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
Rationale:
Reduces attack surface on kernel devs opening the links for MITM
as HTTPS traffic is much harder to manipulate.
Deterministic algorithm:
For each file:
If not .svg:
For each line:
If doesn't contain `\bxmlns\b`:
For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`:
If both the HTTP and HTTPS versions
return 200 OK and serve the same content:
Replace HTTP with HTTPS.
Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
The IMA_APPRAISE_BOOTPARAM config allows enabling different "ima_appraise="
modes - log, fix, enforce - at run time, but not when IMA architecture
specific policies are enabled. This prevents properly labeling the
filesystem on systems where secure boot is supported, but not enabled on the
platform. Only when secure boot is actually enabled should these IMA
appraise modes be disabled.
This patch removes the compile time dependency and makes it a runtime
decision, based on the secure boot state of that platform.
Test results as follows:
-> x86-64 with secure boot enabled
[ 0.015637] Kernel command line: <...> ima_policy=appraise_tcb ima_appraise=fix
[ 0.015668] ima: Secure boot enabled: ignoring ima_appraise=fix boot parameter option
-> powerpc with secure boot disabled
[ 0.000000] Kernel command line: <...> ima_policy=appraise_tcb ima_appraise=fix
[ 0.000000] Secure boot mode disabled
-> Running the system without secure boot and with both options set:
CONFIG_IMA_APPRAISE_BOOTPARAM=y
CONFIG_IMA_ARCH_POLICY=y
Audit prompts "missing-hash" but still allow execution and, consequently,
filesystem labeling:
type=INTEGRITY_DATA msg=audit(07/09/2020 12:30:27.778:1691) : pid=4976
uid=root auid=root ses=2
subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 op=appraise_data
cause=missing-hash comm=bash name=/usr/bin/evmctl dev="dm-0" ino=493150
res=no
Cc: stable@vger.kernel.org
Fixes: d958083a8f ("x86/ima: define arch_get_ima_policy() for x86")
Signed-off-by: Bruno Meneguele <bmeneg@redhat.com>
Cc: stable@vger.kernel.org # 5.0
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
AppArmor meets all the requirements for IMA in terms of audit rules
since commit e79c26d040 ("apparmor: Add support for audit rule
filtering"). Update IMA's Kconfig section for CONFIG_IMA_LSM_RULES to
reflect this.
Fixes: e79c26d040 ("apparmor: Add support for audit rule filtering")
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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 <tyhicks@linux.microsoft.com>
Suggested-by: Casey Schaufler <casey@schaufler-ca.com>
[zohar@linux.ibm.com: reword using the term "filter", not "audit"]
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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 <tyhicks@linux.microsoft.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: kexec@lists.infradead.org
Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Make broader use of ima_rule_contains_lsm_cond() to check if a given
rule contains an LSM conditional. This is a code cleanup and has no
user-facing change.
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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 <tyhicks@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Make args_p be of the char pointer type rather than have it be a void
pointer that gets casted to char pointer when it is used. It is a simple
NUL-terminated string as returned by match_strdup().
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
The args_p member is a simple string that is allocated by
ima_rule_init(). Shallow copy it like other non-LSM references in
ima_rule_entry structs.
There are no longer any necessary error path cleanups to do in
ima_lsm_copy_rule().
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Verifying that a file hash is not blacklisted is currently only
supported for files with appended signatures (modsig). In the future,
this might change.
For now, the "appraise_flag" option is only appropriate for appraise
actions and its "blacklist" value is only appropriate when
CONFIG_IMA_APPRAISE_MODSIG is enabled and "appraise_flag=blacklist" is
only appropriate when "appraise_type=imasig|modsig" is also present.
Make this clear at policy load so that IMA policy authors don't assume
that other uses of "appraise_flag=blacklist" are supported.
Fixes: 273df864cf ("ima: Check against blacklisted hashes for files with modsig")
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reivewed-by: Nayna Jain <nayna@linux.ibm.com>
Tested-by: Nayna Jain <nayna@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
The KEY_CHECK function only supports the uid, pcr, and keyrings
conditionals. Make this clear at policy load so that IMA policy authors
don't assume that other conditionals are supported.
Fixes: 5808611ccc ("IMA: Add KEY_CHECK func to measure keys")
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
The KEXEC_CMDLINE hook function only supports the pcr conditional. Make
this clear at policy load so that IMA policy authors don't assume that
other conditionals are supported.
