License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 22:07:57 +08:00
|
|
|
// SPDX-License-Identifier: GPL-2.0
|
2015-04-22 07:23:47 +08:00
|
|
|
/*
|
2015-05-16 07:26:10 +08:00
|
|
|
* key management facility for FS encryption support.
|
2015-04-22 07:23:47 +08:00
|
|
|
*
|
|
|
|
* Copyright (C) 2015, Google, Inc.
|
|
|
|
*
|
2015-05-16 07:26:10 +08:00
|
|
|
* This contains encryption key functions.
|
2015-04-22 07:23:47 +08:00
|
|
|
*
|
|
|
|
* Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.
|
|
|
|
*/
|
2015-05-16 07:26:10 +08:00
|
|
|
|
2015-04-22 07:23:47 +08:00
|
|
|
#include <keys/user-type.h>
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
#include <linux/hashtable.h>
|
2015-04-22 07:23:47 +08:00
|
|
|
#include <linux/scatterlist.h>
|
2017-06-19 15:27:58 +08:00
|
|
|
#include <crypto/aes.h>
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
#include <crypto/algapi.h>
|
2017-06-19 15:27:58 +08:00
|
|
|
#include <crypto/sha.h>
|
2018-01-06 02:45:00 +08:00
|
|
|
#include <crypto/skcipher.h>
|
2016-11-27 09:32:46 +08:00
|
|
|
#include "fscrypt_private.h"
|
2015-04-22 07:23:47 +08:00
|
|
|
|
2017-06-19 15:27:58 +08:00
|
|
|
static struct crypto_shash *essiv_hash_tfm;
|
|
|
|
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
/* Table of keys referenced by FS_POLICY_FLAG_DIRECT_KEY policies */
|
|
|
|
static DEFINE_HASHTABLE(fscrypt_master_keys, 6); /* 6 bits = 64 buckets */
|
|
|
|
static DEFINE_SPINLOCK(fscrypt_master_keys_lock);
|
|
|
|
|
2018-05-01 06:51:49 +08:00
|
|
|
/*
|
|
|
|
* Key derivation function. This generates the derived key by encrypting the
|
|
|
|
* master key with AES-128-ECB using the inode's nonce as the AES key.
|
2015-04-22 07:23:47 +08:00
|
|
|
*
|
2018-05-01 06:51:49 +08:00
|
|
|
* The master key must be at least as long as the derived key. If the master
|
|
|
|
* key is longer, then only the first 'derived_keysize' bytes are used.
|
2015-04-22 07:23:47 +08:00
|
|
|
*/
|
2018-05-01 06:51:49 +08:00
|
|
|
static int derive_key_aes(const u8 *master_key,
|
|
|
|
const struct fscrypt_context *ctx,
|
|
|
|
u8 *derived_key, unsigned int derived_keysize)
|
2015-04-22 07:23:47 +08:00
|
|
|
{
|
|
|
|
int res = 0;
|
2016-03-22 02:03:02 +08:00
|
|
|
struct skcipher_request *req = NULL;
|
2017-10-18 15:00:44 +08:00
|
|
|
DECLARE_CRYPTO_WAIT(wait);
|
2015-04-22 07:23:47 +08:00
|
|
|
struct scatterlist src_sg, dst_sg;
|
2016-03-22 02:03:02 +08:00
|
|
|
struct crypto_skcipher *tfm = crypto_alloc_skcipher("ecb(aes)", 0, 0);
|
2015-04-22 07:23:47 +08:00
|
|
|
|
|
|
|
if (IS_ERR(tfm)) {
|
|
|
|
res = PTR_ERR(tfm);
|
|
|
|
tfm = NULL;
|
|
|
|
goto out;
|
|
|
|
}
|
2019-01-19 14:48:00 +08:00
|
|
|
crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
|
2016-03-22 02:03:02 +08:00
|
|
|
req = skcipher_request_alloc(tfm, GFP_NOFS);
|
2015-04-22 07:23:47 +08:00
|
|
|
if (!req) {
|
|
|
|
res = -ENOMEM;
|
|
|
|
goto out;
|
|
|
|
}
|
2016-03-22 02:03:02 +08:00
|
|
|
skcipher_request_set_callback(req,
|
2015-04-22 07:23:47 +08:00
|
|
|
CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
|
2017-10-18 15:00:44 +08:00
|
|
|
crypto_req_done, &wait);
|
2018-05-01 06:51:49 +08:00
|
|
|
res = crypto_skcipher_setkey(tfm, ctx->nonce, sizeof(ctx->nonce));
|
2015-04-22 07:23:47 +08:00
|
|
|
if (res < 0)
|
|
|
|
goto out;
|
|
|
|
|
2018-05-01 06:51:49 +08:00
|
|
|
sg_init_one(&src_sg, master_key, derived_keysize);
|
|
|
|
sg_init_one(&dst_sg, derived_key, derived_keysize);
|
|
|
|
skcipher_request_set_crypt(req, &src_sg, &dst_sg, derived_keysize,
|
2017-06-19 15:27:58 +08:00
|
|
|
NULL);
|
2017-10-18 15:00:44 +08:00
|
|
|
res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait);
|
2015-04-22 07:23:47 +08:00
|
|
|
out:
|
2016-03-22 02:03:02 +08:00
|
|
|
skcipher_request_free(req);
|
|
|
|
crypto_free_skcipher(tfm);
|
2015-04-22 07:23:47 +08:00
|
|
|
return res;
|
|
|
|
}
|
|
|
|
|
2018-05-01 06:51:48 +08:00
|
|
|
/*
|
|
|
|
* Search the current task's subscribed keyrings for a "logon" key with
|
|
|
|
* description prefix:descriptor, and if found acquire a read lock on it and
|
|
|
|
* return a pointer to its validated payload in *payload_ret.
