Commit Graph

685 Commits

Author SHA1 Message Date
Austin Kim 6560343559 ima: Fix trivial typos in the comments
There are a few minor typos in the comments. Fix these.

Signed-off-by: Austin Kim <austindh.kim@gmail.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2022-02-15 11:10:03 -05:00
Stefan Berger 89677197ae ima: Do not print policy rule with inactive LSM labels
Before printing a policy rule scan for inactive LSM labels in the policy
rule. Inactive LSM labels are identified by args_p != NULL and
rule == NULL.

Fixes: 483ec26eed ("ima: ima/lsm policy rule loading logic bug fixes")
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Cc: <stable@vger.kernel.org> # v5.6+
Acked-by: Christian Brauner <brauner@kernel.org>
[zohar@linux.ibm.com: Updated "Fixes" tag]
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2022-02-02 11:59:54 -05:00
Roberto Sassu bb8e52e490 ima: Allow template selection with ima_template[_fmt]= after ima_hash=
Commit c2426d2ad5 ("ima: added support for new kernel cmdline parameter
ima_template_fmt") introduced an additional check on the ima_template
variable to avoid multiple template selection.

Unfortunately, ima_template could be also set by the setup function of the
ima_hash= parameter, when it calls ima_template_desc_current(). This causes
attempts to choose a new template with ima_template= or with
ima_template_fmt=, after ima_hash=, to be ignored.

Achieve the goal of the commit mentioned with the new static variable
template_setup_done, so that template selection requests after ima_hash=
are not ignored.

Finally, call ima_init_template_list(), if not already done, to initialize
the list of templates before lookup_template_desc() is called.

Reported-by: Guo Zihua <guozihua@huawei.com>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Cc: stable@vger.kernel.org
Fixes: c2426d2ad5 ("ima: added support for new kernel cmdline parameter ima_template_fmt")
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2022-02-02 11:59:54 -05:00
Stefan Berger f7333b9572 ima: Remove ima_policy file before directory
The removal of ima_dir currently fails since ima_policy still exists, so
remove the ima_policy file before removing the directory.

Fixes: 4af4662fa4 ("integrity: IMA policy")
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Cc: <stable@vger.kernel.org>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2022-02-02 11:59:09 -05:00
Christoph Hellwig 322cbb50de block: remove genhd.h
There is no good reason to keep genhd.h separate from the main blkdev.h
header that includes it.  So fold the contents of genhd.h into blkdev.h
and remove genhd.h entirely.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20220124093913.742411-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-02-02 07:49:59 -07:00
Linus Torvalds 84bfcc0b69 integrity-v5.17
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Merge tag 'integrity-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity

Pull integrity subsystem updates from Mimi Zohar:
 "The few changes are all kexec related:

   - The MOK keys are loaded onto the .platform keyring in order to
     verify the kexec kernel image signature.

     However, the MOK keys should only be trusted when secure boot is
     enabled. Before loading the MOK keys onto the .platform keyring,
     make sure the system is booted in secure boot mode.

   - When carrying the IMA measurement list across kexec, limit dumping
     the measurement list to when dynamic debug or CONFIG_DEBUG is
     enabled.

   - kselftest: add kexec_file_load selftest support for PowerNV and
     other cleanup"

* tag 'integrity-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
  selftests/kexec: Enable secureboot tests for PowerPC
  ima: silence measurement list hexdump during kexec
  selftests/kexec: update searching for the Kconfig
  selftest/kexec: fix "ignored null byte in input" warning
  integrity: Do not load MOK and MOKx when secure boot be disabled
  ima: Fix undefined arch_ima_get_secureboot() and co
2022-01-11 13:11:10 -08:00
Bruno Meneguele 520451e90c ima: silence measurement list hexdump during kexec
Directly calling print_hex_dump() dumps the IMA measurement list on soft
resets (kexec) straight to the syslog (kmsg/dmesg) without considering the
DEBUG flag or the dynamic debug state, causing the output to be always
printed, including during boot time.

Since this output is only valid for IMA debugging, but not necessary on
normal kexec operation, print_hex_dump_debug() adheres to the pr_debug()
behavior: the dump is only printed to syslog when DEBUG is defined or when
explicitly requested by the user through dynamic debugging.

Signed-off-by: Bruno Meneguele <bmeneg@redhat.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2022-01-05 06:22:00 -05:00
Paul Moore 6326948f94 lsm: security_task_getsecid_subj() -> security_current_getsecid_subj()
The security_task_getsecid_subj() LSM hook invites misuse by allowing
callers to specify a task even though the hook is only safe when the
current task is referenced.  Fix this by removing the task_struct
argument to the hook, requiring LSM implementations to use the
current task.  While we are changing the hook declaration we also
rename the function to security_current_getsecid_subj() in an effort
to reinforce that the hook captures the subjective credentials of the
current task and not an arbitrary task on the system.

Reviewed-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-11-22 17:52:47 -05:00
Petr Vorel cc4299ea03 ima: Use strscpy instead of strlcpy
strlcpy is deprecated, use its safer replacement.

Signed-off-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-10-09 22:17:58 -04:00
Petr Vorel 61868acb07 ima_policy: Remove duplicate 'the' in docs comment
Also join string (short enough to be on single line).

Signed-off-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-10-09 22:17:57 -04:00
Curtis Veit 40224c4166 ima: add gid support
IMA currently supports the concept of rules based on uid where the rule
is based on the uid of the file owner or the uid of the user accessing
the file. Provide the ability to have similar rules based on gid.

Signed-off-by: Curtis Veit <veit@vpieng.com>
Co-developed-by: Alex Henrie <alexh@vpitech.com>
Signed-off-by: Alex Henrie <alexh@vpitech.com>
Reviewed-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-10-09 22:17:57 -04:00
Alex Henrie 30d8764a74 ima: fix uid code style problems
scripts/checkpatch.pl wants function arguments to have names; and Mimi
prefers to keep the line length in functions to 80 characters or less.

Signed-off-by: Alex Henrie <alexh@vpitech.com>
Reviewed-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-10-09 22:17:57 -04:00
liqiong eb0782bbdf ima: fix deadlock when traversing "ima_default_rules".
The current IMA ruleset is identified by the variable "ima_rules"
that default to "&ima_default_rules". When loading a custom policy
for the first time, the variable is updated to "&ima_policy_rules"
instead. That update isn't RCU-safe, and deadlocks are possible.
Indeed, some functions like ima_match_policy() may loop indefinitely
when traversing "ima_default_rules" with list_for_each_entry_rcu().

When iterating over the default ruleset back to head, if the list
head is "ima_default_rules", and "ima_rules" have been updated to
"&ima_policy_rules", the loop condition (&entry->list != ima_rules)
stays always true, traversing won't terminate, causing a soft lockup
and RCU stalls.

Introduce a temporary value for "ima_rules" when iterating over
the ruleset to avoid the deadlocks.

Signed-off-by: liqiong <liqiong@nfschina.com>
Reviewed-by: THOBY Simon <Simon.THOBY@viveris.fr>
Fixes: 38d859f991 ("IMA: policy can now be updated multiple times")
Reported-by: kernel test robot <lkp@intel.com> (Fix sparse: incompatible types in comparison expression.)
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-10-09 22:17:52 -04:00
Linus Torvalds aef4892a63 integrity-v5.15
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Merge tag 'integrity-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity

Pull integrity subsystem updates from Mimi Zohar:

 - Limit the allowed hash algorithms when writing security.ima xattrs or
   verifying them, based on the IMA policy and the configured hash
   algorithms.

 - Return the calculated "critical data" measurement hash and size to
   avoid code duplication. (Preparatory change for a proposed LSM.)

 - and a single patch to address a compiler warning.

* tag 'integrity-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
  IMA: reject unknown hash algorithms in ima_get_hash_algo
  IMA: prevent SETXATTR_CHECK policy rules with unavailable algorithms
  IMA: introduce a new policy option func=SETXATTR_CHECK
  IMA: add a policy option to restrict xattr hash algorithms on appraisal
  IMA: add support to restrict the hash algorithms used for file appraisal
  IMA: block writes of the security.ima xattr with unsupported algorithms
  IMA: remove the dependency on CRYPTO_MD5
  ima: Add digest and digest_len params to the functions to measure a buffer
  ima: Return int in the functions to measure a buffer
  ima: Introduce ima_get_current_hash_algo()
  IMA: remove -Wmissing-prototypes warning
2021-09-02 12:51:41 -07:00
THOBY Simon cb181da161 IMA: reject unknown hash algorithms in ima_get_hash_algo
The new function validate_hash_algo() assumed that ima_get_hash_algo()
always return a valid 'enum hash_algo', but it returned the
user-supplied value present in the digital signature without
any bounds checks.

Update ima_get_hash_algo() to always return a valid hash algorithm,
defaulting on 'ima_hash_algo' when the user-supplied value inside
the xattr is invalid.

