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git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinux updates from Paul Moore:
- Introduce the concept of a SELinux "neveraudit" type which prevents
all auditing of the given type/domain.
Taken by itself, the benefit of marking a SELinux domain with the
"neveraudit" tag is likely not very interesting, especially given the
significant overlap with the "dontaudit" tag.
However, given that the "neveraudit" tag applies to *all* auditing of
the tagged domain, we can do some fairly interesting optimizations
when a SELinux domain is marked as both "permissive" and "dontaudit"
(think of the unconfined_t domain).
While this pull request includes optimized inode permission and
getattr hooks, these optimizations require SELinux policy changes,
therefore the improvements may not be visible on standard downstream
Linux distos for a period of time.
- Continue the deprecation process of /sys/fs/selinux/user.
After removing the associated userspace code in 2020, we marked the
/sys/fs/selinux/user interface as deprecated in Linux v6.13 with
pr_warn() and the usual documention update.
This adds a five second sleep after the pr_warn(), following a
previous deprecation process pattern that has worked well for us in
the past in helping identify any existing users that we haven't yet
reached.
- Add a __GFP_NOWARN flag to our initial hash table allocation.
Fuzzers such a syzbot often attempt abnormally large SELinux policy
loads, which the SELinux code gracefully handles by checking for
allocation failures, but not before the allocator emits a warning
which causes the automated fuzzing to flag this as an error and
report it to the list. While we want to continue to support the work
done by the fuzzing teams, we want to focus on proper issues and not
an error case that is already handled safely. Add a NOWARN flag to
quiet the allocator and prevent syzbot from tripping on this again.
- Remove some unnecessary selinuxfs cleanup code, courtesy of Al.
- Update the SELinux in-kernel documentation with pointers to
additional information.
* tag 'selinux-pr-20250725' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
selinux: don't bother with selinuxfs_info_free() on failures
selinux: add __GFP_NOWARN to hashtab_init() allocations
selinux: optimize selinux_inode_getattr/permission() based on neveraudit|permissive
selinux: introduce neveraudit types
documentation: add links to SELinux resources
selinux: add a 5 second sleep to /sys/fs/selinux/user
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Introduce neveraudit types i.e. types that should never trigger
audit messages. This allows the AVC to skip all audit-related
processing for such types. Note that neveraudit differs from
dontaudit not only wrt being applied for all checks with a given
source type but also in that it disables all auditing, not just
permission denials.
When a type is both a permissive type and a neveraudit type,
the security server can short-circuit the security_compute_av()
logic, allowing all permissions and not auditing any permissions.
This change just introduces the basic support but does not yet
further optimize the AVC or hook function logic when a type
is both a permissive type and a dontaudit type.
Suggested-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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If the end result of a security_compute_sid() computation matches the
ssid or tsid, return that SID rather than looking it up again. This
avoids the problem of multiple initial SIDs that map to the same
context.
Cc: stable@vger.kernel.org
Reported-by: Guido Trentalancia <guido@trentalancia.com>
Fixes: ae254858ce07 ("selinux: introduce an initial SID for early boot processes")
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Tested-by: Guido Trentalancia <guido@trentalancia.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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The "linux/parser.h" header was included twice, we only need it once.
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202504121945.Q0GDD0sG-lkp@intel.com/
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Currently, genfscon only supports string prefix match to label files.
Thus, labeling numerous dynamic sysfs entries requires many specific
path rules. For example, labeling device paths such as
`/sys/devices/pci0000:00/0000:00:03.1/<...>/0000:04:00.1/wakeup`
requires listing all specific PCI paths, which is challenging to
maintain. While user-space restorecon can handle these paths with
regular expression rules, relabeling thousands of paths under sysfs
after it is mounted is inefficient compared to using genfscon.
This commit adds wildcard matching to genfscon to make rules more
efficient and expressive. This new behavior is enabled by
genfs_seclabel_wildcard capability. With this capability, genfscon does
wildcard matching instead of prefix matching. When multiple wildcard
rules match against a path, then the longest rule (determined by the
length of the rule string) will be applied. If multiple rules of the
same length match, the first matching rule encountered in the given
genfscon policy will be applied. Users are encouraged to write longer,
more explicit path rules to avoid relying on this behavior.