|
|
|
|
*/
|
|
|
|
static struct key *
|
|
|
|
find_and_lock_process_key(const char *prefix,
|
|
|
|
const u8 descriptor[FS_KEY_DESCRIPTOR_SIZE],
|
|
|
|
unsigned int min_keysize,
|
|
|
|
const struct fscrypt_key **payload_ret)
|
2016-05-05 13:05:01 +08:00
|
|
|
{
|
2017-01-06 05:51:18 +08:00
|
|
|
char *description;
|
2018-05-01 06:51:48 +08:00
|
|
|
struct key *key;
|
2016-05-05 13:05:01 +08:00
|
|
|
const struct user_key_payload *ukp;
|
2018-05-01 06:51:48 +08:00
|
|
|
const struct fscrypt_key *payload;
|
2016-05-05 13:05:01 +08:00
|
|
|
|
2017-01-06 05:51:18 +08:00
|
|
|
description = kasprintf(GFP_NOFS, "%s%*phN", prefix,
|
2018-05-01 06:51:48 +08:00
|
|
|
FS_KEY_DESCRIPTOR_SIZE, descriptor);
|
2017-01-06 05:51:18 +08:00
|
|
|
if (!description)
|
2018-05-01 06:51:48 +08:00
|
|
|
return ERR_PTR(-ENOMEM);
|
2016-05-05 13:05:01 +08:00
|
|
|
|
2018-05-01 06:51:48 +08:00
|
|
|
key = request_key(&key_type_logon, description, NULL);
|
2017-01-06 05:51:18 +08:00
|
|
|
kfree(description);
|
2018-05-01 06:51:48 +08:00
|
|
|
if (IS_ERR(key))
|
|
|
|
return key;
|
|
|
|
|
|
|
|
down_read(&key->sem);
|
|
|
|
ukp = user_key_payload_locked(key);
|
|
|
|
|
|
|
|
if (!ukp) /* was the key revoked before we acquired its semaphore? */
|
|
|
|
goto invalid;
|
|
|
|
|
|
|
|
payload = (const struct fscrypt_key *)ukp->data;
|
|
|
|
|
|
|
|
if (ukp->datalen != sizeof(struct fscrypt_key) ||
|
|
|
|
payload->size < 1 || payload->size > FS_MAX_KEY_SIZE) {
|
|
|
|
fscrypt_warn(NULL,
|
|
|
|
"key with description '%s' has invalid payload",
|
|
|
|
key->description);
|
|
|
|
goto invalid;
|
2017-10-10 03:46:18 +08:00
|
|
|
}
|
2018-05-01 06:51:48 +08:00
|
|
|
|
2018-05-01 06:51:49 +08:00
|
|
|
if (payload->size < min_keysize) {
|
2018-05-01 06:51:48 +08:00
|
|
|
fscrypt_warn(NULL,
|
2018-05-01 06:51:49 +08:00
|
|
|
"key with description '%s' is too short (got %u bytes, need %u+ bytes)",
|
2018-05-01 06:51:48 +08:00
|
|
|
key->description, payload->size, min_keysize);
|
|
|
|
goto invalid;
|
2016-05-05 13:05:01 +08:00
|
|
|
}
|
|
|
|
|
2018-05-01 06:51:48 +08:00
|
|
|
*payload_ret = payload;
|
|
|
|
return key;
|
|
|
|
|
|
|
|
invalid:
|
|
|
|
up_read(&key->sem);
|
|
|
|
key_put(key);
|
|
|
|
return ERR_PTR(-ENOKEY);
|
|
|
|
}
|
|
|
|
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
static struct fscrypt_mode available_modes[] = {
|
2018-05-19 01:58:14 +08:00
|
|
|
[FS_ENCRYPTION_MODE_AES_256_XTS] = {
|
|
|
|
.friendly_name = "AES-256-XTS",
|
|
|
|
.cipher_str = "xts(aes)",
|
|
|
|
.keysize = 64,
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
.ivsize = 16,
|
2018-05-19 01:58:14 +08:00
|
|
|
},
|
|
|
|
[FS_ENCRYPTION_MODE_AES_256_CTS] = {
|
|
|
|
.friendly_name = "AES-256-CTS-CBC",
|
|
|
|
.cipher_str = "cts(cbc(aes))",
|
|
|
|
.keysize = 32,
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
.ivsize = 16,
|
2018-05-19 01:58:14 +08:00
|
|
|
},
|
|
|
|
[FS_ENCRYPTION_MODE_AES_128_CBC] = {
|
|
|
|
.friendly_name = "AES-128-CBC",
|
|
|
|
.cipher_str = "cbc(aes)",
|
|
|
|
.keysize = 16,
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
.ivsize = 16,
|
|
|
|
.needs_essiv = true,
|
2018-05-19 01:58:14 +08:00
|
|
|
},
|
|
|
|
[FS_ENCRYPTION_MODE_AES_128_CTS] = {
|
|
|
|
.friendly_name = "AES-128-CTS-CBC",
|
|
|
|
.cipher_str = "cts(cbc(aes))",
|
|
|
|
.keysize = 16,
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
.ivsize = 16,
|
|
|
|
},
|
|
|
|
[FS_ENCRYPTION_MODE_ADIANTUM] = {
|
|
|
|
.friendly_name = "Adiantum",
|
|
|
|
.cipher_str = "adiantum(xchacha12,aes)",
|
|
|
|
.keysize = 32,
|
|
|
|
.ivsize = 32,
|
2018-05-19 01:58:14 +08:00
|
|
|
},
|
2017-06-19 15:27:58 +08:00
|
|
|
};
|
|
|
|
|
2018-05-19 01:58:14 +08:00
|
|
|
static struct fscrypt_mode *
|
|
|
|
select_encryption_mode(const struct fscrypt_info *ci, const struct inode *inode)
|
2016-09-16 01:32:11 +08:00
|
|
|
{
|
2017-06-19 15:27:58 +08:00
|
|
|
