hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

-------------------------------------------------

Currently, IMA supports the appraise_type=imasig option in the policy to
require file signatures. This patch introduces the new option
appraise_type=meta_immutable to require that file metadata are signed and
immutable. This requirement can be satisfied by portable signatures and
by digest lists if they are marked as immutable.

The main purpose of this option is to ensure that file metadata are correct
at the time of access, so that policies relying on labels can be correctly
enforced. For example, requiring immutable metadata would prevent an
administrator from altering the label assigned to a process during
execve() by changing the label of the executable.
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: NTianxing Zhang <zhangtianxing3@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

-------------------------------------------------

This patch adds support in EVM to verify file metadata digest with digest
lists. Metadata digest, calculated in the same way as for portable
signatures, is searched in the digest lists only if the file has the
security.evm xattr with type EVM_IMA_XATTR_DIGEST_LIST.

If the found digest is marked as immutable, content and xattr/attr updates
are not allowed. Otherwise, after verification, the existing security.evm
with the new type will be replaced with an HMAC, similarly to non-portable
signatures.
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: NTianxing Zhang <zhangtianxing3@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

-------------------------------------------------

IMA-Appraise grants access to files with a valid signature or with actual
file digest equal to the digest included in security.ima.

This patch adds support for appraisal based on digest lists. Instead of
using the reference value from security.ima, this patch checks if the
calculated file digest is included in the uploaded digest lists.

This functionality must be explicitly enabled by providing one of the
following values for the ima_appraise_digest_list= kernel option:

- digest: this mode enables appraisal verification with digest lists until
  EVM is initialized; after that, EVM verification must be successful even
  if the file digest is found in a digest list;

- digest-nometadata: this mode enables appraisal verification with digest
  lists even after EVM has been initialized; files without security.evm are
  allowed if the digest of the content is found in the digest list, and
  security.evm is created with current values of xattrs (trust at first
  use); all files created in this way will have the new security.ima type
  EVM_IMA_XATTR_DIGEST_LIST; they can be accessed later only if this mode
  has been selected.
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: NTianxing Zhang <zhangtianxing3@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

-------------------------------------------------

IMA-Measure creates a new measurement entry every time a file is measured,
unless the same entry is already in the measurement list.

This patch introduces a new type of measurement list, recognizable by the
PCR number specified with the new ima_digest_list_pcr= kernel option. This
type of measurement list includes measurements of digest lists and files
not found in those lists.

The benefit of this patch is the availability of a predictable PCR that
can be used to seal data or TPM keys to the OS software. Unlike standard
measurements, digest list measurements only indicate that files with a
digest in those lists could have been accessed, but not if and when. With
standard measurements, however, the chosen PCR is unlikely predictable.

Both standard and digest list measurements can be generated at the same
time by adding '+' as a prefix to the value of ima_digest_list_pcr=
(example: with ima_digest_list_pcr=+11, IMA generates standard measurements
with PCR 10 and digest list measurements with PCR 11).
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: NTianxing Zhang <zhangtianxing3@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

-------------------------------------------------

Digest lists should be uploaded to IMA as soon as possible, otherwise file
digests would appear in the measurement list or access would be denied if
appraisal is in enforcing mode.

This patch adds a call to ima_load_digest_lists() in integrity_load_keys(),
so that the function is executed when rootfs becomes available, before
files are accessed.

ima_load_digest_lists() iterates in the directory specified as value of
CONFIG_IMA_DIGEST_LISTS_DIR and uploads all digest lists to the kernel.
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: NTianxing Zhang <zhangtianxing3@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

-------------------------------------------------

This patch introduces a new hook called DIGEST_LIST_CHECK to measure
and appraise digest lists in addition to executables and shared libraries,
without including the FILE_CHECK hook in the IMA policy.
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: NTianxing Zhang <zhangtianxing3@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

-------------------------------------------------

This patch introduces three new files in the securityfs filesystem.
digest_list_data: loads a digest list from the specified path and adds the
digests to the hash table; digest_list_data_del: does the same but removes
the digests from the hash table; digests_count: shows the current number of
digests stored in the hash table.
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: NTianxing Zhang <zhangtianxing3@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

-------------------------------------------------

Loading a digest list affects the behavior of IMA for subsequent
operations. For example, if the digest of a file is found in a loaded
digest list, the file won't be added to the measurement list (with PCR 11).
If an administrator loaded the digest list before the IMA policy, he could
hide from verifiers the fact that files in that digest list were accessed.

