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