linux.git/security/integrity/ima/ima.h, branch v5.9

ima: Rename internal filter rule functions

2020-07-20T22:18:23+00:00

Rename IMA's internal filter rule functions from security_filter_rule_*()
to ima_filter_rule_*(). This avoids polluting the security_* namespace,
which is typically reserved for general security subsystem
infrastructure.

Signed-off-by: Tyler Hicks 
Suggested-by: Casey Schaufler 
[zohar@linux.ibm.com: reword using the term "filter", not "audit"]
Signed-off-by: Mimi Zohar

ima: Support additional conditionals in the KEXEC_CMDLINE hook function

2020-07-20T17:28:16+00:00

Take the properties of the kexec kernel's inode and the current task
ownership into consideration when matching a KEXEC_CMDLINE operation to
the rules in the IMA policy. This allows for some uniformity when
writing IMA policy rules for KEXEC_KERNEL_CHECK, KEXEC_INITRAMFS_CHECK,
and KEXEC_CMDLINE operations.

Prior to this patch, it was not possible to write a set of rules like
this:

 dont_measure func=KEXEC_KERNEL_CHECK obj_type=foo_t
 dont_measure func=KEXEC_INITRAMFS_CHECK obj_type=foo_t
 dont_measure func=KEXEC_CMDLINE obj_type=foo_t
 measure func=KEXEC_KERNEL_CHECK
 measure func=KEXEC_INITRAMFS_CHECK
 measure func=KEXEC_CMDLINE

The inode information associated with the kernel being loaded by a
kexec_kernel_load(2) syscall can now be included in the decision to
measure or not

Additonally, the uid, euid, and subj_* conditionals can also now be
used in KEXEC_CMDLINE rules. There was no technical reason as to why
those conditionals weren't being considered previously other than
ima_match_rules() didn't have a valid inode to use so it immediately
bailed out for KEXEC_CMDLINE operations rather than going through the
full list of conditional comparisons.

Signed-off-by: Tyler Hicks 
Cc: Eric Biederman 
Cc: kexec@lists.infradead.org
Reviewed-by: Lakshmi Ramasubramanian 
Signed-off-by: Mimi Zohar

ima: Move comprehensive rule validation checks out of the token parser

2020-07-20T17:28:15+00:00

Use ima_validate_rule(), at the end of the token parsing stage, to
verify combinations of actions, hooks, and flags. This is useful to
increase readability by consolidating such checks into a single function
and also because rule conditionals can be specified in arbitrary order
making it difficult to do comprehensive rule validation until the entire
rule has been parsed.

This allows for the check that ties together the "keyrings" conditional
with the KEY_CHECK function hook to be moved into the final rule
validation.

The modsig check no longer needs to compiled conditionally because the
token parser will ensure that modsig support is enabled before accepting
"imasig|modsig" appraise type values. The final rule validation will
ensure that appraise_type and appraise_flag options are only present in
appraise rules.

Finally, this allows for the check that ties together the "pcr"
conditional with the measure action to be moved into the final rule
validation.

Signed-off-by: Tyler Hicks 
Signed-off-by: Mimi Zohar

ima: Have the LSM free its audit rule

2020-07-17T01:53:55+00:00

Ask the LSM to free its audit rule rather than directly calling kfree().
Both AppArmor and SELinux do additional work in their audit_rule_free()
hooks. Fix memory leaks by allowing the LSMs to perform necessary work.

Fixes: b16942455193 ("ima: use the lsm policy update notifier")
Signed-off-by: Tyler Hicks 
Cc: Janne Karhunen 
Cc: Casey Schaufler 
Reviewed-by: Mimi Zohar 
Signed-off-by: Mimi Zohar

IMA: Add audit log for failure conditions

2020-07-17T01:48:36+00:00

process_buffer_measurement() and ima_alloc_key_entry() functions need to
log an audit message for auditing integrity measurement failures.

Add audit message in these two functions. Remove "pr_devel" log message
in process_buffer_measurement().

