linux/crypto/ahash.c
Mathias Krause 9a5467bf7b crypto: user - fix info leaks in report API
Three errors resulting in kernel memory disclosure:

1/ The structures used for the netlink based crypto algorithm report API
are located on the stack. As snprintf() does not fill the remainder of
the buffer with null bytes, those stack bytes will be disclosed to users
of the API. Switch to strncpy() to fix this.

2/ crypto_report_one() does not initialize all field of struct
crypto_user_alg. Fix this to fix the heap info leak.

3/ For the module name we should copy only as many bytes as
module_name() returns -- not as much as the destination buffer could
hold. But the current code does not and therefore copies random data
from behind the end of the module name, as the module name is always
shorter than CRYPTO_MAX_ALG_NAME.

Also switch to use strncpy() to copy the algorithm's name and
driver_name. They are strings, after all.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2013-02-19 20:27:03 +08:00

534 lines
13 KiB
C

/*
* Asynchronous Cryptographic Hash operations.
*
* This is the asynchronous version of hash.c with notification of
* completion via a callback.
*
* Copyright (c) 2008 Loc Ho <lho@amcc.com>
*
* 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/hash.h>
#include <crypto/scatterwalk.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/cryptouser.h>
#include <net/netlink.h>
#include "internal.h"
struct ahash_request_priv {
crypto_completion_t complete;
void *data;
u8 *result;
void *ubuf[] CRYPTO_MINALIGN_ATTR;
};
static inline struct ahash_alg *crypto_ahash_alg(struct crypto_ahash *hash)
{
return container_of(crypto_hash_alg_common(hash), struct ahash_alg,
halg);
}
static int hash_walk_next(struct crypto_hash_walk *walk)
{
unsigned int alignmask = walk->alignmask;
unsigned int offset = walk->offset;
unsigned int nbytes = min(walk->entrylen,
((unsigned int)(PAGE_SIZE)) - offset);
walk->data = kmap_atomic(walk->pg);
walk->data += offset;
if (offset & alignmask) {
unsigned int unaligned = alignmask + 1 - (offset & alignmask);
if (nbytes > unaligned)
nbytes = unaligned;
}
walk->entrylen -= nbytes;
return nbytes;
}
static int hash_walk_new_entry(struct crypto_hash_walk *walk)
{
struct scatterlist *sg;
sg = walk->sg;
walk->pg = sg_page(sg);
walk->offset = sg->offset;
walk->entrylen = sg->length;
if (walk->entrylen > walk->total)
walk->entrylen = walk->total;
walk->total -= walk->entrylen;
return hash_walk_next(walk);
}
int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
{
unsigned int alignmask = walk->alignmask;
unsigned int nbytes = walk->entrylen;
walk->data -= walk->offset;
if (nbytes && walk->offset & alignmask && !err) {
walk->offset = ALIGN(walk->offset, alignmask + 1);
walk->data += walk->offset;
nbytes = min(nbytes,
((unsigned int)(PAGE_SIZE)) - walk->offset);
walk->entrylen -= nbytes;
return nbytes;
}
kunmap_atomic(walk->data);
crypto_yield(walk->flags);
if (err)
return err;
if (nbytes) {
walk->offset = 0;
walk->pg++;
return hash_walk_next(walk);
}
if (!walk->total)
return 0;
walk->sg = scatterwalk_sg_next(walk->sg);
return hash_walk_new_entry(walk);
}
EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
int crypto_hash_walk_first(struct ahash_request *req,
struct crypto_hash_walk *walk)
{
walk->total = req->nbytes;
if (!walk->total)
return 0;
walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
walk->sg = req->src;
walk->flags = req->base.flags;
return hash_walk_new_entry(walk);
}
EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
int crypto_hash_walk_first_compat(struct hash_desc *hdesc,
struct crypto_hash_walk *walk,
struct scatterlist *sg, unsigned int len)
{
walk->total = len;
if (!walk->total)
return 0;
walk->alignmask = crypto_hash_alignmask(hdesc->tfm);
walk->sg = sg;
walk->flags = hdesc->flags;
return hash_walk_new_entry(walk);
}
static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
unsigned int keylen)
{
unsigned long alignmask = crypto_ahash_alignmask(tfm);
int ret;
u8 *buffer, *alignbuffer;
unsigned long absize;
absize = keylen + alignmask;
buffer = kmalloc(absize, GFP_KERNEL);
if (!buffer)
return -ENOMEM;
alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
memcpy(alignbuffer, key, keylen);
ret = tfm->setkey(tfm, alignbuffer, keylen);