To avoid this situation, this patch prevents usage of digest lists for an
IMA submodule if that submodule didn't process it. If a digest list wasn't
measured, the digest of measured files will not be searched in the digest
list and regular measurement will be performed. The same mechanism applies
for appraisal.
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: NTianxing Zhang <zhangtianxing3@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

-------------------------------------------------

This patch introduces the parser of the compact digest list. The format is
optimized to store a large quantity of data with the same type. It is the
only format supported by the kernel. Digest lists can be uploaded by
writing the path to securityfs, as the same as for IMA policies.

A compact list is a set of consecutive data blocks, each consisting of a
header and a payload. The header indicates the version of the header, the
type of data, type modifiers, the hash algorithm, how many elements and the
length of the payload.

COMPACT_KEY identifies public keys used for signature verification of the
digest lists; COMPACT_PARSER identifies digests of user space parsers
allowed to directly upload parsed digest lists to the kernel; COMPACT_FILE
identifies digests of regular files; COMPACT_METADATA identifies digest of
file metadata.

Type modifiers indicate attributes of the elements included in the payload.
The COMPACT_MOD_IMMUTABLE modifier indicates that a file or metadata are
immutable.

This patch also introduces ima_lookup_loaded_digest() and
ima_add_digest_data_entry() to search and add digests in the new hash table
(ima_digests_htable).
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: NTianxing Zhang <zhangtianxing3@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

-------------------------------------------------

ima_show_htable_violations() and ima_show_measurements_count() both call
ima_show_htable_value() to copy the value of an atomic_long_t variable to
a buffer.

This patch modifies the definition of ima_show_htable_value(), so that this
function can be used in any file_operations structure. The atomic_long_t
variable used as source is chosen depending on the opened file in the
securityfs filesystem.
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: NTianxing Zhang <zhangtianxing3@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

-------------------------------------------------

This patch renames ima_open_policy() and ima_release_policy() respectively
to ima_open_data_upload() and ima_release_data_upload(). They will be used
to implement file operations for interfaces allowing to load data from user
space.

A new flag (IMA_POLICY_BUSY) has been defined to prevent concurrent policy
upload.
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: NTianxing Zhang <zhangtianxing3@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

-------------------------------------------------

ima_write_policy() is being used to load a new policy from user space. This
function can be reused to load different types of data.

This patch renames ima_write_policy() to ima_write_data() and executes the
appropriate actions depending on the opened file in securityfs.

Also, this patch raises the uploaded data size limit to 64M, to accept
files (e.g. digest lists) larger than a policy. The same limit is used for
the SELinux policy.
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: NTianxing Zhang <zhangtianxing3@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

-------------------------------------------------

This patch renames ima_read_policy() to ima_read_file() so that the
function can be used to read files for different purposes. It also adds the
opened file in securityfs as parameter so that the function can determine
which action it should do with the passed data.

This patch replaces kernel_read_file_from_path() with filp_open() +
kernel_read_file() so that the file descriptor can be used for further
checks.
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: NTianxing Zhang <zhangtianxing3@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

-------------------------------------------------

IMA reads the hash algorithm from security.ima, if exists, so that a
signature can be verified with the correct file digest.

This patch moves ima_read_xattr() and ima_get_hash_algo() to ima_main.c, so
that the file digest in the measurement list or in the audit logs can be
compared with a reference value calculated with a specific hash algorithm.

In addition, this patch also allows the usage of security.ima with type
EVM_IMA_XATTR_DIGSIG and signature length zero, so that the xattr can be
used just to specify the hash algorithm.
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: NTianxing Zhang <zhangtianxing3@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

-------------------------------------------------

IMA and EVM have been designed as two independent subsystems: the first for
checking the integrity of file data; the second for checking file metadata.
Making them independent allows users to adopt them incrementally.

