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2022-02-02ima: Do not print policy rule with inactive LSM labelsStefan Berger1-0/+8
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: 483ec26eed42 ("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>
2022-02-02ima: Allow template selection with ima_template[_fmt]= after ima_hash=Roberto Sassu1-3/+7
Commit c2426d2ad5027 ("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: c2426d2ad5027 ("ima: added support for new kernel cmdline parameter ima_template_fmt") Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2022-02-02ima: Remove ima_policy file before directoryStefan Berger1-1/+1
The removal of ima_dir currently fails since ima_policy still exists, so remove the ima_policy file before removing the directory. Fixes: 4af4662fa4a9 ("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>
2022-02-02integrity: check the return value of audit_log_start()Xiaoke Wang1-0/+2
audit_log_start() returns audit_buffer pointer on success or NULL on error, so it is better to check the return value of it. Fixes: 3323eec921ef ("integrity: IMA as an integrity service provider") Signed-off-by: Xiaoke Wang <xkernel.wang@foxmail.com> Cc: <stable@vger.kernel.org> Reviewed-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2022-01-24ima: fix reference leak in asymmetric_verify()Eric Biggers1-6/+9
Don't leak a reference to the key if its algorithm is unknown. Fixes: 947d70597236 ("ima: Support EC keys for signature verification") Cc: <stable@vger.kernel.org> # v5.13+ Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Reviewed-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2022-01-11Merge tag 'integrity-v5.17' of ↵Linus Torvalds2-3/+8
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
2022-01-05ima: silence measurement list hexdump during kexecBruno Meneguele1-3/+3
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>
2021-12-24integrity: Do not load MOK and MOKx when secure boot be disabledLee, Chun-Yi1-0/+5
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>
2021-11-22lsm: security_task_getsecid_subj() -> security_current_getsecid_subj()Paul Moore2-8/+8
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>
2021-10-28evm: mark evm_fixmode as __ro_after_initAustin Kim1-1/+1
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>
2021-10-09ima: Use strscpy instead of strlcpyPetr Vorel2-2/+2
strlcpy is deprecated, use its safer replacement. Signed-off-by: Petr Vorel <pvorel@suse.cz> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-10-09ima_policy: Remove duplicate 'the' in docs commentPetr Vorel1-2/+1
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>
2021-10-09ima: add gid supportCurtis Veit1-27/+174
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>
2021-10-09ima: fix uid code style problemsAlex Henrie1-4/+6
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>
2021-10-09ima: fix deadlock when traversing "ima_default_rules".liqiong1-9/+18
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: 38d859f991f3 ("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>
2021-09-02Merge tag 'integrity-v5.15' of ↵Linus Torvalds10-65/+316
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
2021-08-31Merge tag 'for-5.15/dm-changes' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm 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
2021-08-27efi: Don't use knowledge about efi_guid_t internalsAndy Shevchenko1-1/+1
When print GUIDs supply pointer to the efi_guid_t (guid_t) type rather its internal members. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Serge Hallyn <serge@hallyn.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2021-08-23IMA: reject unknown hash algorithms in ima_get_hash_algoTHOBY Simon1-1/+2
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: 50f742dd9147 ("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>
2021-08-16IMA: prevent SETXATTR_CHECK policy rules with unavailable algorithmsTHOBY Simon1-0/+6
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>
2021-08-16IMA: introduce a new policy option func=SETXATTR_CHECKTHOBY Simon4-17/+96
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>
2021-08-16IMA: add a policy option to restrict xattr hash algorithms on appraisalTHOBY Simon1-4/+70
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>
2021-08-16IMA: add support to restrict the hash algorithms used for file appraisalTHOBY Simon5-12/+41
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>
2021-08-16IMA: block writes of the security.ima xattr with unsupported algorithmsTHOBY Simon2-4/+47
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>
2021-08-16IMA: remove the dependency on CRYPTO_MD5THOBY Simon1-1/+0
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 ab60368ab6a4 ("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>
2021-08-10dm ima: measure data on table loadTushar Sugandhi1-0/+1
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>
2021-07-23ima: Add digest and digest_len params to the functions to measure a bufferRoberto Sassu6-15/+32
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>
2021-07-23ima: Return int in the functions to measure a bufferRoberto Sassu2-22/+28
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>
2021-07-23ima: Introduce ima_get_current_hash_algo()Roberto Sassu1-1/+6
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>
2021-07-23IMA: remove -Wmissing-prototypes warningAustin Kim1-1/+1
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: 41c89b64d718 ("IMA: create machine owner and blacklist keyrings") Cc: stable@vger.kernel.org Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-06-21evm: Check xattr size discrepancy between kernel and userRoberto Sassu1-1/+7
