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linux/net/ceph/crypto.c
David Howells cf7f601c06 KEYS: Add payload preparsing opportunity prior to key instantiate or update 
Give the key type the opportunity to preparse the payload prior to the
instantiation and update routines being called.  This is done with the
provision of two new key type operations:

	int (*preparse)(struct key_preparsed_payload *prep);
	void (*free_preparse)(struct key_preparsed_payload *prep);

If the first operation is present, then it is called before key creation (in
the add/update case) or before the key semaphore is taken (in the update and
instantiate cases).  The second operation is called to clean up if the first
was called.

preparse() is given the opportunity to fill in the following structure:

	struct key_preparsed_payload {
		char		*description;
		void		*type_data[2];
		void		*payload;
		const void	*data;
		size_t		datalen;
		size_t		quotalen;
	};

Before the preparser is called, the first three fields will have been cleared,
the payload pointer and size will be stored in data and datalen and the default
quota size from the key_type struct will be stored into quotalen.

The preparser may parse the payload in any way it likes and may store data in
the type_data[] and payload fields for use by the instantiate() and update()
ops.

The preparser may also propose a description for the key by attaching it as a
string to the description field.  This can be used by passing a NULL or ""
description to the add_key() system call or the key_create_or_update()
function.  This cannot work with request_key() as that required the description
to tell the upcall about the key to be created.

This, for example permits keys that store PGP public keys to generate their own
name from the user ID and public key fingerprint in the key.

The instantiate() and update() operations are then modified to look like this:

	int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);
	int (*update)(struct key *key, struct key_preparsed_payload *prep);

and the new payload data is passed in *prep, whether or not it was preparsed.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-10-08 13:49:48 +10:30