if (!fscrypt_valid_enc_modes(ci->ci_data_mode, ci->ci_filename_mode)) {
|
2019-07-25 02:07:58 +08:00
|
|
|
fscrypt_warn(inode,
|
|
|
|
"Unsupported encryption modes (contents mode %d, filenames mode %d)",
|
|
|
|
ci->ci_data_mode, ci->ci_filename_mode);
|
2018-05-19 01:58:14 +08:00
|
|
|
return ERR_PTR(-EINVAL);
|
2016-09-16 01:32:11 +08:00
|
|
|
}
|
|
|
|
|
2018-05-19 01:58:14 +08:00
|
|
|
if (S_ISREG(inode->i_mode))
|
|
|
|
return &available_modes[ci->ci_data_mode];
|
|
|
|
|
|
|
|
if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
|
|
|
|
return &available_modes[ci->ci_filename_mode];
|
2016-09-16 01:32:11 +08:00
|
|
|
|
2018-05-19 01:58:14 +08:00
|
|
|
WARN_ONCE(1, "fscrypt: filesystem tried to load encryption info for inode %lu, which is not encryptable (file type %d)\n",
|
|
|
|
inode->i_ino, (inode->i_mode & S_IFMT));
|
|
|
|
return ERR_PTR(-EINVAL);
|
2016-09-16 01:32:11 +08:00
|
|
|
}
|
|
|
|
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
/* Find the master key, then derive the inode's actual encryption key */
|
|
|
|
static int find_and_derive_key(const struct inode *inode,
|
|
|
|
const struct fscrypt_context *ctx,
|
|
|
|
u8 *derived_key, const struct fscrypt_mode *mode)
|
2015-04-22 07:23:47 +08:00
|
|
|
{
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
struct key *key;
|
|
|
|
const struct fscrypt_key *payload;
|
|
|
|
int err;
|
|
|
|
|
|
|
|
key = find_and_lock_process_key(FS_KEY_DESC_PREFIX,
|
|
|
|
ctx->master_key_descriptor,
|
|
|
|
mode->keysize, &payload);
|
|
|
|
if (key == ERR_PTR(-ENOKEY) && inode->i_sb->s_cop->key_prefix) {
|
|
|
|
key = find_and_lock_process_key(inode->i_sb->s_cop->key_prefix,
|
|
|
|
ctx->master_key_descriptor,
|
|
|
|
mode->keysize, &payload);
|
|
|
|
}
|
|
|
|
if (IS_ERR(key))
|
|
|
|
return PTR_ERR(key);
|
|
|
|
|
|
|
|
if (ctx->flags & FS_POLICY_FLAG_DIRECT_KEY) {
|
|
|
|
if (mode->ivsize < offsetofend(union fscrypt_iv, nonce)) {
|
2019-07-25 02:07:58 +08:00
|
|
|
fscrypt_warn(inode,
|
|
|
|
"Direct key mode not allowed with %s",
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
mode->friendly_name);
|
|
|
|
err = -EINVAL;
|
|
|
|
} else if (ctx->contents_encryption_mode !=
|
|
|
|
ctx->filenames_encryption_mode) {
|
2019-07-25 02:07:58 +08:00
|
|
|
fscrypt_warn(inode,
|
|
|
|
"Direct key mode not allowed with different contents and filenames modes");
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
err = -EINVAL;
|
|
|
|
} else {
|
|
|
|
memcpy(derived_key, payload->raw, mode->keysize);
|
|
|
|
err = 0;
|
|
|
|
}
|
|
|
|
} else {
|
|
|
|
err = derive_key_aes(payload->raw, ctx, derived_key,
|
|
|
|
mode->keysize);
|
|
|
|
}
|
|
|
|
up_read(&key->sem);
|
|
|
|
key_put(key);
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Allocate and key a symmetric cipher object for the given encryption mode */
|
|
|
|
static struct crypto_skcipher *
|
|
|
|
allocate_skcipher_for_mode(struct fscrypt_mode *mode, const u8 *raw_key,
|
|
|
|
const struct inode *inode)
|
|
|
|
{
|
|
|
|
struct crypto_skcipher *tfm;
|
|
|
|
int err;
|
|
|
|
|
|
|
|
tfm = crypto_alloc_skcipher(mode->cipher_str, 0, 0);
|
|
|
|
if (IS_ERR(tfm)) {
|
2019-07-25 02:07:59 +08:00
|
|
|
if (PTR_ERR(tfm) == -ENOENT)
|
|
|
|
fscrypt_warn(inode,
|
|
|
|
"Missing crypto API support for %s (API name: \"%s\")",
|
|
|
|
mode->friendly_name, mode->cipher_str);
|
|
|
|
else
|
|
|
|
fscrypt_err(inode, "Error allocating '%s' transform: %ld",
|
|
|
|
mode->cipher_str, PTR_ERR(tfm));
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
return tfm;
|
|
|
|
}
|
|
|
|
if (unlikely(!mode->logged_impl_name)) {
|
|
|
|
/*
|
|
|
|
* fscrypt performance can vary greatly depending on which
|
|
|
|
* crypto algorithm implementation is used. Help people debug
|
|
|
|
* performance problems by logging the ->cra_driver_name the
|
|
|
|
* first time a mode is used. Note that multiple threads can
|
|
|
|
* race here, but it doesn't really matter.
