This patch is to move secid and peer_secid from endpoint to association,
and pass asoc to sctp_assoc_request and sctp_sk_clone instead of ep. As
ep is the local endpoint and asoc represents a connection, and in SCTP
one sk/ep could have multiple asoc/connection, saving secid/peer_secid
for new asoc will overwrite the old asoc's.
Note that since asoc can be passed as NULL, security_sctp_assoc_request()
is moved to the place right after the new_asoc is created in
sctp_sf_do_5_1B_init() and sctp_sf_do_unexpected_init().
v1->v2:
- fix the description of selinux_netlbl_skbuff_setsid(), as Jakub noticed.
- fix the annotation in selinux_sctp_assoc_request(), as Richard Noticed.
Fixes: 72e89f5008 ("security: Add support for SCTP security hooks")
Reported-by: Prashanth Prahlad <pprahlad@redhat.com>
Reviewed-by: Richard Haines <richard_c_haines@btinternet.com>
Tested-by: Richard Haines <richard_c_haines@btinternet.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
NOTE: This patch intentionally omits any "Fixes:" metadata or stable
tagging since it removes a SELinux access control check; while
removing the control point is the right thing to do moving forward,
removing it in stable kernels could be seen as a regression.
The original SELinux lockdown implementation in 59438b4647
("security,lockdown,selinux: implement SELinux lockdown") used the
current task's credentials as both the subject and object in the
SELinux lockdown hook, selinux_lockdown(). Unfortunately that
proved to be incorrect in a number of cases as the core kernel was
calling the LSM lockdown hook in places where the credentials from
the "current" task_struct were not the correct credentials to use
in the SELinux access check.
Attempts were made to resolve this by adding a credential pointer
to the LSM lockdown hook as well as suggesting that the single hook
be split into two: one for user tasks, one for kernel tasks; however
neither approach was deemed acceptable by Linus. Faced with the
prospect of either changing the subj/obj in the access check to a
constant context (likely the kernel's label) or removing the SELinux
lockdown check entirely, the SELinux community decided that removing
the lockdown check was preferable.
The supporting changes to the general LSM layer are left intact, this
patch only removes the SELinux implementation.
Acked-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This patch implements two new io_uring access controls, specifically
support for controlling the io_uring "personalities" and
IORING_SETUP_SQPOLL. Controlling the sharing of io_urings themselves
is handled via the normal file/inode labeling and sharing mechanisms.
The io_uring { override_creds } permission restricts which domains
the subject domain can use to override it's own credentials.
Granting a domain the io_uring { override_creds } permission allows
it to impersonate another domain in io_uring operations.
The io_uring { sqpoll } permission restricts which domains can create
asynchronous io_uring polling threads. This is important from a
security perspective as operations queued by this asynchronous thread
inherit the credentials of the thread creator by default; if an
io_uring is shared across process/domain boundaries this could result
in one domain impersonating another. Controlling the creation of
sqpoll threads, and the sharing of io_urings across processes, allow
policy authors to restrict the ability of one domain to impersonate
another via io_uring.
As a quick summary, this patch adds a new object class with two
permissions:
io_uring { override_creds sqpoll }
These permissions can be seen in the two simple policy statements
below:
allow domA_t domB_t : io_uring { override_creds };
allow domA_t self : io_uring { sqpoll };
Signed-off-by: Paul Moore <paul@paul-moore.com>
Add basic Kconfig, an initial (empty) af_mctp source object, and
{AF,PF}_MCTP definitions, and the required definitions for a new
protocol type.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
... along with avc_has_perm_flags() itself, since now it's identical
to avc_has_perm() (as pointed out by Paul Moore)
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[PM: add "selinux:" prefix to subj and tweak for length]
Signed-off-by: Paul Moore <paul@paul-moore.com>
dump_common_audit_data() is safe to use under rcu_read_lock() now;
no need for AVC_NONBLOCKING and games around it
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Paul Moore <paul@paul-moore.com>
seliunx_xfrm_policy_lookup() is hooks of security_xfrm_policy_lookup().
The dir argument is uselss in security_xfrm_policy_lookup(). So
remove the dir argument from selinux_xfrm_policy_lookup() and
security_xfrm_policy_lookup().
Signed-off-by: Zhongjun Tan <tanzhongjun@yulong.com>
[PM: reformat the subject line]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Pull Landlock LSM from James Morris:
"Add Landlock, a new LSM from Mickaël Salaün.
Briefly, Landlock provides for unprivileged application sandboxing.