Signed-off-by: THOBY Simon <Simon.THOBY@viveris.fr>
Reported-by: syzbot+e8bafe7b82c739eaf153@syzkaller.appspotmail.com
Fixes: 50f742dd91 ("IMA: block writes of the security.ima xattr with unsupported algorithms")
Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-08-23 18:22:00 -04:00
THOBY Simon 8ecd39cb61 IMA: prevent SETXATTR_CHECK policy rules with unavailable algorithms
SETXATTR_CHECK policy rules assume that any algorithm listed in the
'appraise_algos' flag must be accepted when performing setxattr() on
the security.ima xattr.  However nothing checks that they are
available in the current kernel.  A userland application could hash
a file with a digest that the kernel wouldn't be able to verify.
However, if SETXATTR_CHECK is not in use, the kernel already forbids
that xattr write.

Verify that algorithms listed in appraise_algos are available to the
current kernel and reject the policy update otherwise. This will fix
the inconsistency between SETXATTR_CHECK and non-SETXATTR_CHECK
behaviors.

That filtering is only performed in ima_parse_appraise_algos() when
updating policies so that we do not have to pay the price of
allocating a hash object every time validate_hash_algo() is called
in ima_inode_setxattr().

Signed-off-by: THOBY Simon <Simon.THOBY@viveris.fr>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-08-16 17:35:35 -04:00
THOBY Simon 4f2946aa0c IMA: introduce a new policy option func=SETXATTR_CHECK
While users can restrict the accepted hash algorithms for the
security.ima xattr file signature when appraising said file, users
cannot restrict the algorithms that can be set on that attribute:
any algorithm built in the kernel is accepted on a write.

Define a new value for the ima policy option 'func' that restricts
globally the hash algorithms accepted when writing the security.ima
xattr.

When a policy contains a rule of the form
	appraise func=SETXATTR_CHECK appraise_algos=sha256,sha384,sha512
only values corresponding to one of these three digest algorithms
will be accepted for writing the security.ima xattr.  Attempting to
write the attribute using another algorithm (or "free-form" data)
will be denied with an audit log message.  In the absence of such a
policy rule, the default is still to only accept hash algorithms
built in the kernel (with all the limitations that entails).

Signed-off-by: THOBY Simon <Simon.THOBY@viveris.fr>
Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-08-16 17:35:35 -04:00
THOBY Simon 583a80ae86 IMA: add a policy option to restrict xattr hash algorithms on appraisal
The kernel has the ability to restrict the set of hash algorithms it
accepts for the security.ima xattr when it appraises files.

Define a new IMA policy rule option "appraise_algos=", using the
mentioned mechanism to expose a user-toggable policy knob to opt-in
to that restriction and select the desired set of algorithms that
must be accepted.

When a policy rule uses the 'appraise_algos' option, appraisal of a
file referenced by that rule will now fail if the digest algorithm
employed to hash the file was not one of those explicitly listed in
the option.  In its absence, any hash algorithm compiled in the
kernel will be accepted.

For example, on a system where SELinux is properly deployed, the rule
	appraise func=BPRM_CHECK obj_type=iptables_exec_t \
		appraise_algos=sha256,sha384
will block the execution of iptables if the xattr security.ima of its
executables were not hashed with either sha256 or sha384.

Signed-off-by: THOBY Simon <Simon.THOBY@viveris.fr>
Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-08-16 17:33:07 -04:00
THOBY Simon 1624dc0086 IMA: add support to restrict the hash algorithms used for file appraisal
The kernel accepts any hash algorithm as a value for the security.ima
xattr. Users may wish to restrict the accepted algorithms to only
support strong cryptographic ones.

Provide the plumbing to restrict the permitted set of hash algorithms
used for verifying file hashes and signatures stored in security.ima
xattr.

Signed-off-by: THOBY Simon <Simon.THOBY@viveris.fr>
Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-08-16 17:30:41 -04:00
THOBY Simon 50f742dd91 IMA: block writes of the security.ima xattr with unsupported algorithms
By default, writes to the extended attributes security.ima will be
allowed even if the hash algorithm used for the xattr is not compiled
in the kernel (which does not make sense because the kernel would not
be able to appraise that file as it lacks support for validating the
hash).

Prevent and audit writes to the security.ima xattr if the hash algorithm
used in the new value is not available in the current kernel.

Signed-off-by: THOBY Simon <Simon.THOBY@viveris.fr>
Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-08-16 17:30:41 -04:00
THOBY Simon 8510505d55 IMA: remove the dependency on CRYPTO_MD5
MD5 is a weak digest algorithm that shouldn't be used for cryptographic
operation. It hinders the efficiency of a patch set that aims to limit
the digests allowed for the extended file attribute namely security.ima.
MD5 is no longer a requirement for IMA, nor should it be used there.

The sole place where we still use the MD5 algorithm inside IMA is setting
the ima_hash algorithm to MD5, if the user supplies 'ima_hash=md5'
parameter on the command line.  With commit ab60368ab6 ("ima: Fallback
to the builtin hash algorithm"), setting "ima_hash=md5" fails gracefully
when CRYPTO_MD5 is not set:
	ima: Can not allocate md5 (reason: -2)
	ima: Allocating md5 failed, going to use default hash algorithm sha256

Remove the CRYPTO_MD5 dependency for IMA.

Signed-off-by: THOBY Simon <Simon.THOBY@viveris.fr>
Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
[zohar@linux.ibm.com: include commit number in patch description for
stable.]
Cc: stable@vger.kernel.org # 4.17
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-08-16 17:29:10 -04:00
Tushar Sugandhi 91ccbbac17 dm ima: measure data on table load
DM configures a block device with various target specific attributes
passed to it as a table.  DM loads the table, and calls each target’s
respective constructors with the attributes as input parameters.
Some of these attributes are critical to ensure the device meets
certain security bar.  Thus, IMA should measure these attributes, to
ensure they are not tampered with, during the lifetime of the device.
So that the external services can have high confidence in the
configuration of the block-devices on a given system.

Some devices may have large tables.  And a given device may change its
state (table-load, suspend, resume, rename, remove, table-clear etc.)
many times.  Measuring these attributes each time when the device
changes its state will significantly increase the size of the IMA logs.
Further, once configured, these attributes are not expected to change
unless a new table is loaded, or a device is removed and recreated.
Therefore the clear-text of the attributes should only be measured
during table load, and the hash of the active/inactive table should be
measured for the remaining device state changes.

Export IMA function ima_measure_critical_data() to allow measurement
of DM device parameters, as well as target specific attributes, during
table load.  Compute the hash of the inactive table and store it for
measurements during future state change.  If a load is called multiple
times, update the inactive table hash with the hash of the latest
populated table.  So that the correct inactive table hash is measured
when the device transitions to different states like resume, remove,
rename, etc.

Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
Signed-off-by: Colin Ian King <colin.king@canonical.com> # leak fix
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-08-10 13:32:40 -04:00
Roberto Sassu ca3c9bdb10 ima: Add digest and digest_len params to the functions to measure a buffer
This patch performs the final modification necessary to pass the buffer
measurement to callers, so that they provide a functionality similar to
ima_file_hash(). It adds the 'digest' and 'digest_len' parameters to
ima_measure_critical_data() and process_buffer_measurement().

These functions calculate the digest even if there is no suitable rule in
the IMA policy and, in this case, they simply return 1 before generating a
new measurement entry.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-07-23 09:27:02 -04:00
Roberto Sassu ce5bb5a86e ima: Return int in the functions to measure a buffer
ima_measure_critical_data() and process_buffer_measurement() currently
don't return a result as, unlike appraisal-related functions, the result is
not used by callers to deny an operation. Measurement-related functions
instead rely on the audit subsystem to notify the system administrator when
an error occurs.

However, ima_measure_critical_data() and process_buffer_measurement() are a
special case, as these are the only functions that can return a buffer
measurement (for files, there is ima_file_hash()). In a subsequent patch,
they will be modified to return the calculated digest.

In preparation to return the result of the digest calculation, this patch
modifies the return type from void to int, and returns 0 if the buffer has
been successfully measured, a negative value otherwise.

Given that the result of the measurement is still not necessary, this patch
does not modify the behavior of existing callers by processing the returned
value. For those, the return value is ignored.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Acked-by: Paul Moore <paul@paul-moore.com> (for the SELinux bits)
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-07-23 09:27:02 -04:00
Roberto Sassu 5d1ef2ce13 ima: Introduce ima_get_current_hash_algo()
Buffer measurements, unlike file measurements, are not accessible after the
measurement is done, as buffers are not suitable for use with the
integrity_iint_cache structure (there is no index, for files it is the
inode number). In the subsequent patches, the measurement (digest) will be
returned directly by the functions that perform the buffer measurement,
ima_measure_critical_data() and process_buffer_measurement().

A caller of those functions also needs to know the algorithm used to
calculate the digest. Instead of adding the algorithm as a new parameter to
the functions, this patch provides it separately with the new function
ima_get_current_hash_algo().

Since the hash algorithm does not change after the IMA setup phase, there
is no risk of races (obtaining a digest calculated with a different
algorithm than the one returned).

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
[zohar@linux.ibm.com: annotate ima_hash_algo as __ro_after_init]
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-07-23 09:25:28 -04:00
Austin Kim a32ad90426 IMA: remove -Wmissing-prototypes warning
With W=1 build, the compiler throws warning message as below:

   security/integrity/ima/ima_mok.c:24:12: warning:
   no previous prototype for ‘ima_mok_init’ [-Wmissing-prototypes]
       __init int ima_mok_init(void)

Silence the warning by adding static keyword to ima_mok_init().

