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Merge tag 'integrity-v5.18' of git://git.kernel.org/pub/scm/linux/ker…
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…nel/git/zohar/linux-integrity

Pull integrity subsystem updates from Mimi Zohar:
 "Except for extending the 'encrypted' key type to support user provided
  data, the rest is code cleanup, __setup() usage bug fix, and a trivial
  change"

* tag 'integrity-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
  MAINTAINERS: add missing security/integrity/platform_certs
  EVM: fix the evm= __setup handler return value
  KEYS: encrypted: Instantiate key with user-provided decrypted data
  ima: define ima_max_digest_data struct without a flexible array variable
  ima: rename IMA_ACTION_FLAGS to IMA_NONACTION_FLAGS
  ima: Return error code obtained from securityfs functions
  MAINTAINERS: add missing "security/integrity" directory
  ima: Fix trivial typos in the comments
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torvalds committed Mar 22, 2022
2 parents 2c5a535 + 4a48b4c commit 7f313ff
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25 changes: 19 additions & 6 deletions Documentation/security/keys/trusted-encrypted.rst
Original file line number Diff line number Diff line change
Expand Up @@ -107,12 +107,13 @@ Encrypted Keys
--------------

Encrypted keys do not depend on a trust source, and are faster, as they use AES
for encryption/decryption. New keys are created from kernel-generated random
numbers, and are encrypted/decrypted using a specified ‘master’ key. The
‘master’ key can either be a trusted-key or user-key type. The main disadvantage
of encrypted keys is that if they are not rooted in a trusted key, they are only
as secure as the user key encrypting them. The master user key should therefore
be loaded in as secure a way as possible, preferably early in boot.
for encryption/decryption. New keys are created either from kernel-generated
random numbers or user-provided decrypted data, and are encrypted/decrypted
using a specified ‘master’ key. The ‘master’ key can either be a trusted-key or
user-key type. The main disadvantage of encrypted keys is that if they are not
rooted in a trusted key, they are only as secure as the user key encrypting
them. The master user key should therefore be loaded in as secure a way as
possible, preferably early in boot.


Usage
Expand Down Expand Up @@ -199,6 +200,8 @@ Usage::

keyctl add encrypted name "new [format] key-type:master-key-name keylen"
ring
keyctl add encrypted name "new [format] key-type:master-key-name keylen
decrypted-data" ring
keyctl add encrypted name "load hex_blob" ring
keyctl update keyid "update key-type:master-key-name"

Expand Down Expand Up @@ -303,6 +306,16 @@ Load an encrypted key "evm" from saved blob::
82dbbc55be2a44616e4959430436dc4f2a7a9659aa60bb4652aeb2120f149ed197c564e0
24717c64 5972dcb82ab2dde83376d82b2e3c09ffc

Instantiate an encrypted key "evm" using user-provided decrypted data::

$ keyctl add encrypted evm "new default user:kmk 32 `cat evm_decrypted_data.blob`" @u
794890253

$ keyctl print 794890253
default user:kmk 32 2375725ad57798846a9bbd240de8906f006e66c03af53b1b382d
bbc55be2a44616e4959430436dc4f2a7a9659aa60bb4652aeb2120f149ed197c564e0247
17c64 5972dcb82ab2dde83376d82b2e3c09ffc

Other uses for trusted and encrypted keys, such as for disk and file encryption
are anticipated. In particular the new format 'ecryptfs' has been defined
in order to use encrypted keys to mount an eCryptfs filesystem. More details
Expand Down
11 changes: 11 additions & 0 deletions MAINTAINERS
Original file line number Diff line number Diff line change
Expand Up @@ -7280,7 +7280,9 @@ Extended Verification Module (EVM)
M: Mimi Zohar <zohar@linux.ibm.com>
L: linux-integrity@vger.kernel.org
S: Supported
T: git git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity.git
F: security/integrity/evm/
F: security/integrity/

