linux/net/ceph/crypto.c

355 lines
7.9 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/ceph/ceph_debug.h>
#include <linux/err.h>
#include <linux/scatterlist.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <crypto/aes.h>
#include <crypto/skcipher.h>
#include <linux/key-type.h>
#include <linux/sched/mm.h>
#include <keys/ceph-type.h>
#include <keys/user-type.h>
#include <linux/ceph/decode.h>
#include "crypto.h"
/*
* Set ->key and ->tfm. The rest of the key should be filled in before
* this function is called.
*/
static int set_secret(struct ceph_crypto_key *key, void *buf)
{
unsigned int noio_flag;
int ret;
key->key = NULL;
key->tfm = NULL;
switch (key->type) {
case CEPH_CRYPTO_NONE:
return 0; /* nothing to do */
case CEPH_CRYPTO_AES:
break;
default:
return -ENOTSUPP;
}
WARN_ON(!key->len);
key->key = kmemdup(buf, key->len, GFP_NOIO);
if (!key->key) {
ret = -ENOMEM;
goto fail;
}
/* crypto_alloc_skcipher() allocates with GFP_KERNEL */
noio_flag = memalloc_noio_save();
key->tfm = crypto_alloc_skcipher("cbc(aes)", 0, CRYPTO_ALG_ASYNC);
memalloc_noio_restore(noio_flag);
if (IS_ERR(key->tfm)) {
ret = PTR_ERR(key->tfm);
key->tfm = NULL;
goto fail;
}
ret = crypto_skcipher_setkey(key->tfm, key->key, key->len);
if (ret)
goto fail;
return 0;
fail:
ceph_crypto_key_destroy(key);
return ret;
}
int ceph_crypto_key_clone(struct ceph_crypto_key *dst,
const struct ceph_crypto_key *src)
{
memcpy(dst, src, sizeof(struct ceph_crypto_key));
return set_secret(dst, src->key);
}
int ceph_crypto_key_encode(struct ceph_crypto_key *key, void **p, void *end)
{
if (*p + sizeof(u16) + sizeof(key->created) +
sizeof(u16) + key->len > end)
return -ERANGE;
ceph_encode_16(p, key->type);
ceph_encode_copy(p, &key->created, sizeof(key->created));
ceph_encode_16(p, key->len);
ceph_encode_copy(p, key->key, key->len);
return 0;
}
int ceph_crypto_key_decode(struct ceph_crypto_key *key, void **p, void *end)
{
int ret;
ceph_decode_need(p, end, 2*sizeof(u16) + sizeof(key->created), bad);
key->type = ceph_decode_16(p);
ceph_decode_copy(p, &key->created, sizeof(key->created));
key->len = ceph_decode_16(p);
ceph_decode_need(p, end, key->len, bad);
ret = set_secret(key, *p);
*p += key->len;
return ret;
bad:
dout("failed to decode crypto key\n");
return -EINVAL;
}
int ceph_crypto_key_unarmor(struct ceph_crypto_key *key, const char *inkey)
{
int inlen = strlen(inkey);
int blen = inlen * 3 / 4;
void *buf, *p;
int ret;
dout("crypto_key_unarmor %s\n", inkey);
buf = kmalloc(blen, GFP_NOFS);
if (!buf)
return -ENOMEM;
blen = ceph_unarmor(buf, inkey, inkey+inlen);
if (blen < 0) {
kfree(buf);
return blen;
}
p = buf;
ret = ceph_crypto_key_decode(key, &p, p + blen);
kfree(buf);
if (ret)
return ret;
dout("crypto_key_unarmor key %p type %d len %d\n", key,
key->type, key->len);
return 0;
}
void ceph_crypto_key_destroy(struct ceph_crypto_key *key)
{
if (key) {
kfree(key->key);
key->key = NULL;
crypto_free_skcipher(key->tfm);
key->tfm = NULL;
}
}
static const u8 *aes_iv = (u8 *)CEPH_AES_IV;
/*
* Should be used for buffers allocated with ceph_kvmalloc().
* Currently these are encrypt out-buffer (ceph_buffer) and decrypt
* in-buffer (msg front).
*
* Dispose of @sgt with teardown_sgtable().
*
* @prealloc_sg is to avoid memory allocation inside sg_alloc_table()
* in cases where a single sg is sufficient. No attempt to reduce the
* number of sgs by squeezing physically contiguous pages together is
* made though, for simplicity.