|
|
|
|
*/
|
|
|
|
mode->logged_impl_name = true;
|
|
|
|
pr_info("fscrypt: %s using implementation \"%s\"\n",
|
|
|
|
mode->friendly_name,
|
|
|
|
crypto_skcipher_alg(tfm)->base.cra_driver_name);
|
|
|
|
}
|
2019-01-19 14:48:00 +08:00
|
|
|
crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
err = crypto_skcipher_setkey(tfm, raw_key, mode->keysize);
|
|
|
|
if (err)
|
|
|
|
goto err_free_tfm;
|
|
|
|
|
|
|
|
return tfm;
|
|
|
|
|
|
|
|
err_free_tfm:
|
|
|
|
crypto_free_skcipher(tfm);
|
|
|
|
return ERR_PTR(err);
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Master key referenced by FS_POLICY_FLAG_DIRECT_KEY policy */
|
|
|
|
struct fscrypt_master_key {
|
|
|
|
struct hlist_node mk_node;
|
|
|
|
refcount_t mk_refcount;
|
|
|
|
const struct fscrypt_mode *mk_mode;
|
|
|
|
struct crypto_skcipher *mk_ctfm;
|
|
|
|
u8 mk_descriptor[FS_KEY_DESCRIPTOR_SIZE];
|
|
|
|
u8 mk_raw[FS_MAX_KEY_SIZE];
|
|
|
|
};
|
|
|
|
|
|
|
|
static void free_master_key(struct fscrypt_master_key *mk)
|
|
|
|
{
|
|
|
|
if (mk) {
|
|
|
|
crypto_free_skcipher(mk->mk_ctfm);
|
|
|
|
kzfree(mk);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
static void put_master_key(struct fscrypt_master_key *mk)
|
|
|
|
{
|
|
|
|
if (!refcount_dec_and_lock(&mk->mk_refcount, &fscrypt_master_keys_lock))
|
2015-04-22 07:23:47 +08:00
|
|
|
return;
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
hash_del(&mk->mk_node);
|
|
|
|
spin_unlock(&fscrypt_master_keys_lock);
|
2015-04-22 07:23:47 +08:00
|
|
|
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
free_master_key(mk);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Find/insert the given master key into the fscrypt_master_keys table. If
|
|
|
|
* found, it is returned with elevated refcount, and 'to_insert' is freed if
|
|
|
|
* non-NULL. If not found, 'to_insert' is inserted and returned if it's
|
|
|
|
* non-NULL; otherwise NULL is returned.
|
|
|
|
*/
|
|
|
|
static struct fscrypt_master_key *
|
|
|
|
find_or_insert_master_key(struct fscrypt_master_key *to_insert,
|
|
|
|
const u8 *raw_key, const struct fscrypt_mode *mode,
|
|
|
|
const struct fscrypt_info *ci)
|
|
|
|
{
|
|
|
|
unsigned long hash_key;
|
|
|
|
struct fscrypt_master_key *mk;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Careful: to avoid potentially leaking secret key bytes via timing
|
|
|
|
* information, we must key the hash table by descriptor rather than by
|
|
|
|
* raw key, and use crypto_memneq() when comparing raw keys.
|
|
|
|
*/
|
|
|
|
|
|
|
|
BUILD_BUG_ON(sizeof(hash_key) > FS_KEY_DESCRIPTOR_SIZE);
|
|
|
|
memcpy(&hash_key, ci->ci_master_key_descriptor, sizeof(hash_key));
|
|
|
|
|
|
|
|
spin_lock(&fscrypt_master_keys_lock);
|
|
|
|
hash_for_each_possible(fscrypt_master_keys, mk, mk_node, hash_key) {
|
|
|
|
if (memcmp(ci->ci_master_key_descriptor, mk->mk_descriptor,
|
|
|
|
FS_KEY_DESCRIPTOR_SIZE) != 0)
|
|
|
|
continue;
|
|
|
|
if (mode != mk->mk_mode)
|
|
|
|
continue;
|
|
|
|
if (crypto_memneq(raw_key, mk->mk_raw, mode->keysize))
|
|
|
|
continue;
|
|
|
|
/* using existing tfm with same (descriptor, mode, raw_key) */
|
|
|
|
refcount_inc(&mk->mk_refcount);
|
|
|
|
spin_unlock(&fscrypt_master_keys_lock);
|
|
|
|
free_master_key(to_insert);
|
|
|
|
return mk;
|
|
|
|
}
|
|
|
|
if (to_insert)
|
|
|
|
hash_add(fscrypt_master_keys, &to_insert->mk_node, hash_key);
|
|
|
|
spin_unlock(&fscrypt_master_keys_lock);
|
|
|
|
return to_insert;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Prepare to encrypt directly using the master key in the given mode */
|
|
|
|
static struct fscrypt_master_key *
|
|
|
|
fscrypt_get_master_key(const struct fscrypt_info *ci, struct fscrypt_mode *mode,
|
|
|
|
const u8 *raw_key, const struct inode *inode)
|
|
|
|
{
|
|
|
|
struct fscrypt_master_key *mk;
|
|
|
|
int err;
|
|
|
|
|
|
|
|
/* Is there already a tfm for this key? */
|
|
|
|
mk = find_or_insert_master_key(NULL, raw_key, mode, ci);
|
|
|
|
if (mk)
|
|
|
|
return mk;
|
|
|
|
|
|
|
|
/* Nope, allocate one. */
|
|
|
|
mk = kzalloc(sizeof(*mk), GFP_NOFS);
|
|
|
|
if (!mk)
|
|
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
refcount_set(&mk->mk_refcount, 1);
|
|
|
|
mk->mk_mode = mode;
|
|
|
|
mk->mk_ctfm = allocate_skcipher_for_mode(mode, raw_key, inode);
|
|
|
|
if (IS_ERR(mk->mk_ctfm)) {
|
|
|
|
err = PTR_ERR(mk->mk_ctfm);
|
|
|
|
mk->mk_ctfm = NULL;
|
|
|
|
goto err_free_mk;
|
|
|
|
}
|
|
|
|
memcpy(mk->mk_descriptor, ci->ci_master_key_descriptor,
|
|
|
|
FS_KEY_DESCRIPTOR_SIZE);
|
|
|
|
memcpy(mk->mk_raw, raw_key, mode->keysize);
|
|
|
|
|
|
|
