Граф коммитов

262 Коммитов

Автор SHA1 Сообщение Дата
Davidlohr Bueso 23c8cec8cf ipc/msg: introduce msgctl(MSG_STAT_ANY)
There is a permission discrepancy when consulting msq ipc object
metadata between /proc/sysvipc/msg (0444) and the MSG_STAT shmctl
command.  The later does permission checks for the object vs S_IRUGO.
As such there can be cases where EACCESS is returned via syscall but the
info is displayed anyways in the procfs files.

While this might have security implications via info leaking (albeit no
writing to the msq metadata), this behavior goes way back and showing
all the objects regardless of the permissions was most likely an
overlook - so we are stuck with it.  Furthermore, modifying either the
syscall or the procfs file can cause userspace programs to break (ie
ipcs).  Some applications require getting the procfs info (without root
privileges) and can be rather slow in comparison with a syscall -- up to
500x in some reported cases for shm.

This patch introduces a new MSG_STAT_ANY command such that the msq ipc
object permissions are ignored, and only audited instead.  In addition,
I've left the lsm security hook checks in place, as if some policy can
block the call, then the user has no other choice than just parsing the
procfs file.

Link: http://lkml.kernel.org/r/20180215162458.10059-4-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Reported-by: Robert Kettler <robert.kettler@outlook.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11 10:28:37 -07:00
Davidlohr Bueso a280d6dc77 ipc/sem: introduce semctl(SEM_STAT_ANY)
There is a permission discrepancy when consulting shm ipc object
metadata between /proc/sysvipc/sem (0444) and the SEM_STAT semctl
command.  The later does permission checks for the object vs S_IRUGO.
As such there can be cases where EACCESS is returned via syscall but the
info is displayed anyways in the procfs files.

While this might have security implications via info leaking (albeit no
writing to the sma metadata), this behavior goes way back and showing
all the objects regardless of the permissions was most likely an
overlook - so we are stuck with it.  Furthermore, modifying either the
syscall or the procfs file can cause userspace programs to break (ie
ipcs).  Some applications require getting the procfs info (without root
privileges) and can be rather slow in comparison with a syscall -- up to
500x in some reported cases for shm.

This patch introduces a new SEM_STAT_ANY command such that the sem ipc
object permissions are ignored, and only audited instead.  In addition,
I've left the lsm security hook checks in place, as if some policy can
block the call, then the user has no other choice than just parsing the
procfs file.

Link: http://lkml.kernel.org/r/20180215162458.10059-3-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Reported-by: Robert Kettler <robert.kettler@outlook.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11 10:28:37 -07:00
Davidlohr Bueso c21a6970ae ipc/shm: introduce shmctl(SHM_STAT_ANY)
Patch series "sysvipc: introduce STAT_ANY commands", v2.

The following patches adds the discussed (see [1]) new command for shm
as well as for sems and msq as they are subject to the same
discrepancies for ipc object permission checks between the syscall and
via procfs.  These new commands are justified in that (1) we are stuck
with this semantics as changing syscall and procfs can break userland;
and (2) some users can benefit from performance (for large amounts of
shm segments, for example) from not having to parse the procfs
interface.

Once merged, I will submit the necesary manpage updates.  But I'm thinking
something like:

: diff --git a/man2/shmctl.2 b/man2/shmctl.2
: index 7bb503999941..bb00bbe21a57 100644
: --- a/man2/shmctl.2
: +++ b/man2/shmctl.2
: @@ -41,6 +41,7 @@
:  .\" 2005-04-25, mtk -- noted aberrant Linux behavior w.r.t. new
:  .\"	attaches to a segment that has already been marked for deletion.
:  .\" 2005-08-02, mtk: Added IPC_INFO, SHM_INFO, SHM_STAT descriptions.
: +.\" 2018-02-13, dbueso: Added SHM_STAT_ANY description.
:  .\"
:  .TH SHMCTL 2 2017-09-15 "Linux" "Linux Programmer's Manual"
:  .SH NAME
: @@ -242,6 +243,18 @@ However, the
:  argument is not a segment identifier, but instead an index into
:  the kernel's internal array that maintains information about
:  all shared memory segments on the system.
: +.TP
: +.BR SHM_STAT_ANY " (Linux-specific)"
: +Return a
: +.I shmid_ds
: +structure as for
: +.BR SHM_STAT .
: +However, the
: +.I shm_perm.mode
: +is not checked for read access for
: +.IR shmid ,
: +resembing the behaviour of
: +/proc/sysvipc/shm.
:  .PP
:  The caller can prevent or allow swapping of a shared
:  memory segment with the following \fIcmd\fP values:
: @@ -287,7 +300,7 @@ operation returns the index of the highest used entry in the
:  kernel's internal array recording information about all
:  shared memory segments.
:  (This information can be used with repeated
: -.B SHM_STAT
: +.B SHM_STAT/SHM_STAT_ANY
:  operations to obtain information about all shared memory segments
:  on the system.)
:  A successful
: @@ -328,7 +341,7 @@ isn't accessible.
:  \fIshmid\fP is not a valid identifier, or \fIcmd\fP
:  is not a valid command.
:  Or: for a
: -.B SHM_STAT
: +.B SHM_STAT/SHM_STAT_ANY
:  operation, the index value specified in
:  .I shmid
:  referred to an array slot that is currently unused.

This patch (of 3):

There is a permission discrepancy when consulting shm ipc object metadata
between /proc/sysvipc/shm (0444) and the SHM_STAT shmctl command.  The
later does permission checks for the object vs S_IRUGO.  As such there can
be cases where EACCESS is returned via syscall but the info is displayed
anyways in the procfs files.

While this might have security implications via info leaking (albeit no
writing to the shm metadata), this behavior goes way back and showing all
the objects regardless of the permissions was most likely an overlook - so
we are stuck with it.  Furthermore, modifying either the syscall or the
procfs file can cause userspace programs to break (ie ipcs).  Some
applications require getting the procfs info (without root privileges) and
can be rather slow in comparison with a syscall -- up to 500x in some
reported cases.

This patch introduces a new SHM_STAT_ANY command such that the shm ipc
object permissions are ignored, and only audited instead.  In addition,
I've left the lsm security hook checks in place, as if some policy can
block the call, then the user has no other choice than just parsing the
procfs file.

[1] https://lkml.org/lkml/2017/12/19/220

Link: http://lkml.kernel.org/r/20180215162458.10059-2-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Robert Kettler <robert.kettler@outlook.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11 10:28:37 -07:00
Linus Torvalds f8cf2f16a7 Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull integrity updates from James Morris:
 "A mixture of bug fixes, code cleanup, and continues to close
  IMA-measurement, IMA-appraisal, and IMA-audit gaps.

  Also note the addition of a new cred_getsecid LSM hook by Matthew
  Garrett:

     For IMA purposes, we want to be able to obtain the prepared secid
     in the bprm structure before the credentials are committed. Add a
     cred_getsecid hook that makes this possible.

  which is used by a new CREDS_CHECK target in IMA:

     In ima_bprm_check(), check with both the existing process
     credentials and the credentials that will be committed when the new
     process is started. This will not change behaviour unless the
     system policy is extended to include CREDS_CHECK targets -
     BPRM_CHECK will continue to check the same credentials that it did
     previously"

* 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  ima: Fallback to the builtin hash algorithm
  ima: Add smackfs to the default appraise/measure list
  evm: check for remount ro in progress before writing
  ima: Improvements in ima_appraise_measurement()
  ima: Simplify ima_eventsig_init()
  integrity: Remove unused macro IMA_ACTION_RULE_FLAGS
  ima: drop vla in ima_audit_measurement()
  ima: Fix Kconfig to select TPM 2.0 CRB interface
  evm: Constify *integrity_status_msg[]
  evm: Move evm_hmac and evm_hash from evm_main.c to evm_crypto.c
  fuse: define the filesystem as untrusted
  ima: fail signature verification based on policy
  ima: clear IMA_HASH
  ima: re-evaluate files on privileged mounted filesystems
  ima: fail file signature verification on non-init mounted filesystems
  IMA: Support using new creds in appraisal policy
  security: Add a cred_getsecid hook
2018-04-07 16:53:59 -07:00
Linus Torvalds 706ffc8c26 Merge branch 'next-smack' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull smack update from James Morris:
 "One small change for Automotive Grade Linux"

* 'next-smack' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  Smack: Handle CGROUP2 in the same way that CGROUP
2018-04-07 16:44:33 -07:00
Linus Torvalds 3612605a5a Merge branch 'next-general' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull general security layer updates from James Morris:

 - Convert security hooks from list to hlist, a nice cleanup, saving
   about 50% of space, from Sargun Dhillon.