This change resulted in nice real-world performance improvements. For
example, boot times on test Android devices were reduced by 15%. This
improvement is due to the elimination of the "restorecon -R /sys" step
during boot, which takes more than two seconds in the worst case.
Signed-off-by: Takaya Saeki <takayas@chromium.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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The network address, either an IPv4 or IPv6 one, is not modified.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Retrieve the netif_wildcard policy capability in security_netif_sid()
from the locked active policy instead of the cached value in
selinux_state.
Fixes: 8af43b61c17e ("selinux: support wildcard network interface names")
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
[PM: /netlabel/netif/ due to a typo in the description]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Add support for wildcard matching of network interface names. This is
useful for auto-generated interfaces, for example podman creates network
interfaces for containers with the naming scheme podman0, podman1,
podman2, ...
To maintain backward compatibility guard this feature with a new policy
capability 'netif_wildcard'.
Netifcon definitions are compared against in the order given by the
policy, so userspace tools should sort them in a reasonable order.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinux updates from Paul Moore:
- Extended permissions supported in conditional policy
The SELinux extended permissions, aka "xperms", allow security admins
to target individuals ioctls, and recently netlink messages, with
their SELinux policy. Adding support for conditional policies allows
admins to toggle the granular xperms using SELinux booleans, helping
pave the way for greater use of xperms in general purpose SELinux
policies. This change bumps the maximum SELinux policy version to 34.
- Fix a SCTP/SELinux error return code inconsistency
Depending on the loaded SELinux policy, specifically it's
EXTSOCKCLASS support, the bind(2) LSM/SELinux hook could return
different error codes due to the SELinux code checking the socket's
SELinux object class (which can vary depending on EXTSOCKCLASS) and
not the socket's sk_protocol field. We fix this by doing the obvious,
and looking at the sock->sk_protocol field instead of the object
class.
- Makefile fixes to properly cleanup av_permissions.h
Add av_permissions.h to "targets" so that it is properly cleaned up
using the kbuild infrastructure.
- A number of smaller improvements by Christian Göttsche
A variety of straightforward changes to reduce code duplication,
reduce pointer lookups, migrate void pointers to defined types,
simplify code, constify function parameters, and correct iterator
types.
* tag 'selinux-pr-20250121' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
selinux: make more use of str_read() when loading the policy
selinux: avoid unnecessary indirection in struct level_datum
selinux: use known type instead of void pointer
selinux: rename comparison functions for clarity
selinux: rework match_ipv6_addrmask()
selinux: constify and reconcile function parameter names
selinux: avoid using types indicating user space interaction
selinux: supply missing field initializers
selinux: add netlink nlmsg_type audit message
selinux: add support for xperms in conditional policies
selinux: Fix SCTP error inconsistency in selinux_socket_bind()
selinux: use native iterator types
selinux: add generated av_permissions.h to targets
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The functions context_cmp(), mls_context_cmp() and ebitmap_cmp() are not
traditional C style compare functions returning -1, 0, and 1 for less
than, equal, and greater than; they only return whether their arguments
are equal.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Constify parameters, add size hints, and simplify control flow.
According to godbolt the same assembly is generated.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Align the parameter names between declarations and definitions, and
constify read-only parameters.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: tweak the subject line]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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In commit d1d991efaf34 ("selinux: Add netlink xperm support") a new
extended permission was added ("nlmsg"). This was the second extended
permission implemented in selinux ("ioctl" being the first one).
Extended permissions are associated with a base permission. It was found
that, in the access vector cache (avc), the extended permission did not
keep track of its base permission. This is an issue for a domain that is
using both extended permissions (i.e., a domain calling ioctl() on a
netlink socket). In this case, the extended permissions were
overlapping.
Keep track of the base permission in the cache. A new field "base_perm"
is added to struct extended_perms_decision to make sure that the
extended permission refers to the correct policy permission. A new field
"base_perms" is added to struct extended_perms to quickly decide if
extended permissions apply.
