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![Waiman Long](/assets/img/avatar_default.png)
As said by Linus: A symmetric naming is only helpful if it implies symmetries in use. Otherwise it's actively misleading. In "kzalloc()", the z is meaningful and an important part of what the caller wants. In "kzfree()", the z is actively detrimental, because maybe in the future we really _might_ want to use that "memfill(0xdeadbeef)" or something. The "zero" part of the interface isn't even _relevant_. The main reason that kzfree() exists is to clear sensitive information that should not be leaked to other future users of the same memory objects. Rename kzfree() to kfree_sensitive() to follow the example of the recently added kvfree_sensitive() and make the intention of the API more explicit. In addition, memzero_explicit() is used to clear the memory to make sure that it won't get optimized away by the compiler. The renaming is done by using the command sequence: git grep -w --name-only kzfree |\ xargs sed -i 's/kzfree/kfree_sensitive/' followed by some editing of the kfree_sensitive() kerneldoc and adding a kzfree backward compatibility macro in slab.h. [akpm@linux-foundation.org: fs/crypto/inline_crypt.c needs linux/slab.h] [akpm@linux-foundation.org: fix fs/crypto/inline_crypt.c some more] Suggested-by: Joe Perches <joe@perches.com> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: David Howells <dhowells@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Joe Perches <joe@perches.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: David Rientjes <rientjes@google.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: "Jason A . Donenfeld" <Jason@zx2c4.com> Link: http://lkml.kernel.org/r/20200616154311.12314-3-longman@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
188 lines
4.5 KiB
C
188 lines
4.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* seqiv: Sequence Number IV Generator
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*
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* This generator generates an IV based on a sequence number by xoring it
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* with a salt. This algorithm is mainly useful for CTR and similar modes.
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*
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* Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
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*/
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#include <crypto/internal/geniv.h>
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#include <crypto/scatterwalk.h>
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#include <crypto/skcipher.h>
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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static void seqiv_aead_encrypt_complete2(struct aead_request *req, int err)
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{
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struct aead_request *subreq = aead_request_ctx(req);
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struct crypto_aead *geniv;
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if (err == -EINPROGRESS)
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return;
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if (err)
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goto out;
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geniv = crypto_aead_reqtfm(req);
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memcpy(req->iv, subreq->iv, crypto_aead_ivsize(geniv));
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out:
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kfree_sensitive(subreq->iv);
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}
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static void seqiv_aead_encrypt_complete(struct crypto_async_request *base,
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int err)
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{
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struct aead_request *req = base->data;
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seqiv_aead_encrypt_complete2(req, err);
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aead_request_complete(req, err);
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}
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static int seqiv_aead_encrypt(struct aead_request *req)
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{
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struct crypto_aead *geniv = crypto_aead_reqtfm(req);
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struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);
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struct aead_request *subreq = aead_request_ctx(req);
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crypto_completion_t compl;
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void *data;
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u8 *info;
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unsigned int ivsize = 8;
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int err;
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if (req->cryptlen < ivsize)
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return -EINVAL;
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aead_request_set_tfm(subreq, ctx->child);
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compl = req->base.complete;
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data = req->base.data;
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info = req->iv;
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if (req->src != req->dst) {
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SYNC_SKCIPHER_REQUEST_ON_STACK(nreq, ctx->sknull);
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skcipher_request_set_sync_tfm(nreq, ctx->sknull);
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skcipher_request_set_callback(nreq, req->base.flags,
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NULL, NULL);
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skcipher_request_set_crypt(nreq, req->src, req->dst,
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req->assoclen + req->cryptlen,
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NULL);
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err = crypto_skcipher_encrypt(nreq);
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if (err)
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return err;
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}
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if (unlikely(!IS_ALIGNED((unsigned long)info,
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crypto_aead_alignmask(geniv) + 1))) {
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info = kmemdup(req->iv, ivsize, req->base.flags &
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CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL :
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GFP_ATOMIC);
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if (!info)
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return -ENOMEM;
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compl = seqiv_aead_encrypt_complete;
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data = req;
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}
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aead_request_set_callback(subreq, req->base.flags, compl, data);
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aead_request_set_crypt(subreq, req->dst, req->dst,
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req->cryptlen - ivsize, info);
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aead_request_set_ad(subreq, req->assoclen + ivsize);
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crypto_xor(info, ctx->salt, ivsize);
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scatterwalk_map_and_copy(info, req->dst, req->assoclen, ivsize, 1);
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err = crypto_aead_encrypt(subreq);
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if (unlikely(info != req->iv))
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seqiv_aead_encrypt_complete2(req, err);
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return err;
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}
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static int seqiv_aead_decrypt(struct aead_request *req)
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{
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struct crypto_aead *geniv = crypto_aead_reqtfm(req);
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struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);
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struct aead_request *subreq = aead_request_ctx(req);
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crypto_completion_t compl;
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void *data;
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unsigned int ivsize = 8;
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if (req->cryptlen < ivsize + crypto_aead_authsize(geniv))
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return -EINVAL;
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aead_request_set_tfm(subreq, ctx->child);
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compl = req->base.complete;
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data = req->base.data;
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aead_request_set_callback(subreq, req->base.flags, compl, data);
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aead_request_set_crypt(subreq, req->src, req->dst,
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req->cryptlen - ivsize, req->iv);
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aead_request_set_ad(subreq, req->assoclen + ivsize);
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scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0);
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return crypto_aead_decrypt(subreq);
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}
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static int seqiv_aead_create(struct crypto_template *tmpl, struct rtattr **tb)
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{
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struct aead_instance *inst;
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int err;
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inst = aead_geniv_alloc(tmpl, tb);
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if (IS_ERR(inst))
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return PTR_ERR(inst);
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err = -EINVAL;
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if (inst->alg.ivsize != sizeof(u64))
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goto free_inst;
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inst->alg.encrypt = seqiv_aead_encrypt;
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inst->alg.decrypt = seqiv_aead_decrypt;
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inst->alg.init = aead_init_geniv;
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inst->alg.exit = aead_exit_geniv;
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inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);
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inst->alg.base.cra_ctxsize += inst->alg.ivsize;
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err = aead_register_instance(tmpl, inst);
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if (err) {
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free_inst:
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inst->free(inst);
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}
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return err;
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}
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static struct crypto_template seqiv_tmpl = {
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.name = "seqiv",
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.create = seqiv_aead_create,
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.module = THIS_MODULE,
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};
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static int __init seqiv_module_init(void)
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{
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return crypto_register_template(&seqiv_tmpl);
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}
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static void __exit seqiv_module_exit(void)
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{
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crypto_unregister_template(&seqiv_tmpl);
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}
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subsys_initcall(seqiv_module_init);
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module_exit(seqiv_module_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Sequence Number IV Generator");
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MODULE_ALIAS_CRYPTO("seqiv");
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