Systems in lockdown mode should block the kexec of untrusted kernels.
For x86 and ARM we can ensure that a kernel is trustworthy by validating
a PE signature, but this isn't possible on other architectures. On those
platforms we can use IMA digital signatures instead. Add a function to
determine whether IMA has or will verify signatures for a given event type,
and if so permit kexec_file() even if the kernel is otherwise locked down.
This is restricted to cases where CONFIG_INTEGRITY_TRUSTED_KEYRING is set
in order to prevent an attacker from loading additional keys at runtime.
Signed-off-by: NMatthew Garrett <mjg59@google.com>
Acked-by: NMimi Zohar <zohar@linux.ibm.com>
Cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: linux-integrity@vger.kernel.org
Signed-off-by: NJames Morris <jmorris@namei.org>

This is a preparatory patch for kexec_file_load() lockdown.  A locked down
kernel needs to prevent unsigned kernel images from being loaded with
kexec_file_load().  Currently, the only way to force the signature
verification is compiling with KEXEC_VERIFY_SIG.  This prevents loading
usigned images even when the kernel is not locked down at runtime.

This patch splits KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE.
Analogous to the MODULE_SIG and MODULE_SIG_FORCE for modules, KEXEC_SIG
turns on the signature verification but allows unsigned images to be
loaded.  KEXEC_SIG_FORCE disallows images without a valid signature.
Signed-off-by: NJiri Bohac <jbohac@suse.cz>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NMatthew Garrett <mjg59@google.com>
cc: kexec@lists.infradead.org
Signed-off-by: NJames Morris <jmorris@namei.org>

If the IMA template contains the "modsig" or "d-modsig" field, then the
modsig should be added to the measurement list when the file is appraised.

And that is what normally happens, but if a measurement rule caused a file
containing a modsig to be measured before a different rule causes it to be
appraised, the resulting measurement entry will not contain the modsig
because it is only fetched during appraisal. When the appraisal rule
triggers, it won't store a new measurement containing the modsig because
the file was already measured.

We need to detect that situation and store an additional measurement with
the modsig. This is done by adding an IMA_MEASURE action flag if we read a
modsig and the IMA template contains a modsig field.
Suggested-by: NMimi Zohar <zohar@linux.ibm.com>
Signed-off-by: NThiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

Define new "d-modsig" template field which holds the digest that is
expected to match the one contained in the modsig, and also new "modsig"
template field which holds the appended file signature.

Add a new "ima-modsig" defined template descriptor with the new fields as
well as the ones from the "ima-sig" descriptor.

Change ima_store_measurement() to accept a struct modsig * argument so that
it can be passed along to the templates via struct ima_event_data.
Suggested-by: NMimi Zohar <zohar@linux.ibm.com>
Signed-off-by: NThiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

Obtain the modsig and calculate its corresponding hash in
ima_collect_measurement().
Signed-off-by: NThiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

Implement the appraise_type=imasig|modsig option, allowing IMA to read and
verify modsig signatures.

In case a file has both an xattr signature and an appended modsig, IMA will
only use the appended signature if the key used by the xattr signature
isn't present in the IMA or platform keyring.

Because modsig verification needs to convert from an integrity keyring id
to the keyring itself, add an integrity_keyring_from_id() function in
digsig.c so that integrity_modsig_verify() can use it.
Signed-off-by: NThiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

A buffer(kexec boot command line arguments) measured into IMA
measuremnt list cannot be appraised, without already being
aware of the buffer contents. Since hashes are non-reversible,
raw buffer is needed for validation or regenerating hash for
appraisal/attestation.

Add support to store/read the buffer contents in HEX.
The kexec cmdline hash is stored in the "d-ng" field of the
template data.  It can be verified using
sudo cat /sys/kernel/security/integrity/ima/ascii_runtime_measurements |
  grep  kexec-cmdline | cut -d' ' -f 6 | xxd -r -p | sha256sum

- Add two new fields to ima_event_data to hold the buf and
buf_len
- Add a new template field 'buf' to be used to store/read
the buffer data.
- Updated process_buffer_meaurement to add the buffer to
ima_event_data. process_buffer_measurement added in
"Define a new IMA hook to measure the boot command line
 arguments"
- Add a new template policy name ima-buf to represent
'd-ng|n-ng|buf'
Signed-off-by: NPrakhar Srivastava <prsriva02@gmail.com>
Reviewed-by: NRoberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: NJames Morris <jamorris@linux.microsoft.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

Currently during soft reboot(kexec_file_load) boot command line
arguments are not measured. Define hooks needed to measure kexec
command line arguments during soft reboot(kexec_file_load).

