forked from KFire-Android/kernel_omap_otter-common
-
Notifications
You must be signed in to change notification settings - Fork 1
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
[CRYPTO] seqiv: Add 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. This patch also sets it as the default IV generator for ctr. Signed-off-by: Herbert Xu <[email protected]>
- Loading branch information
Showing
4 changed files
with
198 additions
and
0 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,186 @@ | ||
/* | ||
* 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 <[email protected]> | ||
* | ||
* 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/skcipher.h> | ||
#include <linux/err.h> | ||
#include <linux/init.h> | ||
#include <linux/kernel.h> | ||
#include <linux/module.h> | ||
#include <linux/random.h> | ||
#include <linux/spinlock.h> | ||
#include <linux/string.h> | ||
|
||
struct seqiv_ctx { | ||
spinlock_t lock; | ||
u8 salt[] __attribute__ ((aligned(__alignof__(u32)))); | ||
}; | ||
|
||
static void seqiv_complete2(struct skcipher_givcrypt_request *req, int err) | ||
{ | ||
struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req); | ||
struct crypto_ablkcipher *geniv; | ||
|
||
if (err == -EINPROGRESS) | ||
return; | ||
|
||
if (err) | ||
goto out; | ||
|
||
geniv = skcipher_givcrypt_reqtfm(req); | ||
memcpy(req->creq.info, subreq->info, crypto_ablkcipher_ivsize(geniv)); | ||
|
||
out: | ||
kfree(subreq->info); | ||
} | ||
|
||
static void seqiv_complete(struct crypto_async_request *base, int err) | ||
{ | ||
struct skcipher_givcrypt_request *req = base->data; | ||
|
||
seqiv_complete2(req, err); | ||
skcipher_givcrypt_complete(req, err); | ||
} | ||
|
||
static int seqiv_givencrypt(struct skcipher_givcrypt_request *req) | ||
{ | ||
struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req); | ||
struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv); | ||
struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req); | ||
crypto_completion_t complete; | ||
void *data; | ||
u8 *info; | ||
__be64 seq; | ||
unsigned int ivsize; | ||
unsigned int len; | ||
int err; | ||
|
||
ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv)); | ||
|
||
complete = req->creq.base.complete; | ||
data = req->creq.base.data; | ||
info = req->creq.info; | ||
|
||
ivsize = crypto_ablkcipher_ivsize(geniv); | ||
|
||
if (unlikely(!IS_ALIGNED((unsigned long)info, | ||
crypto_ablkcipher_alignmask(geniv) + 1))) { | ||
info = kmalloc(ivsize, req->creq.base.flags & | ||
CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL: | ||
GFP_ATOMIC); | ||
if (!info) | ||
return -ENOMEM; | ||
|
||
complete = seqiv_complete; | ||
data = req; | ||
} | ||
|
||
ablkcipher_request_set_callback(subreq, req->creq.base.flags, complete, | ||
data); | ||
ablkcipher_request_set_crypt(subreq, req->creq.src, req->creq.dst, | ||
req->creq.nbytes, info); | ||
|
||
len = ivsize; | ||
if (ivsize > sizeof(u64)) { | ||
memset(info, 0, ivsize - sizeof(u64)); | ||
len = sizeof(u64); | ||
} | ||
seq = cpu_to_be64(req->seq); | ||
memcpy(info + ivsize - len, &seq, len); | ||
crypto_xor(info, ctx->salt, ivsize); | ||
|
||
memcpy(req->giv, info, ivsize); | ||
|
||
err = crypto_ablkcipher_encrypt(subreq); | ||
if (unlikely(info != req->creq.info)) | ||
seqiv_complete2(req, err); | ||
return err; | ||
} | ||
|
||
static int seqiv_givencrypt_first(struct skcipher_givcrypt_request *req) | ||
{ | ||
struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req); | ||
struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv); | ||
|
||
spin_lock_bh(&ctx->lock); | ||
if (crypto_ablkcipher_crt(geniv)->givencrypt != seqiv_givencrypt_first) | ||
goto unlock; | ||
|
||
crypto_ablkcipher_crt(geniv)->givencrypt = seqiv_givencrypt; | ||
get_random_bytes(ctx->salt, crypto_ablkcipher_ivsize(geniv)); | ||
|
||
unlock: | ||
spin_unlock_bh(&ctx->lock); | ||
|
||
return seqiv_givencrypt(req); | ||
} | ||
|
||
static int seqiv_init(struct crypto_tfm *tfm) | ||
{ | ||
struct crypto_ablkcipher *geniv = __crypto_ablkcipher_cast(tfm); | ||
struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv); | ||
|
||
spin_lock_init(&ctx->lock); | ||
|
||
tfm->crt_ablkcipher.reqsize = sizeof(struct ablkcipher_request); | ||
|
||
return skcipher_geniv_init(tfm); | ||
} | ||
|
||
static struct crypto_template seqiv_tmpl; | ||
|
||
static struct crypto_instance *seqiv_alloc(struct rtattr **tb) | ||
{ | ||
struct crypto_instance *inst; | ||
|
||
inst = skcipher_geniv_alloc(&seqiv_tmpl, tb, 0, 0); | ||
if (IS_ERR(inst)) | ||
goto out; | ||
|
||
inst->alg.cra_ablkcipher.givencrypt = seqiv_givencrypt_first; | ||
|
||
inst->alg.cra_init = seqiv_init; | ||
inst->alg.cra_exit = skcipher_geniv_exit; | ||
|
||
inst->alg.cra_alignmask |= __alignof__(u32) - 1; | ||
|
||
inst->alg.cra_ctxsize = sizeof(struct seqiv_ctx); | ||
inst->alg.cra_ctxsize += inst->alg.cra_ablkcipher.ivsize; | ||
|
||
out: | ||
return inst; | ||
} | ||
|
||
static struct crypto_template seqiv_tmpl = { | ||
.name = "seqiv", | ||
.alloc = seqiv_alloc, | ||
.free = skcipher_geniv_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"); |