Signed-off-by: Austin Kim <austin.kim@lge.com>
Fixes: 41c89b64d7 ("IMA: create machine owner and blacklist keyrings")
Cc: stable@vger.kernel.org
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-07-23 08:05:06 -04:00
Tushar Sugandhi 52c208397c IMA: support for duplicate measurement records
IMA measures contents of a given file/buffer/critical-data record,
and properly re-measures it on change.  However, IMA does not measure
the duplicate value for a given record, since TPM extend is a very
expensive operation.  For example, if the record changes from value
'v#1' to 'v#2', and then back to 'v#1', IMA will not measure and log
the last change to 'v#1', since the hash of 'v#1' for that record is
already present in the IMA htable.  This limits the ability of an
external attestation service to accurately determine the current state
of the system.  The service would incorrectly conclude that the latest
value of the given record on the system is 'v#2', and act accordingly.

Define and use a new Kconfig option IMA_DISABLE_HTABLE to permit
duplicate records in the IMA measurement list.

In addition to the duplicate measurement records described above,
other duplicate file measurement records may be included in the log,
when CONFIG_IMA_DISABLE_HTABLE is enabled.  For example,
    - i_version is not enabled,
    - i_generation changed,
    - same file present on different filesystems,
    - an inode is evicted from dcache

Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
Reviewed-by: Petr Vorel <pvorel@suse.cz>
[zohar@linux.ibm.com: updated list of duplicate measurement records]
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-06-11 12:54:13 -04:00
Lakshmi Ramasubramanian c67913492f ima: Fix warning: no previous prototype for function 'ima_add_kexec_buffer'
The function prototype for ima_add_kexec_buffer() is present
in 'linux/ima.h'.  But this header file is not included in
ima_kexec.c where the function is implemented.  This results
in the following compiler warning when "-Wmissing-prototypes" flag
is turned on:

  security/integrity/ima/ima_kexec.c:81:6: warning: no previous prototype
  for function 'ima_add_kexec_buffer' [-Wmissing-prototypes]

Include the header file 'linux/ima.h' in ima_kexec.c to fix
the compiler warning.

Fixes: dce92f6b11 (arm64: Enable passing IMA log to next kernel on kexec)
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-06-11 11:27:03 -04:00
Mimi Zohar 55748ac6a6 ima: differentiate between EVM failures in the audit log
Differentiate between an invalid EVM portable signature failure
from other EVM HMAC/signature failures.

Reviewed-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-06-10 16:36:41 -04:00
Gustavo A. R. Silva 7d2201d462 ima: Fix fall-through warning for Clang
In preparation to enable -Wimplicit-fallthrough for Clang, fix a
fall-through warning by explicitly adding a break statement instead
of just letting the code fall through to the next case.

Link: https://github.com/KSPP/linux/issues/115
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-06-08 23:33:48 -04:00
Roberto Sassu 531bf6a88d ima: Pass NULL instead of 0 to ima_get_action() in ima_file_mprotect()
This patch fixes the sparse warning:

sparse: warning: Using plain integer as NULL pointer

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-06-08 16:29:10 -04:00
Roberto Sassu 8c559415f6 ima: Include header defining ima_post_key_create_or_update()
This patch fixes the sparse warning for ima_post_key_create_or_update() by
adding the header file that defines the prototype (linux/ima.h).

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-06-08 16:29:10 -04:00
Roberto Sassu 6b26285f44 ima/evm: Fix type mismatch
The endianness of a variable written to the measurement list cannot be
determined at compile time, as it depends on the value of the
ima_canonical_fmt global variable (set through a kernel option with the
same name if the machine is big endian).

If ima_canonical_fmt is false, the endianness of a variable is the same as
the machine; if ima_canonical_fmt is true, the endianness is little endian.
The warning arises due to this type of instruction:

var = cpu_to_leXX(var)

which tries to assign a value in little endian to a variable with native
endianness (little or big endian).

Given that the variables set with this instruction are not used in any
operation but just written to a buffer, it is safe to force the type of the
value being set to be the same of the type of the variable with:

var = (__force <var type>)cpu_to_leXX(var)

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-06-08 16:29:10 -04:00
Roberto Sassu 24c9ae23bd ima: Set correct casting types
The code expects that the values being parsed from a buffer when the
ima_canonical_fmt global variable is true are in little endian. Thus, this
patch sets the casting types accordingly.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-06-08 16:29:10 -04:00
Roberto Sassu 88016de3ab ima: Define new template evm-sig
With the recent introduction of the evmsig template field, remote verifiers
can obtain the EVM portable signature instead of the IMA signature, to
verify file metadata.

After introducing the new fields to include file metadata in the
measurement list, this patch finally defines the evm-sig template, whose
format is:

d-ng|n-ng|evmsig|xattrnames|xattrlengths|xattrvalues|iuid|igid|imode

xattrnames, xattrlengths and xattrvalues are populated only from defined
EVM protected xattrs, i.e. the ones that EVM considers to verify the
portable signature. xattrnames and xattrlengths are populated only if the
xattr is present.

xattrnames and xattrlengths are not necessary for verifying the EVM
portable signature, but they are included for completeness of information,
if a remote verifier wants to infer more from file metadata.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-06-03 10:02:37 -04:00
Roberto Sassu 8314b6732a ima: Define new template fields xattrnames, xattrlengths and xattrvalues
This patch defines the new template fields xattrnames, xattrlengths and
xattrvalues, which contain respectively a list of xattr names (strings,
separated by |), lengths (u32, hex) and values (hex). If an xattr is not
present, the name and length are not displayed in the measurement list.

Reported-by: kernel test robot <lkp@intel.com> (Missing prototype def)
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-06-02 18:56:13 -04:00
Roberto Sassu f8216f6b95 ima: Define new template field imode
This patch defines the new template field imode, which includes the
inode mode. It can be used by a remote verifier to verify the EVM portable
signature, if it was included with the template fields sig or evmsig.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-06-01 15:17:30 -04:00
Roberto Sassu 7dcfeacc5a ima: Define new template fields iuid and igid
This patch defines the new template fields iuid and igid, which include
respectively the inode UID and GID. For idmapped mounts, still the original
UID and GID are provided.

These fields can be used to verify the EVM portable signature, if it was
included with the template fields sig or evmsig.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-06-01 15:17:30 -04:00
Roberto Sassu cde1391a0b ima: Add ima_show_template_uint() template library function
This patch introduces the new function ima_show_template_uint(). This can
be used for showing integers of different sizes in ASCII format. The
function ima_show_template_data_ascii() automatically determines how to
print a stored integer by checking the integer size.

If integers have been written in canonical format,
ima_show_template_data_ascii() calls the appropriate leXX_to_cpu() function
to correctly display the value.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-06-01 15:17:30 -04:00
Roberto Sassu ed1b472fc1 ima: Don't remove security.ima if file must not be appraised
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: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-06-01 12:30:51 -04:00
Roberto Sassu 026d7fc92a ima: Introduce template field evmsig and write to field sig as fallback
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.

Suggested-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-06-01 12:30:51 -04:00
Roberto Sassu 7aa5783d95 ima: Allow imasig requirement to be satisfied by EVM portable signatures
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: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-06-01 12:30:51 -04:00
Roberto Sassu cdef685be5 evm: Allow xattr/attr operations for portable signatures
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: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-05-21 12:48:39 -04:00
Roberto Sassu e3ccfe1ad7 evm: Introduce evm_revalidate_status()
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_revalidate_status(), which callers of
evm_verifyxattr() can use in their xattr hooks to determine whether
re-validation is necessary and to do the proper actions. IMA calls it in
its xattr 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: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-05-21 12:47:12 -04:00
Roberto Sassu aa2ead71d9 evm: Load EVM key in ima_load_x509() to avoid appraisal
The public builtin keys do not need to be appraised by IMA as the
restriction on the IMA/EVM trusted keyrings ensures that a key can be
loaded only if it is signed with a key on the builtin or secondary
keyrings.

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 trusted 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, which crosses the normal IMA and EVM boundary.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-05-21 12:47:04 -04:00
Linus Torvalds e6f0bf09f0 integrity-v5.13
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Merge tag 'integrity-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity

Pull IMA updates from Mimi Zohar:
 "In addition to loading the kernel module signing key onto the builtin
  keyring, load it onto the IMA keyring as well.

  Also six trivial changes and bug fixes"

* tag 'integrity-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
  ima: ensure IMA_APPRAISE_MODSIG has necessary dependencies
  ima: Fix fall-through warnings for Clang
  integrity: Add declarations to init_once void arguments.
  ima: Fix function name error in comment.
  ima: enable loading of build time generated key on .ima keyring
  ima: enable signing of modules with build time generated key
  keys: cleanup build time module signing keys
  ima: Fix the error code for restoring the PCR value
  ima: without an IMA policy loaded, return quickly
2021-05-01 15:32:18 -07:00
Linus Torvalds 0080665fbd Devicetree updates for v5.13:
- Refactoring powerpc and arm64 kexec DT handling to common code. This
   enables IMA on arm64.
 
 - Add kbuild support for applying DT overlays at build time. The first
   user are the DT unittests.
 
 - Fix kerneldoc formatting and W=1 warnings in drivers/of/
 
 - Fix handling 64-bit flag on PCI resources
 
 - Bump dtschema version required to v2021.2.1
 
 - Enable undocumented compatible checks for dtbs_check. This allows
   tracking of missing binding schemas.
 