The kernel and the user obtain an xattr value in two different ways: kernel (EVM): uses vfs_getxattr_alloc() which obtains the xattr value from the filesystem handler (raw value); user (ima-evm-utils): uses vfs_getxattr() which obtains the xattr value from the LSMs (normalized value). Normally, this does not have an impact unless security.selinux is set with setfattr, with a value not terminated by '\0' (this is not the recommended way, security.selinux should be set with the appropriate tools such as chcon and restorecon). In this case, the kernel and the user see two different xattr values: the former sees the xattr value without '\0' (raw value), the latter sees the value with '\0' (value normalized by SELinux). This could result in two different verification outcomes from EVM and ima-evm-utils, if a signature was calculated with a security.selinux value terminated by '\0' and the value set in the filesystem is not terminated by '\0'. The former would report verification failure due to the missing '\0', while the latter would report verification success (because it gets the normalized value with '\0'). This patch mitigates this issue by comparing in evm_calc_hmac_or_hash() the size of the xattr returned by the two xattr functions and by warning the user if there is a discrepancy. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Suggested-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-06-20evm: output EVM digest calculation infoMimi Zohar2-0/+47
Output the data used in calculating the EVM digest and the resulting digest as ascii hexadecimal strings. Suggested-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com> (CONFIG_DYNAMIC_DEBUG) Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com> Reported-by: kernel test robot <lkp@intel.com> (Use %zu for size_t) Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-06-11IMA: support for duplicate measurement recordsTushar Sugandhi2-2/+10
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>
2021-06-11ima: Fix warning: no previous prototype for function 'ima_add_kexec_buffer'Lakshmi Ramasubramanian1-0/+1
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: dce92f6b11c3 (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>
2021-06-10ima: differentiate between EVM failures in the audit logMimi Zohar1-1/+2
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>
2021-06-08ima: Fix fall-through warning for ClangGustavo A. R. Silva1-0/+1
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>
2021-06-08ima: Pass NULL instead of 0 to ima_get_action() in ima_file_mprotect()Roberto Sassu1-1/+1
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>
2021-06-08ima: Include header defining ima_post_key_create_or_update()Roberto Sassu1-0/+1
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>
2021-06-08ima/evm: Fix type mismatchRoberto Sassu4-11/+12
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>
2021-06-08ima: Set correct casting typesRoberto Sassu2-9/+10
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>
2021-06-03evm: Don't return an error in evm_write_xattrs() if audit is not enabledRoberto Sassu1-1/+1
This patch avoids that evm_write_xattrs() returns an error when audit is not enabled. The ab variable can be NULL and still be passed to the other audit_log_() functions, as those functions do not include any instruction. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-06-03ima: Define new template evm-sigRoberto Sassu1-1/+4
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>
2021-06-02ima: Define new template fields xattrnames, xattrlengths and xattrvaluesRoberto Sassu4-0/+148
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>
2021-06-01evm: Verify portable signatures against all protected xattrsRoberto Sassu4-12/+68
Currently, the evm_config_default_xattrnames array contains xattr names only related to LSMs which are enabled in the kernel configuration. However, EVM portable signatures do not depend on local information and a vendor might include in the signature calculation xattrs that are not enabled in the target platform. Just including all xattrs names in evm_config_default_xattrnames is not a safe approach, because a target system might have already calculated signatures or HMACs based only on the enabled xattrs. After applying this patch, EVM would verify those signatures and HMACs with all xattrs instead. The non-enabled ones, which could possibly exist, would cause a verification error. Thus, this patch adds a new field named enabled to the xattr_list structure, which is set to true if the LSM associated to a given xattr name is enabled in the kernel configuration. The non-enabled xattrs are taken into account only in evm_calc_hmac_or_hash(), if the passed security.evm type is EVM_XATTR_PORTABLE_DIGSIG. The new function evm_protected_xattr_if_enabled() has been defined so that IMA can include all protected xattrs and not only the enabled ones in the measurement list, if the new template fields xattrnames, xattrlengths or xattrvalues have been included in the template format. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-06-01ima: Define new template field imodeRoberto Sassu3-0/+26
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>
2021-06-01ima: Define new template fields iuid and igidRoberto Sassu3-0/+53
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>
2021-06-01ima: Add ima_show_template_uint() template library functionRoberto Sassu2-1/+39
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>
2021-06-01ima: Don't remove security.ima if file must not be appraisedRoberto Sassu1-2/+0
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>
2021-06-01ima: Introduce template field evmsig and write to field sig as fallbackRoberto Sassu3-1/+36
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>
2021-06-01ima: Allow imasig requirement to be satisfied by EVM portable signaturesRoberto Sassu1-7/+17
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>
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