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Author SHA1 Message Date
Christian Göttsche
fd5a90ff1e selinux: avoid implicit conversions in mls code
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>
2023-08-03 22:19:57 -04:00
Christian Göttsche
c17c55c2d1 selinux: use identical iterator type in hashtab_duplicate()
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>
2023-08-03 22:19:56 -04:00
Christian Göttsche
f01dd59045 selinux: move debug functions into debug configuration
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>
2023-07-28 14:09:24 -04:00
Christian Göttsche
55a0e73806 selinux: introduce SECURITY_SELINUX_DEBUG configuration
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>
2023-07-20 16:21:52 -04:00
Stephen Smalley
0fe53224bf selinux: update my email address
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>
2023-07-19 11:27:02 -04:00
Christian Göttsche
e5faa839c3 selinux: add missing newlines in pr_err() statements
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>
2023-07-19 11:12:48 -04:00
Christian Göttsche
08a12b39e2 selinux: drop avtab_search()
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>
2023-07-19 11:04:28 -04:00
Christian Göttsche
0e83c9c6fb selinux: fix implicit conversions in the symtab
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>
2023-07-18 18:29:49 -04:00
Christian Göttsche
7128578c79 selinux: use consistent type for AV rule specifier
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>
2023-07-18 18:29:49 -04:00
Christian Göttsche
f785c54101 selinux: avoid avtab overflows
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>
2023-07-18 18:29:47 -04:00
Christian Göttsche
bbea03f474 selinux: check for multiplication overflow in put_entry()
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>
2023-07-18 18:29:46 -04:00
Ondrej Mosnacek
5b0eea835d selinux: introduce an initial SID for early boot processes
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>
2023-07-10 14:23:56 -04:00
Christian Göttsche
447a568800 selinux: avoid bool as identifier name
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>
2023-06-05 17:04:01 -04:00
Christian Göttsche
8bfbd046a3 selinux: deprecated fs ocon
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>
2023-05-23 15:37:56 -04:00
Christian Göttsche
ed99135f76 selinux: keep context struct members in sync
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>
2023-05-18 13:38:39 -04:00
Paul Moore
c52df19e37 selinux: small cleanups in selinux_audit_rule_init()
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>
2023-05-08 16:53:41 -04:00
Christian Göttsche
4158cb6000 selinux: declare read-only data arrays const
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>
2023-05-08 16:52:05 -04:00
Christian Göttsche
4595ae8c4a selinux: retain const qualifier on string literal in avtab_hash_eval()
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>
2023-05-08 16:49:14 -04:00
Christian Göttsche
3d9047a064 selinux: adjust typos in comments
Found by codespell(1)

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-05-08 16:44:01 -04:00
Christian Göttsche
53f3517ae0 selinux: do not leave dangling pointer behind
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>
2023-05-08 16:37:42 -04:00
Stephen Smalley
e67b79850f selinux: stop passing selinux_state pointers and their offspring
Linus observed that the pervasive passing of selinux_state pointers
introduced by me in commit aa8e712cee ("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>
2023-03-14 15:22:45 -04:00
Linus Torvalds
57888f7b95 selinux/stable-6.2 PR 20221212
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Merge tag 'selinux-pr-20221212' of 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
2022-12-13 09:32:05 -08:00
Paul Moore
048be15649 selinux: remove the sidtab context conversion indirect calls
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>
2022-11-09 11:00:49 -05:00
GONG, Ruiqi
abe3c63144 selinux: enable use of both GFP_KERNEL and GFP_ATOMIC in convert_context()
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: ee1a84fdfe ("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>
2022-10-19 09:55:53 -04:00
Christian Göttsche
6354324d8a selinux: declare read-only parameters const
Declare ebitmap, mls_level and mls_context parameters const where they
are only read from.  This allows callers to supply pointers to const
as arguments and increases readability.

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-08-30 17:14:36 -04:00
Xiu Jianfeng
15ec76fb29 selinux: Add boundary check in put_entry()
Just like next_entry(), boundary check is necessary to prevent memory
out-of-bound access.

Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-06-14 21:52:37 -04:00
Xiu Jianfeng
73de1befcc selinux: fix memleak in security_read_state_kernel()
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>
2022-06-13 19:31:53 -04:00
Linus Torvalds
efd1df1982 selinux/stable-5.19 PR 20220523
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Merge tag 'selinux-pr-20220523' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull selinux updates from Paul Moore:
 "We've got twelve patches queued for v5.19, with most being fairly
  minor. The highlights are below:

   - The checkreqprot and runtime disable knobs have been deprecated for
     some time with no active users that we can find. In an effort to
     move things along we are adding a pause when the knobs are used to
     help make the deprecation more noticeable in case anyone is still
     using these hacks in the shadows.