The point of intersection is in IMA-Appraise, which calls evm_verifyxattr()
to ensure that security.ima wasn't modified during an offline attack. The
design choice, to ensure incremental adoption, was to continue appraisal
verification if evm_verifyxattr() returns INTEGRITY_UNKNOWN. This value is
returned when EVM is not enabled in the kernel configuration, or if the
HMAC key has not been loaded yet.

Although this choice appears legitimate, it might not be suitable for
hardened systems, where the administrator expects that access is denied if
there is any error. An attacker could intentionally delete the EVM keys
from the system and set the file digest in security.ima to the actual file
digest so that the final appraisal status is INTEGRITY_PASS.

This patch allows such hardened systems to strictly enforce an access
control policy based on the validity of signatures/HMACs, by introducing
two new values for the ima_appraise= kernel option: enforce-evm and
log-evm.

Cc: stable@vger.kernel.org
Fixes: 2fe5d6de ("ima: integrity appraisal extension")
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: NTianxing Zhang <zhangtianxing3@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

---------------------------

Files might come from a remote source and might have xattrs, including
security.ima. It should not be IMA task to decide whether security.ima
should be kept or not. This patch removes the removexattr() system
call in ima_inode_post_setattr().
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: NMimi Zohar <zohar@linux.ibm.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

---------------------------

With the patch to accept EVM portable signatures when the
appraise_type=imasig requirement is specified in the policy, appraisal can
be successfully done even if the file does not have an IMA signature.

However, remote attestation would not see that a different signature type
was used, as only IMA signatures can be included in the measurement list.
This patch solves the issue by introducing the new template field 'evmsig'
to show EVM portable signatures and by including its value in the existing
field 'sig' if the IMA signature is not found.
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Suggested-by: NMimi Zohar <zohar@linux.ibm.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

---------------------------

System administrators can require that all accessed files have a signature
by specifying appraise_type=imasig in a policy rule.

Currently, IMA signatures satisfy this requirement. Appended signatures may
also satisfy this requirement, but are not applicable as IMA signatures.
IMA/appended signatures ensure data source authentication for file content
and prevent any change. EVM signatures instead ensure data source
authentication for file metadata. Given that the digest or signature of the
file content must be included in the metadata, EVM signatures provide the
same file data guarantees of IMA signatures, as well as providing file
metadata guarantees.

This patch lets systems protected with EVM signatures pass appraisal
verification if the appraise_type=imasig requirement is specified in the
policy. This facilitates deployment in the scenarios where only EVM
signatures are available.

The patch makes the following changes:

file xattr types:
security.ima: IMA_XATTR_DIGEST/IMA_XATTR_DIGEST_NG
security.evm: EVM_XATTR_PORTABLE_DIGSIG

execve(), mmap(), open() behavior (with appraise_type=imasig):
before: denied (file without IMA signature, imasig requirement not met)
after: allowed (file with EVM portable signature, imasig requirement met)

open(O_WRONLY) behavior (without appraise_type=imasig):
before: allowed (file without IMA signature, not immutable)
after: denied (file with EVM portable signature, immutable)

In addition, similarly to IMA signatures, this patch temporarily allows
new files without or with incomplete metadata to be opened so that content
can be written.
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: NMimi Zohar <zohar@linux.ibm.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

---------------------------

With the patch to allow xattr/attr operations if a portable signature
verification fails, cp and tar can copy all xattrs/attrs so that at the
end of the process verification succeeds.

However, it might happen that the xattrs/attrs are already set to the
correct value (taken at signing time) and signature verification succeeds
before the copy has completed. For example, an archive might contains files
owned by root and the archive is extracted by root.

Then, since portable signatures are immutable, all subsequent operations
fail (e.g. fchown()), even if the operation is legitimate (does not alter
the current value).

This patch avoids this problem by reporting successful operation to user
space when that operation does not alter the current value of xattrs/attrs.
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

---------------------------

If files with portable signatures are copied from one location to another
or are extracted from an archive, verification can temporarily fail until
all xattrs/attrs are set in the destination. Only portable signatures may
be moved or copied from one file to another, as they don't depend on
system-specific information such as the inode generation. Instead portable
signatures must include security.ima.

Unlike other security.evm types, EVM portable signatures are also
immutable. Thus, it wouldn't be a problem to allow xattr/attr operations
when verification fails, as portable signatures will never be replaced with
the HMAC on possibly corrupted xattrs/attrs.