From Mickaël's cover letter:
"The goal of Landlock is to enable to restrict ambient rights (e.g.
global filesystem access) for a set of processes. Because Landlock
is a stackable LSM [1], it makes possible to create safe security
sandboxes as new security layers in addition to the existing
system-wide access-controls. This kind of sandbox is expected to
help mitigate the security impact of bugs or unexpected/malicious
behaviors in user-space applications. Landlock empowers any
process, including unprivileged ones, to securely restrict
themselves.
Landlock is inspired by seccomp-bpf but instead of filtering
syscalls and their raw arguments, a Landlock rule can restrict the
use of kernel objects like file hierarchies, according to the
kernel semantic. Landlock also takes inspiration from other OS
sandbox mechanisms: XNU Sandbox, FreeBSD Capsicum or OpenBSD
Pledge/Unveil.
In this current form, Landlock misses some access-control features.
This enables to minimize this patch series and ease review. This
series still addresses multiple use cases, especially with the
combined use of seccomp-bpf: applications with built-in sandboxing,
init systems, security sandbox tools and security-oriented APIs [2]"
The cover letter and v34 posting is here:
https://lore.kernel.org/linux-security-module/20210422154123.13086-1-mic@digikod.net/
See also:
https://landlock.io/
This code has had extensive design discussion and review over several
years"
Link: https://lore.kernel.org/lkml/50db058a-7dde-441b-a7f9-f6837fe8b69f@schaufler-ca.com/ [1]
Link: https://lore.kernel.org/lkml/f646e1c7-33cf-333f-070c-0a40ad0468cd@digikod.net/ [2]
* tag 'landlock_v34' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
landlock: Enable user space to infer supported features
landlock: Add user and kernel documentation
samples/landlock: Add a sandbox manager example
selftests/landlock: Add user space tests
landlock: Add syscall implementations
arch: Wire up Landlock syscalls
fs,security: Add sb_delete hook
landlock: Support filesystem access-control
LSM: Infrastructure management of the superblock
landlock: Add ptrace restrictions
landlock: Set up the security framework and manage credentials
landlock: Add ruleset and domain management
landlock: Add object management
Pull selinux updates from Paul Moore:
- Add support for measuring the SELinux state and policy capabilities
using IMA.
- A handful of SELinux/NFS patches to compare the SELinux state of one
mount with a set of mount options. Olga goes into more detail in the
patch descriptions, but this is important as it allows more
flexibility when using NFS and SELinux context mounts.
- Properly differentiate between the subjective and objective LSM
credentials; including support for the SELinux and Smack. My clumsy
attempt at a proper fix for AppArmor didn't quite pass muster so John
is working on a proper AppArmor patch, in the meantime this set of
patches shouldn't change the behavior of AppArmor in any way. This
change explains the bulk of the diffstat beyond security/.
- Fix a problem where we were not properly terminating the permission
list for two SELinux object classes.
* tag 'selinux-pr-20210426' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
selinux: add proper NULL termination to the secclass_map permissions
smack: differentiate between subjective and objective task credentials
selinux: clarify task subjective and objective credentials
lsm: separate security_task_getsecid() into subjective and objective variants
nfs: account for selinux security context when deciding to share superblock
nfs: remove unneeded null check in nfs_fill_super()
lsm,selinux: add new hook to compare new mount to an existing mount
selinux: fix misspellings using codespell tool
selinux: fix misspellings using codespell tool
selinux: measure state and policy capabilities
selinux: Allow context mounts for unpriviliged overlayfs
This patch adds the missing NULL termination to the "bpf" and
"perf_event" object class permission lists.
This missing NULL termination should really only affect the tools
under scripts/selinux, with the most important being genheaders.c,
although in practice this has not been an issue on any of my dev/test
systems. If the problem were to manifest itself it would likely
result in bogus permissions added to the end of the object class;
thankfully with no access control checks using these bogus
permissions and no policies defining these permissions the impact
would likely be limited to some noise about undefined permissions
during policy load.
Cc: stable@vger.kernel.org
Fixes: ec27c3568a ("selinux: bpf: Add selinux check for eBPF syscall operations")
Fixes: da97e18458 ("perf_event: Add support for LSM and SELinux checks")
Signed-off-by: Paul Moore <paul@paul-moore.com>
Pull selinux fixes from Paul Moore:
"Three SELinux patches:
- Fix a problem where a local variable is used outside its associated
function. Thankfully this can only be triggered by reloading the
SELinux policy, which is a restricted operation for other obvious
reasons.
- Fix some incorrect, and inconsistent, audit and printk messages
when loading the SELinux policy.
