Revision 0fb9a1abc8c97f858997e962694eb36b4517144e authored by Mathieu Desnoyers on 09 July 2018, 19:51:52 UTC, committed by Thomas Gleixner on 10 July 2018, 20:18:52 UTC
Update rseq uapi header comments to reflect that user-space need to do thread-local loads/stores from/to the struct rseq fields. As a consequence of this added requirement, the kernel does not need to perform loads/stores with single-copy atomicity. Update the comment associated to the "flags" fields to describe more accurately that it's only useful to facilitate single-stepping through rseq critical sections with debuggers. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-api@vger.kernel.org Cc: Peter Zijlstra <peterz@infradead.org> Cc: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Watson <davejwatson@fb.com> Cc: Paul Turner <pjt@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Chris Lameter <cl@linux.com> Cc: Ben Maurer <bmaurer@fb.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Joel Fernandes <joelaf@google.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Link: https://lkml.kernel.org/r/20180709195155.7654-4-mathieu.desnoyers@efficios.com
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seqiv.c
/*
* seqiv: Sequence Number IV Generator
*
* This generator generates an IV based on a sequence number by xoring it
* with a salt. This algorithm is mainly useful for CTR and similar modes.
*
* Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
*
* 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/internal/geniv.h>
#include <crypto/scatterwalk.h>
#include <crypto/skcipher.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/string.h>
static void seqiv_free(struct crypto_instance *inst);
static void seqiv_aead_encrypt_complete2(struct aead_request *req, int err)
{
struct aead_request *subreq = aead_request_ctx(req);
struct crypto_aead *geniv;
if (err == -EINPROGRESS)
return;
if (err)
goto out;
geniv = crypto_aead_reqtfm(req);
memcpy(req->iv, subreq->iv, crypto_aead_ivsize(geniv));
out:
kzfree(subreq->iv);
}
static void seqiv_aead_encrypt_complete(struct crypto_async_request *base,
int err)
{
struct aead_request *req = base->data;
seqiv_aead_encrypt_complete2(req, err);
aead_request_complete(req, err);
}
static int seqiv_aead_encrypt(struct aead_request *req)
{
struct crypto_aead *geniv = crypto_aead_reqtfm(req);
struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);
struct aead_request *subreq = aead_request_ctx(req);
crypto_completion_t compl;
void *data;
u8 *info;
unsigned int ivsize = 8;
int err;
if (req->cryptlen < ivsize)
return -EINVAL;
aead_request_set_tfm(subreq, ctx->child);
compl = req->base.complete;
data = req->base.data;
info = req->iv;
if (req->src != req->dst) {
SKCIPHER_REQUEST_ON_STACK(nreq, ctx->sknull);
skcipher_request_set_tfm(nreq, ctx->sknull);
skcipher_request_set_callback(nreq, req->base.flags,
NULL, NULL);
skcipher_request_set_crypt(nreq, req->src, req->dst,
req->assoclen + req->cryptlen,
NULL);
err = crypto_skcipher_encrypt(nreq);
if (err)
return err;
}
if (unlikely(!IS_ALIGNED((unsigned long)info,
crypto_aead_alignmask(geniv) + 1))) {
info = kmalloc(ivsize, req->base.flags &
CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL:
GFP_ATOMIC);
if (!info)
return -ENOMEM;
memcpy(info, req->iv, ivsize);
compl = seqiv_aead_encrypt_complete;
data = req;
}
aead_request_set_callback(subreq, req->base.flags, compl, data);
aead_request_set_crypt(subreq, req->dst, req->dst,
req->cryptlen - ivsize, info);
aead_request_set_ad(subreq, req->assoclen + ivsize);
crypto_xor(info, ctx->salt, ivsize);
scatterwalk_map_and_copy(info, req->dst, req->assoclen, ivsize, 1);
err = crypto_aead_encrypt(subreq);
if (unlikely(info != req->iv))
seqiv_aead_encrypt_complete2(req, err);
return err;
}
static int seqiv_aead_decrypt(struct aead_request *req)
{
struct crypto_aead *geniv = crypto_aead_reqtfm(req);
struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);
struct aead_request *subreq = aead_request_ctx(req);
crypto_completion_t compl;
void *data;
unsigned int ivsize = 8;
if (req->cryptlen < ivsize + crypto_aead_authsize(geniv))
return -EINVAL;
aead_request_set_tfm(subreq, ctx->child);
compl = req->base.complete;
data = req->base.data;
aead_request_set_callback(subreq, req->base.flags, compl, data);
aead_request_set_crypt(subreq, req->src, req->dst,
req->cryptlen - ivsize, req->iv);
aead_request_set_ad(subreq, req->assoclen + ivsize);
scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0);
return crypto_aead_decrypt(subreq);
}
static int seqiv_aead_create(struct crypto_template *tmpl, struct rtattr **tb)
{
struct aead_instance *inst;
int err;
inst = aead_geniv_alloc(tmpl, tb, 0, 0);
if (IS_ERR(inst))
return PTR_ERR(inst);
err = -EINVAL;
if (inst->alg.ivsize != sizeof(u64))
goto free_inst;
inst->alg.encrypt = seqiv_aead_encrypt;
inst->alg.decrypt = seqiv_aead_decrypt;
inst->alg.init = aead_init_geniv;
inst->alg.exit = aead_exit_geniv;
inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);
inst->alg.base.cra_ctxsize += inst->alg.ivsize;
err = aead_register_instance(tmpl, inst);
if (err)
goto free_inst;
out:
return err;
free_inst:
aead_geniv_free(inst);
goto out;
}
static int seqiv_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);
if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & CRYPTO_ALG_TYPE_MASK)
return -EINVAL;
return seqiv_aead_create(tmpl, tb);
}
static void seqiv_free(struct crypto_instance *inst)
{
aead_geniv_free(aead_instance(inst));
}
static struct crypto_template seqiv_tmpl = {
.name = "seqiv",
.create = seqiv_create,
.free = seqiv_free,
.module = THIS_MODULE,
};
static int __init seqiv_module_init(void)
{
return crypto_register_template(&seqiv_tmpl);
}
static void __exit seqiv_module_exit(void)
{
crypto_unregister_template(&seqiv_tmpl);
}
module_init(seqiv_module_init);
module_exit(seqiv_module_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Sequence Number IV Generator");
MODULE_ALIAS_CRYPTO("seqiv");
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