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Merge branch 'keys-misc' into keys-next 

Miscellaneous keyrings changes.

Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
David Howells 2016-04-12 20:09:34 +01:00
parent 3c9d6296b7 ddbb411487
commit 6e007f3186
11 changed files with 428 additions and 50 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
Documentation/security/keys.txt
View File

@ -823,6 +823,36 @@ The keyctl syscall functions are:
A process must have search permission on the key for this function to be
successful.
(*) Compute a Diffie-Hellman shared secret or public key
long keyctl(KEYCTL_DH_COMPUTE, struct keyctl_dh_params *params,
char *buffer, size_t buflen);
The params struct contains serial numbers for three keys:
- The prime, p, known to both parties
- The local private key
- The base integer, which is either a shared generator or the
remote public key
The value computed is:
result = base ^ private (mod prime)
If the base is the shared generator, the result is the local
public key. If the base is the remote public key, the result is
the shared secret.
The buffer length must be at least the length of the prime, or zero.
If the buffer length is nonzero, the length of the result is
returned when it is successfully calculated and copied in to the
buffer. When the buffer length is zero, the minimum required
buffer length is returned.
This function will return error EOPNOTSUPP if the key type is not
supported, error ENOKEY if the key could not be found, or error
EACCES if the key is not readable by the caller.
===============
KERNEL SERVICES

10
include/uapi/linux/keyctl.h
View File

@ -12,6 +12,8 @@
#ifndef _LINUX_KEYCTL_H
#define _LINUX_KEYCTL_H
#include <linux/types.h>
/* special process keyring shortcut IDs */
#define KEY_SPEC_THREAD_KEYRING -1 /* - key ID for thread-specific keyring */
#define KEY_SPEC_PROCESS_KEYRING -2 /* - key ID for process-specific keyring */
@ -57,5 +59,13 @@
#define KEYCTL_INSTANTIATE_IOV 20 /* instantiate a partially constructed key */
#define KEYCTL_INVALIDATE 21 /* invalidate a key */
#define KEYCTL_GET_PERSISTENT 22 /* get a user's persistent keyring */
#define KEYCTL_DH_COMPUTE 23 /* Compute Diffie-Hellman values */
/* keyctl structures */
struct keyctl_dh_params {
__s32 private;
__s32 prime;
__s32 base;
};
#endif /* _LINUX_KEYCTL_H */

1
security/integrity/Kconfig
View File

@ -35,7 +35,6 @@ config INTEGRITY_ASYMMETRIC_KEYS
default n
select ASYMMETRIC_KEY_TYPE
select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
select PUBLIC_KEY_ALGO_RSA
select CRYPTO_RSA
select X509_CERTIFICATE_PARSER
help

15
security/keys/Kconfig
View File

@ -41,6 +41,10 @@ config BIG_KEYS
bool "Large payload keys"
depends on KEYS
depends on TMPFS
select CRYPTO
select CRYPTO_AES
select CRYPTO_ECB
select CRYPTO_RNG
help
This option provides support for holding large keys within the kernel
(for example Kerberos ticket caches). The data may be stored out to
@ -81,3 +85,14 @@ config ENCRYPTED_KEYS
Userspace only ever sees/stores encrypted blobs.
If you are unsure as to whether this is required, answer N.
config KEY_DH_OPERATIONS
bool "Diffie-Hellman operations on retained keys"
depends on KEYS
select MPILIB
help
This option provides support for calculating Diffie-Hellman
public keys and shared secrets using values stored as keys
in the kernel.
If you are unsure as to whether this is required, answer N.