 - Only pass the cred, not the secid, to kill_pid_info_as_cred and
   security_task_kill (as the secid can be determined from the cred),
   from Stephen Smalley.

 - Close a potential race in kernel_read_file(), by making the file
   unwritable before calling the LSM check (vs after), from Kees Cook.

* 'next-general' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  security: convert security hooks to use hlist
  exec: Set file unwritable before LSM check
  usb, signal, security: only pass the cred, not the secid, to kill_pid_info_as_cred and security_task_kill
2018-04-07 11:11:41 -07:00
Eric W. Biederman 0d79cbf83b ipc/smack: Tidy up from the change in type of the ipc security hooks
Rename the variables shp, sma, msq to isp. As that is how the code already
refers to those variables.

Collapse smack_of_shm, smack_of_sem, and smack_of_msq into smack_of_ipc,
as the three functions had become completely identical.

Collapse smack_shm_alloc_security, smack_sem_alloc_security and
smack_msg_queue_alloc_security into smack_ipc_alloc_security as the three
functions had become identical.

Collapse smack_shm_free_security, smack_sem_free_security and
smack_msg_queue_free_security into smack_ipc_free_security as the
three functions had become identical.

Requested-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-03-27 15:53:57 -05:00
James Morris d54d27c957 Merge branch 'smack-for-4.17' of git://github.com/cschaufler/next-smack into next-smack
Pull request from Casey.
2018-03-27 09:16:31 +11:00
Matthew Garrett 3ec3011326 security: Add a cred_getsecid hook
For IMA purposes, we want to be able to obtain the prepared secid in the
bprm structure before the credentials are committed. Add a cred_getsecid
hook that makes this possible.

Signed-off-by: Matthew Garrett <mjg59@google.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2018-03-23 06:31:11 -04:00
Eric W. Biederman d8c6e85432 msg/security: Pass kern_ipc_perm not msg_queue into the msg_queue security hooks
All of the implementations of security hooks that take msg_queue only
access q_perm the struct kern_ipc_perm member.  This means the
dependencies of the msg_queue security hooks can be simplified by
passing the kern_ipc_perm member of msg_queue.

Making this change will allow struct msg_queue to become private to
ipc/msg.c.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-03-22 21:22:26 -05:00
Eric W. Biederman 7191adff2a shm/security: Pass kern_ipc_perm not shmid_kernel into the shm security hooks
All of the implementations of security hooks that take shmid_kernel only
access shm_perm the struct kern_ipc_perm member.  This means the
dependencies of the shm security hooks can be simplified by passing
the kern_ipc_perm member of shmid_kernel..

Making this change will allow struct shmid_kernel to become private to ipc/shm.c.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-03-22 21:08:27 -05:00
Eric W. Biederman aefad9593e sem/security: Pass kern_ipc_perm not sem_array into the sem security hooks
All of the implementations of security hooks that take sem_array only
access sem_perm the struct kern_ipc_perm member.  This means the
dependencies of the sem security hooks can be simplified by passing
the kern_ipc_perm member of sem_array.

Making this change will allow struct sem and struct sem_array
to become private to ipc/sem.c.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-03-22 21:07:51 -05:00
Stephen Smalley 6b4f3d0105 usb, signal, security: only pass the cred, not the secid, to kill_pid_info_as_cred and security_task_kill
commit d178bc3a70 ("user namespace: usb:
 make usb urbs user namespace aware (v2)") changed kill_pid_info_as_uid
to kill_pid_info_as_cred, saving and passing a cred structure instead of
uids.  Since the secid can be obtained from the cred, drop the secid fields
from the usb_dev_state and async structures, and drop the secid argument to
kill_pid_info_as_cred.  Replace the secid argument to security_task_kill
with the cred.  Update SELinux, Smack, and AppArmor to use the cred, which
avoids the need for Smack and AppArmor to use a secid at all in this hook.
Further changes to Smack might still be required to take full advantage of
this change, since it should now be possible to perform capability
checking based on the supplied cred.  The changes to Smack and AppArmor
have only been compile-tested.

