This commit reverts 5b0eea835d ("selinux: introduce an initial SID
for early boot processes") as it was found to cause problems on
distros with old SELinux userspace tools/libraries, specifically
Ubuntu 16.04.
Hopefully we will be able to re-add this functionality at a later
date, but let's revert this for now to help ensure a stable and
backwards compatible SELinux tree.
Link: https://lore.kernel.org/selinux/87edkseqf8.fsf@mail.lhotse
Acked-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Three LSMs register the implementations for the "capget" hook: AppArmor,
SELinux, and the normal capability code. Looking at the function
implementations we may observe that the first parameter "target" is not
changing.
Mark the first argument "target" of LSM hook security_capget() as
"const" since it will not be changing in the LSM hook.
cap_capget() LSM hook declaration exceeds the 80 characters per line
limit. Split the function declaration to multiple lines to decrease the
line length.
Signed-off-by: Khadija Kamran <kamrankhadijadj@gmail.com>
Acked-by: John Johansen <john.johansen@canonical.com>
[PM: align the cap_capget() declaration, spelling fixes]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Use GFP_KERNEL instead of GFP_ATOMIC while reading a binary policy in
sens_read() and cat_read(), similar to surrounding code.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
After commit f22f9aaf6c ("selinux: remove the runtime disable
functionality"), the comment on selinux_hooks[] is out-of-date,
remove the last paragraph about runtime disable functionality.
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Use u32 as the output parameter type in security_get_classes() and
security_get_permissions(), based on the type of the symtab nprim
member.
Declare the read-only class string parameter of
security_get_permissions() const.
Avoid several implicit conversions by using the identical type for the
destination.
Use the type identical to the source for local variables.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: cleanup extra whitespace in subject]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Use u32 for ebitmap bits and sensitivity levels, char for the default
range of a class.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: description tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Use the identical type u32 for the loop iterator.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: remove extra whitespace in subject]
Signed-off-by: Paul Moore <paul@paul-moore.com>
avtab_hash_eval() and hashtab_stat() are only used in policydb.c when
the configuration SECURITY_SELINUX_DEBUG is enabled.
Move the function definitions under that configuration as well and
provide empty definitions in case SECURITY_SELINUX_DEBUG is disabled, to
avoid using #ifdef in the callers.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
In case virtual memory is being marked as executable by default, SELinux
checks regarding explicit potential dangerous use are disabled.
Inform the user about it.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The policy database code contains several debug output statements
related to hashtable utilization. Those are guarded by the macro
DEBUG_HASHES, which is neither documented nor set anywhere.
Introduce a new Kconfig configuration guarding this and potential
other future debugging related code. Disable the setting by default.
Suggested-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: fixed line lengths in the help text]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Perf traces of network-related workload shows a measurable overhead
inside the network-related selinux hooks while zeroing the
lsm_network_audit struct.
In most cases we can delay the initialization of such structure to the
usage point, avoiding such overhead in a few cases.
Additionally, the audit code accesses the IP address information only
for AF_INET* families, and selinux_parse_skb() will fill-out the
relevant fields in such cases. When the family field is zeroed or the
initialization is followed by the mentioned parsing, the zeroing can be
limited to the sk, family and netif fields.
By factoring out the audit-data initialization to new helpers, this
patch removes some duplicate code and gives small but measurable
performance gain under UDP flood.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The kernel print statements do not append an implicit newline to format
strings.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: subject line tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
avtab_search() shares the same logic with avtab_search_node(), except
that it returns, if found, a pointer to the struct avtab_node member
datum instead of the node itself. Since the member is an embedded
struct, and not a pointer, the returned value of avtab_search() and
avtab_search_node() will always in unison either be NULL or non-NULL.
Drop avtab_search() and replace its calls by avtab_search_node() to
deduplicate logic and adopt the only caller caring for the type of
the returned value accordingly.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Change "NSA SELinux" to just "SELinux" in Kconfig help text and
comments. While NSA was the original primary developer and continues to
help maintain SELinux, SELinux has long since transitioned to a wide
community of developers and maintainers. SELinux has been part of the
mainline Linux kernel for nearly 20 years now [1] and has received
contributions from many individuals and organizations.
[1] https://lore.kernel.org/lkml/Pine.LNX.4.44.0308082228470.1852-100000@home.osdl.org/
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Use the type bool as parameter type in
selinux_status_update_setenforce(). The related function
enforcing_enabled() returns the type bool, while the struct
selinux_kernel_status member enforcing uses an u32.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: subject line tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
hashtab_init() takes an u32 as size parameter type.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: subject line tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
The specifier for avtab keys is always supplied with a type of u16,
either as a macro to security_compute_sid() or the member specified of
the struct avtab_key.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Use the identical types in assignments of local variables for the
destination.
