| Age | Commit message (Collapse) | Author |
|---|
|
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>
|
|
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>
|
|
The object context type `fs`, not to be confused with the well used
object context type `fscon`, was introduced in the initial git commit
1da177e4c3f4 ("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>
|
|
Commit 53f3517ae087 ("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: 53f3517ae087 ("selinux: do not leave dangling pointer behind")
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
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>
|
|
Found by codespell(1)
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: 12b29f34558b ("selinux: support deferred mapping of contexts")
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
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>
|
|
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
|
|
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>
|
|
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>
|
|
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>
|
|
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>
|
|
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>
|
|
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
|
|
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: c7c556f1e81b ("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>
|
|
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>
|
|
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>
|
|
Wrap macro into `do { } while (0)` to avoid Clang emitting warnings
about extra semicolons.
Similar to userspace commit
https://github.com/SELinuxProject/selinux/commit/9d85aa60d12e468e7fd510c2b5475b5299b71622
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: whitespace/indenting tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
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>
|
|
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>
|
|
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
...
|
|
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>
|
|
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>
|
|
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>
|
|
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>
|
|
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>
|
|
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>
|
|
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>
|
|
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>
|
|
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()
|
|
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>
|
|
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: 03414a49ad5f ("selinux: do not allocate hashtabs dynamically")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
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>
|
|
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>
|
|
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
|
|
It should not return 0 when SID 0 is assigned to isids.
This patch fixes it.
Cc: stable@vger.kernel.org
Fixes: e3e0b582c321a ("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>
|
|
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>
|
|
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>
|
|
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>
|
|
This makes the code a bit easier to reason about.
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
We can do the allocation + copying of expr.nodes in one go using
kmemdup().
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
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
|
|
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
|
|
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>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinux fixes from Paul Moore:
"Three SELinux fixes.
These fix known problems relating to (re)loading SELinux policy or
changing the policy booleans, and pass our test suite without problem"
* tag 'selinux-pr-20210409' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
selinux: fix race between old and new sidtab
selinux: fix cond_list corruption when changing booleans
selinux: make nslot handling in avtab more robust
|
|
Since commit 1b8b31a2e612 ("selinux: convert policy read-write lock to
RCU"), there is a small window during policy load where the new policy
pointer has already been installed, but some threads may still be
holding the old policy pointer in their read-side RCU critical sections.
This means that there may be conflicting attempts to add a new SID entry
to both tables via sidtab_context_to_sid().
See also (and the rest of the thread):
https://lore.kernel.org/selinux/CAFqZXNvfux46_f8gnvVvRYMKoes24nwm2n3sPbMjrB8vKTW00g@mail.gmail.com/
Fix this by installing the new policy pointer under the old sidtab's
spinlock along with marking the old sidtab as "frozen". Then, if an
attempt to add new entry to a "frozen" sidtab is detected, make
sidtab_context_to_sid() return -ESTALE to indicate that a new policy
has been installed and that the caller will have to abort the policy
transaction and try again after re-taking the policy pointer (which is
guaranteed to be a newer policy). This requires adding a retry-on-ESTALE
logic to all callers of sidtab_context_to_sid(), but fortunately these
are easy to determine and aren't that many.
This seems to be the simplest solution for this problem, even if it
looks somewhat ugly. Note that other places in the kernel (e.g.
do_mknodat() in fs/namei.c) use similar stale-retry patterns, so I think
it's reasonable.
Cc: stable@vger.kernel.org
Fixes: 1b8b31a2e612 ("selinux: convert policy read-write lock to RCU")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
Currently, duplicate_policydb_cond_list() first copies the whole
conditional avtab and then tries to link to the correct entries in
cond_dup_av_list() using avtab_search(). However, since the conditional
avtab may contain multiple entries with the same key, this approach
often fails to find the right entry, potentially leading to wrong rules
being activated/deactivated when booleans are changed.
To fix this, instead start with an empty conditional avtab and add the
individual entries one-by-one while building the new av_lists. This
approach leads to the correct result, since each entry is present in the
av_lists exactly once.
The issue can be reproduced with Fedora policy as follows:
# sesearch -s ftpd_t -t public_content_rw_t -c dir -p create -A
allow ftpd_t non_security_file_type:dir { add_name create getattr ioctl link lock open read remove_name rename reparent rmdir search setattr unlink watch watch_reads write }; [ ftpd_full_access ]:True
allow ftpd_t public_content_rw_t:dir { add_name create link remove_name rename reparent rmdir setattr unlink watch watch_reads write }; [ ftpd_anon_write ]:True
# setsebool ftpd_anon_write=off ftpd_connect_all_unreserved=off ftpd_connect_db=off ftpd_full_access=off
On fixed kernels, the sesearch output is the same after the setsebool
command:
# sesearch -s ftpd_t -t public_content_rw_t -c dir -p create -A
allow ftpd_t non_security_file_type:dir { add_name create getattr ioctl link lock open read remove_name rename reparent rmdir search setattr unlink watch watch_reads write }; [ ftpd_full_access ]:True
allow ftpd_t public_content_rw_t:dir { add_name create link remove_name rename reparent rmdir setattr unlink watch watch_reads write }; [ ftpd_anon_write ]:True
While on the broken kernels, it will be different:
# sesearch -s ftpd_t -t public_content_rw_t -c dir -p create -A
allow ftpd_t non_security_file_type:dir { add_name create getattr ioctl link lock open read remove_name rename reparent rmdir search setattr unlink watch watch_reads write }; [ ftpd_full_access ]:True
allow ftpd_t non_security_file_type:dir { add_name create getattr ioctl link lock open read remove_name rename reparent rmdir search setattr unlink watch watch_reads write }; [ ftpd_full_access ]:True
allow ftpd_t non_security_file_type:dir { add_name create getattr ioctl link lock open read remove_name rename reparent rmdir search setattr unlink watch watch_reads write }; [ ftpd_full_access ]:True
While there, also simplify the computation of nslots. This changes the
nslots values for nrules 2 or 3 to just two slots instead of 4, which
makes the sequence more consistent.
Cc: stable@vger.kernel.org
Fixes: c7c556f1e81b ("selinux: refactor changing booleans")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