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Paul Moore <paul@paul-moore.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <james.morris@microsoft.com>
2018-03-07 09:05:53 +11:00
José Bollo 58c442f34c Smack: Handle CGROUP2 in the same way that CGROUP
The new file system CGROUP2 isn't actually handled
by smack. This changes makes Smack treat equally
CGROUP and CGROUP2 items.

Signed-off-by: José Bollo <jose.bollo@iot.bzh>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2018-02-28 09:27:12 -08:00
Casey Schaufler d19dfe58b7 Smack: Privilege check on key operations
Smack: Privilege check on key operations

Operations on key objects are subjected to Smack policy
even if the process is privileged. This is inconsistent
with the general behavior of Smack and may cause issues
with authentication by privileged daemons. This patch
allows processes with CAP_MAC_OVERRIDE to access keys
even if the Smack rules indicate otherwise.

Reported-by: Jose Bollo <jobol@nonadev.net>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2018-01-10 09:29:14 -08:00
Vasyl Gomonovych da49b5dad1 Smack: fix dereferenced before check
This patch fixes the warning reported by smatch:
security/smack/smack_lsm.c:2872 smack_socket_connect() warn:
variable dereferenced before check 'sock->sk' (see line 2869)

Signed-off-by: Vasyl Gomonovych <gomonovych@gmail.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-12-27 14:43:19 -08:00
Linus Torvalds 55b3a0cb5a Merge branch 'next-general' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull general security subsystem updates from James Morris:
 "TPM (from Jarkko):
   - essential clean up for tpm_crb so that ARM64 and x86 versions do
     not distract each other as much as before

   - /dev/tpm0 rejects now too short writes (shorter buffer than
     specified in the command header

   - use DMA-safe buffer in tpm_tis_spi

   - otherwise mostly minor fixes.

  Smack:
   - base support for overlafs

  Capabilities:
   - BPRM_FCAPS fixes, from Richard Guy Briggs:

     The audit subsystem is adding a BPRM_FCAPS record when auditing
     setuid application execution (SYSCALL execve). This is not expected
     as it was supposed to be limited to when the file system actually
     had capabilities in an extended attribute. It lists all
     capabilities making the event really ugly to parse what is
     happening. The PATH record correctly records the setuid bit and
     owner. Suppress the BPRM_FCAPS record on set*id.

  TOMOYO:
   - Y2038 timestamping fixes"

* 'next-general' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (28 commits)
  MAINTAINERS: update the IMA, EVM, trusted-keys, encrypted-keys entries
  Smack: Base support for overlayfs
  MAINTAINERS: remove David Safford as maintainer for encrypted+trusted keys
  tomoyo: fix timestamping for y2038
  capabilities: audit log other surprising conditions
  capabilities: fix logic for effective root or real root
  capabilities: invert logic for clarity
  capabilities: remove a layer of conditional logic
  capabilities: move audit log decision to function
  capabilities: use intuitive names for id changes
  capabilities: use root_priveleged inline to clarify logic
  capabilities: rename has_cap to has_fcap
  capabilities: intuitive names for cap gain status
  capabilities: factor out cap_bprm_set_creds privileged root
  tpm, tpm_tis: use ARRAY_SIZE() to define TPM_HID_USR_IDX
  tpm: fix duplicate inline declaration specifier
  tpm: fix type of a local variables in tpm_tis_spi.c
  tpm: fix type of a local variable in tpm2_map_command()
  tpm: fix type of a local variable in tpm2_get_cc_attrs_tbl()
  tpm-dev-common: Reject too short writes
  ...
2017-11-13 10:30:44 -08:00
Casey Schaufler d6d80cb57b Smack: Base support for overlayfs
Supply the Smack module hooks in support of overlayfs.
Ensure that the Smack label of new files gets the correct
value when a directory is transmuting. Original implementation
by Romanini Daniele, with a few tweaks added.