Since KEXEC_CMDLINE's inception, ima_match_rules() has always returned
true on any loaded KEXEC_CMDLINE rule without any consideration for
other conditionals present in the rule. Make it clear that pcr is the
only supported KEXEC_CMDLINE conditional by returning an error during
policy load.
An example of why this is a problem can be explained with the following
rule:
dont_measure func=KEXEC_CMDLINE obj_type=foo_t
An IMA policy author would have assumed that rule is valid because the
parser accepted it but the result was that measurements for all
KEXEC_CMDLINE operations would be disabled.
Fixes: b0935123a1 ("IMA: Define a new hook to measure the kexec boot command line arguments")
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Buffer based hook functions, such as KEXEC_CMDLINE and KEY_CHECK, can
only measure. The process_buffer_measurement() function quietly ignores
all actions except measure so make this behavior clear at the time of
policy load.
The parsing of the keyrings conditional had a check to ensure that it
was only specified with measure actions but the check should be on the
hook function and not the keyrings conditional since
"appraise func=KEY_CHECK" is not a valid rule.
Fixes: b0935123a1 ("IMA: Define a new hook to measure the kexec boot command line arguments")
Fixes: 5808611ccc ("IMA: Add KEY_CHECK func to measure keys")
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Use ima_free_rule() to fix memory leaks of allocated ima_rule_entry
members, such as .fsname and .keyrings, when an error is encountered
during rule parsing.
Set the args_p pointer to NULL after freeing it in the error path of
ima_lsm_rule_init() so that it isn't freed twice.
This fixes a memory leak seen when loading an rule that contains an
additional piece of allocated memory, such as an fsname, followed by an
invalid conditional:
# echo "measure fsname=tmpfs bad=cond" > /sys/kernel/security/ima/policy
-bash: echo: write error: Invalid argument
# echo scan > /sys/kernel/debug/kmemleak
# cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff98e7e4ece6c0 (size 8):
comm "bash", pid 672, jiffies 4294791843 (age 21.855s)
hex dump (first 8 bytes):
74 6d 70 66 73 00 6b a5 tmpfs.k.
backtrace:
[<00000000abab7413>] kstrdup+0x2e/0x60
[<00000000f11ede32>] ima_parse_add_rule+0x7d4/0x1020
[<00000000f883dd7a>] ima_write_policy+0xab/0x1d0
[<00000000b17cf753>] vfs_write+0xde/0x1d0
[<00000000b8ddfdea>] ksys_write+0x68/0xe0
[<00000000b8e21e87>] do_syscall_64+0x56/0xa0
[<0000000089ea7b98>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fixes: f1b08bbcbd ("ima: define a new policy condition based on the filesystem name")
Fixes: 2b60c0eced ("IMA: Read keyrings= option from the IMA policy")
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Create a function, ima_free_rule(), to free all memory associated with
an ima_rule_entry. Use the new function to fix memory leaks of allocated
ima_rule_entry members, such as .fsname and .keyrings, when deleting a
list of rules.
Make the existing ima_lsm_free_rule() function specific to the LSM
audit rule array of an ima_rule_entry and require that callers make an
additional call to kfree to free the ima_rule_entry itself.
This fixes a memory leak seen when loading by a valid rule that contains
an additional piece of allocated memory, such as an fsname, followed by
an invalid rule that triggers a policy load failure:
# echo -e "dont_measure fsname=securityfs\nbad syntax" > \
/sys/kernel/security/ima/policy
-bash: echo: write error: Invalid argument
# echo scan > /sys/kernel/debug/kmemleak
# cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff9bab67ca12c0 (size 16):
comm "bash", pid 684, jiffies 4295212803 (age 252.344s)
hex dump (first 16 bytes):
73 65 63 75 72 69 74 79 66 73 00 6b 6b 6b 6b a5 securityfs.kkkk.
backtrace:
[<00000000adc80b1b>] kstrdup+0x2e/0x60
[<00000000d504cb0d>] ima_parse_add_rule+0x7d4/0x1020
[<00000000444825ac>] ima_write_policy+0xab/0x1d0
[<000000002b7f0d6c>] vfs_write+0xde/0x1d0
[<0000000096feedcf>] ksys_write+0x68/0xe0
[<0000000052b544a2>] do_syscall_64+0x56/0xa0
[<000000007ead1ba7>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fixes: f1b08bbcbd ("ima: define a new policy condition based on the filesystem name")
Fixes: 2b60c0eced ("IMA: Read keyrings= option from the IMA policy")
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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: b169424551 ("ima: use the lsm policy update notifier")
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Cc: Janne Karhunen <janne.karhunen@gmail.com>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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 <maurizio.drocco@ibm.com>
Reviewed-by: Bruno Meneguele <bmeneg@redhat.com>
Tested-by: Bruno Meneguele <bmeneg@redhat.com> (TPM 1.2, TPM 2.0)
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Make sure IMA is enabled before checking mprotect change. Addresses
report of a 3.7% regression of boot-time.dhcp.
