linux/crypto/shash.c
Yehuda Sadeh f4f689933c crypto: shash - Fix unaligned calculation with short length
When the total length is shorter than the calculated number of unaligned bytes, the call to shash->update breaks. For example, calling crc32c on unaligned buffer with length of 1 can result in a system crash.

Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2009-03-27 13:03:51 +08:00

506 lines
13 KiB
C

/*
* Synchronous Cryptographic Hash operations.
*
* Copyright (c) 2008 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/scatterwalk.h>
#include <crypto/internal/hash.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include "internal.h"
static const struct crypto_type crypto_shash_type;
static int shash_setkey_unaligned(struct crypto_shash *tfm, const u8 *key,
unsigned int keylen)
{
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned long alignmask = crypto_shash_alignmask(tfm);
unsigned long absize;
u8 *buffer, *alignbuffer;
int err;
absize = keylen + (alignmask & ~(CRYPTO_MINALIGN - 1));
buffer = kmalloc(absize, GFP_KERNEL);
if (!buffer)
return -ENOMEM;
alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
memcpy(alignbuffer, key, keylen);
err = shash->setkey(tfm, alignbuffer, keylen);
memset(alignbuffer, 0, keylen);
kfree(buffer);
return err;
}
int crypto_shash_setkey(struct crypto_shash *tfm, const u8 *key,
unsigned int keylen)
{
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned long alignmask = crypto_shash_alignmask(tfm);
if (!shash->setkey)
return -ENOSYS;
if ((unsigned long)key & alignmask)
return shash_setkey_unaligned(tfm, key, keylen);
return shash->setkey(tfm, key, keylen);
}
EXPORT_SYMBOL_GPL(crypto_shash_setkey);
static inline unsigned int shash_align_buffer_size(unsigned len,
unsigned long mask)
{
return len + (mask & ~(__alignof__(u8 __attribute__ ((aligned))) - 1));
}
static int shash_update_unaligned(struct shash_desc *desc, const u8 *data,
unsigned int len)
{
struct crypto_shash *tfm = desc->tfm;
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned long alignmask = crypto_shash_alignmask(tfm);
unsigned int unaligned_len = alignmask + 1 -
((unsigned long)data & alignmask);
u8 buf[shash_align_buffer_size(unaligned_len, alignmask)]
__attribute__ ((aligned));
if (unaligned_len > len)
unaligned_len = len;
memcpy(buf, data, unaligned_len);
return shash->update(desc, buf, unaligned_len) ?:
shash->update(desc, data + unaligned_len, len - unaligned_len);
}
int crypto_shash_update(struct shash_desc *desc, const u8 *data,
unsigned int len)
{
struct crypto_shash *tfm = desc->tfm;
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned long alignmask = crypto_shash_alignmask(tfm);
if ((unsigned long)data & alignmask)
return shash_update_unaligned(desc, data, len);
return shash->update(desc, data, len);
}
EXPORT_SYMBOL_GPL(crypto_shash_update);
static int shash_final_unaligned(struct shash_desc *desc, u8 *out)
{
struct crypto_shash *tfm = desc->tfm;
unsigned long alignmask = crypto_shash_alignmask(tfm);
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned int ds = crypto_shash_digestsize(tfm);
u8 buf[shash_align_buffer_size(ds, alignmask)]
__attribute__ ((aligned));
int err;
err = shash->final(desc, buf);
memcpy(out, buf, ds);
return err;
}
int crypto_shash_final(struct shash_desc *desc, u8 *out)
{
struct crypto_shash *tfm = desc->tfm;
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned long alignmask = crypto_shash_alignmask(tfm);
if ((unsigned long)out & alignmask)
return shash_final_unaligned(desc, out);
return shash->final(desc, out);
}
EXPORT_SYMBOL_GPL(crypto_shash_final);
static int shash_finup_unaligned(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out)
{
return crypto_shash_update(desc, data, len) ?:
crypto_shash_final(desc, out);
}
int crypto_shash_finup(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out)
{
struct crypto_shash *tfm = desc->tfm;
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned long alignmask = crypto_shash_alignmask(tfm);
if (((unsigned long)data | (unsigned long)out) & alignmask ||
!shash->finup)
return shash_finup_unaligned(desc, data, len, out);
return shash->finup(desc, data, len, out);
}
EXPORT_SYMBOL_GPL(crypto_shash_finup);