- A new ima hook ima_kexec_cmdline is defined to be called by the
kexec code.
- A new function process_buffer_measurement is defined to measure
the buffer hash into the IMA measurement list.
- A new func policy KEXEC_CMDLINE is defined to control the
 measurement.
Signed-off-by: NPrakhar Srivastava <prsriva02@gmail.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

Admins may wish to log different measurements using different IMA
templates. Add support for overriding the default template on a per-rule
basis.
Inspired-by: NRoberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: NMatthew Garrett <mjg59@google.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

Don't do lazy policy updates while running the rule matching,
run the updates as they happen.

Depends on commit f242064c5df3 ("LSM: switch to blocking policy update notifiers")
Signed-off-by: NJanne Karhunen <janne.karhunen@gmail.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation version 2 of the license

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 315 file(s).
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NAllison Randal <allison@lohutok.net>
Reviewed-by: NArmijn Hemel <armijn@tjaldur.nl>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531190115.503150771@linutronix.deSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The kernel calls deny_write_access() to prevent a file already opened
for write from being executed and also prevents files being executed
from being opened for write.  For some reason this does not extend to
files being mmap'ed execute.

From an IMA perspective, measuring/appraising the integrity of a file
being mmap'ed shared execute, without first making sure the file cannot
be modified, makes no sense.  This patch prevents files, in policy,
already mmap'ed shared write, from being mmap'ed execute.
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

If tmpfiles can be made persistent, then newly created tmpfiles need to
be treated like any other new files in policy.

This patch indicates which newly created tmpfiles are in policy, causing
the file hash to be calculated on __fput().
Reported-by: NIgnaz Forster <ignaz.forster@gmx.de>
[rgoldwyn@suse.com: Call ima_post_create_tmpfile() in vfs_tmpfile() as
opposed to do_tmpfile(). This will help the case for overlayfs where
copy_up is denied while overwriting a file.]
Signed-off-by: NGoldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

In commit 4f83d5ea ("security: integrity: make ima_main explicitly
non-modular") I'd removed <linux/module.h> after assuming that the
function is_module_sig_enforced() was an LSM function and not a core
kernel module function.

Unfortunately the typical .config selections used in build testing
provide an implicit <linux/module.h> presence, and so normal/typical
build testing did not immediately reveal my incorrect assumption.

Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: linux-ima-devel@lists.sourceforge.net
Cc: linux-security-module@vger.kernel.org
Reported-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NJames Morris <james.morris@microsoft.com>

Use the aptly named function rather than open coding the check. No
functional changes.
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

The Makefile/Kconfig entry controlling compilation of this code is:

obj-$(CONFIG_IMA) += ima.o
ima-y := ima_fs.o ima_queue.o ima_init.o ima_main.o ima_crypto.o ima_api.o \
         ima_policy.o ima_template.o ima_template_lib.o

security/integrity/ima/Kconfig:config IMA
security/integrity/ima/Kconfig- bool "Integrity Measurement Architecture(IMA)"

...meaning that it currently is not being built as a module by anyone.

Lets remove the couple traces of modular infrastructure use, so that
when reading the driver there is no doubt it is builtin-only.

We also delete the MODULE_LICENSE tag etc. since all that information
is already contained at the top of the file in the comments.

Cc: Mimi Zohar <zohar@linux.ibm.com>
Cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: linux-ima-devel@lists.sourceforge.net
Cc: linux-security-module@vger.kernel.org
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NJames Morris <james.morris@microsoft.com>

When CONFIG_KEXEC_VERIFY_SIG is enabled, the kexec_file_load syscall
requires the kexec'd kernel image to be signed. Distros are concerned
about totally disabling the kexec_load syscall. As a compromise, the
kexec_load syscall will only be disabled when CONFIG_KEXEC_VERIFY_SIG
is configured and the system is booted with secureboot enabled.