Merge tail calls into return statements.
Avoid using leading underscores for function local variable.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: subject line tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Use a consistent type of u32 for sequence numbers.
Use a non-negative and input parameter matching type for the hash
result.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: subject line tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Use the identical type sel_netif_hashfn() returns.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: subject line tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Align the type with the one used in selinux_notify_policy_change() and
the sequence member of struct selinux_kernel_status.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: subject line tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Prevent inserting more than the supported U32_MAX number of entries.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The function is always inlined and most of the time both relevant
arguments are compile time constants, allowing compilers to elide the
check. Also the function is part of outputting the policy, which is not
performance critical.
Also convert the type of the third parameter into a size_t, since it
should always be a non-negative number of elements.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The sk_getsecid hook shouldn't need to modify its socket argument.
Make it const so that callers of security_sk_classify_flow() can use a
const struct sock *.
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, SELinux doesn't allow distinguishing between kernel threads
and userspace processes that are started before the policy is first
loaded - both get the label corresponding to the kernel SID. The only
way a process that persists from early boot can get a meaningful label
is by doing a voluntary dyntransition or re-executing itself.
Reusing the kernel label for userspace processes is problematic for
several reasons:
1. The kernel is considered to be a privileged domain and generally
needs to have a wide range of permissions allowed to work correctly,
which prevents the policy writer from effectively hardening against
early boot processes that might remain running unintentionally after
the policy is loaded (they represent a potential extra attack surface
that should be mitigated).
2. Despite the kernel being treated as a privileged domain, the policy
writer may want to impose certain special limitations on kernel
threads that may conflict with the requirements of intentional early
boot processes. For example, it is a good hardening practice to limit
what executables the kernel can execute as usermode helpers and to
confine the resulting usermode helper processes. However, a
(legitimate) process surviving from early boot may need to execute a
different set of executables.
3. As currently implemented, overlayfs remembers the security context of
the process that created an overlayfs mount and uses it to bound
subsequent operations on files using this context. If an overlayfs
mount is created before the SELinux policy is loaded, these "mounter"
checks are made against the kernel context, which may clash with
restrictions on the kernel domain (see 2.).
To resolve this, introduce a new initial SID (reusing the slot of the
former "init" initial SID) that will be assigned to any userspace
process started before the policy is first loaded. This is easy to do,
as we can simply label any process that goes through the
bprm_creds_for_exec LSM hook with the new init-SID instead of
propagating the kernel SID from the parent.
To provide backwards compatibility for existing policies that are
unaware of this new semantic of the "init" initial SID, introduce a new
policy capability "userspace_initial_context" and set the "init" SID to
the same context as the "kernel" SID unless this capability is set by
the policy.
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
In the process of reverting back to directly accessing the global
selinux_state pointer we left behind some artifacts in the
selinux_policycap_XXX() helper functions. This patch cleans up
some of that left-behind cruft.
Signed-off-by: Paul Moore <paul@paul-moore.com>
Currently, the LSM infrastructure supports only one LSM providing an xattr
and EVM calculating the HMAC on that xattr, plus other inode metadata.
Allow all LSMs to provide one or multiple xattrs, by extending the security
blob reservation mechanism. Introduce the new lbs_xattr_count field of the
lsm_blob_sizes structure, so that each LSM can specify how many xattrs it
needs, and the LSM infrastructure knows how many xattr slots it should
allocate.
Modify the inode_init_security hook definition, by passing the full
xattr array allocated in security_inode_init_security(), and the current
number of xattr slots in that array filled by LSMs. The first parameter
would allow EVM to access and calculate the HMAC on xattrs supplied by
other LSMs, the second to not leave gaps in the xattr array, when an LSM
requested but did not provide xattrs (e.g. if it is not initialized).
Introduce lsm_get_xattr_slot(), which LSMs can call as many times as the
number specified in the lbs_xattr_count field of the lsm_blob_sizes
structure. During each call, lsm_get_xattr_slot() increments the number of
filled xattrs, so that at the next invocation it returns the next xattr
slot to fill.
Cleanup security_inode_init_security(). Unify the !initxattrs and
initxattrs case by simply not allocating the new_xattrs array in the
former. Update the documentation to reflect the changes, and fix the
description of the xattr name, as it is not allocated anymore.
Adapt both SELinux and Smack to use the new definition of the
inode_init_security hook, and to call lsm_get_xattr_slot() to obtain and
fill the reserved slots in the xattr array.
Move the xattr->name assignment after the xattr->value one, so that it is
done only in case of successful memory allocation.
Finally, change the default return value of the inode_init_security hook
from zero to -EOPNOTSUPP, so that BPF LSM correctly follows the hook
conventions.