kzfree(buffer);
return ret;
}
int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
unsigned int keylen)
{
unsigned long alignmask = crypto_ahash_alignmask(tfm);
if ((unsigned long)key & alignmask)
return ahash_setkey_unaligned(tfm, key, keylen);
return tfm->setkey(tfm, key, keylen);
}
EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
unsigned int keylen)
{
return -ENOSYS;
}
static inline unsigned int ahash_align_buffer_size(unsigned len,
unsigned long mask)
{
return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
}
static void ahash_op_unaligned_finish(struct ahash_request *req, int err)
{
struct ahash_request_priv *priv = req->priv;
if (err == -EINPROGRESS)
return;
if (!err)
memcpy(priv->result, req->result,
crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
kzfree(priv);
}
static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
{
struct ahash_request *areq = req->data;
struct ahash_request_priv *priv = areq->priv;
crypto_completion_t complete = priv->complete;
void *data = priv->data;
ahash_op_unaligned_finish(areq, err);
complete(data, err);
}
static int ahash_op_unaligned(struct ahash_request *req,
int (*op)(struct ahash_request *))
{
struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
unsigned long alignmask = crypto_ahash_alignmask(tfm);
unsigned int ds = crypto_ahash_digestsize(tfm);
struct ahash_request_priv *priv;
int err;
priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
(req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
GFP_KERNEL : GFP_ATOMIC);
if (!priv)
return -ENOMEM;
priv->result = req->result;
priv->complete = req->base.complete;
priv->data = req->base.data;
req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
req->base.complete = ahash_op_unaligned_done;
req->base.data = req;
req->priv = priv;
err = op(req);
ahash_op_unaligned_finish(req, err);
return err;
}
static int crypto_ahash_op(struct ahash_request *req,
int (*op)(struct ahash_request *))
{
struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
unsigned long alignmask = crypto_ahash_alignmask(tfm);
if ((unsigned long)req->result & alignmask)
return ahash_op_unaligned(req, op);
return op(req);
}
int crypto_ahash_final(struct ahash_request *req)
{
return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
}
EXPORT_SYMBOL_GPL(crypto_ahash_final);
int crypto_ahash_finup(struct ahash_request *req)
{
return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
}
EXPORT_SYMBOL_GPL(crypto_ahash_finup);
int crypto_ahash_digest(struct ahash_request *req)
{
return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->digest);
}
EXPORT_SYMBOL_GPL(crypto_ahash_digest);
static void ahash_def_finup_finish2(struct ahash_request *req, int err)
{
struct ahash_request_priv *priv = req->priv;
if (err == -EINPROGRESS)
return;
if (!err)
memcpy(priv->result, req->result,
crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
kzfree(priv);
}
static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
{
struct ahash_request *areq = req->data;
struct ahash_request_priv *priv = areq->priv;
crypto_completion_t complete = priv->complete;
void *data = priv->data;
ahash_def_finup_finish2(areq, err);
complete(data, err);
}
static int ahash_def_finup_finish1(struct ahash_request *req, int err)
{
if (err)
goto out;
req->base.complete = ahash_def_finup_done2;
req->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
err = crypto_ahash_reqtfm(req)->final(req);
out:
ahash_def_finup_finish2(req, err);
return err;
}
static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
{
struct ahash_request *areq = req->data;
struct ahash_request_priv *priv = areq->priv;
crypto_completion_t complete = priv->complete;
void *data = priv->data;
err = ahash_def_finup_finish1(areq, err);
complete(data, err);
}
static int ahash_def_finup(struct ahash_request *req)
{
struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
unsigned long alignmask = crypto_ahash_alignmask(tfm);
unsigned int ds = crypto_ahash_digestsize(tfm);
struct ahash_request_priv *priv;
priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
(req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
GFP_KERNEL : GFP_ATOMIC);
if (!priv)
return -ENOMEM;
priv->result = req->result;
priv->complete = req->base.complete;