This patch disables the kexec_load syscall only for systems booted with
secureboot enabled.

[zohar@linux.ibm.com: add missing mesage on kexec_load failure]
Signed-off-by: NNayna Jain <nayna@linux.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Peter Jones <pjones@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

Constify some static data that is never modified,
so that it is placed in .rodata.
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

Some systems are memory constrained but they need to load very large
firmwares.  The firmware subsystem allows drivers to request this
firmware be loaded from the filesystem, but this requires that the
entire firmware be loaded into kernel memory first before it's provided
to the driver.  This can lead to a situation where we map the firmware
twice, once to load the firmware into kernel memory and once to copy the
firmware into the final resting place.

To resolve this problem, commit a098ecd2 ("firmware: support loading
into a pre-allocated buffer") introduced request_firmware_into_buf() API
that allows drivers to request firmware be loaded directly into a
pre-allocated buffer.

Do devices using pre-allocated memory run the risk of the firmware being
accessible to the device prior to the completion of IMA's signature
verification any more than when using two buffers? (Refer to mailing list
discussion[1]).

Only on systems with an IOMMU can the access be prevented.  As long as
the signature verification completes prior to the DMA map is performed,
the device can not access the buffer.  This implies that the same buffer
can not be re-used.  Can we ensure the buffer has not been DMA mapped
before using the pre-allocated buffer?

[1] https://lkml.org/lkml/2018/7/10/56Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NJames Morris <james.morris@microsoft.com>

Both the init_module and finit_module syscalls call either directly
or indirectly the security_kernel_read_file LSM hook.  This patch
replaces the direct call in init_module with a call to the new
security_kernel_load_data hook and makes the corresponding changes
in SELinux, LoadPin, and IMA.
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Cc: Kees Cook <keescook@chromium.org>
Acked-by: NJessica Yu <jeyu@kernel.org>
Acked-by: NPaul Moore <paul@paul-moore.com>
Acked-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NJames Morris <james.morris@microsoft.com>

With an IMA policy requiring signed firmware, this patch prevents
the sysfs fallback method of loading firmware.
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Reviewed-by: NKees Cook <keescook@chromium.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Matthew Garrett <mjg59@google.com>
Signed-off-by: NJames Morris <james.morris@microsoft.com>

The original kexec_load syscall can not verify file signatures, nor can
the kexec image be measured.  Based on policy, deny the kexec_load
syscall.
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Reviewed-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NJames Morris <james.morris@microsoft.com>

just check ->f_mode in ima_appraise_measurement()
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

match_string() returns the index of an array for a matching string,
which can be used intead of open coded variant.
Signed-off-by: NYisheng Xie <xieyisheng1@huawei.com>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

Don't differentiate, for now, between kernel_read_file_id READING_FIRMWARE
and READING_FIRMWARE_PREALLOC_BUFFER enumerations.

Fixes: a098ecd2 firmware: support loading into a pre-allocated buffer (since 4.8)
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Serge E. Hallyn <serge@hallyn.com>
Cc: Stephen Boyd <stephen.boyd@linaro.org>

Commit a756024e ("ima: added ima_policy_flag variable") replaced
ima_initialized with ima_policy_flag, but didn't remove ima_initialized.
This patch removes it.
Signed-off-by: NPetr Vorel <pvorel@suse.cz>
Reviewed-by: NJames Morris <james.morris@microsoft.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

IMA requires having it's hash algorithm be compiled-in due to it's
early use.  The default IMA algorithm is protected by Kconfig to be
compiled-in.

The ima_hash kernel parameter allows to choose the hash algorithm. When
the specified algorithm is not available or available as a module, IMA
initialization fails, which leads to a kernel panic (mknodat syscall calls
ima_post_path_mknod()).  Therefore as fallback we force IMA to use
the default builtin Kconfig hash algorithm.