 - DT docs improvements. Regroup the DT docs and add the example schema
   and DT kernel ABI docs to the doc build.
 
 - Convert Broadcom Bluetooth and video-mux bindings to schema
 
 - Add QCom sm8250 Venus video codec binding schema
 
 - Add vendor prefixes for AESOP, YIC System Co., Ltd, and Siliconfile
   Technologies Inc.
 
 - Cleanup of DT schema type references on common properties and
   standard unit properties
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Merge tag 'devicetree-for-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux

Pull devicetree updates from Rob Herring:

 - Refactor powerpc and arm64 kexec DT handling to common code. This
   enables IMA on arm64.

 - Add kbuild support for applying DT overlays at build time. The first
   user are the DT unittests.

 - Fix kerneldoc formatting and W=1 warnings in drivers/of/

 - Fix handling 64-bit flag on PCI resources

 - Bump dtschema version required to v2021.2.1

 - Enable undocumented compatible checks for dtbs_check. This allows
   tracking of missing binding schemas.

 - DT docs improvements. Regroup the DT docs and add the example schema
   and DT kernel ABI docs to the doc build.

 - Convert Broadcom Bluetooth and video-mux bindings to schema

 - Add QCom sm8250 Venus video codec binding schema

 - Add vendor prefixes for AESOP, YIC System Co., Ltd, and Siliconfile
   Technologies Inc.

 - Cleanup of DT schema type references on common properties and
   standard unit properties

* tag 'devicetree-for-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (64 commits)
  powerpc: If kexec_build_elf_info() fails return immediately from elf64_load()
  powerpc: Free fdt on error in elf64_load()
  of: overlay: Fix kerneldoc warning in of_overlay_remove()
  of: linux/of.h: fix kernel-doc warnings
  of/pci: Add IORESOURCE_MEM_64 to resource flags for 64-bit memory addresses
  dt-bindings: bcm4329-fmac: add optional brcm,ccode-map
  docs: dt: update writing-schema.rst references
  dt-bindings: media: venus: Add sm8250 dt schema
  of: base: Fix spelling issue with function param 'prop'
  docs: dt: Add DT API documentation
  of: Add missing 'Return' section in kerneldoc comments
  of: Fix kerneldoc output formatting
  docs: dt: Group DT docs into relevant sub-sections
  docs: dt: Make 'Devicetree' wording more consistent
  docs: dt: writing-schema: Include the example schema in the doc build
  docs: dt: writing-schema: Remove spurious indentation
  dt-bindings: Fix reference in submitting-patches.rst to the DT ABI doc
  dt-bindings: ddr: Add optional manufacturer and revision ID to LPDDR3
  dt-bindings: media: video-interfaces: Drop the example
  devicetree: bindings: clock: Minor typo fix in the file armada3700-tbg-clock.txt
  ...
2021-04-28 15:50:24 -07:00
Gustavo A. R. Silva 28073eb09c ima: Fix fall-through warnings for Clang
In preparation to enable -Wimplicit-fallthrough for Clang, fix multiple
warnings by explicitly adding multiple break statements instead of just
letting the code fall through to the next case.

Link: https://github.com/KSPP/linux/issues/115
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-04-20 16:54:14 -04:00
Jiele Zhao 41d75dd962 ima: Fix function name error in comment.
The original function name was ima_path_check().  The policy parsing
still supports PATH_CHECK.   Commit 9bbb6cad01 ("ima: rename
ima_path_check to ima_file_check") renamed the function to
ima_file_check(), but missed modifying the function name in the
comment.

Fixes: 9bbb6cad01 ("ima: rename ima_path_check to ima_file_check").

Signed-off-by: Jiele Zhao <unclexiaole@gmail.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-04-09 12:17:30 -04:00
Li Huafei 7990ccafaa ima: Fix the error code for restoring the PCR value
In ima_restore_measurement_list(), hdr[HDR_PCR].data is pointing to a
buffer of type u8, which contains the dumped 32-bit pcr value.
Currently, only the least significant byte is used to restore the pcr
value. We should convert hdr[HDR_PCR].data to a pointer of type u32
before fetching the value to restore the correct pcr value.

Fixes: 47fdee60b4 ("ima: use ima_parse_buf() to parse measurements headers")
Signed-off-by: Li Huafei <lihuafei1@huawei.com>
Reviewed-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-03-24 07:14:53 -04:00
Paul Moore 4ebd7651bf lsm: separate security_task_getsecid() into subjective and objective variants
Of the three LSMs that implement the security_task_getsecid() LSM
hook, all three LSMs provide the task's objective security
credentials.  This turns out to be unfortunate as most of the hook's
callers seem to expect the task's subjective credentials, although
a small handful of callers do correctly expect the objective
credentials.

This patch is the first step towards fixing the problem: it splits
the existing security_task_getsecid() hook into two variants, one
for the subjective creds, one for the objective creds.

  void security_task_getsecid_subj(struct task_struct *p,
				   u32 *secid);
  void security_task_getsecid_obj(struct task_struct *p,
				  u32 *secid);

While this patch does fix all of the callers to use the correct
variant, in order to keep this patch focused on the callers and to
ease review, the LSMs continue to use the same implementation for
both hooks.  The net effect is that this patch should not change
the behavior of the kernel in any way, it will be up to the latter
LSM specific patches in this series to change the hook
implementations and return the correct credentials.

Acked-by: Mimi Zohar <zohar@linux.ibm.com> (IMA)
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-03-22 15:23:32 -04:00
Mimi Zohar f873b28f26 ima: without an IMA policy loaded, return quickly
Unless an IMA policy is loaded, don't bother checking for an appraise
policy rule.  Return immediately.

Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-03-22 15:12:26 -04:00
Lakshmi Ramasubramanian fee3ff99bc powerpc: Move arch independent ima kexec functions to drivers/of/kexec.c
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: Prakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Tested-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210221174930.27324-11-nramas@linux.microsoft.com
2021-03-08 12:06:29 -07:00
Lakshmi Ramasubramanian 0c605158be powerpc: Move ima buffer fields to struct kimage
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: Prakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Suggested-by: Will Deacon <will@kernel.org>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210221174930.27324-9-nramas@linux.microsoft.com
2021-03-08 12:06:29 -07:00
Linus Torvalds c03c21ba6f Keyrings miscellany
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Merge tag 'keys-misc-20210126' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull keyring updates from David Howells:
 "Here's a set of minor keyrings fixes/cleanups that I've collected from
  various people for the upcoming merge window.

  A couple of them might, in theory, be visible to userspace:

   - Make blacklist_vet_description() reject uppercase letters as they
     don't match the all-lowercase hex string generated for a blacklist
     search.

     This may want reconsideration in the future, but, currently, you
     can't add to the blacklist keyring from userspace and the only
     source of blacklist keys generates lowercase descriptions.

   - Fix blacklist_init() to use a new KEY_ALLOC_* flag to indicate that
     it wants KEY_FLAG_KEEP to be set rather than passing KEY_FLAG_KEEP
     into keyring_alloc() as KEY_FLAG_KEEP isn't a valid alloc flag.

     This isn't currently a problem as the blacklist keyring isn't
     currently writable by userspace.

  The rest of the patches are cleanups and I don't think they should
  have any visible effect"

* tag 'keys-misc-20210126' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  watch_queue: rectify kernel-doc for init_watch()
  certs: Replace K{U,G}IDT_INIT() with GLOBAL_ROOT_{U,G}ID
  certs: Fix blacklist flag type confusion
  PKCS#7: Fix missing include
  certs: Fix blacklisted hexadecimal hash string check
  certs/blacklist: fix kernel doc interface issue
  crypto: public_key: Remove redundant header file from public_key.h
  keys: remove trailing semicolon in macro definition
  crypto: pkcs7: Use match_string() helper to simplify the code
  PKCS#7: drop function from kernel-doc pkcs7_validate_trust_one
  encrypted-keys: Replace HTTP links with HTTPS ones
  crypto: asymmetric_keys: fix some comments in pkcs7_parser.h
  KEYS: remove redundant memset
  security: keys: delete repeated words in comments
  KEYS: asymmetric: Fix kerneldoc
  security/keys: use kvfree_sensitive()
  watch_queue: Drop references to /dev/watch_queue
  keys: Remove outdated __user annotations
  security: keys: Fix fall-through warnings for Clang
2021-02-23 16:09:23 -08:00
Linus Torvalds 7d6beb71da idmapped-mounts-v5.12
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Merge tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux

Pull idmapped mounts from Christian Brauner:
 "This introduces idmapped mounts which has been in the making for some
  time. Simply put, different mounts can expose the same file or
  directory with different ownership. This initial implementation comes
  with ports for fat, ext4 and with Christoph's port for xfs with more
  filesystems being actively worked on by independent people and
  maintainers.

  Idmapping mounts handle a wide range of long standing use-cases. Here
  are just a few:

   - Idmapped mounts make it possible to easily share files between
     multiple users or multiple machines especially in complex
     scenarios. For example, idmapped mounts will be used in the
     implementation of portable home directories in
     systemd-homed.service(8) where they allow users to move their home
     directory to an external storage device and use it on multiple
     computers where they are assigned different uids and gids. This
     effectively makes it possible to assign random uids and gids at
     login time.

