Revision fea20995976f4b2e8968f852a18e280487d42f0d authored by Paul Kocialkowski on 10 July 2017, 19:33:05 UTC, committed by Thierry Reding on 27 July 2017, 14:57:34 UTC
When there is no device to attach to the IOMMU domain, as may be the case when the device-tree does not contain the proper iommu node, it is best to keep going without IOMMU support rather than failing. This allows the driver to probe and function instead of taking down all of the tegra drm driver, leading to missing display support. Signed-off-by: Paul Kocialkowski <contact@paulk.fr> Fixes: 404bfb78daf3 ("gpu: host1x: Add IOMMU support") Reviewed-by: Mikko Perttunen <mperttunen@nvidia.com> Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com> Signed-off-by: Thierry Reding <treding@nvidia.com> Link: https://patchwork.freedesktop.org/patch/msgid/20170710193305.5987-1-contact@paulk.fr
1 parent b9670ca
big_key.c
/* Large capacity key type
*
* Copyright (C) 2013 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#define pr_fmt(fmt) "big_key: "fmt
#include <linux/init.h>
#include <linux/seq_file.h>
#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>
#include <crypto/skcipher.h>
/*
* Layout of key payload words.
*/
enum {
big_key_data,
big_key_path,
big_key_path_2nd_part,
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
* least as large as the data.
*/
#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
*/
struct key_type key_type_big_key = {
.name = "big_key",
.preparse = big_key_preparse,
.free_preparse = big_key_free_preparse,
.instantiate = generic_key_instantiate,
.revoke = big_key_revoke,
.destroy = big_key_destroy,
.describe = big_key_describe,
.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_skcipher *big_key_skcipher;
/*
* 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;
SKCIPHER_REQUEST_ON_STACK(req, big_key_skcipher);
if (crypto_skcipher_setkey(big_key_skcipher, key, ENC_KEY_SIZE)) {
ret = -EAGAIN;
goto error;
}
skcipher_request_set_tfm(req, big_key_skcipher);
skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
NULL, NULL);
sg_init_one(&sgio, data, datalen);
skcipher_request_set_crypt(req, &sgio, &sgio, datalen, NULL);
if (op == BIG_KEY_ENC)
ret = crypto_skcipher_encrypt(req);
else
ret = crypto_skcipher_decrypt(req);
skcipher_request_zero(req);
error:
return ret;
}
/*
* Preparse a big key
*/
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;
ret = -EINVAL;
if (datalen <= 0 || datalen > 1024 * 1024 || !prep->data)
goto error;
/* Set an arbitrary quota */
prep->quotalen = 16;
prep->payload.data[big_key_len] = (void *)(unsigned long)datalen;
if (datalen > BIG_KEY_FILE_THRESHOLD) {
/* Create a shmem file to store the data in. This will permit the data
* to be swapped out if needed.
*
* File content is stored encrypted with randomly generated key.
*/
size_t enclen = ALIGN(datalen, crypto_skcipher_blocksize(big_key_skcipher));
/* 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;
}
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;
goto err_fput;
}
/* 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;
prep->payload.data[big_key_data] = data;
memcpy(data, prep->data, prep->datalen);
}
return 0;
err_fput:
fput(file);
err_enckey:
kfree(enckey);
error:
kfree(data);
return ret;
}
/*
* Clear preparsement.
*/
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);
}
kfree(prep->payload.data[big_key_data]);
}
/*
* dispose of the links from a revoked keyring
* - called with the key sem write-locked
*/
void big_key_revoke(struct key *key)
{
struct path *path = (struct path *)&key->payload.data[big_key_path];
/* clear the quota */
key_payload_reserve(key, 0);
if (key_is_instantiated(key) &&
(size_t)key->payload.data[big_key_len] > BIG_KEY_FILE_THRESHOLD)
vfs_truncate(path, 0);
}
/*
* dispose of the data dangling from the corpse of a big_key key
*/
void big_key_destroy(struct key *key)
{
size_t datalen = (size_t)key->payload.data[big_key_len];
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;
}
kfree(key->payload.data[big_key_data]);
key->payload.data[big_key_data] = NULL;
}
/*
* describe the big_key key
*/
void big_key_describe(const struct key *key, struct seq_file *m)
{
size_t datalen = (size_t)key->payload.data[big_key_len];
seq_puts(m, key->description);
if (key_is_instantiated(key))
seq_printf(m, ": %zu [%s]",
datalen,
datalen > BIG_KEY_FILE_THRESHOLD ? "file" : "buff");
}
/*
* read the key data
* - the key's semaphore is read-locked
*/
long big_key_read(const struct key *key, char __user *buffer, size_t buflen)
{
size_t datalen = (size_t)key->payload.data[big_key_len];
long ret;
if (!buffer || buflen < datalen)
return datalen;
if (datalen > BIG_KEY_FILE_THRESHOLD) {
struct path *path = (struct path *)&key->payload.data[big_key_path];
struct file *file;
u8 *data;
u8 *enckey = (u8 *)key->payload.data[big_key_data];
size_t enclen = ALIGN(datalen, crypto_skcipher_blocksize(big_key_skcipher));
data = kmalloc(enclen, GFP_KERNEL);
if (!data)
return -ENOMEM;
file = dentry_open(path, O_RDONLY, current_cred());
if (IS_ERR(file)) {
ret = PTR_ERR(file);
goto error;
}
/* 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],
datalen) != 0)
ret = -EFAULT;
}
return ret;
}
/*
* Register key type
*/
static int __init big_key_init(void)
{
struct crypto_skcipher *cipher;
struct crypto_rng *rng;
int ret;
rng = crypto_alloc_rng(big_key_rng_name, 0, 0);
if (IS_ERR(rng)) {
pr_err("Can't alloc rng: %ld\n", PTR_ERR(rng));
return PTR_ERR(rng);
}
big_key_rng = rng;
/* seed RNG */
ret = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(rng));
if (ret) {
pr_err("Can't reset rng: %d\n", ret);
goto error_rng;
}
/* init block cipher */
cipher = crypto_alloc_skcipher(big_key_alg_name, 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(cipher)) {
ret = PTR_ERR(cipher);
pr_err("Can't alloc crypto: %d\n", ret);
goto error_rng;
}
big_key_skcipher = cipher;
ret = register_key_type(&key_type_big_key);
if (ret < 0) {
pr_err("Can't register type: %d\n", ret);
goto error_cipher;
}
return 0;
error_cipher:
crypto_free_skcipher(big_key_skcipher);
error_rng:
crypto_free_rng(big_key_rng);
return ret;
}
late_initcall(big_key_init);
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