   - We've added the anonymous inode class name to the AVC audit records
     when anonymous inodes are involved. This should make writing policy
     easier when anonymous inodes are involved.

   - More constification work. This is fairly straightforward and the
     source of most of the diffstat.

   - The usual minor cleanups: remove unnecessary assignments, assorted
     style/checkpatch fixes, kdoc fixes, macro while-loop
     encapsulations, #include tweaks, etc"

* tag 'selinux-pr-20220523' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  security: declare member holding string literal const
  selinux: log anon inode class name
  selinux: declare data arrays const
  selinux: fix indentation level of mls_ops block
  selinux: include necessary headers in headers
  selinux: avoid extra semicolon
  selinux: update parameter documentation
  selinux: resolve checkpatch errors
  selinux: don't sleep when CONFIG_SECURITY_SELINUX_CHECKREQPROT_VALUE is true
  selinux: checkreqprot is deprecated, add some ssleep() discomfort
  selinux: runtime disable is deprecated, add some ssleep() discomfort
  selinux: Remove redundant assignments
2022-05-24 13:06:32 -07:00
Ondrej Mosnacek
6254bd3db3 selinux: fix bad cleanup on error in hashtab_duplicate()
The code attempts to free the 'new' pointer using kmem_cache_free(),
which is wrong because this function isn't responsible of freeing it.
Instead, the function should free new->htable and clear the contents of
*new (to prevent double-free).

Cc: stable@vger.kernel.org
Fixes: c7c556f1e8 ("selinux: refactor changing booleans")
Reported-by: Wander Lairson Costa <wander@redhat.com>
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-05-17 18:34:35 -04:00
Christian Göttsche
ded34574d4 selinux: declare data arrays const
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>
2022-05-03 15:53:49 -04:00
Christian Göttsche
a9029d9704 selinux: fix indentation level of mls_ops block
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>
2022-05-03 14:26:53 -04:00
Christian Göttsche
1d4e8036cb selinux: avoid extra semicolon
Wrap macro into `do { } while (0)` to avoid Clang emitting warnings
about extra semicolons.
Similar to userspace commit
9d85aa60d1

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: whitespace/indenting tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-05-03 14:07:11 -04:00
Christian Göttsche
ede17552b1 selinux: resolve checkpatch errors
Reported by checkpatch:

    security/selinux/nlmsgtab.c
    ---------------------------
    ERROR: that open brace { should be on the previous line
    #29: FILE: security/selinux/nlmsgtab.c:29:
    +static const struct nlmsg_perm nlmsg_route_perms[] =
    +{

    ERROR: that open brace { should be on the previous line
    #97: FILE: security/selinux/nlmsgtab.c:97:
    +static const struct nlmsg_perm nlmsg_tcpdiag_perms[] =
    +{

    ERROR: that open brace { should be on the previous line
    #105: FILE: security/selinux/nlmsgtab.c:105:
    +static const struct nlmsg_perm nlmsg_xfrm_perms[] =
    +{

    ERROR: that open brace { should be on the previous line
    #134: FILE: security/selinux/nlmsgtab.c:134:
    +static const struct nlmsg_perm nlmsg_audit_perms[] =
    +{

    security/selinux/ss/policydb.c
    ------------------------------
    ERROR: that open brace { should be on the previous line
    #318: FILE: security/selinux/ss/policydb.c:318:
    +static int (*destroy_f[SYM_NUM]) (void *key, void *datum, void *datap) =
    +{

    ERROR: that open brace { should be on the previous line
    #674: FILE: security/selinux/ss/policydb.c:674:
    +static int (*index_f[SYM_NUM]) (void *key, void *datum, void *datap) =
    +{

    ERROR: that open brace { should be on the previous line
    #1643: FILE: security/selinux/ss/policydb.c:1643:
    +static int (*read_f[SYM_NUM]) (struct policydb *p, struct symtab *s, void *fp) =
    +{

    ERROR: that open brace { should be on the previous line
    #3246: FILE: security/selinux/ss/policydb.c:3246:
    +                               void *datap) =
    +{

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-05-03 13:59:15 -04:00
Michal Orzel
0a9876f36b selinux: Remove redundant assignments
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>
2022-04-04 15:38:53 -04:00
Linus Torvalds
c269497d24 selinux/stable-5.18 PR 20220321
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Merge tag 'selinux-pr-20220321' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull selinux updates from Paul Moore:
 "We've got a number of SELinux patches queued up, the highlights are:

   - Fixup the security_fs_context_parse_param() LSM hook so it executes
     all of the LSM hook implementations unless a serious error occurs.