   - It is possible to share files from the host with unprivileged
     containers without having to change ownership permanently through
     chown(2).

   - It is possible to idmap a container's rootfs and without having to
     mangle every file. For example, Chromebooks use it to share the
     user's Download folder with their unprivileged containers in their
     Linux subsystem.

   - It is possible to share files between containers with
     non-overlapping idmappings.

   - Filesystem that lack a proper concept of ownership such as fat can
     use idmapped mounts to implement discretionary access (DAC)
     permission checking.

   - They allow users to efficiently changing ownership on a per-mount
     basis without having to (recursively) chown(2) all files. In
     contrast to chown (2) changing ownership of large sets of files is
     instantenous with idmapped mounts. This is especially useful when
     ownership of a whole root filesystem of a virtual machine or
     container is changed. With idmapped mounts a single syscall
     mount_setattr syscall will be sufficient to change the ownership of
     all files.

   - Idmapped mounts always take the current ownership into account as
     idmappings specify what a given uid or gid is supposed to be mapped
     to. This contrasts with the chown(2) syscall which cannot by itself
     take the current ownership of the files it changes into account. It
     simply changes the ownership to the specified uid and gid. This is
     especially problematic when recursively chown(2)ing a large set of
     files which is commong with the aforementioned portable home
     directory and container and vm scenario.

   - Idmapped mounts allow to change ownership locally, restricting it
     to specific mounts, and temporarily as the ownership changes only
     apply as long as the mount exists.

  Several userspace projects have either already put up patches and
  pull-requests for this feature or will do so should you decide to pull
  this:

   - systemd: In a wide variety of scenarios but especially right away
     in their implementation of portable home directories.

         https://systemd.io/HOME_DIRECTORY/

   - container runtimes: containerd, runC, LXD:To share data between
     host and unprivileged containers, unprivileged and privileged
     containers, etc. The pull request for idmapped mounts support in
     containerd, the default Kubernetes runtime is already up for quite
     a while now: https://github.com/containerd/containerd/pull/4734

   - The virtio-fs developers and several users have expressed interest
     in using this feature with virtual machines once virtio-fs is
     ported.

   - ChromeOS: Sharing host-directories with unprivileged containers.

  I've tightly synced with all those projects and all of those listed
  here have also expressed their need/desire for this feature on the
  mailing list. For more info on how people use this there's a bunch of
  talks about this too. Here's just two recent ones:

      https://www.cncf.io/wp-content/uploads/2020/12/Rootless-Containers-in-Gitpod.pdf
      https://fosdem.org/2021/schedule/event/containers_idmap/

  This comes with an extensive xfstests suite covering both ext4 and
  xfs:

      https://git.kernel.org/brauner/xfstests-dev/h/idmapped_mounts

  It covers truncation, creation, opening, xattrs, vfscaps, setid
  execution, setgid inheritance and more both with idmapped and
  non-idmapped mounts. It already helped to discover an unrelated xfs
  setgid inheritance bug which has since been fixed in mainline. It will
  be sent for inclusion with the xfstests project should you decide to
  merge this.

  In order to support per-mount idmappings vfsmounts are marked with
  user namespaces. The idmapping of the user namespace will be used to
  map the ids of vfs objects when they are accessed through that mount.
  By default all vfsmounts are marked with the initial user namespace.
  The initial user namespace is used to indicate that a mount is not
  idmapped. All operations behave as before and this is verified in the
  testsuite.

  Based on prior discussions we want to attach the whole user namespace
  and not just a dedicated idmapping struct. This allows us to reuse all
  the helpers that already exist for dealing with idmappings instead of
  introducing a whole new range of helpers. In addition, if we decide in
  the future that we are confident enough to enable unprivileged users
  to setup idmapped mounts the permission checking can take into account
  whether the caller is privileged in the user namespace the mount is
  currently marked with.

  The user namespace the mount will be marked with can be specified by
  passing a file descriptor refering to the user namespace as an
  argument to the new mount_setattr() syscall together with the new
  MOUNT_ATTR_IDMAP flag. The system call follows the openat2() pattern
  of extensibility.

  The following conditions must be met in order to create an idmapped
  mount:

   - The caller must currently have the CAP_SYS_ADMIN capability in the
     user namespace the underlying filesystem has been mounted in.

   - The underlying filesystem must support idmapped mounts.

   - The mount must not already be idmapped. This also implies that the
     idmapping of a mount cannot be altered once it has been idmapped.

   - The mount must be a detached/anonymous mount, i.e. it must have
     been created by calling open_tree() with the OPEN_TREE_CLONE flag
     and it must not already have been visible in the filesystem.

  The last two points guarantee easier semantics for userspace and the
  kernel and make the implementation significantly simpler.

  By default vfsmounts are marked with the initial user namespace and no
  behavioral or performance changes are observed.

  The manpage with a detailed description can be found here:

      1d7b902e28

  In order to support idmapped mounts, filesystems need to be changed
  and mark themselves with the FS_ALLOW_IDMAP flag in fs_flags. The
  patches to convert individual filesystem are not very large or
  complicated overall as can be seen from the included fat, ext4, and
  xfs ports. Patches for other filesystems are actively worked on and
  will be sent out separately. The xfstestsuite can be used to verify
  that port has been done correctly.

  The mount_setattr() syscall is motivated independent of the idmapped
  mounts patches and it's been around since July 2019. One of the most
  valuable features of the new mount api is the ability to perform
  mounts based on file descriptors only.

  Together with the lookup restrictions available in the openat2()
  RESOLVE_* flag namespace which we added in v5.6 this is the first time
  we are close to hardened and race-free (e.g. symlinks) mounting and
  path resolution.

  While userspace has started porting to the new mount api to mount
  proper filesystems and create new bind-mounts it is currently not
  possible to change mount options of an already existing bind mount in
  the new mount api since the mount_setattr() syscall is missing.

  With the addition of the mount_setattr() syscall we remove this last
  restriction and userspace can now fully port to the new mount api,
  covering every use-case the old mount api could. We also add the
  crucial ability to recursively change mount options for a whole mount
  tree, both removing and adding mount options at the same time. This
  syscall has been requested multiple times by various people and
  projects.

  There is a simple tool available at

      https://github.com/brauner/mount-idmapped

  that allows to create idmapped mounts so people can play with this
  patch series. I'll add support for the regular mount binary should you
  decide to pull this in the following weeks:

  Here's an example to a simple idmapped mount of another user's home
  directory:

	u1001@f2-vm:/$ sudo ./mount --idmap both:1000:1001:1 /home/ubuntu/ /mnt

	u1001@f2-vm:/$ ls -al /home/ubuntu/
	total 28
	drwxr-xr-x 2 ubuntu ubuntu 4096 Oct 28 22:07 .
	drwxr-xr-x 4 root   root   4096 Oct 28 04:00 ..
	-rw------- 1 ubuntu ubuntu 3154 Oct 28 22:12 .bash_history
	-rw-r--r-- 1 ubuntu ubuntu  220 Feb 25  2020 .bash_logout
	-rw-r--r-- 1 ubuntu ubuntu 3771 Feb 25  2020 .bashrc
	-rw-r--r-- 1 ubuntu ubuntu  807 Feb 25  2020 .profile
	-rw-r--r-- 1 ubuntu ubuntu    0 Oct 16 16:11 .sudo_as_admin_successful
	-rw------- 1 ubuntu ubuntu 1144 Oct 28 00:43 .viminfo

	u1001@f2-vm:/$ ls -al /mnt/
	total 28
	drwxr-xr-x  2 u1001 u1001 4096 Oct 28 22:07 .
	drwxr-xr-x 29 root  root  4096 Oct 28 22:01 ..
	-rw-------  1 u1001 u1001 3154 Oct 28 22:12 .bash_history
	-rw-r--r--  1 u1001 u1001  220 Feb 25  2020 .bash_logout
	-rw-r--r--  1 u1001 u1001 3771 Feb 25  2020 .bashrc
	-rw-r--r--  1 u1001 u1001  807 Feb 25  2020 .profile
	-rw-r--r--  1 u1001 u1001    0 Oct 16 16:11 .sudo_as_admin_successful
	-rw-------  1 u1001 u1001 1144 Oct 28 00:43 .viminfo

	u1001@f2-vm:/$ touch /mnt/my-file

	u1001@f2-vm:/$ setfacl -m u:1001:rwx /mnt/my-file

	u1001@f2-vm:/$ sudo setcap -n 1001 cap_net_raw+ep /mnt/my-file

	u1001@f2-vm:/$ ls -al /mnt/my-file
	-rw-rwxr--+ 1 u1001 u1001 0 Oct 28 22:14 /mnt/my-file

	u1001@f2-vm:/$ ls -al /home/ubuntu/my-file
	-rw-rwxr--+ 1 ubuntu ubuntu 0 Oct 28 22:14 /home/ubuntu/my-file

	u1001@f2-vm:/$ getfacl /mnt/my-file
	getfacl: Removing leading '/' from absolute path names
	# file: mnt/my-file
	# owner: u1001
	# group: u1001
	user::rw-
	user:u1001:rwx
	group::rw-
	mask::rwx
	other::r--

	u1001@f2-vm:/$ getfacl /home/ubuntu/my-file
	getfacl: Removing leading '/' from absolute path names
	# file: home/ubuntu/my-file
	# owner: ubuntu
	# group: ubuntu
	user::rw-
	user:ubuntu:rwx
	group::rw-
	mask::rwx
	other::r--"

* tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: (41 commits)
  xfs: remove the possibly unused mp variable in xfs_file_compat_ioctl
  xfs: support idmapped mounts
  ext4: support idmapped mounts
  fat: handle idmapped mounts
  tests: add mount_setattr() selftests
  fs: introduce MOUNT_ATTR_IDMAP
  fs: add mount_setattr()
  fs: add attr_flags_to_mnt_flags helper
  fs: split out functions to hold writers
  namespace: only take read lock in do_reconfigure_mnt()
  mount: make {lock,unlock}_mount_hash() static
  namespace: take lock_mount_hash() directly when changing flags
  nfs: do not export idmapped mounts
  overlayfs: do not mount on top of idmapped mounts
  ecryptfs: do not mount on top of idmapped mounts
  ima: handle idmapped mounts
  apparmor: handle idmapped mounts
  fs: make helpers idmap mount aware
  exec: handle idmapped mounts
  would_dump: handle idmapped mounts
  ...
2021-02-23 13:39:45 -08:00
Mimi Zohar cccb0efdef Merge branch 'ima-kexec-fixes' into next-integrity 2021-02-10 16:34:06 -05:00
Lakshmi Ramasubramanian f31e3386a4 ima: Free IMA measurement buffer after kexec syscall
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: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Suggested-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Fixes: 7b8589cc29 ("ima: on soft reboot, save the measurement list")
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-02-10 15:49:38 -05:00
Lakshmi Ramasubramanian 6d14c65178 ima: Free IMA measurement buffer on error
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: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Suggested-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Fixes: 7b8589cc29 ("ima: on soft reboot, save the measurement list")
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-02-10 15:49:35 -05:00
Raphael Gianotti b3f82afc10 IMA: Measure kernel version in early boot
The integrity of a kernel can be verified by the boot loader on cold
boot, and during kexec, by the current running kernel, before it is
loaded. However, it is still possible that the new kernel being
loaded is older than the current kernel, and/or has known
vulnerabilities. Therefore, it is imperative that an attestation
service be able to verify the version of the kernel being loaded on
the client, from cold boot and subsequent kexec system calls,
ensuring that only kernels with versions known to be good are loaded.

Measure the kernel version using ima_measure_critical_data() early on
in the boot sequence, reducing the chances of known kernel
vulnerabilities being exploited. With IMA being part of the kernel,
this overall approach makes the measurement itself more trustworthy.

To enable measuring the kernel version "ima_policy=critical_data"
needs to be added to the kernel command line arguments.
For example,
        BOOT_IMAGE=/boot/vmlinuz-5.11.0-rc3+ root=UUID=fd643309-a5d2-4ed3-b10d-3c579a5fab2f ro nomodeset ima_policy=critical_data

If runtime measurement of the kernel version is ever needed, the
following should be added to /etc/ima/ima-policy:

        measure func=CRITICAL_DATA label=kernel_info

To extract the measured data after boot, the following command can be used:

        grep -m 1 "kernel_version" \
        /sys/kernel/security/integrity/ima/ascii_runtime_measurements

Sample output from the command above:

        10 a8297d408e9d5155728b619761d0dd4cedf5ef5f ima-buf
        sha256:5660e19945be0119bc19cbbf8d9c33a09935ab5d30dad48aa11f879c67d70988
        kernel_version 352e31312e302d7263332d31363138372d676564623634666537383234342d6469727479

The above hex-ascii string corresponds to the kernel version
(e.g. xxd -r -p):

        5.11.0-rc3-16187-gedb64fe78244-dirty

Signed-off-by: Raphael Gianotti <raphgi@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-01-26 19:06:41 -05:00
Christian Brauner a2d2329e30
ima: handle idmapped mounts
IMA does sometimes access the inode's i_uid and compares it against the
rules' fowner. Enable IMA to handle idmapped mounts by passing down the
mount's user namespace. We simply make use of the helpers we introduced
before. If the initial user namespace is passed nothing changes so
non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-27-christian.brauner@ubuntu.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24 14:27:20 +01:00
Tycho Andersen c7c7a1a18a
xattr: handle idmapped mounts
When interacting with extended attributes the vfs verifies that the
caller is privileged over the inode with which the extended attribute is
associated. For posix access and posix default extended attributes a uid
or gid can be stored on-disk. Let the functions handle posix extended
attributes on idmapped mounts. If the inode is accessed through an
idmapped mount we need to map it according to the mount's user
namespace. Afterwards the checks are identical to non-idmapped mounts.
This has no effect for e.g. security xattrs since they don't store uids
or gids and don't perform permission checks on them like posix acls do.

Link: https://lore.kernel.org/r/20210121131959.646623-10-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Tycho Andersen <tycho@tycho.pizza>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24 14:27:17 +01:00
David Howells 4993e1f947 certs: Fix blacklist flag type confusion
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: 734114f878 ("KEYS: Add a system blacklist keyring")
Reported-by: Mickaël Salaün <mic@linux.microsoft.com>
Signed-off-by: David 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>
2021-01-21 16:16:10 +00:00
Lakshmi Ramasubramanian 03cee16836 IMA: define a builtin critical data measurement policy
Define a new critical data builtin policy to allow measuring
early kernel integrity critical data before a custom IMA policy
is loaded.

Update the documentation on kernel parameters to document
the new critical data builtin policy.

Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-01-14 23:41:43 -05:00
Tushar Sugandhi 9f5d7d23cc IMA: extend critical data hook to limit the measurement based on a label
The IMA hook ima_measure_critical_data() does not support a way to
specify the source of the critical data provider.  Thus, the data
measurement cannot be constrained based on the data source label
in the IMA policy.

Extend the IMA hook ima_measure_critical_data() to support passing
the data source label as an input parameter, so that the policy rule can
be used to limit the measurements based on the label.

Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-01-14 23:41:38 -05:00
Tushar Sugandhi 47d76a4840 IMA: limit critical data measurement based on a label
Integrity critical data may belong to a single subsystem or it may
arise from cross subsystem interaction.  Currently there is no mechanism
to group or limit the data based on certain label.  Limiting and
grouping critical data based on a label would make it flexible and
configurable to measure.

Define "label:=", a new IMA policy condition, for the IMA func
CRITICAL_DATA to allow grouping and limiting measurement of integrity
critical data.

Limit the measurement to the labels that are specified in the IMA
policy - CRITICAL_DATA+"label:=".  If "label:=" is not provided with
the func CRITICAL_DATA, measure all the input integrity critical data.

Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-01-14 23:41:34 -05:00
Tushar Sugandhi c4e43aa2ee IMA: add policy rule to measure critical data
A new IMA policy rule is needed for the IMA hook
ima_measure_critical_data() and the corresponding func CRITICAL_DATA for
measuring the input buffer.  The policy rule should ensure the buffer
would get measured only when the policy rule allows the action.  The
policy rule should also support the necessary constraints (flags etc.)
for integrity critical buffer data measurements.

Add policy rule support for measuring integrity critical data.

Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-01-14 23:41:29 -05:00
Tushar Sugandhi d6e645012d IMA: define a hook to measure kernel integrity critical data
IMA provides capabilities to measure file and buffer data.  However,
various data structures, policies, and states stored in kernel memory
also impact the integrity of the system.  Several kernel subsystems
contain such integrity critical data.  These kernel subsystems help
protect the integrity of the system.  Currently, IMA does not provide a
generic function for measuring kernel integrity critical data.

Define ima_measure_critical_data, a new IMA hook, to measure kernel
integrity critical data.

Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-01-14 23:41:26 -05:00
Tushar Sugandhi 291af651b3 IMA: add support to measure buffer data hash
The original IMA buffer data measurement sizes were small (e.g.  boot
command line), but the new buffer data measurement use cases have data
sizes that are a lot larger.  Just as IMA measures the file data hash,
not the file data, IMA should similarly support the option for measuring
buffer data hash.

Introduce a boolean parameter to support measuring buffer data hash,
which would be much smaller, instead of the buffer itself.

Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-01-14 23:41:23 -05:00
Tushar Sugandhi 2b4a2474a2 IMA: generalize keyring specific measurement constructs
IMA functions such as ima_match_keyring(), process_buffer_measurement(),
ima_match_policy() etc.  handle data specific to keyrings.  Currently,
these constructs are not generic to handle any func specific data.
This makes it harder to extend them without code duplication.

Refactor the keyring specific measurement constructs to be generic and
reusable in other measurement scenarios.

Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-01-14 23:41:13 -05:00
Linus Torvalds 4a1106afee EFI updates collected by Ard Biesheuvel:
- Don't move BSS section around pointlessly in the x86 decompressor
  - Refactor helper for discovering the EFI secure boot mode
  - Wire up EFI secure boot to IMA for arm64
  - Some fixes for the capsule loader
  - Expose the RT_PROP table via the EFI test module
  - Relax DT and kernel placement restrictions on ARM
 
 + followup fixes:
 
  - fix the build breakage on IA64 caused by recent capsule loader changes
  - suppress a type mismatch build warning in the expansion of
        EFI_PHYS_ALIGN on ARM
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Merge tag 'efi_updates_for_v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull EFI updates from Borislav Petkov:
 "These got delayed due to a last minute ia64 build issue which got
  fixed in the meantime.