This patch first introduces a new integrity status called
INTEGRITY_FAIL_IMMUTABLE, that allows callers of
evm_verify_current_integrity() to detect that a portable signature didn't
pass verification and then adds an exception in evm_protect_xattr() and
evm_inode_setattr() for this status and returns 0 instead of -EPERM.
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: NMimi Zohar <zohar@linux.ibm.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

---------------------------

When a file is being created, LSMs can set the initial label with the
inode_init_security hook. If no HMAC key is loaded, the new file will have
LSM xattrs but not the HMAC. It is also possible that the file remains
without protected xattrs after creation if no active LSM provided it.

Unfortunately, EVM will deny any further metadata operation on new files,
as evm_protect_xattr() will always return the INTEGRITY_NOLABEL error, or
INTEGRITY_NOXATTRS if no protected xattrs exist. This would limit the
usability of EVM when only a public key is loaded, as commands such as cp
or tar with the option to preserve xattrs won't work.

This patch ignores these errors when they won't be an issue, if no HMAC key
is loaded and cannot be loaded in the future (which can be enforced by
setting the EVM_SETUP_COMPLETE initialization flag).
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

---------------------------

When EVM_ALLOW_METADATA_WRITES is set, EVM allows any operation on
metadata. Its main purpose is to allow users to freely set metadata when it
is protected by a portable signature, until an HMAC key is loaded.

However, callers of evm_verifyxattr() are not notified about metadata
changes and continue to rely on the last status returned by the function.
For example IMA, since it caches the appraisal result, will not call again
evm_verifyxattr() until the appraisal flags are cleared, and will grant
access to the file even if there was a metadata operation that made the
portable signature invalid.

This patch introduces evm_status_revalidate(), which callers of
evm_verifyxattr() can use in their xattr post hooks to determine whether
re-validation is necessary and to do the proper actions. IMA calls it in
its xattr post hooks to reset the appraisal flags, so that the EVM status
is re-evaluated after a metadata operation.

Lastly, this patch also adds a call to evm_reset_status() in
evm_inode_post_setattr() to invalidate the cached EVM status after a
setattr operation.
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

---------------------------

ima_inode_setxattr() and ima_inode_removexattr() hooks are called before an
operation is performed. Thus, ima_reset_appraise_flags() should not be
called there, as flags might be unnecessarily reset if the operation is
denied.

This patch introduces the post hooks ima_inode_post_setxattr() and
ima_inode_post_removexattr(), and adds the call to
ima_reset_appraise_flags() in the new functions.
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

---------------------------

EVM_ALLOW_METADATA_WRITES is an EVM initialization flag that can be set to
temporarily disable metadata verification until all xattrs/attrs necessary
to verify an EVM portable signature are copied to the file. This flag is
cleared when EVM is initialized with an HMAC key, to avoid that the HMAC is
calculated on unverified xattrs/attrs.

Currently EVM unnecessarily denies setting this flag if EVM is initialized
with a public key, which is not a concern as it cannot be used to trust
xattrs/attrs updates. This patch removes this limitation.

Cc: stable@vger.kernel.org # 4.16.x
Fixes: ae1ba167 ("EVM: Allow userland to permit modification of EVM-protected metadata")
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

---------------------------

Public keys do not need to be appraised by IMA as the restriction on the
IMA/EVM keyrings ensures that a key can be loaded only if it is signed with
a key in the primary or secondary keyring.

However, when evm_load_x509() is called, appraisal is already enabled and
a valid IMA signature must be added to the EVM key to pass verification.

Since the restriction is applied on both IMA and EVM keyrings, it is safe
to disable appraisal also when the EVM key is loaded. This patch calls
evm_load_x509() inside ima_load_x509() if CONFIG_IMA_LOAD_X509 is enabled.
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: NMimi Zohar <zohar@linux.ibm.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

---------------------------

evm_inode_init_security() requires an HMAC key to calculate the HMAC on
initial xattrs provided by LSMs. However, it checks generically whether a
key has been loaded, including also public keys, which is not correct as
public keys are not suitable to calculate the HMAC.