|
return find_or_insert_master_key(mk, raw_key, mode, ci);
|
|
|
|
|
|
|
|
err_free_mk:
|
|
|
|
free_master_key(mk);
|
|
|
|
return ERR_PTR(err);
|
2015-04-22 07:23:47 +08:00
|
|
|
}
|
|
|
|
|
2017-06-19 15:27:58 +08:00
|
|
|
static int derive_essiv_salt(const u8 *key, int keysize, u8 *salt)
|
|
|
|
{
|
|
|
|
struct crypto_shash *tfm = READ_ONCE(essiv_hash_tfm);
|
|
|
|
|
|
|
|
/* init hash transform on demand */
|
|
|
|
if (unlikely(!tfm)) {
|
|
|
|
struct crypto_shash *prev_tfm;
|
|
|
|
|
|
|
|
tfm = crypto_alloc_shash("sha256", 0, 0);
|
|
|
|
if (IS_ERR(tfm)) {
|
2019-07-25 02:07:59 +08:00
|
|
|
if (PTR_ERR(tfm) == -ENOENT)
|
|
|
|
fscrypt_warn(NULL,
|
|
|
|
"Missing crypto API support for SHA-256");
|
|
|
|
else
|
|
|
|
fscrypt_err(NULL,
|
|
|
|
"Error allocating SHA-256 transform: %ld",
|
|
|
|
PTR_ERR(tfm));
|
2017-06-19 15:27:58 +08:00
|
|
|
return PTR_ERR(tfm);
|
|
|
|
}
|
|
|
|
prev_tfm = cmpxchg(&essiv_hash_tfm, NULL, tfm);
|
|
|
|
if (prev_tfm) {
|
|
|
|
crypto_free_shash(tfm);
|
|
|
|
tfm = prev_tfm;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
{
|
|
|
|
SHASH_DESC_ON_STACK(desc, tfm);
|
|
|
|
desc->tfm = tfm;
|
|
|
|
|
|
|
|
return crypto_shash_digest(desc, key, keysize, salt);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
static int init_essiv_generator(struct fscrypt_info *ci, const u8 *raw_key,
|
|
|
|
int keysize)
|
|
|
|
{
|
|
|
|
int err;
|
|
|
|
struct crypto_cipher *essiv_tfm;
|
|
|
|
u8 salt[SHA256_DIGEST_SIZE];
|
|
|
|
|
|
|
|
essiv_tfm = crypto_alloc_cipher("aes", 0, 0);
|
|
|
|
if (IS_ERR(essiv_tfm))
|
|
|
|
return PTR_ERR(essiv_tfm);
|
|
|
|
|
|
|
|
ci->ci_essiv_tfm = essiv_tfm;
|
|
|
|
|
|
|
|
err = derive_essiv_salt(raw_key, keysize, salt);
|
|
|
|
if (err)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Using SHA256 to derive the salt/key will result in AES-256 being
|
|
|
|
* used for IV generation. File contents encryption will still use the
|
|
|
|
* configured keysize (AES-128) nevertheless.
|
|
|
|
*/
|
|
|
|
err = crypto_cipher_setkey(essiv_tfm, salt, sizeof(salt));
|
|
|
|
if (err)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
out:
|
|
|
|
memzero_explicit(salt, sizeof(salt));
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
/*
|
|
|
|
* Given the encryption mode and key (normally the derived key, but for
|
|
|
|
* FS_POLICY_FLAG_DIRECT_KEY mode it's the master key), set up the inode's
|
|
|
|
* symmetric cipher transform object(s).
|
|
|
|
*/
|
|
|
|
static int setup_crypto_transform(struct fscrypt_info *ci,
|
|
|
|
struct fscrypt_mode *mode,
|
|
|
|
const u8 *raw_key, const struct inode *inode)
|
|
|
|
{
|
|
|
|
struct fscrypt_master_key *mk;
|
|
|
|
struct crypto_skcipher *ctfm;
|
|
|
|
int err;
|
|
|
|
|
|
|
|
if (ci->ci_flags & FS_POLICY_FLAG_DIRECT_KEY) {
|
|
|
|
mk = fscrypt_get_master_key(ci, mode, raw_key, inode);
|
|
|
|
if (IS_ERR(mk))
|
|
|
|
return PTR_ERR(mk);
|
|
|
|
ctfm = mk->mk_ctfm;
|
|
|
|
} else {
|
|
|
|
mk = NULL;
|
|
|
|
ctfm = allocate_skcipher_for_mode(mode, raw_key, inode);
|
|
|
|
if (IS_ERR(ctfm))
|
|
|
|
return PTR_ERR(ctfm);
|
|
|
|
}
|
|
|
|
ci->ci_master_key = mk;
|
|
|
|
ci->ci_ctfm = ctfm;
|
|
|
|
|
|
|
|
if (mode->needs_essiv) {
|
|
|
|
/* ESSIV implies 16-byte IVs which implies !DIRECT_KEY */
|
|
|
|
WARN_ON(mode->ivsize != AES_BLOCK_SIZE);
|
|
|
|
WARN_ON(ci->ci_flags & FS_POLICY_FLAG_DIRECT_KEY);
|
|
|
|
|
|
|
|
err = init_essiv_generator(ci, raw_key, mode->keysize);
|
|
|
|
if (err) {
|
2019-07-25 02:07:58 +08:00
|
|
|
fscrypt_warn(inode,
|
|
|
|
"Error initializing ESSIV generator: %d",
|
|
|
|
err);
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
return err;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void put_crypt_info(struct fscrypt_info *ci)
|
|
|
|
{
|
|
|
|
if (!ci)
|
|
|
|
return;
|
|
|
|
|
|
|
|
if (ci->ci_master_key) {
|
|
|
|
put_master_key(ci->ci_master_key);
|
|
|
|
} else {
|
|
|
|
crypto_free_skcipher(ci->ci_ctfm);
|
|
|
|
crypto_free_cipher(ci->ci_essiv_tfm);
|
|
|
|
}
|
|
|
|
kmem_cache_free(fscrypt_info_cachep, ci);
|
|
|
|
}
|
|
|
|
|
fscrypt: remove broken support for detecting keyring key revocation
Filesystem encryption ostensibly supported revoking a keyring key that
had been used to "unlock" encrypted files, causing those files to become
"locked" again. This was, however, buggy for several reasons, the most
severe of which was that when key revocation happened to be detected for
an inode, its fscrypt_info was immediately freed, even while other
threads could be using it for encryption or decryption concurrently.