  EFI updates collected by Ard Biesheuvel:

   - Don't move BSS section around pointlessly in the x86 decompressor

   - Refactor helper for discovering the EFI secure boot mode

   - Wire up EFI secure boot to IMA for arm64

   - Some fixes for the capsule loader

   - Expose the RT_PROP table via the EFI test module

   - Relax DT and kernel placement restrictions on ARM

  with a few followup fixes:

   - fix the build breakage on IA64 caused by recent capsule loader
     changes

   - suppress a type mismatch build warning in the expansion of
     EFI_PHYS_ALIGN on ARM"

* tag 'efi_updates_for_v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  efi: arm: force use of unsigned type for EFI_PHYS_ALIGN
  efi: ia64: disable the capsule loader
  efi: stub: get rid of efi_get_max_fdt_addr()
  efi/efi_test: read RuntimeServicesSupported
  efi: arm: reduce minimum alignment of uncompressed kernel
  efi: capsule: clean scatter-gather entries from the D-cache
  efi: capsule: use atomic kmap for transient sglist mappings
  efi: x86/xen: switch to efi_get_secureboot_mode helper
  arm64/ima: add ima_arch support
  ima: generalize x86/EFI arch glue for other EFI architectures
  efi: generalize efi_get_secureboot
  efi/libstub: EFI_GENERIC_STUB_INITRD_CMDLINE_LOADER should not default to yes
  efi/x86: Only copy the compressed kernel image in efi_relocate_kernel()
  efi/libstub/x86: simplify efi_is_native()
2020-12-24 12:40:07 -08:00
Linus Torvalds e20a9b92dd integrity-v5.11
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Merge tag 'integrity-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity

Pull integrity subsystem updates from Mimi Zohar:
 "Just three patches here. Other integrity changes are being upstreamed
  via EFI (defines a common EFI secure and trusted boot IMA policy) and
  BPF LSM (exporting the IMA file cache hash info based on inode).

  The three patches included here:

   - bug fix: fail calculating the file hash, when a file not opened for
     read and the attempt to re-open it for read fails.

   - defer processing the "ima_appraise" boot command line option to
     avoid enabling different modes (e.g. fix, log) to when the secure
     boot flag is available on arm.

   - defines "ima-buf" as the default IMA buffer measurement template in
     preparation for the builtin integrity "critical data" policy"

* tag 'integrity-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
  ima: Don't modify file descriptor mode on the fly
  ima: select ima-buf template for buffer measurement
  ima: defer arch_ima_get_secureboot() call to IMA init time
2020-12-16 11:06:07 -08:00
Roberto Sassu 207cdd565d ima: Don't modify file descriptor mode on the fly
Commit a408e4a86b ("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: 0014cc04e8 ima: Set file->f_mode
Fixes: 2fe5d6def1 ("ima: integrity appraisal extension")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-11-29 07:02:53 -05:00
KP Singh 403319be5d ima: Implement ima_inode_hash
This is in preparation to add a helper for BPF LSM programs to use
IMA hashes when attached to LSM hooks. There are LSM hooks like
inode_unlink which do not have a struct file * argument and cannot
use the existing ima_file_hash API.

An inode based API is, therefore, useful in LSM based detections like an
executable trying to delete itself which rely on the inode_unlink LSM
hook.

Moreover, the ima_file_hash function does nothing with the struct file
pointer apart from calling file_inode on it and converting it to an
inode.

Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Mimi Zohar <zohar@linux.ibm.com>
Link: https://lore.kernel.org/bpf/20201124151210.1081188-2-kpsingh@chromium.org
2020-11-26 00:04:04 +01:00
Lakshmi Ramasubramanian dea87d0889 ima: select ima-buf template for buffer measurement
The default IMA template used for all policy rules is the value set
for CONFIG_IMA_DEFAULT_TEMPLATE if the policy rule does not specify
a template. The default IMA template for buffer measurements should be
'ima-buf' - so that the measured buffer is correctly included in the IMA
measurement log entry.

With the default template format, buffer measurements are added to
the measurement list, but do not include the buffer data, making it
difficult, if not impossible, to validate. Including 'ima-buf'
template records in the measurement list by default, should not impact
existing attestation servers without 'ima-buf' template support.

Initialize a global 'ima-buf' template and select that template,
by default, for buffer measurements.

Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-11-20 13:52:43 -05:00
Chester Lin 25519d6834 ima: generalize x86/EFI arch glue for other EFI architectures
Move the x86 IMA arch code into security/integrity/ima/ima_efi.c,
so that we will be able to wire it up for arm64 in a future patch.

Co-developed-by: Chester Lin <clin@suse.com>
Signed-off-by: Chester Lin <clin@suse.com>
Acked-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-11-06 07:40:42 +01:00
Ard Biesheuvel b000d5cb95 ima: defer arch_ima_get_secureboot() call to IMA init time
Chester reports that it is necessary to introduce a new way to pass
the EFI secure boot status between the EFI stub and the core kernel
on ARM systems. The usual way of obtaining this information is by
checking the SecureBoot and SetupMode EFI variables, but this can
only be done after the EFI variable workqueue is created, which
occurs in a subsys_initcall(), whereas arch_ima_get_secureboot()
is called much earlier by the IMA framework.

However, the IMA framework itself is started as a late_initcall,
and the only reason the call to arch_ima_get_secureboot() occurs
so early is because it happens in the context of a __setup()
callback that parses the ima_appraise= command line parameter.

So let's refactor this code a little bit, by using a core_param()
callback to capture the command line argument, and deferring any
reasoning based on its contents to the IMA init routine.

Cc: Chester Lin <clin@suse.com>
Cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Link: https://lore.kernel.org/linux-arm-kernel/20200904072905.25332-2-clin@suse.com/
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reported-by: kernel test robot <lkp@intel.com> [missing core_param()]
[zohar@linux.ibm.com: included linux/module.h]
Tested-by: Chester Lin <clin@suse.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-11-02 14:19:01 -05:00
Gustavo A. R. Silva 4739eeafb9 ima: Replace zero-length array with flexible-array member
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-arrays

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-10-29 17:22:59 -05:00
Linus Torvalds 840e5bb326 integrity-v5.10
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Merge tag 'integrity-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity

Pull integrity updates from Mimi Zohar:
 "Continuing IMA policy rule cleanup and validation in particular for
  measuring keys, adding/removing/updating informational and error
  messages (e.g. "ima_appraise" boot command line option), and other bug
  fixes (e.g. minimal data size validation before use, return code and
  NULL pointer checking)"

* tag 'integrity-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
  ima: Fix NULL pointer dereference in ima_file_hash
  evm: Check size of security.evm before using it
  ima: Remove semicolon at the end of ima_get_binary_runtime_size()
  ima: Don't ignore errors from crypto_shash_update()
  ima: Use kmemdup rather than kmalloc+memcpy
  integrity: include keyring name for unknown key request
  ima: limit secure boot feedback scope for appraise
  integrity: invalid kernel parameters feedback
  ima: add check for enforced appraise option
  integrity: Use current_uid() in integrity_audit_message()
  ima: Fail rule parsing when asymmetric key measurement isn't supportable
  ima: Pre-parse the list of keyrings in a KEY_CHECK rule
2020-10-15 15:58:18 -07:00
Kees Cook 0fa8e08464 fs/kernel_file_read: Add "offset" arg for partial reads
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: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201002173828.2099543-14-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-05 13:37:04 +02:00
Scott Branden 34736daeec IMA: Add support for file reads without contents
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: Scott Branden <scott.branden@broadcom.com>
Link: https://lore.kernel.org/lkml/20200706232309.12010-10-scott.branden@broadcom.com/
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Link: https://lore.kernel.org/r/20201002173828.2099543-13-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-05 13:37:04 +02:00
Kees Cook 2039bda1fa LSM: Add "contents" flag to kernel_read_file hook
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: Kees Cook <keescook@chromium.org>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Link: https://lore.kernel.org/r/20201002173828.2099543-12-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-05 13:37:03 +02:00
Kees Cook 4f2d99b06b firmware_loader: Use security_post_load_data()
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: Kees Cook <keescook@chromium.org>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Link: https://lore.kernel.org/r/20201002173828.2099543-10-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-05 13:37:03 +02:00
Kees Cook b64fcae74b LSM: Introduce kernel_post_load_data() hook
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: Kees Cook <keescook@chromium.org>
Reviewed-by: KP Singh <kpsingh@google.com>
Link: https://lore.kernel.org/r/20201002173828.2099543-9-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-05 13:37:03 +02:00
Kees Cook 885352881f fs/kernel_read_file: Add file_size output argument
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: Kees Cook <keescook@chromium.org>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Acked-by: Scott Branden <scott.branden@broadcom.com>
Link: https://lore.kernel.org/r/20201002173828.2099543-8-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-05 13:37:03 +02:00
Kees Cook 113eeb5177 fs/kernel_read_file: Switch buffer size arg to size_t
In preparation for further refactoring of kernel_read_file*(), rename
the "max_size" argument to the more accurate "buf_size", and correct
its type to size_t. Add kerndoc to explain the specifics of how the
arguments will be used. Note that with buf_size now size_t, it can no
longer be negative (and was never called with a negative value). Adjust
callers to use it as a "maximum size" when *buf is NULL.

Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Acked-by: Scott Branden <scott.branden@broadcom.com>
Link: https://lore.kernel.org/r/20201002173828.2099543-7-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-05 13:34:19 +02:00
Kees Cook f7a4f689bc fs/kernel_read_file: Remove redundant size argument
In preparation for refactoring kernel_read_file*(), remove the redundant
"size" argument which is not needed: it can be included in the return
code, with callers adjusted. (VFS reads already cannot be larger than
INT_MAX.)

Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Acked-by: Scott Branden <scott.branden@broadcom.com>
Link: https://lore.kernel.org/r/20201002173828.2099543-6-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-05 13:34:18 +02:00
Scott Branden b89999d004 fs/kernel_read_file: Split into separate include file
Move kernel_read_file* out of linux/fs.h to its own linux/kernel_read_file.h
include file. That header gets pulled in just about everywhere
and doesn't really need functions not related to the general fs interface.

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: James Morris <jamorris@linux.microsoft.com>
Link: https://lore.kernel.org/r/20200706232309.12010-2-scott.branden@broadcom.com
Link: https://lore.kernel.org/r/20201002173828.2099543-4-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-05 13:34:18 +02:00
Kees Cook c307459b9d fs/kernel_read_file: Remove FIRMWARE_PREALLOC_BUFFER enum
FIRMWARE_PREALLOC_BUFFER is a "how", not a "what", and confuses the LSMs
that are interested in filtering between types of things. The "how"
should be an internal detail made uninteresting to the LSMs.

Fixes: a098ecd2fa ("firmware: support loading into a pre-allocated buffer")
Fixes: fd90bc559b ("ima: based on policy verify firmware signatures (pre-allocated buffer)")
Fixes: 4f0496d8ff ("ima: based on policy warn about loading firmware (pre-allocated buffer)")
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: Scott Branden <scott.branden@broadcom.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20201002173828.2099543-2-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-05 13:34:18 +02:00
KP Singh aa662fc04f ima: Fix NULL pointer dereference in ima_file_hash
ima_file_hash can be called when there is no iint->ima_hash available
even though the inode exists in the integrity cache. It is fairly
common for a file to not have a hash. (e.g. an mknodat, prior to the
file being closed).

Another example where this can happen (suggested by Jann Horn):

Process A does:

	while(1) {
		unlink("/tmp/imafoo");
		fd = open("/tmp/imafoo", O_RDWR|O_CREAT|O_TRUNC, 0700);
		if (fd == -1) {
			perror("open");
			continue;
		}
		write(fd, "A", 1);
		close(fd);
	}

and Process B does:

	while (1) {
		int fd = open("/tmp/imafoo", O_RDONLY);
		if (fd == -1)
			continue;
    		char *mapping = mmap(NULL, 0x1000, PROT_READ|PROT_EXEC,
			 	     MAP_PRIVATE, fd, 0);
		if (mapping != MAP_FAILED)
			munmap(mapping, 0x1000);
		close(fd);
  	}

Due to the race to get the iint->mutex between ima_file_hash and
process_measurement iint->ima_hash could still be NULL.

Fixes: 6beea7afcc ("ima: add the ability to query the cached hash of a given file")
Signed-off-by: KP Singh <kpsingh@google.com>
Reviewed-by: Florent Revest <revest@chromium.org>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-09-16 17:43:02 -04:00
Roberto Sassu 4be92db3b5 ima: Remove semicolon at the end of ima_get_binary_runtime_size()
This patch removes the unnecessary semicolon at the end of
ima_get_binary_runtime_size().

Cc: stable@vger.kernel.org
Fixes: d158847ae8 ("ima: maintain memory size needed for serializing the measurement list")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-09-15 13:47:41 -04:00
Roberto Sassu 60386b8540 ima: Don't ignore errors from crypto_shash_update()
Errors returned by crypto_shash_update() are not checked in
ima_calc_boot_aggregate_tfm() and thus can be overwritten at the next
iteration of the loop. This patch adds a check after calling
crypto_shash_update() and returns immediately if the result is not zero.

Cc: stable@vger.kernel.org
Fixes: 3323eec921 ("integrity: IMA as an integrity service provider")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-09-15 13:47:37 -04:00
Alex Dewar f60c826d03 ima: Use kmemdup rather than kmalloc+memcpy
Issue identified with Coccinelle.

Signed-off-by: Alex Dewar <alex.dewar90@gmail.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-09-15 09:57:48 -04:00
Bruno Meneguele e4d7e2df3a ima: limit secure boot feedback scope for appraise
Only emit an unknown/invalid message when setting the IMA appraise mode
to anything other than "enforce", when secureboot is enabled.

Signed-off-by: Bruno Meneguele <bmeneg@redhat.com>
[zohar@linux.ibm.com: updated commit message]
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-09-09 20:01:55 -04:00
Bruno Meneguele 7fe2bb7e7e integrity: invalid kernel parameters feedback
Don't silently ignore unknown or invalid ima_{policy,appraise,hash} and evm
kernel boot command line options.

Signed-off-by: Bruno Meneguele <bmeneg@redhat.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-09-08 22:03:50 -04:00
Bruno Meneguele 4afb28ab03 ima: add check for enforced appraise option
The "enforce" string is allowed as an option for ima_appraise= kernel
paramenter per kernel-paramenters.txt and should be considered on the
parameter setup checking as a matter of completeness. Also it allows futher
checking on the options being passed by the user.

Signed-off-by: Bruno Meneguele <bmeneg@redhat.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-09-08 22:02:57 -04:00
Tyler Hicks 48ce1ddce1 ima: Fail rule parsing when asymmetric key measurement isn't supportable
Measuring keys is currently only supported for asymmetric keys. In the
future, this might change.

For now, the "func=KEY_CHECK" and "keyrings=" options are only
appropriate when CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS is enabled. Make
this clear at policy load so that IMA policy authors don't assume that
these policy language constructs are supported.

Fixes: 2b60c0eced ("IMA: Read keyrings= option from the IMA policy")
Fixes: 5808611ccc ("IMA: Add KEY_CHECK func to measure keys")
Suggested-by: Nayna Jain <nayna@linux.ibm.com>
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Reviewed-by: Nayna Jain <nayna@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-08-31 17:45:14 -04:00
Tyler Hicks 176377d97d ima: Pre-parse the list of keyrings in a KEY_CHECK rule
The ima_keyrings buffer was used as a work buffer for strsep()-based
parsing of the "keyrings=" option of an IMA policy rule. This parsing
was re-performed each time an asymmetric key was added to a kernel
keyring for each loaded policy rule that contained a "keyrings=" option.

An example rule specifying this option is:

 measure func=KEY_CHECK keyrings=a|b|c

The rule says to measure asymmetric keys added to any of the kernel
keyrings named "a", "b", or "c". The size of the buffer size was
equal to the size of the largest "keyrings=" value seen in a previously
loaded rule (5 + 1 for the NUL-terminator in the previous example) and
the buffer was pre-allocated at the time of policy load.

The pre-allocated buffer approach suffered from a couple bugs:

1) There was no locking around the use of the buffer so concurrent key
   add operations, to two different keyrings, would result in the
   strsep() loop of ima_match_keyring() to modify the buffer at the same
   time. This resulted in unexpected results from ima_match_keyring()
   and, therefore, could cause unintended keys to be measured or keys to
   not be measured when IMA policy intended for them to be measured.

2) If the kstrdup() that initialized entry->keyrings in ima_parse_rule()
   failed, the ima_keyrings buffer was freed and set to NULL even when a
   valid KEY_CHECK rule was previously loaded. The next KEY_CHECK event
   would trigger a call to strcpy() with a NULL destination pointer and
   crash the kernel.

Remove the need for a pre-allocated global buffer by parsing the list of
keyrings in a KEY_CHECK rule at the time of policy load. The
ima_rule_entry will contain an array of string pointers which point to
the name of each keyring specified in the rule. No string processing
needs to happen at the time of asymmetric key add so iterating through
the list and doing a string comparison is all that's required at the
time of policy check.

In the process of changing how the "keyrings=" policy option is handled,
a couple additional bugs were fixed:

1) The rule parser accepted rules containing invalid "keyrings=" values
   such as "a|b||c", "a|b|", or simply "|".

2) The /sys/kernel/security/ima/policy file did not display the entire
   "keyrings=" value if the list of keyrings was longer than what could
   fit in the fixed size tbuf buffer in ima_policy_show().

Fixes: 5c7bac9fb2 ("IMA: pre-allocate buffer to hold keyrings string")
Fixes: 2b60c0eced ("IMA: Read keyrings= option from the IMA policy")
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Reviewed-by: Nayna Jain <nayna@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-08-31 17:45:02 -04:00
Gustavo A. R. Silva df561f6688 treewide: Use fallthrough pseudo-keyword
Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-08-23 17:36:59 -05:00
Linus Torvalds ce13266d97 Minor fixes for v5.9.
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Merge tag 'for-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

Pull security subsystem updates from James Morris:
 "A couple of minor documentation updates only for this release"

* tag 'for-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  LSM: drop duplicated words in header file comments
  Replace HTTP links with HTTPS ones: security
2020-08-11 14:30:36 -07:00