*/
static int setup_sgtable(struct sg_table *sgt, struct scatterlist *prealloc_sg,
const void *buf, unsigned int buf_len)
{
struct scatterlist *sg;
const bool is_vmalloc = is_vmalloc_addr(buf);
unsigned int off = offset_in_page(buf);
unsigned int chunk_cnt = 1;
unsigned int chunk_len = PAGE_ALIGN(off + buf_len);
int i;
int ret;
if (buf_len == 0) {
memset(sgt, 0, sizeof(*sgt));
return -EINVAL;
}
if (is_vmalloc) {
chunk_cnt = chunk_len >> PAGE_SHIFT;
chunk_len = PAGE_SIZE;
}
if (chunk_cnt > 1) {
ret = sg_alloc_table(sgt, chunk_cnt, GFP_NOFS);
if (ret)
return ret;
} else {
WARN_ON(chunk_cnt != 1);
sg_init_table(prealloc_sg, 1);
sgt->sgl = prealloc_sg;
sgt->nents = sgt->orig_nents = 1;
}
for_each_sg(sgt->sgl, sg, sgt->orig_nents, i) {
struct page *page;
unsigned int len = min(chunk_len - off, buf_len);
if (is_vmalloc)
page = vmalloc_to_page(buf);
else
page = virt_to_page(buf);
sg_set_page(sg, page, len, off);
off = 0;
buf += len;
buf_len -= len;
}
WARN_ON(buf_len != 0);
return 0;
}
static void teardown_sgtable(struct sg_table *sgt)
{
if (sgt->orig_nents > 1)
sg_free_table(sgt);
}
static int ceph_aes_crypt(const struct ceph_crypto_key *key, bool encrypt,
void *buf, int buf_len, int in_len, int *pout_len)
{
SKCIPHER_REQUEST_ON_STACK(req, key->tfm);
struct sg_table sgt;
struct scatterlist prealloc_sg;
char iv[AES_BLOCK_SIZE] __aligned(8);
int pad_byte = AES_BLOCK_SIZE - (in_len & (AES_BLOCK_SIZE - 1));
int crypt_len = encrypt ? in_len + pad_byte : in_len;
int ret;
WARN_ON(crypt_len > buf_len);
if (encrypt)
memset(buf + in_len, pad_byte, pad_byte);
ret = setup_sgtable(&sgt, &prealloc_sg, buf, crypt_len);
if (ret)
return ret;
memcpy(iv, aes_iv, AES_BLOCK_SIZE);
skcipher_request_set_tfm(req, key->tfm);
skcipher_request_set_callback(req, 0, NULL, NULL);
skcipher_request_set_crypt(req, sgt.sgl, sgt.sgl, crypt_len, iv);
/*
print_hex_dump(KERN_ERR, "key: ", DUMP_PREFIX_NONE, 16, 1,
key->key, key->len, 1);
print_hex_dump(KERN_ERR, " in: ", DUMP_PREFIX_NONE, 16, 1,
buf, crypt_len, 1);
*/
if (encrypt)
ret = crypto_skcipher_encrypt(req);
else
ret = crypto_skcipher_decrypt(req);
skcipher_request_zero(req);
if (ret) {
pr_err("%s %scrypt failed: %d\n", __func__,
encrypt ? "en" : "de", ret);
goto out_sgt;
}
/*
print_hex_dump(KERN_ERR, "out: ", DUMP_PREFIX_NONE, 16, 1,
buf, crypt_len, 1);
*/
if (encrypt) {
*pout_len = crypt_len;
} else {
pad_byte = *(char *)(buf + in_len - 1);
if (pad_byte > 0 && pad_byte <= AES_BLOCK_SIZE &&
in_len >= pad_byte) {
*pout_len = in_len - pad_byte;
} else {
pr_err("%s got bad padding %d on in_len %d\n",
__func__, pad_byte, in_len);
ret = -EPERM;
goto out_sgt;
}
}
out_sgt:
teardown_sgtable(&sgt);
return ret;
}
int ceph_crypt(const struct ceph_crypto_key *key, bool encrypt,
void *buf, int buf_len, int in_len, int *pout_len)
{
switch (key->type) {
case CEPH_CRYPTO_NONE:
*pout_len = in_len;
return 0;
case CEPH_CRYPTO_AES:
return ceph_aes_crypt(key, encrypt, buf, buf_len, in_len,
pout_len);
default:
return -ENOTSUPP;
}
}
static int ceph_key_preparse(struct key_preparsed_payload *prep)
{
struct ceph_crypto_key *ckey;
size_t datalen = prep->datalen;
int ret;
void *p;
ret = -EINVAL;
if (datalen <= 0 || datalen > 32767 || !prep->data)
goto err;
ret = -ENOMEM;
ckey = kmalloc(sizeof(*ckey), GFP_KERNEL);
if (!ckey)
goto err;
/* TODO ceph_crypto_key_decode should really take const input */
p = (void *)prep->data;
ret = ceph_crypto_key_decode(ckey, &p, (char*)prep->data+datalen);
if (ret < 0)
goto err_ckey;
prep->payload.data[0] = ckey;
prep->quotalen = datalen;
return 0;
err_ckey:
kfree(ckey);
err:
return ret;
}
static void ceph_key_free_preparse(struct key_preparsed_payload *prep)
{
struct ceph_crypto_key *ckey = prep->payload.data[0];
ceph_crypto_key_destroy(ckey);
kfree(ckey);
}
static void ceph_key_destroy(struct key *key)
{
struct ceph_crypto_key *ckey = key->payload.data[0];
ceph_crypto_key_destroy(ckey);
kfree(ckey);
}
struct key_type key_type_ceph = {
.name = "ceph",
.preparse = ceph_key_preparse,
.free_preparse = ceph_key_free_preparse,
.instantiate = generic_key_instantiate,
.destroy = ceph_key_destroy,
};
int ceph_crypto_init(void) {
return register_key_type(&key_type_ceph);
}
void ceph_crypto_shutdown(void) {
unregister_key_type(&key_type_ceph);
}