While it is in theory possible to retrieve the base permission from the
access vector, the same base permission may not be mapped to the same
bit for each class (e.g., "nlmsg" is mapped to a different bit for
"netlink_route_socket" and "netlink_audit_socket"). Instead, use a
constant (AVC_EXT_IOCTL or AVC_EXT_NLMSG) provided by the caller.
Fixes: d1d991efaf34 ("selinux: Add netlink xperm support")
Signed-off-by: Thiébaud Weksteen <tweek@google.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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When evaluating extended permissions, ignore unknown permissions instead
of calling BUG(). This commit ensures that future permissions can be
added without interfering with older kernels.
Cc: stable@vger.kernel.org
Fixes: fa1aa143ac4a ("selinux: extended permissions for ioctls")
Signed-off-by: Thiébaud Weksteen <tweek@google.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Add support for extended permission rules in conditional policies.
Currently the kernel accepts such rules already, but evaluating a
security decision will hit a BUG() in
services_compute_xperms_decision(). Thus reject extended permission
rules in conditional policies for current policy versions.
Add a new policy version for this feature.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Tested-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm
Pull lsm updates from Paul Moore:
"Thirteen patches, all focused on moving away from the current 'secid'
LSM identifier to a richer 'lsm_prop' structure.
This move will help reduce the translation that is necessary in many
LSMs, offering better performance, and make it easier to support
different LSMs in the future"
* tag 'lsm-pr-20241112' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm:
lsm: remove lsm_prop scaffolding
netlabel,smack: use lsm_prop for audit data
audit: change context data from secid to lsm_prop
lsm: create new security_cred_getlsmprop LSM hook
audit: use an lsm_prop in audit_names
lsm: use lsm_prop in security_inode_getsecid
lsm: use lsm_prop in security_current_getsecid
audit: update shutdown LSM data
lsm: use lsm_prop in security_ipc_getsecid
audit: maintain an lsm_prop in audit_context
lsm: add lsmprop_to_secctx hook
lsm: use lsm_prop in security_audit_rule_match
lsm: add the lsm_prop data structure
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Remove the scaffold member from the lsm_prop. Remove the
remaining places it is being set.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: subj line tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Change the secid parameter of security_audit_rule_match
to a lsm_prop structure pointer. Pass the entry from the
lsm_prop structure for the approprite slot to the LSM hook.
Change the users of security_audit_rule_match to use the
lsm_prop instead of a u32. The scaffolding function lsmprop_init()
fills the structure with the value of the old secid, ensuring that
it is available to the appropriate module hook. The sources of
the secid, security_task_getsecid() and security_inode_getsecid(),
will be converted to use the lsm_prop structure later in the series.
At that point the use of lsmprop_init() is dropped.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: subject line tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Reuse the existing extended permissions infrastructure to support
policies based on the netlink message types.
A new policy capability "netlink_xperm" is introduced. When disabled,
the previous behaviour is preserved. That is, netlink_send will rely on
the permission mappings defined in nlmsgtab.c (e.g, nlmsg_read for
RTM_GETADDR on NETLINK_ROUTE). When enabled, the mappings are ignored
and the generic "nlmsg" permission is used instead.
The new "nlmsg" permission is an extended permission. The 16 bits of the
extended permission are mapped to the nlmsg_type field.
Example policy on Android, preventing regular apps from accessing the
device's MAC address and ARP table, but allowing this access to
privileged apps, looks as follows:
allow netdomain self:netlink_route_socket {
create read getattr write setattr lock append connect getopt
setopt shutdown nlmsg
};
allowxperm netdomain self:netlink_route_socket nlmsg ~{
RTM_GETLINK RTM_GETNEIGH RTM_GETNEIGHTBL
};
allowxperm priv_app self:netlink_route_socket nlmsg {
RTM_GETLINK RTM_GETNEIGH RTM_GETNEIGHTBL
};
The constants in the example above (e.g., RTM_GETLINK) are explicitly
defined in the policy.