This could be exploited to crash the kernel or worse.
This patch fixes the use-after-free by removing the code which detects
the keyring key having been revoked, invalidated, or expired. Instead,
an encrypted inode that is "unlocked" now simply remains unlocked until
it is evicted from memory. Note that this is no worse than the case for
block device-level encryption, e.g. dm-crypt, and it still remains
possible for a privileged user to evict unused pages, inodes, and
dentries by running 'sync; echo 3 > /proc/sys/vm/drop_caches', or by
simply unmounting the filesystem. In fact, one of those actions was
already needed anyway for key revocation to work even somewhat sanely.
This change is not expected to break any applications.
In the future I'd like to implement a real API for fscrypt key
revocation that interacts sanely with ongoing filesystem operations ---
waiting for existing operations to complete and blocking new operations,
and invalidating and sanitizing key material and plaintext from the VFS
caches. But this is a hard problem, and for now this bug must be fixed.
This bug affected almost all versions of ext4, f2fs, and ubifs
encryption, and it was potentially reachable in any kernel configured
with encryption support (CONFIG_EXT4_ENCRYPTION=y,
CONFIG_EXT4_FS_ENCRYPTION=y, CONFIG_F2FS_FS_ENCRYPTION=y, or
CONFIG_UBIFS_FS_ENCRYPTION=y). Note that older kernels did not use the
shared fs/crypto/ code, but due to the potential security implications
of this bug, it may still be worthwhile to backport this fix to them.
Fixes: b7236e21d55f ("ext4 crypto: reorganize how we store keys in the inode")
Cc: stable@vger.kernel.org # v4.2+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Acked-by: Michael Halcrow <mhalcrow@google.com>
2017-02-22 07:07:11 +08:00
|
|
|
int fscrypt_get_encryption_info(struct inode *inode)
|
2015-04-22 07:23:47 +08:00
|
|
|
{
|
2015-05-16 07:26:10 +08:00
|
|
|
struct fscrypt_info *crypt_info;
|
|
|
|
struct fscrypt_context ctx;
|
2018-05-19 01:58:14 +08:00
|
|
|
struct fscrypt_mode *mode;
|
2016-11-14 09:41:09 +08:00
|
|
|
u8 *raw_key = NULL;
|
2015-04-22 07:23:47 +08:00
|
|
|
int res;
|
|
|
|
|
2019-04-12 05:32:15 +08:00
|
|
|
if (fscrypt_has_encryption_key(inode))
|
fscrypt: remove broken support for detecting keyring key revocation
Filesystem encryption ostensibly supported revoking a keyring key that
had been used to "unlock" encrypted files, causing those files to become
"locked" again. This was, however, buggy for several reasons, the most
severe of which was that when key revocation happened to be detected for
an inode, its fscrypt_info was immediately freed, even while other
threads could be using it for encryption or decryption concurrently.
This could be exploited to crash the kernel or worse.
This patch fixes the use-after-free by removing the code which detects
the keyring key having been revoked, invalidated, or expired. Instead,
an encrypted inode that is "unlocked" now simply remains unlocked until
it is evicted from memory. Note that this is no worse than the case for
block device-level encryption, e.g. dm-crypt, and it still remains
possible for a privileged user to evict unused pages, inodes, and
dentries by running 'sync; echo 3 > /proc/sys/vm/drop_caches', or by
simply unmounting the filesystem. In fact, one of those actions was
already needed anyway for key revocation to work even somewhat sanely.
This change is not expected to break any applications.
In the future I'd like to implement a real API for fscrypt key
revocation that interacts sanely with ongoing filesystem operations ---
waiting for existing operations to complete and blocking new operations,
and invalidating and sanitizing key material and plaintext from the VFS
caches. But this is a hard problem, and for now this bug must be fixed.
This bug affected almost all versions of ext4, f2fs, and ubifs
encryption, and it was potentially reachable in any kernel configured
with encryption support (CONFIG_EXT4_ENCRYPTION=y,
CONFIG_EXT4_FS_ENCRYPTION=y, CONFIG_F2FS_FS_ENCRYPTION=y, or
CONFIG_UBIFS_FS_ENCRYPTION=y). Note that older kernels did not use the
shared fs/crypto/ code, but due to the potential security implications
of this bug, it may still be worthwhile to backport this fix to them.