Reported-by: Nicolas Bouchinet <nicolas.bouchinet@clip-os.org>
Link: https://lore.kernel.org/linux-integrity/Y1FTSIo+1x+4X0LS@archlinux/
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: minor comment and variable tweaks, approved by RS]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Avoid using the identifier `bool` to improve support with future C
standards. C23 is about to make `bool` a predefined macro (see N2654).
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
As noted in the comments of this commit, the current SELinux Makefile
requires features found in make v4.3 or later, which is problematic
as the Linux Kernel currently only requires make v3.82. This patch
fixes the SELinux Makefile so that it works properly on these older
versions of make, and adds a couple of comments to the Makefile about
how it can be improved once make v4.3 is required by the kernel.
Fixes: 6f933aa7df ("selinux: more Makefile tweaks")
Signed-off-by: Paul Moore <paul@paul-moore.com>
Currently, when an NFS filesystem that supports passing LSM/SELinux
labels is mounted during early boot (before the SELinux policy is
loaded), it ends up mounted without the labeling support (i.e. with
Fedora policy all files get the generic NFS label
system_u:object_r:nfs_t:s0).
This is because the information that the NFS mount supports passing
labels (communicated to the LSM layer via the kern_flags argument of
security_set_mnt_opts()) gets lost and when the policy is loaded the
mount is initialized as if the passing is not supported.
Fix this by noting the "native labeling" in newsbsec->flags (using a new
SE_SBNATIVE flag) on the pre-policy-loaded call of
selinux_set_mnt_opts() and then making sure it is respected on the
second call from delayed_superblock_init().
Additionally, make inode_doinit_with_dentry() initialize the inode's
label from its extended attributes whenever it doesn't find it already
intitialized by the filesystem. This is needed to properly initialize
pre-existing inodes when delayed_superblock_init() is called. It should
not trigger in any other cases (and if it does, it's still better to
initialize the correct label instead of leaving the inode unlabeled).
Fixes: eb9ae68650 ("SELinux: Add new labeling type native labels")
Tested-by: Scott Mayhew <smayhew@redhat.com>
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
[PM: fixed 'Fixes' tag format]
Signed-off-by: Paul Moore <paul@paul-moore.com>
exit_sel_fs() has been removed since commit f22f9aaf6c ("selinux:
remove the runtime disable functionality").
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The object context type `fs`, not to be confused with the well used
object context type `fscon`, was introduced in the initial git commit
1da177e4c3 ("Linux-2.6.12-rc2") but never actually used since.
The paper "A Security Policy Configuration for the Security-Enhanced
Linux" [1] mentions it under `7.2 File System Contexts` but also states:
Currently, this configuration is unused.
The policy statement defining such object contexts is `fscon`, e.g.:
fscon 2 3 gen_context(system_u:object_r:conA_t,s0) \
gen_context(system_u:object_r:conB_t,s0)
It is not documented at selinuxproject.org or in the SELinux notebook
and not supported by the Reference Policy buildsystem - the statement is
not properly sorted - and thus not used in the Reference or Fedora
Policy.
Print a warning message at policy load for each such object context:
SELinux: void and deprecated fs ocon 02:03
This topic was initially highlighted by Nicolas Iooss [2].
[1]: https://media.defense.gov/2021/Jul/29/2002815735/-1/-1/0/SELINUX-SECURITY-POLICY-CONFIGURATION-REPORT.PDF
[2]: https://lore.kernel.org/selinux/CAJfZ7=mP2eJaq2BfO3y0VnwUJaY2cS2p=HZMN71z1pKjzaT0Eg@mail.gmail.com/
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: tweaked deprecation comment, description line wrapping]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Include all necessary headers in header files to enable third party
applications, like LSP servers, to resolve all used symbols.
ibpkey.h: include "flask.h" for SECINITSID_UNLABELED
initial_sid_to_string.h: include <linux/stddef.h> for NULL
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Commit 53f3517ae0 ("selinux: do not leave dangling pointer behind")
reset the `str` field of the `context` struct in an OOM error branch.
In this struct the fields `str` and `len` are coupled and should be kept
in sync. Set the length to zero according to the string be set to NULL.
Fixes: 53f3517ae0 ("selinux: do not leave dangling pointer behind")
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Newly added subflows should inherit the LSM label from the associated
MPTCP socket regardless of the current context.
This patch implements the above copying sid and class from the MPTCP
socket context, deleting the existing subflow label, if any, and then
re-creating the correct one.
The new helper reuses the selinux_netlbl_sk_security_free() function,
and the latter can end-up being called multiple times with the same
argument; we additionally need to make it idempotent.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Paul Moore <paul@paul-moore.com>
A few small tweaks to selinux_audit_rule_init():
- Adjust how we use the @rc variable so we are not doing any extra
work in the common/success case.