It is possible to generate policies to support kernels that may or
may not have the capability enabled by generating a rule for each
scenario. For instance:
allow domain self:netlink_audit_socket nlmsg_read;
allow domain self:netlink_audit_socket nlmsg;
allowxperm domain self:netlink_audit_socket nlmsg { AUDIT_GET };
The approach of defining a new permission ("nlmsg") instead of relying
on the existing permissions (e.g., "nlmsg_read", "nlmsg_readpriv" or
"nlmsg_tty_audit") has been preferred because:
1. This is similar to the other extended permission ("ioctl");
2. With the new extended permission, the coarse-grained mapping is not
necessary anymore. It could eventually be removed, which would be
impossible if the extended permission was defined below these.
3. Having a single extra extended permission considerably simplifies
the implementation here and in libselinux.
Signed-off-by: Thiébaud Weksteen <tweek@google.com>
Signed-off-by: Bram Bonné <brambonne@google.com>
[PM: manual merge fixes for sock_skip_has_perm()]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Simplifies the logic for determining the security context type in
security_compute_sid, enhancing readability and efficiency.
Consolidates default type assignment logic next to type transition
checks, removing redundancy and improving code flow.
Signed-off-by: Canfeng Guo <guocanfeng@uniontech.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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A panic happens in ima_match_policy:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
PGD 42f873067 P4D 0
Oops: 0000 [#1] SMP NOPTI
CPU: 5 PID: 1286325 Comm: kubeletmonit.sh
Kdump: loaded Tainted: P
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS 0.0.0 02/06/2015
RIP: 0010:ima_match_policy+0x84/0x450
Code: 49 89 fc 41 89 cf 31 ed 89 44 24 14 eb 1c 44 39
7b 18 74 26 41 83 ff 05 74 20 48 8b 1b 48 3b 1d
f2 b9 f4 00 0f 84 9c 01 00 00 <44> 85 73 10 74 ea
44 8b 6b 14 41 f6 c5 01 75 d4 41 f6 c5 02 74 0f
RSP: 0018:ff71570009e07a80 EFLAGS: 00010207
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000200
RDX: ffffffffad8dc7c0 RSI: 0000000024924925 RDI: ff3e27850dea2000
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffffabfce739
R10: ff3e27810cc42400 R11: 0000000000000000 R12: ff3e2781825ef970
R13: 00000000ff3e2785 R14: 000000000000000c R15: 0000000000000001
FS: 00007f5195b51740(0000)
GS:ff3e278b12d40000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000010 CR3: 0000000626d24002 CR4: 0000000000361ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
ima_get_action+0x22/0x30
process_measurement+0xb0/0x830
? page_add_file_rmap+0x15/0x170
? alloc_set_pte+0x269/0x4c0
? prep_new_page+0x81/0x140
? simple_xattr_get+0x75/0xa0
? selinux_file_open+0x9d/0xf0
ima_file_check+0x64/0x90
path_openat+0x571/0x1720
do_filp_open+0x9b/0x110
? page_counter_try_charge+0x57/0xc0
? files_cgroup_alloc_fd+0x38/0x60
? __alloc_fd+0xd4/0x250
? do_sys_open+0x1bd/0x250
do_sys_open+0x1bd/0x250
do_syscall_64+0x5d/0x1d0
entry_SYSCALL_64_after_hwframe+0x65/0xca
Commit c7423dbdbc9e ("ima: Handle -ESTALE returned by
ima_filter_rule_match()") introduced call to ima_lsm_copy_rule within a
RCU read-side critical section which contains kmalloc with GFP_KERNEL.
This implies a possible sleep and violates limitations of RCU read-side
critical sections on non-PREEMPT systems.
Sleeping within RCU read-side critical section might cause
synchronize_rcu() returning early and break RCU protection, allowing a
UAF to happen.
