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>
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
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>
The security of Machine Owner Key (MOK) relies on secure boot. When
secure boot is disabled, EFI firmware will not verify binary code. Then
arbitrary efi binary code can modify MOK when rebooting.
This patch prevents MOK/MOKx be loaded when secure boot be disabled.
Signed-off-by: "Lee, Chun-Yi" <jlee@suse.com>
Reviewed-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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>
The evm_fixmode is only configurable by command-line option and it is never
modified outside initcalls, so declaring it with __ro_after_init is better.
Signed-off-by: Austin Kim <austin.kim@lge.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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>
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>
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>
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
Pull device mapper updates from Mike Snitzer:
- Add DM infrastructure for IMA-based remote attestion. These changes
are the basis for deploying DM-based storage in a "cloud" that must
validate configurations end-users run to maintain trust. These DM
changes allow supported DM targets' configurations to be measured via
IMA. But the policy and enforcement (of which configurations are
valid) is managed by something outside the kernel (e.g. Keylime).
- Fix DM crypt scalability regression on systems with many cpus due to
percpu_counter spinlock contention in crypt_page_alloc().
- Use in_hardirq() instead of deprecated in_irq() in DM crypt.
- Add event counters to DM writecache to allow users to further assess
how the writecache is performing.
- Various code cleanup in DM writecache's main IO mapping function.
* tag 'for-5.15/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
dm crypt: use in_hardirq() instead of deprecated in_irq()
dm ima: update dm documentation for ima measurement support
dm ima: update dm target attributes for ima measurements
dm ima: add a warning in dm_init if duplicate ima events are not measured
dm ima: prefix ima event name related to device mapper with dm_
dm ima: add version info to dm related events in ima log
dm ima: prefix dm table hashes in ima log with hash algorithm
dm crypt: Avoid percpu_counter spinlock contention in crypt_page_alloc()
dm: add documentation for IMA measurement support
dm: update target status functions to support IMA measurement
dm ima: measure data on device rename
dm ima: measure data on table clear
dm ima: measure data on device remove
dm ima: measure data on device resume
dm ima: measure data on table load
dm writecache: add event counters
dm writecache: report invalid return from writecache_map helpers
dm writecache: further writecache_map() cleanup
dm writecache: factor out writecache_map_remap_origin()
dm writecache: split up writecache_map() to improve code readability
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>
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>
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>
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>
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>
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>
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>
Stefan Berger
Roberto Sassu
Xiaoke Wang
Eric Biggers
Linus Torvalds
Bruno Meneguele
Lee, Chun-Yi
Paul Moore
Austin Kim
Petr Vorel
Curtis Veit
Alex Henrie
liqiong
Andy Shevchenko
THOBY Simon