1
security/keys/Makefile
View File

@ -19,6 +19,7 @@ obj-$(CONFIG_KEYS_COMPAT) += compat.o
obj-$(CONFIG_PROC_FS) += proc.o
obj-$(CONFIG_SYSCTL) += sysctl.o
obj-$(CONFIG_PERSISTENT_KEYRINGS) += persistent.o
obj-$(CONFIG_KEY_DH_OPERATIONS) += dh.o
#
# Key types

200
security/keys/big_key.c
View File

@ -14,8 +14,10 @@
#include <linux/file.h>
#include <linux/shmem_fs.h>
#include <linux/err.h>
#include <linux/scatterlist.h>
#include <keys/user-type.h>
#include <keys/big_key-type.h>
#include <crypto/rng.h>
/*
* Layout of key payload words.
@ -27,6 +29,14 @@ enum {
big_key_len,
};
/*
* Crypto operation with big_key data
*/
enum big_key_op {
BIG_KEY_ENC,
BIG_KEY_DEC,
};
/*
* If the data is under this limit, there's no point creating a shm file to
* hold it as the permanently resident metadata for the shmem fs will be at
@ -34,6 +44,11 @@ enum {
*/
#define BIG_KEY_FILE_THRESHOLD (sizeof(struct inode) + sizeof(struct dentry))
/*
* Key size for big_key data encryption
*/
#define ENC_KEY_SIZE 16
/*
* big_key defined keys take an arbitrary string as the description and an
* arbitrary blob of data as the payload
@ -49,6 +64,54 @@ struct key_type key_type_big_key = {
.read = big_key_read,
};
/*
* Crypto names for big_key data encryption
*/
static const char big_key_rng_name[] = "stdrng";
static const char big_key_alg_name[] = "ecb(aes)";
/*
* Crypto algorithms for big_key data encryption
*/
static struct crypto_rng *big_key_rng;
static struct crypto_blkcipher *big_key_blkcipher;
/*
* Generate random key to encrypt big_key data
*/
static inline int big_key_gen_enckey(u8 *key)
{
return crypto_rng_get_bytes(big_key_rng, key, ENC_KEY_SIZE);
}
/*
* Encrypt/decrypt big_key data
*/
static int big_key_crypt(enum big_key_op op, u8 *data, size_t datalen, u8 *key)
{
int ret = -EINVAL;
struct scatterlist sgio;
struct blkcipher_desc desc;
if (crypto_blkcipher_setkey(big_key_blkcipher, key, ENC_KEY_SIZE)) {
ret = -EAGAIN;
goto error;
}
desc.flags = 0;
desc.tfm = big_key_blkcipher;
sg_init_one(&sgio, data, datalen);
if (op == BIG_KEY_ENC)
ret = crypto_blkcipher_encrypt(&desc, &sgio, &sgio, datalen);
else
ret = crypto_blkcipher_decrypt(&desc, &sgio, &sgio, datalen);
error:
return ret;
}
/*
* Preparse a big key
*/
@ -56,6 +119,8 @@ int big_key_preparse(struct key_preparsed_payload *prep)
{
struct path *path = (struct path *)&prep->payload.data[big_key_path];
struct file *file;
u8 *enckey;
u8 *data = NULL;
ssize_t written;
size_t datalen = prep->datalen;
int ret;
@ -73,16 +138,43 @@ int big_key_preparse(struct key_preparsed_payload *prep)
/* Create a shmem file to store the data in. This will permit the data
* to be swapped out if needed.
*
* TODO: Encrypt the stored data with a temporary key.
* File content is stored encrypted with randomly generated key.
*/
file = shmem_kernel_file_setup("", datalen, 0);
if (IS_ERR(file)) {
ret = PTR_ERR(file);
size_t enclen = ALIGN(datalen, crypto_blkcipher_blocksize(big_key_blkcipher));
/* prepare aligned data to encrypt */
data = kmalloc(enclen, GFP_KERNEL);
if (!data)
return -ENOMEM;
memcpy(data, prep->data, datalen);
memset(data + datalen, 0x00, enclen - datalen);
/* generate random key */
enckey = kmalloc(ENC_KEY_SIZE, GFP_KERNEL);
if (!enckey) {
ret = -ENOMEM;
goto error;
}
written = kernel_write(file, prep->data, prep->datalen, 0);
if (written != datalen) {
ret = big_key_gen_enckey(enckey);
if (ret)
goto err_enckey;
/* encrypt aligned data */
ret = big_key_crypt(BIG_KEY_ENC, data, enclen, enckey);
if (ret)
goto err_enckey;
/* save aligned data to file */
file = shmem_kernel_file_setup("", enclen, 0);