Originally, support for signature verification was introduced to verify a
possibly immutable initial ram disk, when no new files are created, and to
switch to HMAC for the root filesystem. By that time, an HMAC key should
have been loaded and usable to calculate HMACs for new files.

More recently support for requiring an HMAC key was removed from the
kernel, so that signature verification can be used alone. Since this is a
legitimate use case, evm_inode_init_security() should not return an error
when no HMAC key has been loaded.

This patch fixes this problem by replacing the evm_key_loaded() check with
a check of the EVM_INIT_HMAC flag in evm_initialized.

Cc: stable@vger.kernel.org # 4.5.x
Fixes: 26ddabfe ("evm: enable EVM when X509 certificate is loaded")
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: NMimi Zohar <zohar@linux.ibm.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

mainline inclusion
from linux-next
commit fee3ff99
category: feature
bugzilla: 46864
CVE: NA

--------------------------------

The functions defined in "arch/powerpc/kexec/ima.c" handle setting up
and freeing the resources required to carry over the IMA measurement
list from the current kernel to the next kernel across kexec system call.
These functions do not have architecture specific code, but are
currently limited to powerpc.

Move remove_ima_buffer() and setup_ima_buffer() calls into
of_kexec_alloc_and_setup_fdt() defined in "drivers/of/kexec.c".

Move the remaining architecture independent functions from
"arch/powerpc/kexec/ima.c" to "drivers/of/kexec.c".
Delete "arch/powerpc/kexec/ima.c" and "arch/powerpc/include/asm/ima.h".
Remove references to the deleted files and functions in powerpc and
in ima.
Co-developed-by: NPrakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: NPrakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: NLakshmi Ramasubramanian <nramas@linux.microsoft.com>
Reviewed-by: NThiago Jung Bauermann <bauerman@linux.ibm.com>
Tested-by: NThiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: NRob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210221174930.27324-11-nramas@linux.microsoft.comSigned-off-by: NLi Huafei <lihuafei1@huawei.com>
Reviewed-by: NYang Jihong <yangjihong1@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

mainline inclusion
from linux-next
commit 0c605158
category: feature
bugzilla: 46864
CVE: NA

--------------------------------

The fields ima_buffer_addr and ima_buffer_size in "struct kimage_arch"
for powerpc are used to carry forward the IMA measurement list across
kexec system call.  These fields are not architecture specific, but are
currently limited to powerpc.

arch_ima_add_kexec_buffer() defined in "arch/powerpc/kexec/ima.c"
sets ima_buffer_addr and ima_buffer_size for the kexec system call.
This function does not have architecture specific code, but is
currently limited to powerpc.

Move ima_buffer_addr and ima_buffer_size to "struct kimage".
Set ima_buffer_addr and ima_buffer_size in ima_add_kexec_buffer()
in security/integrity/ima/ima_kexec.c.
Co-developed-by: NPrakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: NPrakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: NLakshmi Ramasubramanian <nramas@linux.microsoft.com>
Suggested-by: NWill Deacon <will@kernel.org>
Reviewed-by: NThiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: NRob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210221174930.27324-9-nramas@linux.microsoft.comSigned-off-by: NLi Huafei <lihuafei1@huawei.com>
Reviewed-by: NYang Jihong <yangjihong1@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

stable inclusion
from stable-5.10.20
commit d7b0efadc3eb8b2cc5dcefae3650d0b492683c44
bugzilla: 50608

--------------------------------

[ Upstream commit 4993e1f9 ]

KEY_FLAG_KEEP is not meant to be passed to keyring_alloc() or key_alloc(),
as these only take KEY_ALLOC_* flags.  KEY_FLAG_KEEP has the same value as
KEY_ALLOC_BYPASS_RESTRICTION, but fortunately only key_create_or_update()
uses it.  LSMs using the key_alloc hook don't check that flag.

KEY_FLAG_KEEP is then ignored but fortunately (again) the root user cannot
write to the blacklist keyring, so it is not possible to remove a key/hash
from it.

Fix this by adding a KEY_ALLOC_SET_KEEP flag that tells key_alloc() to set
KEY_FLAG_KEEP on the new key.  blacklist_init() can then, correctly, pass
this to keyring_alloc().

We can also use this in ima_mok_init() rather than setting the flag
manually.