The root cause of this issue could be described as follows:
| Thread A | Thread B |
| |ima_match_policy |
| | rcu_read_lock |
|ima_lsm_update_rule | |
| synchronize_rcu | |
| | kmalloc(GFP_KERNEL)|
| | sleep |
==> synchronize_rcu returns early
| kfree(entry) | |
| | entry = entry->next|
==> UAF happens and entry now becomes NULL (or could be anything).
| | entry->action |
==> Accessing entry might cause panic.
To fix this issue, we are converting all kmalloc that is called within
RCU read-side critical section to use GFP_ATOMIC.
Fixes: c7423dbdbc9e ("ima: Handle -ESTALE returned by ima_filter_rule_match()")
Cc: stable@vger.kernel.org
Signed-off-by: GUO Zihua <guozihua@huawei.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: fixed missing comment, long lines, !CONFIG_IMA_LSM_RULES case]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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The usage of printk_ratelimit() is discouraged, see
include/linux/printk.h, thus use pr_warn_ratelimited().
While editing this line address the following checkpatch warning:
WARNING: Integer promotion: Using 'h' in '%hu' is unnecessary
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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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.
Another small backwards compatibility measure is needed in
security_sid_to_context_core() for before the initial SELinux policy
load - see the code comment for explanation.
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Stephen Smalley <stephen.smalley.work@gmail.com>
[PM: edited comments based on feedback/discussion]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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The loops upper bound represent the number of permissions used (for the
current class or in general). The limit for this is 32, thus we might
left shift of one less, 31. Shifting a base of 1 results in undefined
behavior; use (u32)1 as base.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Security classes have only up to 32 permissions, hence using an u16 is
sufficient (while improving padding in struct selinux_mapping).
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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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>
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Update my email address; MAINTAINERS was updated some time ago.
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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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>
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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>
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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>
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Found by codespell(1)
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Linus observed that the pervasive passing of selinux_state pointers
introduced by me in commit aa8e712cee93 ("selinux: wrap global selinux
state") adds overhead and complexity without providing any
benefit. The original idea was to pave the way for SELinux namespaces
but those have not yet been implemented and there isn't currently
a concrete plan to do so. Remove the passing of the selinux_state
pointers, reverting to direct use of the single global selinux_state,
and likewise remove passing of child pointers like the selinux_avc.
The selinux_policy pointer remains as it is needed for atomic switching
of policies.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202303101057.mZ3Gv5fK-lkp@intel.com/
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinux updates from Paul Moore:
"Two SELinux patches: one increases the sleep time on deprecated
functionality, and one removes the indirect calls in the sidtab
context conversion code"
* tag 'selinux-pr-20221212' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
selinux: remove the sidtab context conversion indirect calls
selinux: increase the deprecation sleep for checkreqprot and runtime disable
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The sidtab conversion code has support for multiple context
conversion routines through the use of function pointers and
indirect calls. However, the reality is that all current users rely
on the same conversion routine: convert_context(). This patch does
away with this extra complexity and replaces the indirect calls
with direct function calls; allowing us to remove a layer of
obfuscation and create cleaner, more maintainable code.
Reviewed-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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The following warning was triggered on a hardware environment:
SELinux: Converting 162 SID table entries...
BUG: sleeping function called from invalid context at
__might_sleep+0x60/0x74 0x0
in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 5943, name: tar
CPU: 7 PID: 5943 Comm: tar Tainted: P O 5.10.0 #1
Call trace:
dump_backtrace+0x0/0x1c8
show_stack+0x18/0x28
dump_stack+0xe8/0x15c
___might_sleep+0x168/0x17c
__might_sleep+0x60/0x74
__kmalloc_track_caller+0xa0/0x7dc
kstrdup+0x54/0xac
convert_context+0x48/0x2e4
sidtab_context_to_sid+0x1c4/0x36c
security_context_to_sid_core+0x168/0x238
security_context_to_sid_default+0x14/0x24
inode_doinit_use_xattr+0x164/0x1e4
inode_doinit_with_dentry+0x1c0/0x488
selinux_d_instantiate+0x20/0x34
security_d_instantiate+0x70/0xbc
d_splice_alias+0x4c/0x3c0
ext4_lookup+0x1d8/0x200 [ext4]
__lookup_slow+0x12c/0x1e4
walk_component+0x100/0x200
path_lookupat+0x88/0x118
filename_lookup+0x98/0x130
user_path_at_empty+0x48/0x60
vfs_statx+0x84/0x140
vfs_fstatat+0x20/0x30
__se_sys_newfstatat+0x30/0x74
__arm64_sys_newfstatat+0x1c/0x2c
el0_svc_common.constprop.0+0x100/0x184
do_el0_svc+0x1c/0x2c
el0_svc+0x20/0x34
el0_sync_handler+0x80/0x17c
el0_sync+0x13c/0x140
SELinux: Context system_u:object_r:pssp_rsyslog_log_t:s0:c0 is
not valid (left unmapped).