static int shash_digest_unaligned(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out)
{
return crypto_shash_init(desc) ?:
crypto_shash_update(desc, data, len) ?:
crypto_shash_final(desc, out);
}
int crypto_shash_digest(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out)
{
struct crypto_shash *tfm = desc->tfm;
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned long alignmask = crypto_shash_alignmask(tfm);
if (((unsigned long)data | (unsigned long)out) & alignmask ||
!shash->digest)
return shash_digest_unaligned(desc, data, len, out);
return shash->digest(desc, data, len, out);
}
EXPORT_SYMBOL_GPL(crypto_shash_digest);
int crypto_shash_import(struct shash_desc *desc, const u8 *in)
{
struct crypto_shash *tfm = desc->tfm;
struct shash_alg *alg = crypto_shash_alg(tfm);
memcpy(shash_desc_ctx(desc), in, crypto_shash_descsize(tfm));
if (alg->reinit)
alg->reinit(desc);
return 0;
}
EXPORT_SYMBOL_GPL(crypto_shash_import);
static int shash_async_setkey(struct crypto_ahash *tfm, const u8 *key,
unsigned int keylen)
{
struct crypto_shash **ctx = crypto_ahash_ctx(tfm);
return crypto_shash_setkey(*ctx, key, keylen);
}
static int shash_async_init(struct ahash_request *req)
{
struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
struct shash_desc *desc = ahash_request_ctx(req);
desc->tfm = *ctx;
desc->flags = req->base.flags;
return crypto_shash_init(desc);
}
static int shash_async_update(struct ahash_request *req)
{
struct shash_desc *desc = ahash_request_ctx(req);
struct crypto_hash_walk walk;
int nbytes;
for (nbytes = crypto_hash_walk_first(req, &walk); nbytes > 0;
nbytes = crypto_hash_walk_done(&walk, nbytes))
nbytes = crypto_shash_update(desc, walk.data, nbytes);
return nbytes;
}
static int shash_async_final(struct ahash_request *req)
{
return crypto_shash_final(ahash_request_ctx(req), req->result);
}
static int shash_async_digest(struct ahash_request *req)
{
struct scatterlist *sg = req->src;
unsigned int offset = sg->offset;
unsigned int nbytes = req->nbytes;
int err;
if (nbytes < min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset)) {
struct crypto_shash **ctx =
crypto_ahash_ctx(crypto_ahash_reqtfm(req));
struct shash_desc *desc = ahash_request_ctx(req);
void *data;
desc->tfm = *ctx;
desc->flags = req->base.flags;
data = crypto_kmap(sg_page(sg), 0);
err = crypto_shash_digest(desc, data + offset, nbytes,
req->result);
crypto_kunmap(data, 0);
crypto_yield(desc->flags);
goto out;
}
err = shash_async_init(req);
if (err)
goto out;
err = shash_async_update(req);
if (err)
goto out;
err = shash_async_final(req);
out:
return err;
}
static void crypto_exit_shash_ops_async(struct crypto_tfm *tfm)
{
struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
crypto_free_shash(*ctx);
}
static int crypto_init_shash_ops_async(struct crypto_tfm *tfm)
{
struct crypto_alg *calg = tfm->__crt_alg;
struct shash_alg *alg = __crypto_shash_alg(calg);
struct ahash_tfm *crt = &tfm->crt_ahash;
struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
struct crypto_shash *shash;
if (!crypto_mod_get(calg))
return -EAGAIN;
shash = crypto_create_tfm(calg, &crypto_shash_type);
if (IS_ERR(shash)) {
crypto_mod_put(calg);
return PTR_ERR(shash);
}
*ctx = shash;
tfm->exit = crypto_exit_shash_ops_async;
crt->init = shash_async_init;
crt->update = shash_async_update;
crt->final = shash_async_final;
crt->digest = shash_async_digest;
crt->setkey = shash_async_setkey;
crt->digestsize = alg->digestsize;
crt->reqsize = sizeof(struct shash_desc) + crypto_shash_descsize(shash);
return 0;
}
static int shash_compat_setkey(struct crypto_hash *tfm, const u8 *key,
unsigned int keylen)
{
struct shash_desc *desc = crypto_hash_ctx(tfm);
return crypto_shash_setkey(desc->tfm, key, keylen);
}
static int shash_compat_init(struct hash_desc *hdesc)
{
struct shash_desc *desc = crypto_hash_ctx(hdesc->tfm);
desc->flags = hdesc->flags;
return crypto_shash_init(desc);
}
static int shash_compat_update(struct hash_desc *hdesc, struct scatterlist *sg,
unsigned int len)
{
struct shash_desc *desc = crypto_hash_ctx(hdesc->tfm);
struct crypto_hash_walk walk;
int nbytes;
for (nbytes = crypto_hash_walk_first_compat(hdesc, &walk, sg, len);
nbytes > 0; nbytes = crypto_hash_walk_done(&walk, nbytes))