- Related to the above, rework the 'out' jump label so that the
success and error paths are different, simplifying both.
- Cleanup some of the vertical whitespace while we are making the
other changes.
Signed-off-by: Paul Moore <paul@paul-moore.com>
The array of mount tokens in only used in match_opt_prefix() and never
modified.
The array of symtab names is never modified and only used in the
DEBUG_HASHES configuration as output.
The array of files for the SElinux filesystem sub-directory `ss` is
similar to the other `struct tree_descr` usages only read from to
construct the containing entries.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The second parameter `tag` of avtab_hash_eval() is only used for
printing. In policydb_index() it is called with a string literal:
avtab_hash_eval(&p->te_avtab, "rules");
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: slight formatting tweak in description]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Commit 539813e418 ("selinux: stop returning node from avc_insert()")
converted the return value of avc_insert() to void but left the now
unnecessary trailing return statement.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Since commit f22f9aaf6c ("selinux: remove the runtime disable
functionality") the function avc_disable() is no longer used.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
In case mls_context_cpy() fails due to OOM set the free'd pointer in
context_cpy() to NULL to avoid it potentially being dereferenced or
free'd again in future. Freeing a NULL pointer is well-defined and a
hard NULL dereference crash is at least not exploitable and should give
a workable stack trace.
Fixes: 12b29f3455 ("selinux: support deferred mapping of contexts")
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
A few small tweaks to improve the SELinux Makefile:
- Define a new variable, 'genhdrs', to represent both flask.h and
av_permissions.h; this should help ensure consistent processing for
both generated headers.
- Move the 'ccflags-y' variable closer to the top, just after the
main 'obj-$(CONFIG_SECURITY_SELINUX)' definition to make it more
visible and improve the grouping in the Makefile.
- Rework some of the vertical whitespace to improve some of the
grouping in the Makefile.
Reviewed-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The Makefile rule responsible for building flask.h and
av_permissions.h only lists flask.h as a target which means that
av_permissions.h is only generated when flask.h needs to be
generated. This patch fixes this by adding av_permissions.h as a
target to the rule.
Fixes: 8753f6bec3 ("selinux: generate flask headers during kernel build")
Signed-off-by: Paul Moore <paul@paul-moore.com>
Make the flask.h target depend on the genheaders binary instead of
classmap.h to ensure that it is rebuilt if any of the dependencies of
genheaders are changed.
Notably this fixes flask.h not being rebuilt when
initial_sid_to_string.h is modified.
Fixes: 8753f6bec3 ("selinux: generate flask headers during kernel build")
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>
The callers haven't used the returned node since
commit 21193dcd1f ("SELinux: more careful use of avd in
avc_has_perm_noaudit") and the return value assignments were removed in
commit 0a9876f36b ("selinux: Remove redundant assignments"). Stop
returning the node altogether and make the functions return void.
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
PM: minor subj tweak, repair whitespace damage
Signed-off-by: Paul Moore <paul@paul-moore.com>
After working with the larger SELinux-based distros for several
years, we're finally at a place where we can disable the SELinux
runtime disable functionality. The existing kernel deprecation
notice explains the functionality and why we want to remove it:
The selinuxfs "disable" node allows SELinux to be disabled at
runtime prior to a policy being loaded into the kernel. If
disabled via this mechanism, SELinux will remain disabled until
the system is rebooted.
The preferred method of disabling SELinux is via the "selinux=0"
boot parameter, but the selinuxfs "disable" node was created to
make it easier for systems with primitive bootloaders that did not
allow for easy modification of the kernel command line.
Unfortunately, allowing for SELinux to be disabled at runtime makes
it difficult to secure the kernel's LSM hooks using the
"__ro_after_init" feature.
It is that last sentence, mentioning the '__ro_after_init' hardening,
which is the real motivation for this change, and if you look at the
diffstat you'll see that the impact of this patch reaches across all
the different LSMs, helping prevent tampering at the LSM hook level.
From a SELinux perspective, it is important to note that if you
continue to disable SELinux via "/etc/selinux/config" it may appear
that SELinux is disabled, but it is simply in an uninitialized state.
If you load a policy with `load_policy -i`, you will see SELinux
come alive just as if you had loaded the policy during early-boot.
It is also worth noting that the "/sys/fs/selinux/disable" file is
always writable now, regardless of the Kconfig settings, but writing
to the file has no effect on the system, other than to display an
error on the console if a non-zero/true value is written.
Finally, in the several years where we have been working on
deprecating this functionality, there has only been one instance of
someone mentioning any user visible breakage. In this particular
case it was an individual's kernel test system, and the workaround
documented in the deprecation notice ("selinux=0" on the kernel
command line) resolved the issue without problem.
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