if (IS_ERR(file)) {
ret = PTR_ERR(file);
goto err_enckey;
}
written = kernel_write(file, data, enclen, 0);
if (written != enclen) {
ret = written;
if (written >= 0)
ret = -ENOMEM;
@ -92,12 +184,15 @@ int big_key_preparse(struct key_preparsed_payload *prep)
/* Pin the mount and dentry to the key so that we can open it again
* later
*/
prep->payload.data[big_key_data] = enckey;
*path = file->f_path;
path_get(path);
fput(file);
kfree(data);
} else {
/* Just store the data in a buffer */
void *data = kmalloc(datalen, GFP_KERNEL);
if (!data)
return -ENOMEM;
@ -108,7 +203,10 @@ int big_key_preparse(struct key_preparsed_payload *prep)
err_fput:
fput(file);
err_enckey:
kfree(enckey);
error:
kfree(data);
return ret;
}
@ -119,10 +217,10 @@ void big_key_free_preparse(struct key_preparsed_payload *prep)
{
if (prep->datalen > BIG_KEY_FILE_THRESHOLD) {
struct path *path = (struct path *)&prep->payload.data[big_key_path];
path_put(path);
} else {
kfree(prep->payload.data[big_key_data]);
}
kfree(prep->payload.data[big_key_data]);
}
/*
@ -147,15 +245,15 @@ void big_key_destroy(struct key *key)
{
size_t datalen = (size_t)key->payload.data[big_key_len];
if (datalen) {
if (datalen > BIG_KEY_FILE_THRESHOLD) {
struct path *path = (struct path *)&key->payload.data[big_key_path];
path_put(path);
path->mnt = NULL;
path->dentry = NULL;
} else {
kfree(key->payload.data[big_key_data]);
key->payload.data[big_key_data] = NULL;
}
kfree(key->payload.data[big_key_data]);
key->payload.data[big_key_data] = NULL;
}
/*
@ -188,17 +286,41 @@ long big_key_read(const struct key *key, char __user *buffer, size_t buflen)
if (datalen > BIG_KEY_FILE_THRESHOLD) {
struct path *path = (struct path *)&key->payload.data[big_key_path];
struct file *file;
loff_t pos;
u8 *data;
u8 *enckey = (u8 *)key->payload.data[big_key_data];
size_t enclen = ALIGN(datalen, crypto_blkcipher_blocksize(big_key_blkcipher));
data = kmalloc(enclen, GFP_KERNEL);
if (!data)
return -ENOMEM;
file = dentry_open(path, O_RDONLY, current_cred());
if (IS_ERR(file))
return PTR_ERR(file);
if (IS_ERR(file)) {
ret = PTR_ERR(file);
goto error;
}
pos = 0;
ret = vfs_read(file, buffer, datalen, &pos);
fput(file);
if (ret >= 0 && ret != datalen)
/* read file to kernel and decrypt */
ret = kernel_read(file, 0, data, enclen);
if (ret >= 0 && ret != enclen) {
ret = -EIO;
goto err_fput;
}
ret = big_key_crypt(BIG_KEY_DEC, data, enclen, enckey);
if (ret)
goto err_fput;
ret = datalen;
/* copy decrypted data to user */
if (copy_to_user(buffer, data, datalen) != 0)
ret = -EFAULT;
err_fput:
fput(file);
error:
kfree(data);
} else {
ret = datalen;
if (copy_to_user(buffer, key->payload.data[big_key_data],
@ -209,8 +331,48 @@ long big_key_read(const struct key *key, char __user *buffer, size_t buflen)
return ret;
}
/*
* Register key type
*/
static int __init big_key_init(void)
{
return register_key_type(&key_type_big_key);
}
/*
* Initialize big_key crypto and RNG algorithms
*/
static int __init big_key_crypto_init(void)
{
int ret = -EINVAL;
/* init RNG */
big_key_rng = crypto_alloc_rng(big_key_rng_name, 0, 0);
if (IS_ERR(big_key_rng)) {
big_key_rng = NULL;
return -EFAULT;
}
/* seed RNG */
ret = crypto_rng_reset(big_key_rng, NULL, crypto_rng_seedsize(big_key_rng));
if (ret)
goto error;
/* init block cipher */
big_key_blkcipher = crypto_alloc_blkcipher(big_key_alg_name, 0, 0);
if (IS_ERR(big_key_blkcipher)) {
big_key_blkcipher = NULL;
ret = -EFAULT;
goto error;
}
return 0;
error:
crypto_free_rng(big_key_rng);
big_key_rng = NULL;
return ret;
}
device_initcall(big_key_init);
late_initcall(big_key_crypto_init);