Note that this doesn't fix an observable bug with the current
implementation but it is required to allow addition of new hashes to the
blacklist in the future without making it possible for them to be removed.

Fixes: 734114f8 ("KEYS: Add a system blacklist keyring")
Reported-by: NMickaël Salaün <mic@linux.microsoft.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
cc: Mickaël Salaün <mic@linux.microsoft.com>
cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

stable inclusion
from stable-5.10.20
commit c365d333e97ac80caf39471b37514b8cbe4536e1
bugzilla: 50608

--------------------------------

[ Upstream commit f31e3386 ]

IMA allocates kernel virtual memory to carry forward the measurement
list, from the current kernel to the next kernel on kexec system call,
in ima_add_kexec_buffer() function.  This buffer is not freed before
completing the kexec system call resulting in memory leak.

Add ima_buffer field in "struct kimage" to store the virtual address
of the buffer allocated for the IMA measurement list.
Free the memory allocated for the IMA measurement list in
kimage_file_post_load_cleanup() function.
Signed-off-by: NLakshmi Ramasubramanian <nramas@linux.microsoft.com>
Suggested-by: NTyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: NThiago Jung Bauermann <bauerman@linux.ibm.com>
Reviewed-by: NTyler Hicks <tyhicks@linux.microsoft.com>
Fixes: 7b8589cc ("ima: on soft reboot, save the measurement list")
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

stable inclusion
from stable-5.10.20
commit 1facf2415b98fd8dbf6f9b3388c3bd654c01154a
bugzilla: 50608

--------------------------------

[ Upstream commit 6d14c651 ]

IMA allocates kernel virtual memory to carry forward the measurement
list, from the current kernel to the next kernel on kexec system call,
in ima_add_kexec_buffer() function.  In error code paths this memory
is not freed resulting in memory leak.

Free the memory allocated for the IMA measurement list in
the error code paths in ima_add_kexec_buffer() function.
Signed-off-by: NLakshmi Ramasubramanian <nramas@linux.microsoft.com>
Suggested-by: NTyler Hicks <tyhicks@linux.microsoft.com>
Fixes: 7b8589cc ("ima: on soft reboot, save the measurement list")
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

stable inclusion
from stable-5.10.20
commit 494e9ec12c1b3bf2532b2a518d7206137a01cb6a
bugzilla: 50608

--------------------------------

[ Upstream commit ccf11dba ]

tmp_tfm is allocated, but not freed on subsequent kmalloc failure, which
leads to a memory leak.  Free tmp_tfm.

Fixes: d46eb369 ("evm: crypto hash replaced by shash")
Signed-off-by: NDinghao Liu <dinghao.liu@zju.edu.cn>
[zohar@linux.ibm.com: formatted/reworded patch description]
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

stable inclusion
from stable-5.10.4
commit 0f2206e3d90a9f131b8cfc3f7629c698aa625ce4
bugzilla: 46903

--------------------------------

commit 207cdd56 upstream.

Commit a408e4a8 ("ima: open a new file instance if no read
permissions") already introduced a second open to measure a file when the
original file descriptor does not allow it. However, it didn't remove the
existing method of changing the mode of the original file descriptor, which
is still necessary if the current process does not have enough privileges
to open a new one.

Changing the mode isn't really an option, as the filesystem might need to
do preliminary steps to make the read possible. Thus, this patch removes
the code and keeps the second open as the only option to measure a file
when it is unreadable with the original file descriptor.

Cc: <stable@vger.kernel.org> # 4.20.x: 0014cc04 ima: Set file->f_mode
Fixes: 2fe5d6de ("ima: integrity appraisal extension")
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

There is a regular need in the kernel to provide a way to declare having a
dynamically sized set of trailing elements in a structure. Kernel code should
always use “flexible array members”[1] for these cases. The older style of
one-element or zero-length arrays should no longer be used[2].

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.9-rc1/process/deprecated.html#zero-length-and-one-element-arraysSigned-off-by: NGustavo A. R. Silva <gustavoars@kernel.org>

To perform partial reads, callers of kernel_read_file*() must have a
non-NULL file_size argument and a preallocated buffer. The new "offset"
argument can then be used to seek to specific locations in the file to
fill the buffer to, at most, "buf_size" per call.