EXTENSIBLE FIRMWARE INTERFACE (EFI)
M: Ard Biesheuvel <ardb@kernel.org>
Expand Down Expand Up @@ -9537,6 +9539,7 @@ L: linux-integrity@vger.kernel.org
S: Supported
T: git git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity.git
F: security/integrity/ima/
F: security/integrity/

INTEL 810/815 FRAMEBUFFER DRIVER
M: Antonino Daplas <adaplas@gmail.com>
Expand Down Expand Up @@ -10675,6 +10678,14 @@ F: include/linux/keyctl.h
F: include/uapi/linux/keyctl.h
F: security/keys/

KEYS/KEYRINGS_INTEGRITY
M: Jarkko Sakkinen <jarkko@kernel.org>
M: Mimi Zohar <zohar@linux.ibm.com>
L: linux-integrity@vger.kernel.org
L: keyrings@vger.kernel.org
S: Supported
F: security/integrity/platform_certs

KFENCE
M: Alexander Potapenko <glider@google.com>
M: Marco Elver <elver@google.com>
Expand Down
2 changes: 1 addition & 1 deletion security/integrity/evm/evm_main.c
Original file line number Diff line number Diff line change
Expand Up @@ -86,7 +86,7 @@ static int __init evm_set_fixmode(char *str)
else
pr_err("invalid \"%s\" mode", str);

return 0;
return 1;
}
__setup("evm=", evm_set_fixmode);

Expand Down
12 changes: 5 additions & 7 deletions security/integrity/ima/ima_api.c
Original file line number Diff line number Diff line change
Expand Up @@ -217,14 +217,11 @@ int ima_collect_measurement(struct integrity_iint_cache *iint,
const char *audit_cause = "failed";
struct inode *inode = file_inode(file);
const char *filename = file->f_path.dentry->d_name.name;
struct ima_max_digest_data hash;
int result = 0;
int length;
void *tmpbuf;
u64 i_version;
struct {
struct ima_digest_data hdr;
char digest[IMA_MAX_DIGEST_SIZE];
} hash;

/*
* Always collect the modsig, because IMA might have already collected
Expand All @@ -238,9 +235,10 @@ int ima_collect_measurement(struct integrity_iint_cache *iint,
goto out;

/*
* Dectecting file change is based on i_version. On filesystems
* which do not support i_version, support is limited to an initial
* measurement/appraisal/audit.
* Detecting file change is based on i_version. On filesystems
* which do not support i_version, support was originally limited
* to an initial measurement/appraisal/audit, but was modified to
* assume the file changed.
*/
i_version = inode_query_iversion(inode);
hash.hdr.algo = algo;
Expand Down
31 changes: 23 additions & 8 deletions security/integrity/ima/ima_fs.c
Original file line number Diff line number Diff line change
Expand Up @@ -452,47 +452,61 @@ static const struct file_operations ima_measure_policy_ops = {

int __init ima_fs_init(void)
{
int ret;

ima_dir = securityfs_create_dir("ima", integrity_dir);
if (IS_ERR(ima_dir))
return -1;
return PTR_ERR(ima_dir);

ima_symlink = securityfs_create_symlink("ima", NULL, "integrity/ima",
NULL);
if (IS_ERR(ima_symlink))
if (IS_ERR(ima_symlink)) {
ret = PTR_ERR(ima_symlink);
goto out;
}

binary_runtime_measurements =
securityfs_create_file("binary_runtime_measurements",
S_IRUSR | S_IRGRP, ima_dir, NULL,
&ima_measurements_ops);
if (IS_ERR(binary_runtime_measurements))
if (IS_ERR(binary_runtime_measurements)) {
ret = PTR_ERR(binary_runtime_measurements);
goto out;
}

ascii_runtime_measurements =
securityfs_create_file("ascii_runtime_measurements",
S_IRUSR | S_IRGRP, ima_dir, NULL,
&ima_ascii_measurements_ops);
if (IS_ERR(ascii_runtime_measurements))
if (IS_ERR(ascii_runtime_measurements)) {
ret = PTR_ERR(ascii_runtime_measurements);
goto out;
}