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#include <linux/ceph/ceph_debug.h>
#include <linux/err.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <crypto/hash.h>
#include <linux/key-type.h>
#include <keys/ceph-type.h>
#include <linux/ceph/decode.h>
#include "crypto.h"
int ceph_crypto_key_clone(struct ceph_crypto_key *dst,
const struct ceph_crypto_key *src)
{
memcpy(dst, src, sizeof(struct ceph_crypto_key));
dst->key = kmemdup(src->key, src->len, GFP_NOFS);
if (!dst->key)
return -ENOMEM;
return 0;
}
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)
{
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);
key->key = kmalloc(key->len, GFP_NOFS);
if (!key->key)
return -ENOMEM;
ceph_decode_copy(p, key->key, key->len);
return 0;
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;
}
#define AES_KEY_SIZE 16
static struct crypto_blkcipher *ceph_crypto_alloc_cipher(void)
{
return crypto_alloc_blkcipher("cbc(aes)", 0, CRYPTO_ALG_ASYNC);
}
static const u8 *aes_iv = (u8 *)CEPH_AES_IV;
static int ceph_aes_encrypt(const void *key, int key_len,
void *dst, size_t *dst_len,
const void *src, size_t src_len)
{
struct scatterlist sg_in[2], sg_out[1];
struct crypto_blkcipher *tfm = ceph_crypto_alloc_cipher();
struct blkcipher_desc desc = { .tfm = tfm, .flags = 0 };
int ret;
void *iv;
int ivsize;
size_t zero_padding = (0x10 - (src_len & 0x0f));
char pad[16];
if (IS_ERR(tfm))
return PTR_ERR(tfm);
memset(pad, zero_padding, zero_padding);
*dst_len = src_len + zero_padding;
crypto_blkcipher_setkey((void *)tfm, key, key_len);
sg_init_table(sg_in, 2);
sg_set_buf(&sg_in[0], src, src_len);
sg_set_buf(&sg_in[1], pad, zero_padding);
sg_init_table(sg_out, 1);
sg_set_buf(sg_out, dst, *dst_len);
iv = crypto_blkcipher_crt(tfm)->iv;
ivsize = crypto_blkcipher_ivsize(tfm);
memcpy(iv, aes_iv, ivsize);
/*
print_hex_dump(KERN_ERR, "enc key: ", DUMP_PREFIX_NONE, 16, 1,
key, key_len, 1);
print_hex_dump(KERN_ERR, "enc src: ", DUMP_PREFIX_NONE, 16, 1,
src, src_len, 1);
print_hex_dump(KERN_ERR, "enc pad: ", DUMP_PREFIX_NONE, 16, 1,
pad, zero_padding, 1);
*/
ret = crypto_blkcipher_encrypt(&desc, sg_out, sg_in,
src_len + zero_padding);
crypto_free_blkcipher(tfm);
if (ret < 0)
pr_err("ceph_aes_crypt failed %d\n", ret);
/*
print_hex_dump(KERN_ERR, "enc out: ", DUMP_PREFIX_NONE, 16, 1,
dst, *dst_len, 1);
*/
return 0;
}
static int ceph_aes_encrypt2(const void *key, int key_len, void *dst,
size_t *dst_len,
const void *src1, size_t src1_len,
const void *src2, size_t src2_len)
{
struct scatterlist sg_in[3], sg_out[1];
struct crypto_blkcipher *tfm = ceph_crypto_alloc_cipher();
struct blkcipher_desc desc = { .tfm = tfm, .flags = 0 };
int ret;
void *iv;
int ivsize;
size_t zero_padding = (0x10 - ((src1_len + src2_len) & 0x0f));
char pad[16];
if (IS_ERR(tfm))
return PTR_ERR(tfm);
memset(pad, zero_padding, zero_padding);
*dst_len = src1_len + src2_len + zero_padding;
crypto_blkcipher_setkey((void *)tfm, key, key_len);
sg_init_table(sg_in, 3);
sg_set_buf(&sg_in[0], src1, src1_len);
sg_set_buf(&sg_in[1], src2, src2_len);
sg_set_buf(&sg_in[2], pad, zero_padding);
sg_init_table(sg_out, 1);
sg_set_buf(sg_out, dst, *dst_len);
iv = crypto_blkcipher_crt(tfm)->iv;
ivsize = crypto_blkcipher_ivsize(tfm);
memcpy(iv, aes_iv, ivsize);
/*
print_hex_dump(KERN_ERR, "enc key: ", DUMP_PREFIX_NONE, 16, 1,
key, key_len, 1);
print_hex_dump(KERN_ERR, "enc src1: ", DUMP_PREFIX_NONE, 16, 1,
src1, src1_len, 1);
print_hex_dump(KERN_ERR, "enc src2: ", DUMP_PREFIX_NONE, 16, 1,
src2, src2_len, 1);
print_hex_dump(KERN_ERR, "enc pad: ", DUMP_PREFIX_NONE, 16, 1,
pad, zero_padding, 1);
*/
ret = crypto_blkcipher_encrypt(&desc, sg_out, sg_in,
src1_len + src2_len + zero_padding);
crypto_free_blkcipher(tfm);
if (ret < 0)
pr_err("ceph_aes_crypt2 failed %d\n", ret);
/*
print_hex_dump(KERN_ERR, "enc out: ", DUMP_PREFIX_NONE, 16, 1,
dst, *dst_len, 1);
*/
return 0;
}
static int ceph_aes_decrypt(const void *key, int key_len,
void *dst, size_t *dst_len,
const void *src, size_t src_len)
{
struct scatterlist sg_in[1], sg_out[2];
struct crypto_blkcipher *tfm = ceph_crypto_alloc_cipher();
struct blkcipher_desc desc = { .tfm = tfm };
char pad[16];
void *iv;
int ivsize;
int ret;
int last_byte;
if (IS_ERR(tfm))
return PTR_ERR(tfm);
crypto_blkcipher_setkey((void *)tfm, key, key_len);
sg_init_table(sg_in, 1);
sg_init_table(sg_out, 2);
sg_set_buf(sg_in, src, src_len);
sg_set_buf(&sg_out[0], dst, *dst_len);
sg_set_buf(&sg_out[1], pad, sizeof(pad));
iv = crypto_blkcipher_crt(tfm)->iv;
ivsize = crypto_blkcipher_ivsize(tfm);
memcpy(iv, aes_iv, ivsize);
/*
print_hex_dump(KERN_ERR, "dec key: ", DUMP_PREFIX_NONE, 16, 1,
key, key_len, 1);
print_hex_dump(KERN_ERR, "dec in: ", DUMP_PREFIX_NONE, 16, 1,
src, src_len, 1);
*/
ret = crypto_blkcipher_decrypt(&desc, sg_out, sg_in, src_len);
crypto_free_blkcipher(tfm);
if (ret < 0) {
pr_err("ceph_aes_decrypt failed %d\n", ret);
return ret;
