linux-stable.git/security/integrity/ima, branch linux-5.17.y

ima: remove the IMA_TEMPLATE Kconfig option

2022-06-09T08:26:25+00:00

commit 891163adf180bc369b2f11c9dfce6d2758d2a5bd upstream.

The original 'ima' measurement list template contains a hash, defined
as 20 bytes, and a null terminated pathname, limited to 255
characters.  Other measurement list templates permit both larger hashes
and longer pathnames.  When the "ima" template is configured as the
default, a new measurement list template (ima_template=) must be
specified before specifying a larger hash algorithm (ima_hash=) on the
boot command line.

To avoid this boot command line ordering issue, remove the legacy "ima"
template configuration option, allowing it to still be specified on the
boot command line.

The root cause of this issue is that during the processing of ima_hash,
we would try to check whether the hash algorithm is compatible with the
template. If the template is not set at the moment we do the check, we
check the algorithm against the configured default template. If the
default template is "ima", then we reject any hash algorithm other than
sha1 and md5.

For example, if the compiled default template is "ima", and the default
algorithm is sha1 (which is the current default). In the cmdline, we put
in "ima_hash=sha256 ima_template=ima-ng". The expected behavior would be
that ima starts with ima-ng as the template and sha256 as the hash
algorithm. However, during the processing of "ima_hash=",
"ima_template=" has not been processed yet, and hash_setup would check
the configured hash algorithm against the compiled default: ima, and
reject sha256. So at the end, the hash algorithm that is actually used
will be sha1.

With template "ima" removed from the configured default, we ensure that
the default tempalte would at least be "ima-ng" which allows for
basically any hash algorithm.

This change would not break the algorithm compatibility checks for IMA.

Fixes: 4286587dccd43 ("ima: add Kconfig default measurement list template")
Signed-off-by: GUO Zihua 
Cc: 
Signed-off-by: Mimi Zohar 
Signed-off-by: Greg Kroah-Hartman

ima: Do not print policy rule with inactive LSM labels

2022-02-02T16:59:54+00:00

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 
Cc:  # v5.6+
Acked-by: Christian Brauner 
[zohar@linux.ibm.com: Updated "Fixes" tag]
Signed-off-by: Mimi Zohar

ima: Allow template selection with ima_template[_fmt]= after ima_hash=

2022-02-02T16:59:54+00:00

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 
Signed-off-by: Roberto Sassu 
Cc: stable@vger.kernel.org
Fixes: c2426d2ad5027 ("ima: added support for new kernel cmdline parameter ima_template_fmt")
Signed-off-by: Mimi Zohar

ima: Remove ima_policy file before directory

2022-02-02T16:59:09+00:00

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 
Cc: 
Acked-by: Christian Brauner 
Signed-off-by: Mimi Zohar

Merge tag 'integrity-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity

2022-01-11T21:11:10+00:00

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

ima: silence measurement list hexdump during kexec

2022-01-05T11:22:00+00:00

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 
Signed-off-by: Mimi Zohar

lsm: security_task_getsecid_subj() -> security_current_getsecid_subj()

2021-11-22T22:52:47+00:00

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 
Reviewed-by: Casey Schaufler 
Signed-off-by: Paul Moore

ima: Use strscpy instead of strlcpy

2021-10-10T02:17:58+00:00

strlcpy is deprecated, use its safer replacement.

Signed-off-by: Petr Vorel 
Signed-off-by: Mimi Zohar

ima_policy: Remove duplicate 'the' in docs comment

2021-10-10T02:17:57+00:00

Also join string (short enough to be on single line).

Signed-off-by: Petr Vorel 
Signed-off-by: Mimi Zohar

ima: add gid support

2021-10-10T02:17:57+00:00

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 
Co-developed-by: Alex Henrie 
Signed-off-by: Alex Henrie 
Reviewed-by: Petr Vorel 
Signed-off-by: Mimi Zohar