Fixed crash:

$ grep CONFIG_CRYPTO_MD4 .config
CONFIG_CRYPTO_MD4=m

[    0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-4.12.14-2.3-default root=UUID=74ae8202-9ca7-4e39-813b-22287ec52f7a video=1024x768-16 plymouth.ignore-serial-consoles console=ttyS0 console=tty resume=/dev/disk/by-path/pci-0000:00:07.0-part3 splash=silent showopts ima_hash=md4
...
[    1.545190] ima: Can not allocate md4 (reason: -2)
...
[    2.610120] BUG: unable to handle kernel NULL pointer dereference at           (null)
[    2.611903] IP: ima_match_policy+0x23/0x390
[    2.612967] PGD 0 P4D 0
[    2.613080] Oops: 0000 [#1] SMP
[    2.613080] Modules linked in: autofs4
[    2.613080] Supported: Yes
[    2.613080] CPU: 0 PID: 1 Comm: systemd Not tainted 4.12.14-2.3-default #1
[    2.613080] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014
[    2.613080] task: ffff88003e2d0040 task.stack: ffffc90000190000
[    2.613080] RIP: 0010:ima_match_policy+0x23/0x390
[    2.613080] RSP: 0018:ffffc90000193e88 EFLAGS: 00010296
[    2.613080] RAX: 0000000000000000 RBX: 000000000000000c RCX: 0000000000000004
[    2.613080] RDX: 0000000000000010 RSI: 0000000000000001 RDI: ffff880037071728
[    2.613080] RBP: 0000000000008000 R08: 0000000000000000 R09: 0000000000000000
[    2.613080] R10: 0000000000000008 R11: 61c8864680b583eb R12: 00005580ff10086f
[    2.613080] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000008000
[    2.613080] FS:  00007f5c1da08940(0000) GS:ffff88003fc00000(0000) knlGS:0000000000000000
[    2.613080] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    2.613080] CR2: 0000000000000000 CR3: 0000000037002000 CR4: 00000000003406f0
[    2.613080] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[    2.613080] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[    2.613080] Call Trace:
[    2.613080]  ? shmem_mknod+0xbf/0xd0
[    2.613080]  ima_post_path_mknod+0x1c/0x40
[    2.613080]  SyS_mknod+0x210/0x220
[    2.613080]  entry_SYSCALL_64_fastpath+0x1a/0xa5
[    2.613080] RIP: 0033:0x7f5c1bfde570
[    2.613080] RSP: 002b:00007ffde1c90dc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000085
[    2.613080] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5c1bfde570
[    2.613080] RDX: 0000000000000000 RSI: 0000000000008000 RDI: 00005580ff10086f
[    2.613080] RBP: 00007ffde1c91040 R08: 00005580ff10086f R09: 0000000000000000
[    2.613080] R10: 0000000000104000 R11: 0000000000000246 R12: 00005580ffb99660
[    2.613080] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000002
[    2.613080] Code: 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 41 57 41 56 44 8d 14 09 41 55 41 54 55 53 44 89 d3 09 cb 48 83 ec 38 48 8b 05 c5 03 29 01 <4c> 8b 20 4c 39 e0 0f 84 d7 01 00 00 4c 89 44 24 08 89 54 24 20
[    2.613080] RIP: ima_match_policy+0x23/0x390 RSP: ffffc90000193e88
[    2.613080] CR2: 0000000000000000
[    2.613080] ---[ end trace 9a9f0a8a73079f6a ]---
[    2.673052] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009
[    2.673052]
[    2.675337] Kernel Offset: disabled
[    2.676405] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009
Signed-off-by: NPetr Vorel <pvorel@suse.cz>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

This patch addresses the fuse privileged mounted filesystems in
environments which are unwilling to accept the risk of trusting the
signature verification and want to always fail safe, but are for example
using a pre-built kernel.

This patch defines a new builtin policy named "fail_securely", which can
be specified on the boot command line as an argument to "ima_policy=".
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Seth Forshee <seth.forshee@canonical.com>
Cc: Dongsu Park <dongsu@kinvolk.io>
Cc: Alban Crequy <alban@kinvolk.io>
Acked-by: NSerge Hallyn <serge@hallyn.com>
Acked-by: N"Eric W. Biederman" <ebiederm@xmission.com>

This patch addresses the fuse privileged mounted filesystems in a "secure"
environment, with a correctly enforced security policy, which is willing
to assume the inherent risk of specific fuse filesystems that are well
defined and properly implemented.