It was found that within a critical section of spin_lock_irqsave in
sidtab_context_to_sid(), convert_context() (hooked by
sidtab_convert_params.func) might cause the process to sleep via
allocating memory with GFP_KERNEL, which is problematic.
As Ondrej pointed out [1], convert_context()/sidtab_convert_params.func
has another caller sidtab_convert_tree(), which is okay with GFP_KERNEL.
Therefore, fix this problem by adding a gfp_t argument for
convert_context()/sidtab_convert_params.func and pass GFP_KERNEL/_ATOMIC
properly in individual callers.
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20221018120111.1474581-1-gongruiqi1@huawei.com/ [1]
Reported-by: Tan Ninghao <tanninghao1@huawei.com>
Fixes: ee1a84fdfeed ("selinux: overhaul sidtab to fix bug and improve performance")
Signed-off-by: GONG, Ruiqi <gongruiqi1@huawei.com>
Reviewed-by: Ondrej Mosnacek <omosnace@redhat.com>
[PM: wrap long BUG() output lines, tweak subject line]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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In this function, it directly returns the result of __security_read_policy
without freeing the allocated memory in *data, cause memory leak issue,
so free the memory if __security_read_policy failed.
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
[PM: subject line tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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The arrays for the policy capability names, the initial sid identifiers
and the class and permission names are not changed at runtime. Declare
them const to avoid accidental modification.
Do not override the classmap and the initial sid list in the build time
script genheaders.
Check flose(3) is successful in genheaders.c, otherwise the written data
might be corrupted or incomplete.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: manual merge due to fuzz, minor style tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Add one level of indentation to the code block of the label mls_ops in
constraint_expr_eval(), to adjust the trailing break; to the parent
case: branch.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Get rid of redundant assignments which end up in values not being
read either because they are overwritten or the function ends.
Reported by clang-tidy [deadcode.DeadStores]
Signed-off-by: Michal Orzel <michalorzel.eng@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Those return statements at the end of a void function are redundant.
Reported by clang-tidy [readability-redundant-control-flow]
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Both the lvalue scontextp and rvalue scontext are of the type char*.
Drop the redundant explicit cast not needed since commit 9a59daa03df7
("SELinux: fix sleeping allocation in security_context_to_sid"), where
the type of scontext changed from const char* to char*.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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The path parameter is only read from in security_genfs_sid(),
selinux_policy_genfs_sid() and __security_genfs_sid(). Since a string
literal is passed as argument, declare the parameter const.
Also align the parameter names in the declaration and definition.
Reported by clang [-Wwrite-strings]:
security/selinux/hooks.c:553:60: error: passing 'const char [2]'
to parameter of type 'char *' discards qualifiers
[-Wincompatible-pointer-types-discards-qualifiers]
rc = security_genfs_sid(&selinux_state, ... , /,
^~~
./security/selinux/include/security.h:389:36: note: passing
argument to parameter 'name' here
const char *fstype, char *name, u16 sclass,
^
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: wrapped description]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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There were a number of places in the code where the function
definition did not match the associated comment block as well
at least one file where the appropriate header files were not
included (missing function declaration/prototype); this patch
fixes all of these issue such that building the SELinux code
with "W=1" is now warning free.