All three patches are relatively minor and have been through our
testing with no failures"
* tag 'selinux-pr-20210322' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
selinuxfs: unify policy load error reporting
selinux: fix variable scope issue in live sidtab conversion
selinux: don't log MAC_POLICY_LOAD record on failed policy load
Commit 02a52c5c8c ("selinux: move policy commit after updating
selinuxfs") moved the selinux_policy_commit() call out of
security_load_policy() into sel_write_load(), which caused a subtle yet
rather serious bug.
The problem is that security_load_policy() passes a reference to the
convert_params local variable to sidtab_convert(), which stores it in
the sidtab, where it may be accessed until the policy is swapped over
and RCU synchronized. Before 02a52c5c8c, selinux_policy_commit() was
called directly from security_load_policy(), so the convert_params
pointer remained valid all the way until the old sidtab was destroyed,
but now that's no longer the case and calls to sidtab_context_to_sid()
on the old sidtab after security_load_policy() returns may cause invalid
memory accesses.
This can be easily triggered using the stress test from commit
ee1a84fdfe ("selinux: overhaul sidtab to fix bug and improve
performance"):
```
function rand_cat() {
echo $(( $RANDOM % 1024 ))
}
function do_work() {
while true; do
echo -n "system_u:system_r:kernel_t:s0:c$(rand_cat),c$(rand_cat)" \
>/sys/fs/selinux/context 2>/dev/null || true
done
}
do_work >/dev/null &
do_work >/dev/null &
do_work >/dev/null &
while load_policy; do echo -n .; sleep 0.1; done
kill %1
kill %2
kill %3
```
Fix this by allocating the temporary sidtab convert structures
dynamically and passing them among the
selinux_policy_{load,cancel,commit} functions.
Fixes: 02a52c5c8c ("selinux: move policy commit after updating selinuxfs")
Cc: stable@vger.kernel.org
Tested-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
[PM: merge fuzz in security.h and services.c]
Signed-off-by: Paul Moore <paul@paul-moore.com>
A typo is f out by codespell tool in 422th line of security.h:
$ codespell ./security/selinux/include/
./security.h:422: thie ==> the, this
Fix a typo found by codespell.
Signed-off-by: Xiong Zhenwu <xiong.zhenwu@zte.com.cn>
[PM: subject line tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
SELinux stores the configuration state and the policy capabilities
in kernel memory. Changes to this data at runtime would have an impact
on the security guarantees provided by SELinux. Measuring this data
through IMA subsystem provides a tamper-resistant way for
an attestation service to remotely validate it at runtime.
Measure the configuration state and policy capabilities by calling
the IMA hook ima_measure_critical_data().
To enable SELinux data measurement, the following steps are required:
1, Add "ima_policy=critical_data" to the kernel command line arguments
to enable measuring SELinux data at boot time.
For example,
BOOT_IMAGE=/boot/vmlinuz-5.11.0-rc3+ root=UUID=fd643309-a5d2-4ed3-b10d-3c579a5fab2f ro nomodeset security=selinux ima_policy=critical_data
2, Add the following rule to /etc/ima/ima-policy
measure func=CRITICAL_DATA label=selinux
Sample measurement of SELinux state and policy capabilities:
10 2122...65d8 ima-buf sha256:13c2...1292 selinux-state 696e...303b
Execute the following command to extract the measured data
from the IMA's runtime measurements list:
grep "selinux-state" /sys/kernel/security/integrity/ima/ascii_runtime_measurements | tail -1 | cut -d' ' -f 6 | xxd -r -p
The output should be a list of key-value pairs. For example,
initialized=1;enforcing=0;checkreqprot=1;network_peer_controls=1;open_perms=1;extended_socket_class=1;always_check_network=0;cgroup_seclabel=1;nnp_nosuid_transition=1;genfs_seclabel_symlinks=0;
To verify the measurement is consistent with the current SELinux state
reported on the system, compare the integer values in the following
files with those set in the IMA measurement (using the following commands):
- cat /sys/fs/selinux/enforce
- cat /sys/fs/selinux/checkreqprot
- cat /sys/fs/selinux/policy_capabilities/[capability_file]
Note that the actual verification would be against an expected state
and done on a separate system (likely an attestation server) requiring
"initialized=1;enforcing=1;checkreqprot=0;"
for a secure state and then whatever policy capabilities are actually
set in the expected policy (which can be extracted from the policy
itself via seinfo, for example).
Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Suggested-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Suggested-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Pull IMA updates from Mimi Zohar:
"New is IMA support for measuring kernel critical data, as per usual
based on policy. The first example measures the in memory SELinux
policy. The second example measures the kernel version.