nbytes = crypto_shash_update(desc, walk.data, nbytes);
return nbytes;
}
static int shash_compat_final(struct hash_desc *hdesc, u8 *out)
{
return crypto_shash_final(crypto_hash_ctx(hdesc->tfm), out);
}
static int shash_compat_digest(struct hash_desc *hdesc, struct scatterlist *sg,
unsigned int nbytes, u8 *out)
{
unsigned int offset = sg->offset;
int err;
if (nbytes < min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset)) {
struct shash_desc *desc = crypto_hash_ctx(hdesc->tfm);
void *data;
desc->flags = hdesc->flags;
data = crypto_kmap(sg_page(sg), 0);
err = crypto_shash_digest(desc, data + offset, nbytes, out);
crypto_kunmap(data, 0);
crypto_yield(desc->flags);
goto out;
}
err = shash_compat_init(hdesc);
if (err)
goto out;
err = shash_compat_update(hdesc, sg, nbytes);
if (err)
goto out;
err = shash_compat_final(hdesc, out);
out:
return err;
}
static void crypto_exit_shash_ops_compat(struct crypto_tfm *tfm)
{
struct shash_desc *desc= crypto_tfm_ctx(tfm);
crypto_free_shash(desc->tfm);
}
static int crypto_init_shash_ops_compat(struct crypto_tfm *tfm)
{
struct hash_tfm *crt = &tfm->crt_hash;
struct crypto_alg *calg = tfm->__crt_alg;
struct shash_alg *alg = __crypto_shash_alg(calg);
struct shash_desc *desc = crypto_tfm_ctx(tfm);
struct crypto_shash *shash;
if (!crypto_mod_get(calg))
return -EAGAIN;
shash = crypto_create_tfm(calg, &crypto_shash_type);
if (IS_ERR(shash)) {
crypto_mod_put(calg);
return PTR_ERR(shash);
}
desc->tfm = shash;
tfm->exit = crypto_exit_shash_ops_compat;
crt->init = shash_compat_init;
crt->update = shash_compat_update;
crt->final = shash_compat_final;
crt->digest = shash_compat_digest;
crt->setkey = shash_compat_setkey;
crt->digestsize = alg->digestsize;
return 0;
}
static int crypto_init_shash_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
{
switch (mask & CRYPTO_ALG_TYPE_MASK) {
case CRYPTO_ALG_TYPE_HASH_MASK:
return crypto_init_shash_ops_compat(tfm);
case CRYPTO_ALG_TYPE_AHASH_MASK:
return crypto_init_shash_ops_async(tfm);
}
return -EINVAL;
}
static unsigned int crypto_shash_ctxsize(struct crypto_alg *alg, u32 type,
u32 mask)
{
struct shash_alg *salg = __crypto_shash_alg(alg);
switch (mask & CRYPTO_ALG_TYPE_MASK) {
case CRYPTO_ALG_TYPE_HASH_MASK:
return sizeof(struct shash_desc) + salg->descsize;
case CRYPTO_ALG_TYPE_AHASH_MASK:
return sizeof(struct crypto_shash *);
}
return 0;
}
static int crypto_shash_init_tfm(struct crypto_tfm *tfm,
const struct crypto_type *frontend)
{
return 0;
}
static unsigned int crypto_shash_extsize(struct crypto_alg *alg,
const struct crypto_type *frontend)
{
return alg->cra_ctxsize;
}
static void crypto_shash_show(struct seq_file *m, struct crypto_alg *alg)
__attribute__ ((unused));
static void crypto_shash_show(struct seq_file *m, struct crypto_alg *alg)
{
struct shash_alg *salg = __crypto_shash_alg(alg);
seq_printf(m, "type : shash\n");
seq_printf(m, "blocksize : %u\n", alg->cra_blocksize);
seq_printf(m, "digestsize : %u\n", salg->digestsize);
seq_printf(m, "descsize : %u\n", salg->descsize);
}
static const struct crypto_type crypto_shash_type = {
.ctxsize = crypto_shash_ctxsize,
.extsize = crypto_shash_extsize,
.init = crypto_init_shash_ops,
.init_tfm = crypto_shash_init_tfm,
#ifdef CONFIG_PROC_FS
.show = crypto_shash_show,
#endif
.maskclear = ~CRYPTO_ALG_TYPE_MASK,
.maskset = CRYPTO_ALG_TYPE_MASK,
.type = CRYPTO_ALG_TYPE_SHASH,
.tfmsize = offsetof(struct crypto_shash, base),
};
struct crypto_shash *crypto_alloc_shash(const char *alg_name, u32 type,
u32 mask)
{
return crypto_alloc_tfm(alg_name, &crypto_shash_type, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_alloc_shash);
int crypto_register_shash(struct shash_alg *alg)
{
struct crypto_alg *base = &alg->base;
if (alg->digestsize > PAGE_SIZE / 8 ||
alg->descsize > PAGE_SIZE / 8)
return -EINVAL;
base->cra_type = &crypto_shash_type;
base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
base->cra_flags |= CRYPTO_ALG_TYPE_SHASH;
return crypto_register_alg(base);
}
EXPORT_SYMBOL_GPL(crypto_register_shash);
int crypto_unregister_shash(struct shash_alg *alg)
{
return crypto_unregister_alg(&alg->base);
}
EXPORT_SYMBOL_GPL(crypto_unregister_shash);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Synchronous cryptographic hash type");