Fixes: b7236e21d55f ("ext4 crypto: reorganize how we store keys in the inode")
Cc: stable@vger.kernel.org # v4.2+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Acked-by: Michael Halcrow <mhalcrow@google.com>
2017-02-22 07:07:11 +08:00
|
|
|
return 0;
|
|
|
|
|
2016-12-07 06:53:57 +08:00
|
|
|
res = fscrypt_initialize(inode->i_sb->s_cop->flags);
|
2015-05-16 06:37:24 +08:00
|
|
|
if (res)
|
|
|
|
return res;
|
2015-05-16 07:26:10 +08:00
|
|
|
|
|
|
|
res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
|
|
|
|
if (res < 0) {
|
2017-01-03 04:12:17 +08:00
|
|
|
if (!fscrypt_dummy_context_enabled(inode) ||
|
2019-07-25 02:07:59 +08:00
|
|
|
IS_ENCRYPTED(inode)) {
|
|
|
|
fscrypt_warn(inode,
|
|
|
|
"Error %d getting encryption context",
|
|
|
|
res);
|
2015-05-16 07:26:10 +08:00
|
|
|
return res;
|
2019-07-25 02:07:59 +08:00
|
|
|
}
|
2017-01-03 04:12:17 +08:00
|
|
|
/* Fake up a context for an unencrypted directory */
|
|
|
|
memset(&ctx, 0, sizeof(ctx));
|
2016-09-16 01:32:11 +08:00
|
|
|
ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
|
2015-05-16 07:26:10 +08:00
|
|
|
ctx.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS;
|
|
|
|
ctx.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS;
|
2017-01-03 04:12:17 +08:00
|
|
|
memset(ctx.master_key_descriptor, 0x42, FS_KEY_DESCRIPTOR_SIZE);
|
2015-05-16 07:26:10 +08:00
|
|
|
} else if (res != sizeof(ctx)) {
|
2019-07-25 02:07:59 +08:00
|
|
|
fscrypt_warn(inode,
|
|
|
|
"Unknown encryption context size (%d bytes)", res);
|
2015-04-22 07:23:47 +08:00
|
|
|
return -EINVAL;
|
2015-05-16 07:26:10 +08:00
|
|
|
}
|
2016-09-16 01:32:11 +08:00
|
|
|
|
2019-07-25 02:07:59 +08:00
|
|
|
if (ctx.format != FS_ENCRYPTION_CONTEXT_FORMAT_V1) {
|
|
|
|
fscrypt_warn(inode, "Unknown encryption context version (%d)",
|
|
|
|
ctx.format);
|
2016-09-16 01:32:11 +08:00
|
|
|
return -EINVAL;
|
2019-07-25 02:07:59 +08:00
|
|
|
}
|
2016-09-16 01:32:11 +08:00
|
|
|
|
2019-07-25 02:07:59 +08:00
|
|
|
if (ctx.flags & ~FS_POLICY_FLAGS_VALID) {
|
|
|
|
fscrypt_warn(inode, "Unknown encryption context flags (0x%02x)",
|
|
|
|
ctx.flags);
|
2016-09-16 01:32:11 +08:00
|
|
|
return -EINVAL;
|
2019-07-25 02:07:59 +08:00
|
|
|
}
|
2015-04-22 07:23:47 +08:00
|
|
|
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
crypt_info = kmem_cache_zalloc(fscrypt_info_cachep, GFP_NOFS);
|
2015-04-22 07:23:47 +08:00
|
|
|
if (!crypt_info)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
crypt_info->ci_flags = ctx.flags;
|
|
|
|
crypt_info->ci_data_mode = ctx.contents_encryption_mode;
|
|
|
|
crypt_info->ci_filename_mode = ctx.filenames_encryption_mode;
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
memcpy(crypt_info->ci_master_key_descriptor, ctx.master_key_descriptor,
|
|
|
|
FS_KEY_DESCRIPTOR_SIZE);
|
|
|
|
memcpy(crypt_info->ci_nonce, ctx.nonce, FS_KEY_DERIVATION_NONCE_SIZE);
|
2015-05-13 04:33:00 +08:00
|
|
|
|
2018-05-19 01:58:14 +08:00
|
|
|
mode = select_encryption_mode(crypt_info, inode);
|
|
|
|
if (IS_ERR(mode)) {
|
|
|
|
res = PTR_ERR(mode);
|
2015-05-20 13:26:54 +08:00
|
|
|
goto out;
|
2018-05-19 01:58:14 +08:00
|
|
|
}
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
WARN_ON(mode->ivsize > FSCRYPT_MAX_IV_SIZE);
|
|
|
|
crypt_info->ci_mode = mode;
|
2016-09-16 01:32:11 +08:00
|
|
|
|
2016-11-14 09:41:09 +08:00
|
|
|
/*
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
* This cannot be a stack buffer because it may be passed to the
|
|
|
|
* scatterlist crypto API as part of key derivation.
|
2016-11-14 09:41:09 +08:00
|
|
|
*/
|
|
|
|
res = -ENOMEM;
|
2018-05-19 01:58:14 +08:00
|
|
|
raw_key = kmalloc(mode->keysize, GFP_NOFS);
|
2016-11-14 09:41:09 +08:00
|
|
|
if (!raw_key)
|
|
|
|
goto out;
|
|
|
|
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
res = find_and_derive_key(inode, &ctx, raw_key, mode);
|
2018-05-01 06:51:48 +08:00
|
|
|
if (res)
|
2016-02-06 11:19:01 +08:00
|
|
|
goto out;
|
2018-05-01 06:51:48 +08:00
|
|
|
|
fscrypt: add Adiantum support
Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-01-06 21:36:21 +08:00
|
|
|
res = setup_crypto_transform(crypt_info, mode, raw_key, inode);
|
2015-05-20 13:26:54 +08:00
|
|
|
if (res)
|
|
|
|
goto out;
|
|
|
|
|
2019-04-12 05:32:15 +08:00
|
|
|
if (cmpxchg_release(&inode->i_crypt_info, NULL, crypt_info) == NULL)
|
fscrypt: remove broken support for detecting keyring key revocation
Filesystem encryption ostensibly supported revoking a keyring key that
had been used to "unlock" encrypted files, causing those files to become
"locked" again. This was, however, buggy for several reasons, the most
severe of which was that when key revocation happened to be detected for
an inode, its fscrypt_info was immediately freed, even while other
threads could be using it for encryption or decryption concurrently.
This could be exploited to crash the kernel or worse.