Fixes: 8eb613c0b8 ("ima: verify mprotect change is consistent with mmap policy")
Reported-by: kernel test robot <rong.a.chen@intel.com>
Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Tested-by: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Commit 6cc7c266e5 ("ima: Call ima_calc_boot_aggregate() in
ima_eventdigest_init()") added a call to ima_calc_boot_aggregate() so that
the digest can be recalculated for the boot_aggregate measurement entry if
the 'd' template field has been requested. For the 'd' field, only SHA1 and
MD5 digests are accepted.
Given that ima_eventdigest_init() does not have the __init annotation, all
functions called should not have it. This patch removes __init from
ima_pcrread().
Cc: stable@vger.kernel.org
Fixes: 6cc7c266e5 ("ima: Call ima_calc_boot_aggregate() in ima_eventdigest_init()")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull integrity updates from Mimi Zohar:
"The main changes are extending the TPM 2.0 PCR banks with bank
specific file hashes, calculating the "boot_aggregate" based on other
TPM PCR banks, using the default IMA hash algorithm, instead of SHA1,
as the basis for the cache hash table key, and preventing the mprotect
syscall to circumvent an IMA mmap appraise policy rule.
- In preparation for extending TPM 2.0 PCR banks with bank specific
digests, commit 0b6cf6b97b ("tpm: pass an array of
tpm_extend_digest structures to tpm_pcr_extend()") modified
tpm_pcr_extend(). The original SHA1 file digests were
padded/truncated, before being extended into the other TPM PCR
banks. This pull request calculates and extends the TPM PCR banks
with bank specific file hashes completing the above change.
- The "boot_aggregate", the first IMA measurement list record, is the
"trusted boot" link between the pre-boot environment and the
running OS. With TPM 2.0, the "boot_aggregate" record is not
limited to being based on the SHA1 TPM PCR bank, but can be
calculated based on any enabled bank, assuming the hash algorithm
is also enabled in the kernel.
Other changes include the following and five other bug fixes/code
clean up:
- supporting both a SHA1 and a larger "boot_aggregate" digest in a
custom template format containing both the the SHA1 ('d') and
larger digests ('d-ng') fields.
- Initial hash table key fix, but additional changes would be good"
* tag 'integrity-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
ima: Directly free *entry in ima_alloc_init_template() if digests is NULL
ima: Call ima_calc_boot_aggregate() in ima_eventdigest_init()
ima: Directly assign the ima_default_policy pointer to ima_rules
ima: verify mprotect change is consistent with mmap policy
evm: Fix possible memory leak in evm_calc_hmac_or_hash()
ima: Set again build_ima_appraise variable
ima: Remove redundant policy rule set in add_rules()
ima: Fix ima digest hash table key calculation
ima: Use ima_hash_algo for collision detection in the measurement list
ima: Calculate and extend PCR with digests in ima_template_entry
ima: Allocate and initialize tfm for each PCR bank
ima: Switch to dynamically allocated buffer for template digests
ima: Store template digest directly in ima_template_entry
ima: Evaluate error in init_ima()
ima: Switch to ima_hash_algo for boot aggregate
To support multiple template digests, the static array entry->digest has
been replaced with a dynamically allocated array in commit aa724fe18a
("ima: Switch to dynamically allocated buffer for template digests"). The
array is allocated in ima_alloc_init_template() and if the returned pointer
is NULL, ima_free_template_entry() is called.
However, (*entry)->template_desc is not yet initialized while it is used by
ima_free_template_entry(). This patch fixes the issue by directly freeing
*entry without calling ima_free_template_entry().
Fixes: aa724fe18a ("ima: Switch to dynamically allocated buffer for template digests")
Reported-by: syzbot+223310b454ba6b75974e@syzkaller.appspotmail.com
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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: 3ce1217d6c ("ima: define template fields library and new helpers")
Reported-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