4
security/keys/compat.c
View File

@ -132,6 +132,10 @@ COMPAT_SYSCALL_DEFINE5(keyctl, u32, option,
case KEYCTL_GET_PERSISTENT:
return keyctl_get_persistent(arg2, arg3);
case KEYCTL_DH_COMPUTE:
return keyctl_dh_compute(compat_ptr(arg2), compat_ptr(arg3),
arg4);
default:
return -EOPNOTSUPP;
}

160
security/keys/dh.c Normal file
View File

@ -0,0 +1,160 @@
/* Crypto operations using stored keys
*
* Copyright (c) 2016, Intel Corporation
*
* 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 <linux/mpi.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <keys/user-type.h>
#include "internal.h"
/*
* Public key or shared secret generation function [RFC2631 sec 2.1.1]
*
* ya = g^xa mod p;
* or
* ZZ = yb^xa mod p;
*
* where xa is the local private key, ya is the local public key, g is
* the generator, p is the prime, yb is the remote public key, and ZZ
* is the shared secret.
*
* Both are the same calculation, so g or yb are the "base" and ya or
* ZZ are the "result".
*/
static int do_dh(MPI result, MPI base, MPI xa, MPI p)
{
return mpi_powm(result, base, xa, p);
}
static ssize_t mpi_from_key(key_serial_t keyid, size_t maxlen, MPI *mpi)
{
struct key *key;
key_ref_t key_ref;
long status;
ssize_t ret;
key_ref = lookup_user_key(keyid, 0, KEY_NEED_READ);
if (IS_ERR(key_ref)) {
ret = -ENOKEY;
goto error;
}
key = key_ref_to_ptr(key_ref);
ret = -EOPNOTSUPP;
if (key->type == &key_type_user) {
down_read(&key->sem);
status = key_validate(key);
if (status == 0) {
const struct user_key_payload *payload;
payload = user_key_payload(key);
if (maxlen == 0) {
*mpi = NULL;
ret = payload->datalen;
} else if (payload->datalen <= maxlen) {
*mpi = mpi_read_raw_data(payload->data,
payload->datalen);
if (*mpi)
ret = payload->datalen;
} else {
ret = -EINVAL;
}
}
up_read(&key->sem);
}
key_put(key);
error:
return ret;
}
long keyctl_dh_compute(struct keyctl_dh_params __user *params,
char __user *buffer, size_t buflen)
{
long ret;
MPI base, private, prime, result;
unsigned nbytes;
struct keyctl_dh_params pcopy;
uint8_t *kbuf;
ssize_t keylen;
size_t resultlen;
if (!params || (!buffer && buflen)) {
ret = -EINVAL;
goto out;
}
if (copy_from_user(&pcopy, params, sizeof(pcopy)) != 0) {
ret = -EFAULT;
goto out;
}
keylen = mpi_from_key(pcopy.prime, buflen, &prime);
if (keylen < 0 || !prime) {
/* buflen == 0 may be used to query the required buffer size,
* which is the prime key length.
*/
ret = keylen;
goto out;
}
/* The result is never longer than the prime */
resultlen = keylen;
keylen = mpi_from_key(pcopy.base, SIZE_MAX, &base);
if (keylen < 0 || !base) {
ret = keylen;
goto error1;
}
keylen = mpi_from_key(pcopy.private, SIZE_MAX, &private);
if (keylen < 0 || !private) {
ret = keylen;
goto error2;
}
result = mpi_alloc(0);
if (!result) {
ret = -ENOMEM;
goto error3;
}
kbuf = kmalloc(resultlen, GFP_KERNEL);
if (!kbuf) {
ret = -ENOMEM;
goto error4;
}
ret = do_dh(result, base, private, prime);
if (ret)
goto error5;
ret = mpi_read_buffer(result, kbuf, resultlen, &nbytes, NULL);
if (ret != 0)
goto error5;
ret = nbytes;
if (copy_to_user(buffer, kbuf, nbytes) != 0)
ret = -EFAULT;
error5:
kfree(kbuf);
error4:
mpi_free(result);
error3:
mpi_free(private);
error2:
mpi_free(base);
error1:
mpi_free(prime);
out:
return ret;
}