In addition are four bug fixes to address memory leaks and a missing
'static' function declaration"
* tag 'integrity-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
integrity: Make function integrity_add_key() static
ima: Free IMA measurement buffer after kexec syscall
ima: Free IMA measurement buffer on error
IMA: Measure kernel version in early boot
selinux: include a consumer of the new IMA critical data hook
IMA: define a builtin critical data measurement policy
IMA: extend critical data hook to limit the measurement based on a label
IMA: limit critical data measurement based on a label
IMA: add policy rule to measure critical data
IMA: define a hook to measure kernel integrity critical data
IMA: add support to measure buffer data hash
IMA: generalize keyring specific measurement constructs
evm: Fix memleak in init_desc
SELinux stores the active policy in memory, so the changes to this data
at runtime would have an impact on the security guarantees provided
by SELinux. Measuring in-memory SELinux policy through IMA subsystem
provides a secure way for the attestation service to remotely validate
the policy contents at runtime.
Measure the hash of the loaded policy by calling the IMA hook
ima_measure_critical_data(). Since the size of the loaded policy
can be large (several MB), measure the hash of the policy instead of
the entire policy to avoid bloating the IMA log entry.
To enable SELinux data measurement, the following steps are required:
1, Add "ima_policy=critical_data" to the kernel command line arguments
to enable measuring SELinux data at boot time.
For example,
BOOT_IMAGE=/boot/vmlinuz-5.10.0-rc1+ root=UUID=fd643309-a5d2-4ed3-b10d-3c579a5fab2f ro nomodeset security=selinux ima_policy=critical_data
2, Add the following rule to /etc/ima/ima-policy
measure func=CRITICAL_DATA label=selinux
Sample measurement of the hash of SELinux policy:
To verify the measured data with the current SELinux policy run
the following commands and verify the output hash values match.
sha256sum /sys/fs/selinux/policy | cut -d' ' -f 1
grep "selinux-policy-hash" /sys/kernel/security/integrity/ima/ascii_runtime_measurements | tail -1 | cut -d' ' -f 6
Note that the actual verification of SELinux policy would require loading
the expected policy into an identical kernel on a pristine/known-safe
system and run the sha256sum /sys/kernel/selinux/policy there to get
the expected hash.
Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Suggested-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
This change uses the anon_inodes and LSM infrastructure introduced in
the previous patches to give SELinux the ability to control
anonymous-inode files that are created using the new
anon_inode_getfd_secure() function.
A SELinux policy author detects and controls these anonymous inodes by
adding a name-based type_transition rule that assigns a new security
type to anonymous-inode files created in some domain. The name used
for the name-based transition is the name associated with the
anonymous inode for file listings --- e.g., "[userfaultfd]" or
"[perf_event]".
Example:
type uffd_t;
type_transition sysadm_t sysadm_t : anon_inode uffd_t "[userfaultfd]";
allow sysadm_t uffd_t:anon_inode { create };
(The next patch in this series is necessary for making userfaultfd
support this new interface. The example above is just
for exposition.)
Signed-off-by: Daniel Colascione <dancol@google.com>
Signed-off-by: Lokesh Gidra <lokeshgidra@google.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
It is not referenced outside selinuxfs.c, so remove its extern header
declaration and make it static.
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
As pointed out by Herbert in a recent related patch, the LSM hooks do
not have the necessary address family information to use the flowi
struct safely. As none of the LSMs currently use any of the protocol
specific flowi information, replace the flowi pointers with pointers
to the address family independent flowi_common struct.
Reported-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
It appears to have been needed for selinux_complete_init() in the past,
but today it's useless.
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
checkreqprot data member in selinux_state struct is accessed directly by
SELinux functions to get and set. This could cause unexpected read or
write access to this data member due to compiler optimizations and/or
compiler's reordering of access to this field.
Add helper functions to get and set checkreqprot data member in
selinux_state struct. These helper functions use READ_ONCE and
WRITE_ONCE macros to ensure atomic read or write of memory for
this data member.
Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Suggested-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Suggested-by: Paul Moore <paul@paul-moore.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Use READ_ONCE/WRITE_ONCE for all accesses to the
selinux_state.policycaps booleans to prevent compiler
mischief.
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Remove the security_policydb_len() calls from sel_open_policy() and
instead update the inode size from the size returned from
security_read_policy().
Since after this change security_policydb_len() is only called from
security_load_policy(), remove it entirely and just open-code it there.
Also, since security_load_policy() is always called with policy_mutex
held, make it dereference the policy pointer directly and drop the
unnecessary RCU locking.
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Move the mutex used to synchronize policy changes (reloads and setting
of booleans) from selinux_fs_info to selinux_state and use it in
lockdep checks for rcu_dereference_protected() calls in the security
server functions. This makes the dependency on the mutex explicit
in the code rather than relying on comments.
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Reviewed-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