     We also correct the SELinux hook implementation so that it returns
     zero on success.

   - In addition to a few SELinux mount option parsing fixes, we
     simplified the parsing by moving it earlier in the process.

     The logic was that it was unlikely an admin/user would use the new
     mount API and not have the policy loaded before passing the SELinux
     options.

   - Properly fixed the LSM/SELinux/SCTP hooks with the addition of the
     security_sctp_assoc_established() hook.

     This work was done in conjunction with the netdev folks and should
     complete the move of the SCTP labeling from the endpoints to the
     associations.

   - Fixed a variety of sparse warnings caused by changes in the "__rcu"
     markings of some core kernel structures.

   - Ensure we access the superblock's LSM security blob using the
     stacking-safe accessors.

   - Added the ability for the kernel to always allow FIOCLEX and
     FIONCLEX if the "ioctl_skip_cloexec" policy capability is
     specified.

   - Various constifications improvements, type casting improvements,
     additional return value checks, and dead code/parameter removal.

   - Documentation fixes"

* tag 'selinux-pr-20220321' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux: (23 commits)
  selinux: shorten the policy capability enum names
  docs: fix 'make htmldocs' warning in SCTP.rst
  selinux: allow FIOCLEX and FIONCLEX with policy capability
  selinux: use correct type for context length
  selinux: drop return statement at end of void functions
  security: implement sctp_assoc_established hook in selinux
  security: add sctp_assoc_established hook
  selinux: parse contexts for mount options early
  selinux: various sparse fixes
  selinux: try to use preparsed sid before calling parse_sid()
  selinux: Fix selinux_sb_mnt_opts_compat()
  LSM: general protection fault in legacy_parse_param
  selinux: fix a type cast problem in cred_init_security()
  selinux: drop unused macro
  selinux: simplify cred_init_security
  selinux: do not discard const qualifier in cast
  selinux: drop unused parameter of avtab_insert_node
  selinux: drop cast to same type
  selinux: enclose macro arguments in parenthesis
  selinux: declare name parameter of hash_eval const
  ...
2022-03-21 20:47:54 -07:00
Christian Göttsche
5ea33af9d4 selinux: drop return statement at end of void functions
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>
2022-02-18 10:42:12 -05:00
Vratislav Bendel
186edf7e36 selinux: fix double free of cond_list on error paths
On error path from cond_read_list() and duplicate_policydb_cond_list()
the cond_list_destroy() gets called a second time in caller functions,
resulting in NULL pointer deref.  Fix this by resetting the
cond_list_len to 0 in cond_list_destroy(), making subsequent calls a
noop.

Also consistently reset the cond_list pointer to NULL after freeing.

Cc: stable@vger.kernel.org
Signed-off-by: Vratislav Bendel <vbendel@redhat.com>
[PM: fix line lengths in the description]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-02-02 11:02:10 -05:00
Christian Göttsche
b5e68162f8 selinux: drop unused macro
The macro _DEBUG_HASHES is nowhere used. The configuration DEBUG_HASHES
enables debugging of the SELinux hash tables, but the with an underscore
prefixed macro definition has no direct impact or any documentation.

Reported by clang [-Wunused-macros]

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-01-26 16:17:18 -05:00
Christian Göttsche
056945a96c selinux: drop unused parameter of avtab_insert_node
The parameter cur is not used in avtab_insert_node().

Reported by clang [-Wunused-parameter]

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-01-26 15:37:27 -05:00
Christian Göttsche
0b3c2b3dc9 selinux: drop cast to same type
Both the lvalue scontextp and rvalue scontext are of the type char*.
Drop the redundant explicit cast not needed since commit 9a59daa03d
("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>
2022-01-26 15:25:47 -05:00
Christian Göttsche
9e2fe574c0 selinux: enclose macro arguments in parenthesis
Enclose the macro arguments in parenthesis to avoid potential evaluation
order issues.

Note the xperm and ebitmap macros are still not side-effect safe due to
double evaluation.

Reported by clang-tidy [bugprone-macro-parentheses]

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-01-26 15:13:58 -05:00
Christian Göttsche
d3b1161f29 selinux: declare name parameter of hash_eval const
String literals are passed as second argument to hash_eval(). Also the
parameter is already declared const in the DEBUG_HASHES configuration.