}
if (src_len <= *dst_len)
last_byte = ((char *)dst)[src_len - 1];
else
last_byte = pad[src_len - *dst_len - 1];
if (last_byte <= 16 && src_len >= last_byte) {
*dst_len = src_len - last_byte;
} else {
pr_err("ceph_aes_decrypt got bad padding %d on src len %d\n",
last_byte, (int)src_len);
return -EPERM; /* bad padding */
}
/*
print_hex_dump(KERN_ERR, "dec out: ", DUMP_PREFIX_NONE, 16, 1,
dst, *dst_len, 1);
*/
return 0;
}
static int ceph_aes_decrypt2(const void *key, int key_len,
void *dst1, size_t *dst1_len,
void *dst2, size_t *dst2_len,
const void *src, size_t src_len)
{
struct scatterlist sg_in[1], sg_out[3];
struct crypto_blkcipher *tfm = ceph_crypto_alloc_cipher();
struct blkcipher_desc desc = { .tfm = tfm };
char pad[16];
void *iv;
int ivsize;
int ret;
int last_byte;
if (IS_ERR(tfm))
return PTR_ERR(tfm);
sg_init_table(sg_in, 1);
sg_set_buf(sg_in, src, src_len);
sg_init_table(sg_out, 3);
sg_set_buf(&sg_out[0], dst1, *dst1_len);
sg_set_buf(&sg_out[1], dst2, *dst2_len);
sg_set_buf(&sg_out[2], pad, sizeof(pad));
crypto_blkcipher_setkey((void *)tfm, key, key_len);
iv = crypto_blkcipher_crt(tfm)->iv;
ivsize = crypto_blkcipher_ivsize(tfm);
memcpy(iv, aes_iv, ivsize);
/*
print_hex_dump(KERN_ERR, "dec key: ", DUMP_PREFIX_NONE, 16, 1,
key, key_len, 1);
print_hex_dump(KERN_ERR, "dec in: ", DUMP_PREFIX_NONE, 16, 1,
src, src_len, 1);
*/
ret = crypto_blkcipher_decrypt(&desc, sg_out, sg_in, src_len);
crypto_free_blkcipher(tfm);
if (ret < 0) {
pr_err("ceph_aes_decrypt failed %d\n", ret);
return ret;
}
if (src_len <= *dst1_len)
last_byte = ((char *)dst1)[src_len - 1];
else if (src_len <= *dst1_len + *dst2_len)
last_byte = ((char *)dst2)[src_len - *dst1_len - 1];
else
last_byte = pad[src_len - *dst1_len - *dst2_len - 1];
if (last_byte <= 16 && src_len >= last_byte) {
src_len -= last_byte;
} else {
pr_err("ceph_aes_decrypt got bad padding %d on src len %d\n",
last_byte, (int)src_len);
return -EPERM; /* bad padding */
}
if (src_len < *dst1_len) {
*dst1_len = src_len;
*dst2_len = 0;
} else {
*dst2_len = src_len - *dst1_len;
}
/*
print_hex_dump(KERN_ERR, "dec out1: ", DUMP_PREFIX_NONE, 16, 1,
dst1, *dst1_len, 1);
print_hex_dump(KERN_ERR, "dec out2: ", DUMP_PREFIX_NONE, 16, 1,
dst2, *dst2_len, 1);
*/
return 0;
}
int ceph_decrypt(struct ceph_crypto_key *secret, void *dst, size_t *dst_len,
const void *src, size_t src_len)
{
switch (secret->type) {
case CEPH_CRYPTO_NONE:
if (*dst_len < src_len)
return -ERANGE;
memcpy(dst, src, src_len);
*dst_len = src_len;
return 0;
case CEPH_CRYPTO_AES:
return ceph_aes_decrypt(secret->key, secret->len, dst,
dst_len, src, src_len);
default:
return -EINVAL;
}
}
int ceph_decrypt2(struct ceph_crypto_key *secret,
void *dst1, size_t *dst1_len,
void *dst2, size_t *dst2_len,
const void *src, size_t src_len)
{
size_t t;
switch (secret->type) {
case CEPH_CRYPTO_NONE:
if (*dst1_len + *dst2_len < src_len)
return -ERANGE;
t = min(*dst1_len, src_len);
memcpy(dst1, src, t);
*dst1_len = t;
src += t;
src_len -= t;
if (src_len) {
t = min(*dst2_len, src_len);
memcpy(dst2, src, t);
*dst2_len = t;
}
return 0;
case CEPH_CRYPTO_AES:
return ceph_aes_decrypt2(secret->key, secret->len,
dst1, dst1_len, dst2, dst2_len,
src, src_len);
default:
return -EINVAL;
}
}
int ceph_encrypt(struct ceph_crypto_key *secret, void *dst, size_t *dst_len,
const void *src, size_t src_len)
{
switch (secret->type) {
case CEPH_CRYPTO_NONE:
if (*dst_len < src_len)
return -ERANGE;
memcpy(dst, src, src_len);
*dst_len = src_len;
return 0;
case CEPH_CRYPTO_AES:
return ceph_aes_encrypt(secret->key, secret->len, dst,
dst_len, src, src_len);
default:
return -EINVAL;
}
}
int ceph_encrypt2(struct ceph_crypto_key *secret, void *dst, size_t *dst_len,
const void *src1, size_t src1_len,
const void *src2, size_t src2_len)
{
switch (secret->type) {
case CEPH_CRYPTO_NONE:
if (*dst_len < src1_len + src2_len)
return -ERANGE;
memcpy(dst, src1, src1_len);
memcpy(dst + src1_len, src2, src2_len);
*dst_len = src1_len + src2_len;
return 0;
case CEPH_CRYPTO_AES:
return ceph_aes_encrypt2(secret->key, secret->len, dst, dst_len,
src1, src1_len, src2, src2_len);
default:
return -EINVAL;
}
}
int ceph_key_instantiate(struct key *key, 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 = key_payload_reserve(key, datalen);
if (ret < 0)
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;
key->payload.data = ckey;
return 0;
err_ckey:
kfree(ckey);
err:
return ret;
}
int ceph_key_match(const struct key *key, const void *description)
{
return strcmp(key->description, description) == 0;
}
void ceph_key_destroy(struct key *key) {
struct ceph_crypto_key *ckey = key->payload.data;
ceph_crypto_key_destroy(ckey);
kfree(ckey);
}
struct key_type key_type_ceph = {
.name = "ceph",
.instantiate = ceph_key_instantiate,
.match = ceph_key_match,
.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);
}
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