12
security/keys/internal.h
View File

@ -15,6 +15,7 @@
#include <linux/sched.h>
#include <linux/key-type.h>
#include <linux/task_work.h>
#include <linux/keyctl.h>
struct iovec;
@ -257,6 +258,17 @@ static inline long keyctl_get_persistent(uid_t uid, key_serial_t destring)
}
#endif
#ifdef CONFIG_KEY_DH_OPERATIONS
extern long keyctl_dh_compute(struct keyctl_dh_params __user *, char __user *,
size_t);
#else
static inline long keyctl_dh_compute(struct keyctl_dh_params __user *params,
char __user *buffer, size_t buflen)
{
return -EOPNOTSUPP;
}
#endif
/*
* Debugging key validation
*/

5
security/keys/keyctl.c
View File

@ -1686,6 +1686,11 @@ SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
case KEYCTL_GET_PERSISTENT:
return keyctl_get_persistent((uid_t)arg2, (key_serial_t)arg3);
case KEYCTL_DH_COMPUTE:
return keyctl_dh_compute((struct keyctl_dh_params __user *) arg2,
(char __user *) arg3,
(size_t) arg4);
default:
return -EOPNOTSUPP;
}

40
security/keys/user_defined.c
View File

@ -96,45 +96,25 @@ EXPORT_SYMBOL_GPL(user_free_preparse);
*/
int user_update(struct key *key, struct key_preparsed_payload *prep)
{
struct user_key_payload *upayload, *zap;
size_t datalen = prep->datalen;
struct user_key_payload *zap = NULL;
int ret;
ret = -EINVAL;
if (datalen <= 0 || datalen > 32767 || !prep->data)
goto error;
/* construct a replacement payload */
ret = -ENOMEM;
upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL);
if (!upayload)
goto error;
upayload->datalen = datalen;
memcpy(upayload->data, prep->data, datalen);
/* check the quota and attach the new data */
zap = upayload;
ret = key_payload_reserve(key, prep->datalen);
if (ret < 0)
return ret;
ret = key_payload_reserve(key, datalen);
if (ret == 0) {
/* attach the new data, displacing the old */
if (!test_bit(KEY_FLAG_NEGATIVE, &key->flags))
zap = key->payload.data[0];
else
zap = NULL;
rcu_assign_keypointer(key, upayload);
key->expiry = 0;
}
/* attach the new data, displacing the old */
key->expiry = prep->expiry;
if (!test_bit(KEY_FLAG_NEGATIVE, &key->flags))
zap = rcu_dereference_key(key);
rcu_assign_keypointer(key, prep->payload.data[0]);
prep->payload.data[0] = NULL;
if (zap)
kfree_rcu(zap, rcu);
error:
return ret;
}
EXPORT_SYMBOL_GPL(user_update);
/*