The kexec segment index will be required to extract the corresponding
information for that segment in kimage_map_segment().  Additionally,
kexec_segment already holds the kexec relocation destination address and
size.  Therefore, the prototype of kimage_map_segment() can be changed.

Link: https://lkml.kernel.org/r/20251216014852.8737-1-piliu@redhat.com
Fixes: 07d24902977e ("kexec: enable CMA based contiguous allocation")
Signed-off-by: Pingfan Liu <piliu@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Mimi Zohar <zohar@linux.ibm.com>
Cc: Roberto Sassu <roberto.sassu@huawei.com>
Cc: Alexander Graf <graf@amazon.com>
Cc: Steven Chen <chenste@linux.microsoft.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Pull integrity updates from Mimi Zohar:
 "Bug fixes:

   - defer credentials checking from the bprm_check_security hook to the
     bprm_creds_from_file security hook

   - properly ignore IMA policy rules based on undefined SELinux labels

  IMA policy rule extensions:

   - extend IMA to limit including file hashes in the audit logs
     (dont_audit action)

   - define a new filesystem subtype policy option (fs_subtype)

  Misc:

   - extend IMA to support in-kernel module decompression by deferring
     the IMA signature verification in kernel_read_file() to after the
     kernel module is decompressed"

* tag 'integrity-v6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
  ima: Handle error code returned by ima_filter_rule_match()
  ima: Access decompressed kernel module to verify appended signature
  ima: add fs_subtype condition for distinguishing FUSE instances
  ima: add dont_audit action to suppress audit actions
  ima: Attach CREDS_CHECK IMA hook to bprm_creds_from_file LSM hook

In ima_match_rules(), if ima_filter_rule_match() returns -ENOENT due to
the rule being NULL, the function incorrectly skips the 'if (!rc)' check
and sets 'result = true'. The LSM rule is considered a match, causing
extra files to be measured by IMA.

This issue can be reproduced in the following scenario:
After unloading the SELinux policy module via 'semodule -d', if an IMA
measurement is triggered before ima_lsm_rules is updated,
in ima_match_rules(), the first call to ima_filter_rule_match() returns
-ESTALE. This causes the code to enter the 'if (rc == -ESTALE &&
!rule_reinitialized)' block, perform ima_lsm_copy_rule() and retry. In
ima_lsm_copy_rule(), since the SELinux module has been removed, the rule
becomes NULL, and the second call to ima_filter_rule_match() returns
-ENOENT. This bypasses the 'if (!rc)' check and results in a false match.

Call trace:
  selinux_audit_rule_match+0x310/0x3b8
  security_audit_rule_match+0x60/0xa0
  ima_match_rules+0x2e4/0x4a0
  ima_match_policy+0x9c/0x1e8
  ima_get_action+0x48/0x60
  process_measurement+0xf8/0xa98
  ima_bprm_check+0x98/0xd8
  security_bprm_check+0x5c/0x78
  search_binary_handler+0x6c/0x318
  exec_binprm+0x58/0x1b8
  bprm_execve+0xb8/0x130
  do_execveat_common.isra.0+0x1a8/0x258
  __arm64_sys_execve+0x48/0x68
  invoke_syscall+0x50/0x128
  el0_svc_common.constprop.0+0xc8/0xf0
  do_el0_svc+0x24/0x38
  el0_svc+0x44/0x200
  el0t_64_sync_handler+0x100/0x130
  el0t_64_sync+0x3c8/0x3d0

Fix this by changing 'if (!rc)' to 'if (rc <= 0)' to ensure that error
codes like -ENOENT do not bypass the check and accidentally result in a
successful match.

Fixes: 4af4662fa4a9d ("integrity: IMA policy")
Signed-off-by: Zhao Yipeng <zhaoyipeng5@huawei.com>
Reviewed-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

Currently, when in-kernel module decompression (CONFIG_MODULE_DECOMPRESS)
is enabled, IMA has no way to verify the appended module signature as it
can't decompress the module.

Define a new kernel_read_file_id enumerate READING_MODULE_COMPRESSED so
IMA can calculate the compressed kernel module data hash on
READING_MODULE_COMPRESSED and defer appraising/measuring it until on
READING_MODULE when the module has been decompressed.

Before enabling in-kernel module decompression, a kernel module in
initramfs can still be loaded with ima_policy=secure_boot. So adjust the
kernel module rule in secure_boot policy to allow either an IMA
signature OR an appended signature i.e. to use
"appraise func=MODULE_CHECK appraise_type=imasig|modsig".

Reported-by: Karel Srot <ksrot@redhat.com>
Suggested-by: Mimi Zohar <zohar@linux.ibm.com>
Suggested-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Coiby Xu <coxu@redhat.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

This patch converts IMA and EVM to use the LSM frameworks's initcall
mechanism. It moved the integrity_fs_init() call to ima_fs_init() and
evm_init_secfs(), to work around the fact that there is no "integrity" LSM,
and introduced integrity_fs_fini() to remove the integrity directory, if
empty. Both integrity_fs_init() and integrity_fs_fini() support the
scenario of being called by both the IMA and EVM LSMs.

This patch does not touch any of the platform certificate code that
lives under the security/integrity/platform_certs directory as the
IMA/EVM developers would prefer to address that in a future patchset.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Mimi Zohar <zohar@linux.ibm.com>
[PM: adjust description as discussed over email]
Signed-off-by: Paul Moore <paul@paul-moore.com>

Reduce the duplication between the lsm_id struct and the DEFINE_LSM()
definition by linking the lsm_id struct directly into the individual
LSM's DEFINE_LSM() instance.