Sample audit messages:

[    6.303048] audit: type=1804 audit(1592506281.627:2): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=kernel op=measuring_key cause=ENOMEM comm="swapper/0" name=".builtin_trusted_keys" res=0 errno=-12

[    8.019432] audit: type=1804 audit(1592506283.344:10): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0 op=measuring_kexec_cmdline cause=hashing_error comm="systemd" name="kexec-cmdline" res=0 errno=-22

Signed-off-by: Lakshmi Ramasubramanian 
Suggested-by: Mimi Zohar 
Signed-off-by: Mimi Zohar

ima: extend boot_aggregate with kernel measurements

2020-06-25T00:47:24+00:00

Registers 8-9 are used to store measurements of the kernel and its
command line (e.g., grub2 bootloader with tpm module enabled). IMA
should include them in the boot aggregate. Registers 8-9 should be
only included in non-SHA1 digests to avoid ambiguity.

Signed-off-by: Maurizio Drocco 
Reviewed-by: Bruno Meneguele 
Tested-by: Bruno Meneguele   (TPM 1.2, TPM 2.0)
Signed-off-by: Mimi Zohar

ima: Call ima_calc_boot_aggregate() in ima_eventdigest_init()

2020-06-03T21:20:43+00:00

If the template field 'd' is chosen and the digest to be added to the
measurement entry was not calculated with SHA1 or MD5, it is
recalculated with SHA1, by using the passed file descriptor. However, this
cannot be done for boot_aggregate, because there is no file descriptor.

This patch adds a call to ima_calc_boot_aggregate() in
ima_eventdigest_init(), so that the digest can be recalculated also for the
boot_aggregate entry.

Cc: stable@vger.kernel.org # 3.13.x
Fixes: 3ce1217d6cd5d ("ima: define template fields library and new helpers")
Reported-by: Takashi Iwai 
Signed-off-by: Roberto Sassu 
Signed-off-by: Mimi Zohar

ima: Fix ima digest hash table key calculation

2020-05-08T02:54:07+00:00

Function hash_long() accepts unsigned long, while currently only one byte
is passed from ima_hash_key(), which calculates a key for ima_htable.

Given that hashing the digest does not give clear benefits compared to
using the digest itself, remove hash_long() and return the modulus
calculated on the first two bytes of the digest with the number of slots.
Also reduce the depth of the hash table by doubling the number of slots.

Cc: stable@vger.kernel.org
Fixes: 3323eec921ef ("integrity: IMA as an integrity service provider")
Co-developed-by: Roberto Sassu 
Signed-off-by: Roberto Sassu 
Signed-off-by: Krzysztof Struczynski 
Acked-by: David.Laight@aculab.com (big endian system concerns)
Signed-off-by: Mimi Zohar

ima: Use ima_hash_algo for collision detection in the measurement list

2020-04-20T02:03:39+00:00

Before calculating a digest for each PCR bank, collisions were detected
with a SHA1 digest. This patch includes ima_hash_algo among the algorithms
used to calculate the template digest and checks collisions on that digest.

The position in the measurement entry array of the template digest
calculated with the IMA default hash algorithm is stored in the
ima_hash_algo_idx global variable and is determined at IMA initialization
time.

Signed-off-by: Roberto Sassu 
Signed-off-by: Mimi Zohar

ima: Switch to dynamically allocated buffer for template digests

2020-04-20T02:03:39+00:00

This patch dynamically allocates the array of tpm_digest structures in
ima_alloc_init_template() and ima_restore_template_data(). The size of the
array is equal to the number of PCR banks plus ima_extra_slots, to make
room for SHA1 and the IMA default hash algorithm, when PCR banks with those
algorithms are not allocated.

Calculating the SHA1 digest is mandatory, as SHA1 still remains the default
hash algorithm for the measurement list. When IMA will support the Crypto
Agile format, remaining digests will be also provided.

The position in the measurement entry array of the SHA1 digest is stored in
the ima_sha1_idx global variable and is determined at IMA initialization
time.

Signed-off-by: Roberto Sassu 
Signed-off-by: Mimi Zohar