% make W=1 security/selinux/
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Current code contains a lot of racy patterns when converting an
ocontext's context structure to an SID. This is being done in a "lazy"
fashion, such that the SID is looked up in the SID table only when it's
first needed and then cached in the "sid" field of the ocontext
structure. However, this is done without any locking or memory barriers
and is thus unsafe.
Between commits 24ed7fdae669 ("selinux: use separate table for initial
SID lookup") and 66f8e2f03c02 ("selinux: sidtab reverse lookup hash
table"), this race condition lead to an actual observable bug, because a
pointer to the shared sid field was passed directly to
sidtab_context_to_sid(), which was using this location to also store an
intermediate value, which could have been read by other threads and
interpreted as an SID. In practice this caused e.g. new mounts to get a
wrong (seemingly random) filesystem context, leading to strange denials.
This bug has been spotted in the wild at least twice, see [1] and [2].
Fix the race condition by making all the racy functions use a common
helper that ensures the ocontext::sid accesses are made safely using the
appropriate SMP constructs.
Note that security_netif_sid() was populating the sid field of both
contexts stored in the ocontext, but only the first one was actually
used. The SELinux wiki's documentation on the "netifcon" policy
statement [3] suggests that using only the first context is intentional.
I kept only the handling of the first context here, as there is really
no point in doing the SID lookup for the unused one.
I wasn't able to reproduce the bug mentioned above on any kernel that
includes commit 66f8e2f03c02, even though it has been reported that the
issue occurs with that commit, too, just less frequently. Thus, I wasn't
able to verify that this patch fixes the issue, but it makes sense to
avoid the race condition regardless.
[1] https://github.com/containers/container-selinux/issues/89
[2] https://lists.fedoraproject.org/archives/list/selinux@lists.fedoraproject.org/thread/6DMTAMHIOAOEMUAVTULJD45JZU7IBAFM/
[3] https://selinuxproject.org/page/NetworkStatements#netifcon
Cc: stable@vger.kernel.org
Cc: Xinjie Zheng <xinjie@google.com>
Reported-by: Sujithra Periasamy <sujithra@google.com>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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audit_log_start() may return NULL in below cases:
- when audit is not initialized.
- when audit backlog limit exceeds.
After the call to audit_log_start() is made and then possible NULL audit
buffer argument is passed to audit_log_*() functions,
audit_log_*() functions return immediately in case of a NULL audit buffer
argument.
But it is optimal to return early when audit_log_start() returns NULL,
because it is not necessary for audit_log_*() functions to be called with
NULL audit buffer argument.
So add exception handling for possible NULL audit buffers where
return value can be handled from callers.
Signed-off-by: Austin Kim <austin.kim@lge.com>
[PM: tweak subject line]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Fix function name and add comment for parameter state in ss/services.c
kernel-doc to remove some warnings found by running make W=1 LLVM=1.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Variable rc is set to '-EINVAL' but this value is never read as
it is overwritten or not used later on, hence it is a redundant
assignment and can be removed.
Cleans up the following clang-analyzer warning:
security/selinux/ss/services.c:2103:3: warning: Value stored to 'rc' is
never read [clang-analyzer-deadcode.DeadStores].
security/selinux/ss/services.c:2079:2: warning: Value stored to 'rc' is
never read [clang-analyzer-deadcode.DeadStores].
security/selinux/ss/services.c:2071:2: warning: Value stored to 'rc' is
never read [clang-analyzer-deadcode.DeadStores].
security/selinux/ss/services.c:2062:2: warning: Value stored to 'rc' is
never read [clang-analyzer-deadcode.DeadStores].
security/selinux/ss/policydb.c:2592:3: warning: Value stored to 'rc' is
never read [clang-analyzer-deadcode.DeadStores].
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
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
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git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
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
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Move management of the superblock->sb_security blob out of the
individual security modules and into the security infrastructure.
Instead of allocating the blobs from within the modules, the modules
tell the infrastructure how much space is required, and the space is
allocated there.
Cc: John Johansen <john.johansen@canonical.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
Reviewed-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210422154123.13086-6-mic@digikod.net
Signed-off-by: James Morris <jamorris@linux.microsoft.com>
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