runtime_measurements_count =
securityfs_create_file("runtime_measurements_count",
S_IRUSR | S_IRGRP, ima_dir, NULL,
&ima_measurements_count_ops);
if (IS_ERR(runtime_measurements_count))
if (IS_ERR(runtime_measurements_count)) {
ret = PTR_ERR(runtime_measurements_count);
goto out;
}

violations =
securityfs_create_file("violations", S_IRUSR | S_IRGRP,
ima_dir, NULL, &ima_htable_violations_ops);
if (IS_ERR(violations))
if (IS_ERR(violations)) {
ret = PTR_ERR(violations);
goto out;
}

ima_policy = securityfs_create_file("policy", POLICY_FILE_FLAGS,
ima_dir, NULL,
&ima_measure_policy_ops);
if (IS_ERR(ima_policy))
if (IS_ERR(ima_policy)) {
ret = PTR_ERR(ima_policy);
goto out;
}

return 0;
out:
Expand All @@ -503,5 +517,6 @@ int __init ima_fs_init(void)
securityfs_remove(binary_runtime_measurements);
securityfs_remove(ima_symlink);
securityfs_remove(ima_dir);
return -1;

return ret;
}
5 changes: 1 addition & 4 deletions security/integrity/ima/ima_init.c
Original file line number Diff line number Diff line change
Expand Up @@ -47,12 +47,9 @@ static int __init ima_add_boot_aggregate(void)
struct integrity_iint_cache tmp_iint, *iint = &tmp_iint;
struct ima_event_data event_data = { .iint = iint,
.filename = boot_aggregate_name };
struct ima_max_digest_data hash;
int result = -ENOMEM;
int violation = 0;
struct {
struct ima_digest_data hdr;
char digest[TPM_MAX_DIGEST_SIZE];
} hash;

memset(iint, 0, sizeof(*iint));
memset(&hash, 0, sizeof(hash));
Expand Down
9 changes: 3 additions & 6 deletions security/integrity/ima/ima_main.c
Original file line number Diff line number Diff line change
Expand Up @@ -263,7 +263,7 @@ static int process_measurement(struct file *file, const struct cred *cred,
/* reset appraisal flags if ima_inode_post_setattr was called */
iint->flags &= ~(IMA_APPRAISE | IMA_APPRAISED |
IMA_APPRAISE_SUBMASK | IMA_APPRAISED_SUBMASK |
IMA_ACTION_FLAGS);
IMA_NONACTION_FLAGS);

/*
* Re-evaulate the file if either the xattr has changed or the
Expand Down Expand Up @@ -764,7 +764,7 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,
* call to ima_post_load_data().
*
* Callers of this LSM hook can not measure, appraise, or audit the
* data provided by userspace. Enforce policy rules requring a file
* data provided by userspace. Enforce policy rules requiring a file
* signature (eg. kexec'ed kernel image).
*
* For permission return 0, otherwise return -EACCES.
Expand Down Expand Up @@ -874,10 +874,7 @@ int process_buffer_measurement(struct user_namespace *mnt_userns,
.buf = buf,
.buf_len = size};
struct ima_template_desc *template;
struct {
struct ima_digest_data hdr;
char digest[IMA_MAX_DIGEST_SIZE];
} hash = {};
struct ima_max_digest_data hash;
char digest_hash[IMA_MAX_DIGEST_SIZE];
int digest_hash_len = hash_digest_size[ima_hash_algo];
int violation = 0;
Expand Down
4 changes: 2 additions & 2 deletions security/integrity/ima/ima_policy.c
Original file line number Diff line number Diff line change
Expand Up @@ -428,7 +428,7 @@ static int ima_lsm_update_rule(struct ima_rule_entry *entry)
/*
* ima_lsm_copy_rule() shallow copied all references, except for the
* LSM references, from entry to nentry so we only want to free the LSM
* references and the entry itself. All other memory refrences will now
* references and the entry itself. All other memory references will now
* be owned by nentry.
*/
ima_lsm_free_rule(entry);
Expand Down Expand Up @@ -711,7 +711,7 @@ int ima_match_policy(struct user_namespace *mnt_userns, struct inode *inode,
func, mask, func_data))
continue;