priv->data = req->base.data;
req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
req->base.complete = ahash_def_finup_done1;
req->base.data = req;
req->priv = priv;
return ahash_def_finup_finish1(req, tfm->update(req));
}
static int ahash_no_export(struct ahash_request *req, void *out)
{
return -ENOSYS;
}
static int ahash_no_import(struct ahash_request *req, const void *in)
{
return -ENOSYS;
}
static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
{
struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
struct ahash_alg *alg = crypto_ahash_alg(hash);
hash->setkey = ahash_nosetkey;
hash->export = ahash_no_export;
hash->import = ahash_no_import;
if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
return crypto_init_shash_ops_async(tfm);
hash->init = alg->init;
hash->update = alg->update;
hash->final = alg->final;
hash->finup = alg->finup ?: ahash_def_finup;
hash->digest = alg->digest;
if (alg->setkey)
hash->setkey = alg->setkey;
if (alg->export)
hash->export = alg->export;
if (alg->import)
hash->import = alg->import;
return 0;
}
static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
{
if (alg->cra_type == &crypto_ahash_type)
return alg->cra_ctxsize;
return sizeof(struct crypto_shash *);
}
#ifdef CONFIG_NET
static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
{
struct crypto_report_hash rhash;
strncpy(rhash.type, "ahash", sizeof(rhash.type));
rhash.blocksize = alg->cra_blocksize;
rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
sizeof(struct crypto_report_hash), &rhash))
goto nla_put_failure;
return 0;
nla_put_failure:
return -EMSGSIZE;
}
#else
static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
{
return -ENOSYS;
}
#endif
static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
__attribute__ ((unused));
static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
{
seq_printf(m, "type : ahash\n");
seq_printf(m, "async : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
"yes" : "no");
seq_printf(m, "blocksize : %u\n", alg->cra_blocksize);
seq_printf(m, "digestsize : %u\n",
__crypto_hash_alg_common(alg)->digestsize);
}
const struct crypto_type crypto_ahash_type = {
.extsize = crypto_ahash_extsize,
.init_tfm = crypto_ahash_init_tfm,
#ifdef CONFIG_PROC_FS
.show = crypto_ahash_show,
#endif
.report = crypto_ahash_report,
.maskclear = ~CRYPTO_ALG_TYPE_MASK,
.maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
.type = CRYPTO_ALG_TYPE_AHASH,
.tfmsize = offsetof(struct crypto_ahash, base),
};
EXPORT_SYMBOL_GPL(crypto_ahash_type);
struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
u32 mask)
{
return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
static int ahash_prepare_alg(struct ahash_alg *alg)
{
struct crypto_alg *base = &alg->halg.base;
if (alg->halg.digestsize > PAGE_SIZE / 8 ||
alg->halg.statesize > PAGE_SIZE / 8)
return -EINVAL;
base->cra_type = &crypto_ahash_type;
base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
return 0;
}
int crypto_register_ahash(struct ahash_alg *alg)
{
struct crypto_alg *base = &alg->halg.base;
int err;
err = ahash_prepare_alg(alg);
if (err)
return err;
return crypto_register_alg(base);
}
EXPORT_SYMBOL_GPL(crypto_register_ahash);
int crypto_unregister_ahash(struct ahash_alg *alg)
{
return crypto_unregister_alg(&alg->halg.base);
}
EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
int ahash_register_instance(struct crypto_template *tmpl,
struct ahash_instance *inst)
{
int err;
err = ahash_prepare_alg(&inst->alg);
if (err)
return err;
return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
}
EXPORT_SYMBOL_GPL(ahash_register_instance);
void ahash_free_instance(struct crypto_instance *inst)
{
crypto_drop_spawn(crypto_instance_ctx(inst));
kfree(ahash_instance(inst));
}
EXPORT_SYMBOL_GPL(ahash_free_instance);
int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
struct hash_alg_common *alg,
struct crypto_instance *inst)
{
return crypto_init_spawn2(&spawn->base, &alg->base, inst,
&crypto_ahash_type);
}
EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
{
struct crypto_alg *alg;
alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
}
EXPORT_SYMBOL_GPL(ahash_attr_alg);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Asynchronous cryptographic hash type");