This patch fixes the use-after-free by removing the code which detects
the keyring key having been revoked, invalidated, or expired. Instead,
an encrypted inode that is "unlocked" now simply remains unlocked until
it is evicted from memory. Note that this is no worse than the case for
block device-level encryption, e.g. dm-crypt, and it still remains
possible for a privileged user to evict unused pages, inodes, and
dentries by running 'sync; echo 3 > /proc/sys/vm/drop_caches', or by
simply unmounting the filesystem. In fact, one of those actions was
already needed anyway for key revocation to work even somewhat sanely.
This change is not expected to break any applications.
In the future I'd like to implement a real API for fscrypt key
revocation that interacts sanely with ongoing filesystem operations ---
waiting for existing operations to complete and blocking new operations,
and invalidating and sanitizing key material and plaintext from the VFS
caches. But this is a hard problem, and for now this bug must be fixed.
This bug affected almost all versions of ext4, f2fs, and ubifs
encryption, and it was potentially reachable in any kernel configured
with encryption support (CONFIG_EXT4_ENCRYPTION=y,
CONFIG_EXT4_FS_ENCRYPTION=y, CONFIG_F2FS_FS_ENCRYPTION=y, or
CONFIG_UBIFS_FS_ENCRYPTION=y). Note that older kernels did not use the
shared fs/crypto/ code, but due to the potential security implications
of this bug, it may still be worthwhile to backport this fix to them.
Fixes: b7236e21d55f ("ext4 crypto: reorganize how we store keys in the inode")
Cc: stable@vger.kernel.org # v4.2+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Acked-by: Michael Halcrow <mhalcrow@google.com>
2017-02-22 07:07:11 +08:00
|
|
|
crypt_info = NULL;
|
2015-05-20 13:26:54 +08:00
|
|
|
out:
|
2015-05-16 07:26:10 +08:00
|
|
|
if (res == -ENOKEY)
|
2015-05-20 13:26:54 +08:00
|
|
|
res = 0;
|
2015-05-16 07:26:10 +08:00
|
|
|
put_crypt_info(crypt_info);
|
2016-11-14 09:41:09 +08:00
|
|
|
kzfree(raw_key);
|
2015-04-22 07:23:47 +08:00
|
|
|
return res;
|
|
|
|
}
|
fscrypt: remove broken support for detecting keyring key revocation
Filesystem encryption ostensibly supported revoking a keyring key that
had been used to "unlock" encrypted files, causing those files to become
"locked" again. This was, however, buggy for several reasons, the most
severe of which was that when key revocation happened to be detected for
an inode, its fscrypt_info was immediately freed, even while other
threads could be using it for encryption or decryption concurrently.
This could be exploited to crash the kernel or worse.
This patch fixes the use-after-free by removing the code which detects
the keyring key having been revoked, invalidated, or expired. Instead,
an encrypted inode that is "unlocked" now simply remains unlocked until
it is evicted from memory. Note that this is no worse than the case for
block device-level encryption, e.g. dm-crypt, and it still remains
possible for a privileged user to evict unused pages, inodes, and
dentries by running 'sync; echo 3 > /proc/sys/vm/drop_caches', or by
simply unmounting the filesystem. In fact, one of those actions was
already needed anyway for key revocation to work even somewhat sanely.
This change is not expected to break any applications.
In the future I'd like to implement a real API for fscrypt key
revocation that interacts sanely with ongoing filesystem operations ---
waiting for existing operations to complete and blocking new operations,
and invalidating and sanitizing key material and plaintext from the VFS
caches. But this is a hard problem, and for now this bug must be fixed.
This bug affected almost all versions of ext4, f2fs, and ubifs
encryption, and it was potentially reachable in any kernel configured
with encryption support (CONFIG_EXT4_ENCRYPTION=y,
CONFIG_EXT4_FS_ENCRYPTION=y, CONFIG_F2FS_FS_ENCRYPTION=y, or
CONFIG_UBIFS_FS_ENCRYPTION=y). Note that older kernels did not use the
shared fs/crypto/ code, but due to the potential security implications
of this bug, it may still be worthwhile to backport this fix to them.
Fixes: b7236e21d55f ("ext4 crypto: reorganize how we store keys in the inode")
Cc: stable@vger.kernel.org # v4.2+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Acked-by: Michael Halcrow <mhalcrow@google.com>
2017-02-22 07:07:11 +08:00
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EXPORT_SYMBOL(fscrypt_get_encryption_info);
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2015-04-22 07:23:47 +08:00
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|
|
2019-04-11 04:21:15 +08:00
|
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/**
|
|
|
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* fscrypt_put_encryption_info - free most of an inode's fscrypt data
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*
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* Free the inode's fscrypt_info. Filesystems must call this when the inode is
|
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* being evicted. An RCU grace period need not have elapsed yet.
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*/
|
2018-01-12 12:30:13 +08:00
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void fscrypt_put_encryption_info(struct inode *inode)
|
2015-04-22 07:23:47 +08:00
|
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{
|
2018-01-12 12:30:13 +08:00
|
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put_crypt_info(inode->i_crypt_info);
|
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inode->i_crypt_info = NULL;
|
2015-05-16 07:26:10 +08:00
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}
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EXPORT_SYMBOL(fscrypt_put_encryption_info);
|
2019-04-11 04:21:15 +08:00
|
|
|
|
|
|
|
/**
|
|
|
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* fscrypt_free_inode - free an inode's fscrypt data requiring RCU delay
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*
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* Free the inode's cached decrypted symlink target, if any. Filesystems must
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|
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* call this after an RCU grace period, just before they free the inode.
|
|
|
|
*/
|
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|
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void fscrypt_free_inode(struct inode *inode)
|
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|
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{
|
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|
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if (IS_ENCRYPTED(inode) && S_ISLNK(inode->i_mode)) {
|
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|
|
kfree(inode->i_link);
|
|
|
|
inode->i_link = NULL;
|
|
|
|
}
|
|
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}
|
|
|
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EXPORT_SYMBOL(fscrypt_free_inode);
|