS;
return err;
}
static int pcrypt_aead_init_tfm(struct crypto_aead *tfm)
{
int cpu, cpu_index;
struct aead_instance *inst = aead_alg_instance(tfm);
struct pcrypt_instance_ctx *ictx = aead_instance_ctx(inst);
struct pcrypt_aead_ctx *ctx = crypto_aead_ctx(tfm);
struct crypto_aead *cipher;
cpu_index = (unsigned int)atomic_inc_return(&ictx->tfm_count) %
cpumask_weight(cpu_online_mask);
ctx->cb_cpu = cpumask_first(cpu_online_mask);
for (cpu = 0; cpu < cpu_index; cpu++)
ctx->cb_cpu = cpumask_next(ctx->cb_cpu, cpu_online_mask);
cipher = crypto_spawn_aead(&ictx->spawn);
if (IS_ERR(cipher))
return PTR_ERR(cipher);
ctx->child = cipher;
crypto_aead_set_reqsize(tfm, sizeof(struct pcrypt_request) +
sizeof(struct aead_request) +
crypto_aead_reqsize(cipher));
return 0;
}
static void pcrypt_aead_exit_tfm(struct crypto_aead *tfm)
{
struct pcrypt_aead_ctx *ctx = crypto_aead_ctx(tfm);
crypto_free_aead(ctx->child);
}
static void pcrypt_free(struct aead_instance *inst)
{
struct pcrypt_instance_ctx *ctx = aead_instance_ctx(inst);
crypto_drop_aead(&ctx->spawn);
padata_free_shell(ctx->psdec);
padata_free_shell(ctx->psenc);
kfree(inst);
}
static int pcrypt_init_instance(struct crypto_instance *inst,
struct crypto_alg *alg)
{
if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
"pcrypt(%s)", alg->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
return -ENAMETOOLONG;
memcpy(inst->alg.cra_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
inst->alg.cra_priority = alg->cra_priority + 100;
inst->alg.cra_blocksize = alg->cra_blocksize;
inst->alg.cra_alignmask = alg->cra_alignmask;
return 0;
}
static int pcrypt_create_aead(struct crypto_template *tmpl, struct rtattr **tb,
struct crypto_attr_type *algt)
{
struct pcrypt_instance_ctx *ctx;
struct aead_instance *inst;
struct aead_alg *alg;
u32 mask = crypto_algt_inherited_mask(algt);
int err;
inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
if (!inst)
return -ENOMEM;
err = -ENOMEM;
ctx = aead_instance_ctx(inst);
ctx->psenc = padata_alloc_shell(pencrypt);
if (!ctx->psenc)
goto err_free_inst;
ctx->psdec = padata_alloc_shell(pdecrypt);
if (!ctx->psdec)
goto err_free_inst;
err = crypto_grab_aead(&ctx->spawn, aead_crypto_instance(inst),
crypto_attr_alg_name(tb[1]), 0, mask);
if (err)
goto err_free_inst;
alg = crypto_spawn_aead_alg(&ctx->spawn);
err = pcrypt_init_instance(aead_crypto_instance(inst), &alg->base);
if (err)
goto err_free_inst;
inst->alg.base.cra_flags |= CRYPTO_ALG_ASYNC;
inst->alg.ivsize = crypto_aead_alg_ivsize(alg);
inst->alg.maxauthsize = crypto_aead_alg_maxauthsize(alg);
inst->alg.base.cra_ctxsize = sizeof(struct pcrypt_aead_ctx);
inst->alg.init = pcrypt_aead_init_tfm;
inst->alg.exit = pcrypt_aead_exit_tfm;
inst->alg.setkey = pcrypt_aead_setkey;
inst->alg.setauthsize = pcrypt_aead_setauthsize;
inst->alg.encrypt = pcrypt_aead_encrypt;
inst->alg.decrypt = pcrypt_aead_decrypt;
inst->free = pcrypt_free;
err = aead_register_instance(tmpl, inst);
if (err) {
err_free_inst:
pcrypt_free(inst);
}
return err;
}
static int pcrypt_create(struct crypto_template *tmpl, struct rtattr **tb)
{
struct crypto_attr_type *algt;
algt = crypto_get_attr_type(tb);
if (IS_ERR(algt))
return PTR_ERR(algt);
switch (algt->type & algt->mask & CRYPTO_ALG_TYPE_MASK) {
case CRYPTO_ALG_TYPE_AEAD:
return pcrypt_create_aead(tmpl, tb, algt);
}
return -EINVAL;
}
static int pcrypt_sysfs_add(struct padata_instance *pinst, const char *name)
{
int ret;
pinst->kobj.kset = pcrypt_kset;
ret = kobject_add(&pinst->kobj, NULL, "%s", name);
if (!ret)
kobject_uevent(&pinst->kobj, KOBJ_ADD);
return ret;
}
static int pcrypt_init_padata(struct padata_instance **pinst, const char *name)
{
int ret = -ENOMEM;
*pinst = padata_alloc(name);
if (!*pinst)
return ret;
ret = pcrypt_sysfs_add(*pinst, name);
if (ret)
padata_free(*pinst);
return ret;
}
static struct crypto_template pcrypt_tmpl = {
.name = "pcrypt",
.create = pcrypt_create,
.module = THIS_MODULE,
};
static int __init pcrypt_init(void)
{
int err = -ENOMEM;
pcrypt_kset = kset_create_and_add("pcrypt", NULL, kernel_kobj);
if (!pcrypt_kset)
goto err;
err = pcrypt_init_padata(&pencrypt, "pencrypt");
if (err)
goto err_unreg_kset;
err = pcrypt_init_padata(&pdecrypt, "pdecrypt");
if (err)
goto err_deinit_pencrypt;
return crypto_register_template(&pcrypt_tmpl);
err_deinit_pencrypt:
padata_free(pencrypt);
err_unreg_kset:
kset_unregister(pcrypt_kset);
err:
return err;
}
static void __exit pcrypt_exit(void)
{
crypto_unregister_template(&pcrypt_tmpl);
padata_free(pencrypt);
padata_free(pdecrypt);
kset_unregister(pcrypt_kset);
}
subsys_initcall(pcrypt_init);
module_exit(pcrypt_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
MODULE_DESCRIPTION("Parallel crypto wrapper");
MODULE_ALIAS_CRYPTO("pcrypt");