As there is no way for the kernel to detect file changes, the kernel
ignores the cached file integrity results and re-measures, re-appraises,
and re-audits the file.
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Seth Forshee <seth.forshee@canonical.com>
Cc: Dongsu Park <dongsu@kinvolk.io>
Cc: Alban Crequy <alban@kinvolk.io>
Acked-by: NSerge Hallyn <serge@hallyn.com>
Acked-by: N"Eric W. Biederman" <ebiederm@xmission.com>

The existing BPRM_CHECK functionality in IMA validates against the
credentials of the existing process, not any new credentials that the
child process may transition to. Add an additional CREDS_CHECK target
and refactor IMA to pass the appropriate creds structure. In
ima_bprm_check(), check with both the existing process credentials and
the credentials that will be committed when the new process is started.
This will not change behaviour unless the system policy is extended to
include CREDS_CHECK targets - BPRM_CHECK will continue to check the same
credentials that it did previously.

After this patch, an IMA policy rule along the lines of:

measure func=CREDS_CHECK subj_type=unconfined_t

will trigger if a process is executed and runs as unconfined_t, ignoring
the context of the parent process. This is in contrast to:

measure func=BPRM_CHECK subj_type=unconfined_t

which will trigger if the process that calls exec() is already executing
in unconfined_t, ignoring the context that the child process executes
into.
Signed-off-by: NMatthew Garrett <mjg59@google.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

Changelog:
- initialize ima_creds_status

The function inode_cmp_iversion{+raw} is counter-intuitive, because it
returns true when the counters are different and false when these are equal.

Rename it to inode_eq_iversion{+raw}, which will returns true when
the counters are equal and false otherwise.
Signed-off-by: NGoffredo Baroncelli <kreijack@inwind.it>
Signed-off-by: NJeff Layton <jlayton@redhat.com>

Signed-off-by: NJeff Layton <jlayton@redhat.com>

i_version is only supported by a filesystem when the SB_I_VERSION
flag is set. This patch tests for the SB_I_VERSION flag before using
i_version. If we can't use i_version to detect a file change then we
must assume the file has changed in the last_writer path and remeasure
it.

On filesystems without i_version support IMA used to measure a file
only once and didn't detect any changes to a file. With this patch
IMA now works properly on these filesystems.
Signed-off-by: NSascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

Simple but useful message log to the user in case of module appraise is
forced and fails due to the lack of file descriptor, that might be
caused by kmod calls to compressed modules.
Signed-off-by: NBruno E. O. Meneguele <brdeoliv@redhat.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

ima_rdwr_violation_check() retrieves the full path of a measured file by
calling ima_d_path(). If process_measurement() calls this function, it
reuses the pointer and passes it to the functions to measure/appraise/audit
an accessed file.

After commit bc15ed66 ("ima: fix ima_d_path() possible race with
rename"), ima_d_path() first tries to retrieve the full path by calling
d_absolute_path() and, if there is an error, copies the dentry name to the
buffer passed as argument.

However, ima_rdwr_violation_check() passes to ima_d_path() the pointer of a
local variable. process_measurement() might be reusing the pointer to an
area in the stack which may have been already overwritten after
ima_rdwr_violation_check() returned.

Correct this issue by passing to ima_rdwr_violation_check() the pointer of
a buffer declared in process_measurement().

Fixes: bc15ed66 ("ima: fix ima_d_path() possible race with rename")
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

The builtin ima_appraise_tcb policy, which is specified on the boot
command line, can be replaced with a custom policy, normally early in
the boot process.  Custom policies can be more restrictive in some ways,
like requiring file signatures, but can be less restrictive in other
ways, like not appraising mutable files.  With a less restrictive policy
in place, files in the builtin policy might not be hashed and labeled
with a security.ima hash.  On reboot, files which should be labeled in
the ima_appraise_tcb are not labeled, possibly preventing the system
from booting properly.

To resolve this problem, this patch extends the existing IMA policy
actions "measure", "dont_measure", "appraise", "dont_appraise", and
"audit" with "hash" and "dont_hash".  The new "hash" action will write
the file hash as security.ima, but without requiring the file to be
appraised as well.