Where possible, the LSM hooks can report whether a full file has been
read or not so that the contents can be reasoned about.
Signed-off-by: NKees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201002173828.2099543-14-keescook@chromium.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When the kernel_read_file LSM hook is called with contents=false, IMA
can appraise the file directly, without requiring a filled buffer. When
such a buffer is available, though, IMA can continue to use it instead
of forcing a double read here.
Signed-off-by: NScott Branden <scott.branden@broadcom.com>
Link: https://lore.kernel.org/lkml/20200706232309.12010-10-scott.branden@broadcom.com/Signed-off-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NMimi Zohar <zohar@linux.ibm.com>
Link: https://lore.kernel.org/r/20201002173828.2099543-13-keescook@chromium.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

As with the kernel_load_data LSM hook, add a "contents" flag to the
kernel_read_file LSM hook that indicates whether the LSM can expect
a matching call to the kernel_post_read_file LSM hook with the full
contents of the file. With the coming addition of partial file read
support for kernel_read_file*() API, the LSM will no longer be able
to always see the entire contents of a file during the read calls.

For cases where the LSM must read examine the complete file contents,
it will need to do so on its own every time the kernel_read_file
hook is called with contents=false (or reject such cases). Adjust all
existing LSMs to retain existing behavior.
Signed-off-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NMimi Zohar <zohar@linux.ibm.com>
Link: https://lore.kernel.org/r/20201002173828.2099543-12-keescook@chromium.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Now that security_post_load_data() is wired up, use it instead
of the NULL file argument style of security_post_read_file(),
and update the security_kernel_load_data() call to indicate that a
security_kernel_post_load_data() call is expected.

Wire up the IMA check to match earlier logic. Perhaps a generalized
change to ima_post_load_data() might look something like this:

    return process_buffer_measurement(buf, size,
                                      kernel_load_data_id_str(load_id),
                                      read_idmap[load_id] ?: FILE_CHECK,
                                      0, NULL);
Signed-off-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NMimi Zohar <zohar@linux.ibm.com>
Link: https://lore.kernel.org/r/20201002173828.2099543-10-keescook@chromium.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There are a few places in the kernel where LSMs would like to have
visibility into the contents of a kernel buffer that has been loaded or
read. While security_kernel_post_read_file() (which includes the
buffer) exists as a pairing for security_kernel_read_file(), no such
hook exists to pair with security_kernel_load_data().

Earlier proposals for just using security_kernel_post_read_file() with a
NULL file argument were rejected (i.e. "file" should always be valid for
the security_..._file hooks, but it appears at least one case was
left in the kernel during earlier refactoring. (This will be fixed in
a subsequent patch.)

Since not all cases of security_kernel_load_data() can have a single
contiguous buffer made available to the LSM hook (e.g. kexec image
segments are separately loaded), there needs to be a way for the LSM to
reason about its expectations of the hook coverage. In order to handle
this, add a "contents" argument to the "kernel_load_data" hook that
indicates if the newly added "kernel_post_load_data" hook will be called
with the full contents once loaded. That way, LSMs requiring full contents
can choose to unilaterally reject "kernel_load_data" with contents=false
(which is effectively the existing hook coverage), but when contents=true
they can allow it and later evaluate the "kernel_post_load_data" hook
once the buffer is loaded.

With this change, LSMs can gain coverage over non-file-backed data loads
(e.g. init_module(2) and firmware userspace helper), which will happen
in subsequent patches.

Additionally prepare IMA to start processing these cases.
Signed-off-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NKP Singh <kpsingh@google.com>
Link: https://lore.kernel.org/r/20201002173828.2099543-9-keescook@chromium.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In preparation for adding partial read support, add an optional output
argument to kernel_read_file*() that reports the file size so callers
can reason more easily about their reading progress.
Signed-off-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NMimi Zohar <zohar@linux.ibm.com>
Reviewed-by: NLuis Chamberlain <mcgrof@kernel.org>
Reviewed-by: NJames Morris <jamorris@linux.microsoft.com>
Acked-by: NScott Branden <scott.branden@broadcom.com>
Link: https://lore.kernel.org/r/20201002173828.2099543-8-keescook@chromium.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>