Reported by clang [-Wwrite-strings]:

    security/selinux/ss/policydb.c:1881:26: error: passing
      'const char [8]' to parameter of type 'char *' discards
      qualifiers
            hash_eval(&p->range_tr, rangetr);
                                    ^~~~~~~~~
    security/selinux/ss/policydb.c:707:55: note: passing argument to
      parameter 'hash_name' here
    static inline void hash_eval(struct hashtab *h, char *hash_name)
                                                          ^
    security/selinux/ss/policydb.c:2099:32: error: passing
      'const char [11]' to parameter of type 'char *' discards
      qualifiers
            hash_eval(&p->filename_trans, filenametr);
                                          ^~~~~~~~~~~~
    security/selinux/ss/policydb.c:707:55: note: passing argument to
      parameter 'hash_name' here
    static inline void hash_eval(struct hashtab *h, char *hash_name)
                                                          ^

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: line wrapping in description]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-01-26 13:54:25 -05:00
Christian Göttsche
08df49054f selinux: declare path parameters of _genfs_sid const
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>
2022-01-25 19:59:52 -05:00
Linus Torvalds
a135ce4400 selinux/stable-5.17 PR 20220110
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Merge tag 'selinux-pr-20220110' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull selinux updates from Paul Moore:
 "Nothing too significant, but five SELinux patches for v5.17 that do
  the following:

   - Harden the code through additional use of the struct_size() macro

   - Plug some memory leaks

   - Clean up the code via removal of the security_add_mnt_opt() LSM
     hook and minor tweaks to selinux_add_opt()

   - Rename security_task_getsecid_subj() to better reflect its actual
     behavior/use - now called security_current_getsecid_subj()"

* tag 'selinux-pr-20220110' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: minor tweaks to selinux_add_opt()
  selinux: fix potential memleak in selinux_add_opt()
  security,selinux: remove security_add_mnt_opt()
  selinux: Use struct_size() helper in kmalloc()
  lsm: security_task_getsecid_subj() -> security_current_getsecid_subj()
2022-01-11 13:03:06 -08:00
Xiu Jianfeng
5fe3757289 selinux: Use struct_size() helper in kmalloc()
Make use of struct_size() helper instead of an open-coded calculation.

Link: https://github.com/KSPP/linux/issues/160
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-12-05 21:58:32 -05:00
Ondrej Mosnacek
dc27f3c5d1 selinux: fix NULL-pointer dereference when hashtab allocation fails
When the hash table slot array allocation fails in hashtab_init(),
h->size is left initialized with a non-zero value, but the h->htable
pointer is NULL. This may then cause a NULL pointer dereference, since
the policydb code relies on the assumption that even after a failed
hashtab_init(), hashtab_map() and hashtab_destroy() can be safely called
on it. Yet, these detect an empty hashtab only by looking at the size.

Fix this by making sure that hashtab_init() always leaves behind a valid
empty hashtab when the allocation fails.

Cc: stable@vger.kernel.org
Fixes: 03414a49ad ("selinux: do not allocate hashtabs dynamically")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-11-19 16:11:39 -05:00
Paul Moore
e9fd729293 selinux: fix all of the W=1 build warnings
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>
2021-10-13 16:31:51 -04:00
Ondrej Mosnacek
cbfcd13be5 selinux: fix race condition when computing ocontext SIDs
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 24ed7fdae6 ("selinux: use separate table for initial
SID lookup") and 66f8e2f03c ("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 66f8e2f03c, 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: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-10-11 19:18:04 -04:00
Linus Torvalds
befa491ce6 Merge tag 'selinux-pr-20210830' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinux update from Paul Moore:
 "We've got an unusually small SELinux pull request for v5.15 that
  consists of only one (?!) patch that is really pretty minor when you
  look at it.

  Unsurprisingly it passes all of our tests and merges cleanly on top of
  your tree right now, please merge this for v5.15"

* tag 'selinux-pr-20210830' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: return early for possible NULL audit buffers
2021-08-31 12:53:34 -07:00
Xiu Jianfeng
4c156084da selinux: correct the return value when loads initial sids
It should not return 0 when SID 0 is assigned to isids.
This patch fixes it.

Cc: stable@vger.kernel.org
Fixes: e3e0b582c3 ("selinux: remove unused initial SIDs and improve handling")
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
[PM: remove changelog from description]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-08-02 09:59:50 -04:00