For example, the builtin ima_appraise_tcb policy includes the rule,
"appraise fowner=0".  Adding the "hash fowner=0" rule to a custom
policy, will cause the needed file hashes to be calculated and written
as security.ima xattrs.
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: NStefan Berger <stefanb@linux.vnet.ibm.com>

i_version is only supported by a filesystem when the SB_I_VERSION
flag is set. This patch tests for the SB_I_VERSION flag before using
i_version. If we can't use i_version to detect a file change then we
must assume the file has changed in the last_writer path and remeasure
it.

On filesystems without i_version support IMA used to measure a file
only once and didn't detect any changes to a file. With this patch
IMA now works properly on these filesystems.
Signed-off-by: NSascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NJeff Layton <jlayton@redhat.com>

Before IMA appraisal was introduced, IMA was using own integrity cache
lock along with i_mutex. process_measurement and ima_file_free took
the iint->mutex first and then the i_mutex, while setxattr, chmod and
chown took the locks in reverse order. To resolve the potential deadlock,
i_mutex was moved to protect entire IMA functionality and the redundant
iint->mutex was eliminated.

Solution was based on the assumption that filesystem code does not take
i_mutex further. But when file is opened with O_DIRECT flag, direct-io
implementation takes i_mutex and produces deadlock. Furthermore, certain
other filesystem operations, such as llseek, also take i_mutex.

More recently some filesystems have replaced their filesystem specific
lock with the global i_rwsem to read a file.  As a result, when IMA
attempts to calculate the file hash, reading the file attempts to take
the i_rwsem again.

To resolve O_DIRECT related deadlock problem, this patch re-introduces
iint->mutex. But to eliminate the original chmod() related deadlock
problem, this patch eliminates the requirement for chmod hooks to take
the iint->mutex by introducing additional atomic iint->attr_flags to
indicate calling of the hooks. The allowed locking order is to take
the iint->mutex first and then the i_rwsem.

Original flags were cleared in chmod(), setxattr() or removwxattr()
hooks and tested when file was closed or opened again. New atomic flags
are set or cleared in those hooks and tested to clear iint->flags on
close or on open.

Atomic flags are following:
* IMA_CHANGE_ATTR - indicates that chATTR() was called (chmod, chown,
  chgrp) and file attributes have changed. On file open, it causes IMA
  to clear iint->flags to re-evaluate policy and perform IMA functions
  again.
* IMA_CHANGE_XATTR - indicates that setxattr or removexattr was called
  and extended attributes have changed. On file open, it causes IMA to
  clear iint->flags IMA_DONE_MASK to re-appraise.
* IMA_UPDATE_XATTR - indicates that security.ima needs to be updated.
  It is cleared if file policy changes and no update is needed.
* IMA_DIGSIG - indicates that file security.ima has signature and file
  security.ima must not update to file has on file close.
* IMA_MUST_MEASURE - indicates the file is in the measurement policy.

Fixes: Commit 65523218 ("xfs: remove i_iolock and use i_rwsem in
the VFS inode instead")
Signed-off-by: NDmitry Kasatkin <dmitry.kasatkin@huawei.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

When the user requests MODULE_CHECK policy and its kernel is compiled
with CONFIG_MODULE_SIG_FORCE not set, all modules would not load, just
those loaded in initram time. One option the user would have would be
set a kernel cmdline param (module.sig_enforce) to true, but the IMA
module check code doesn't rely on this value, it checks just
CONFIG_MODULE_SIG_FORCE.

This patch solves this problem checking for the exported value of
module.sig_enforce cmdline param intead of CONFIG_MODULE_SIG_FORCE,
which holds the effective value (CONFIG || param).
Signed-off-by: NBruno E. O. Meneguele <brdeoliv@redhat.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

The hash_setup function always sets the hash_setup_done flag, even
when the hash algorithm is invalid.  This prevents the default hash
algorithm defined as CONFIG_IMA_DEFAULT_HASH from being used.

This patch sets hash_setup_done flag only for valid hash algorithms.

Fixes: e7a2ad7e "ima: enable support for larger default filedata hash
	algorithms"
Signed-off-by: NBoshi Wang <wangboshi@huawei.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>