Linking the lsm_id into the LSM definition also allows us to simplify
the security_add_hooks() function by removing the code which populates
the lsm_idlist[] array and moving it into the normal LSM startup code
where the LSM list is parsed and the individual LSMs are enabled,
making for a cleaner implementation with less overhead at boot.

Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

Linux systems often use FUSE for several different purposes, where the
contents of some FUSE instances can be of more interest for auditing
than others.

Allow distinguishing between them based on the filesystem subtype
(s_subtype) using the new condition "fs_subtype".

The subtype string is supplied by userspace FUSE daemons
when a FUSE connection is initialized, so policy authors who want to
filter based on subtype need to ensure that FUSE mount operations are
sufficiently audited or restricted.

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

"measure", "appraise" and "hash" actions all have corresponding "dont_*"
actions, but "audit" currently lacks that. This means it is not
currently possible to have a policy that audits everything by default,
but excludes specific cases.

This seems to have been an oversight back when the "audit" action was
added.

Add a corresponding "dont_audit" action to enable such uses.

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

Since commit 56305aa9b6fa ("exec: Compute file based creds only once"), the
credentials to be applied to the process after execution are not calculated
anymore for each step of finding intermediate interpreters (including the
final binary), but only after the final binary to be executed without
interpreter has been found.

In particular, that means that the bprm_check_security LSM hook will not
see the updated cred->e[ug]id for the intermediate and for the final binary
to be executed, since the function doing this task has been moved from
prepare_binprm(), which calls the bprm_check_security hook, to
bprm_creds_from_file().

This breaks the IMA expectation for the CREDS_CHECK hook, introduced with
commit d906c10d8a31 ("IMA: Support using new creds in appraisal policy"),
which expects to evaluate "the credentials that will be committed when the
new process is started". This is clearly not the case for the CREDS_CHECK
IMA hook, which is attached to bprm_check_security.

This issue does not affect systems which load a policy with the BPRM_CHECK
hook with no other criteria, as is the case with the built-in "tcb" and/or
"appraise_tcb" IMA policies. The "tcb" built-in policy measures all
executions regardless of the new credentials, and the "appraise_tcb" policy
is written in terms of the file owner, rather than IMA hooks.

However, it does affect systems without a BPRM_CHECK policy rule or with a
BPRM_CHECK policy rule that does not include what CREDS_CHECK evaluates. As
an extreme example, taking a standalone rule like:

measure func=CREDS_CHECK euid=0

This will not measure for example sudo (because CREDS_CHECK still sees the
bprm->cred->euid set to the regular user UID), but only the subsequent
commands after the euid was applied to the children.

Make set[ug]id programs measured/appraised again by splitting
ima_bprm_check() in two separate hook implementations (CREDS_CHECK now
being implemented by ima_creds_check()), and by attaching CREDS_CHECK to
the bprm_creds_from_file LSM hook.

The limitation of this approach is that CREDS_CHECK will not be invoked
anymore for the intermediate interpreters, like it was before, but only for
the final binary. This limitation can be removed only by reverting commit
56305aa9b6fa ("exec: Compute file based creds only once").

Link: https://github.com/linux-integrity/linux/issues/3
Fixes: 56305aa9b6fa ("exec: Compute file based creds only once")
Cc: Serge E. Hallyn <serge@hallyn.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Jann Horn <jannh@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

Currently when both IMA and EVM are in fix mode, the IMA signature will
be reset to IMA hash if a program first stores IMA signature in
security.ima and then writes/removes some other security xattr for the
file.

For example, on Fedora, after booting the kernel with "ima_appraise=fix
evm=fix ima_policy=appraise_tcb" and installing rpm-plugin-ima,
installing/reinstalling a package will not make good reference IMA
signature generated. Instead IMA hash is generated,

    # getfattr -m - -d -e hex /usr/bin/bash
    # file: usr/bin/bash
    security.ima=0x0404...

This happens because when setting security.selinux, the IMA_DIGSIG flag
that had been set early was cleared. As a result, IMA hash is generated
when the file is closed.

Similarly, IMA signature can be cleared on file close after removing
security xattr like security.evm or setting/removing ACL.

Prevent replacing the IMA file signature with a file hash, by preventing
the IMA_DIGSIG flag from being reset.

Here's a minimal C reproducer which sets security.selinux as the last
step which can also replaced by removing security.evm or setting ACL,

    #include <stdio.h>
    #include <sys/xattr.h>
    #include <fcntl.h>
    #include <unistd.h>
    #include <string.h>
    #include <stdlib.h>

    int main() {
        const char* file_path = "/usr/sbin/test_binary";
        const char* hex_string = "030204d33204490066306402304";
        int length = strlen(hex_string);
        char* ima_attr_value;
        int fd;

        fd = open(file_path, O_WRONLY|O_CREAT|O_EXCL, 0644);
        if (fd == -1) {
            perror("Error opening file");
            return 1;
        }

        ima_attr_value = (char*)malloc(length / 2 );
        for (int i = 0, j = 0; i < length; i += 2, j++) {
            sscanf(hex_string + i, "%2hhx", &ima_attr_value[j]);
        }

        if (fsetxattr(fd, "security.ima", ima_attr_value, length/2, 0) == -1) {
            perror("Error setting extended attribute");
            close(fd);
            return 1;
        }

        const char* selinux_value= "system_u:object_r:bin_t:s0";
        if (fsetxattr(fd, "security.selinux", selinux_value, strlen(selinux_value), 0) == -1) {
            perror("Error setting extended attribute");
            close(fd);
            return 1;
        }

        close(fd);

        return 0;
    }

Signed-off-by: Coiby Xu <coxu@redhat.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>