action |= entry->flags & IMA_ACTION_FLAGS;
action |= entry->flags & IMA_NONACTION_FLAGS;

action |= entry->action & IMA_DO_MASK;
if (entry->action & IMA_APPRAISE) {
Expand Down
7 changes: 2 additions & 5 deletions security/integrity/ima/ima_template_lib.c
Original file line number Diff line number Diff line change
Expand Up @@ -272,7 +272,7 @@ static int ima_eventdigest_init_common(const u8 *digest, u32 digestsize,
* digest formats:
* - DATA_FMT_DIGEST: digest
* - DATA_FMT_DIGEST_WITH_ALGO: [<hash algo>] + ':' + '\0' + digest,
* where <hash algo> is provided if the hash algoritm is not
* where <hash algo> is provided if the hash algorithm is not
* SHA1 or MD5
*/
u8 buffer[CRYPTO_MAX_ALG_NAME + 2 + IMA_MAX_DIGEST_SIZE] = { 0 };
Expand Down Expand Up @@ -307,10 +307,7 @@ static int ima_eventdigest_init_common(const u8 *digest, u32 digestsize,
int ima_eventdigest_init(struct ima_event_data *event_data,
struct ima_field_data *field_data)
{
struct {
struct ima_digest_data hdr;
char digest[IMA_MAX_DIGEST_SIZE];
} hash;
struct ima_max_digest_data hash;
u8 *cur_digest = NULL;
u32 cur_digestsize = 0;
struct inode *inode;
Expand Down
14 changes: 12 additions & 2 deletions security/integrity/integrity.h
Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,7 @@
#include <linux/types.h>
#include <linux/integrity.h>
#include <crypto/sha1.h>
#include <crypto/hash.h>
#include <linux/key.h>
#include <linux/audit.h>

Expand All @@ -30,8 +31,8 @@
#define IMA_HASH 0x00000100
#define IMA_HASHED 0x00000200

/* iint cache flags */
#define IMA_ACTION_FLAGS 0xff000000
/* iint policy rule cache flags */
#define IMA_NONACTION_FLAGS 0xff000000
#define IMA_DIGSIG_REQUIRED 0x01000000
#define IMA_PERMIT_DIRECTIO 0x02000000
#define IMA_NEW_FILE 0x04000000
Expand Down Expand Up @@ -110,6 +111,15 @@ struct ima_digest_data {
u8 digest[];
} __packed;

/*
* Instead of wrapping the ima_digest_data struct inside a local structure
* with the maximum hash size, define ima_max_digest_data struct.
*/
struct ima_max_digest_data {
struct ima_digest_data hdr;
u8 digest[HASH_MAX_DIGESTSIZE];
} __packed;

/*
* signature format v2 - for using with asymmetric keys
*/
Expand Down
19 changes: 15 additions & 4 deletions security/keys/Kconfig
Original file line number Diff line number Diff line change
Expand Up @@ -98,10 +98,21 @@ config ENCRYPTED_KEYS
select CRYPTO_RNG
help
This option provides support for create/encrypting/decrypting keys
in the kernel. Encrypted keys are kernel generated random numbers,
which are encrypted/decrypted with a 'master' symmetric key. The
'master' key can be either a trusted-key or user-key type.
Userspace only ever sees/stores encrypted blobs.
in the kernel. Encrypted keys are instantiated using kernel
generated random numbers or provided decrypted data, and are
encrypted/decrypted with a 'master' symmetric key. The 'master'
key can be either a trusted-key or user-key type. Only encrypted
blobs are ever output to Userspace.

If you are unsure as to whether this is required, answer N.

config USER_DECRYPTED_DATA
bool "Allow encrypted keys with user decrypted data"
depends on ENCRYPTED_KEYS
help
This option provides support for instantiating encrypted keys using
user-provided decrypted data. The decrypted data must be hex-ascii
encoded.

If you are unsure as to whether this is required, answer N.

Expand Down
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