Signed-off-by: Romanini Daniele <daniele.romanini@aalto.fi>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2017-11-02 11:26:57 +11:00
Casey Schaufler 57e7ba04d4 lsm: fix smack_inode_removexattr and xattr_getsecurity memleak
security_inode_getsecurity() provides the text string value
of a security attribute. It does not provide a "secctx".
The code in xattr_getsecurity() that calls security_inode_getsecurity()
and then calls security_release_secctx() happened to work because
SElinux and Smack treat the attribute and the secctx the same way.
It fails for cap_inode_getsecurity(), because that module has no
secctx that ever needs releasing. It turns out that Smack is the
one that's doing things wrong by not allocating memory when instructed
to do so by the "alloc" parameter.

The fix is simple enough. Change the security_release_secctx() to
kfree() because it isn't a secctx being returned by
security_inode_getsecurity(). Change Smack to allocate the string when
told to do so.

Note: this also fixes memory leaks for LSMs which implement
inode_getsecurity but not release_secctx, such as capabilities.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reported-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: stable@vger.kernel.org
Signed-off-by: James Morris <james.l.morris@oracle.com>
2017-10-04 18:03:15 +11:00
Kees Cook 35b372b76f smack: Remove redundant pdeath_signal clearing
This removes the redundant pdeath_signal clearing in Smack: the check in
smack_bprm_committing_creds() matches the check in smack_bprm_set_creds()
(which used to be in the now-removed smack_bprm_securexec() hook) and
since secureexec is now being checked for clearing pdeath_signal, this
is redundant to the common exec code.

Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
2017-08-01 12:03:12 -07:00
Kees Cook ccbb6e1065 smack: Refactor to remove bprm_secureexec hook
The Smack bprm_secureexec hook can be merged with the bprm_set_creds
hook since it's dealing with the same information, and all of the details
are finalized during the first call to the bprm_set_creds hook via
prepare_binprm() (subsequent calls due to binfmt_script, etc, are ignored
via bprm->called_set_creds).

Here, the test can just happen at the end of the bprm_set_creds hook,
and the bprm_secureexec hook can be dropped.

Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
2017-08-01 12:03:07 -07:00
Kees Cook ddb4a1442d exec: Rename bprm->cred_prepared to called_set_creds
The cred_prepared bprm flag has a misleading name. It has nothing to do
with the bprm_prepare_cred hook, and actually tracks if bprm_set_creds has
been called. Rename this flag and improve its comment.

Cc: David Howells <dhowells@redhat.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: John Johansen <john.johansen@canonical.com>
Acked-by: James Morris <james.l.morris@oracle.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
2017-08-01 12:02:48 -07:00
Casey Schaufler 51d59af26f Smack: Safer check for a socket in file_receive
The check of S_ISSOCK() in smack_file_receive() is not
appropriate if the passed descriptor is a socket.

Reported-by: Stephen Smalley <sds@tyco.nsa.gov>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-06-01 09:27:12 -07:00
Tetsuo Handa c3c8dc9f13 smack: fix double free in smack_parse_opts_str()
smack_parse_opts_str() calls kfree(opts->mnt_opts) when kcalloc() for
opts->mnt_opts_flags failed. But it should not have called it because
security_free_mnt_opts() will call kfree(opts->mnt_opts).

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
fixes: 3bf2789cad ("smack: allow mount opts setting over filesystems with binary mount data")
Cc: Vivek Trivedi <t.vivek@samsung.com>
Cc: Amit Sahrawat <a.sahrawat@samsung.com>
Cc: Casey Schaufler <casey@schaufler-ca.com>
2017-04-04 15:41:15 -07:00
James Morris ca97d939db security: mark LSM hooks as __ro_after_init
Mark all of the registration hooks as __ro_after_init (via the
__lsm_ro_after_init macro).

Signed-off-by: James Morris <james.l.morris@oracle.com>
Acked-by:  Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Kees Cook <keescook@chromium.org>
2017-03-06 11:00:15 +11:00
Linus Torvalds f1ef09fde1 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull namespace updates from Eric Biederman:
 "There is a lot here. A lot of these changes result in subtle user
  visible differences in kernel behavior. I don't expect anything will
  care but I will revert/fix things immediately if any regressions show
  up.

  From Seth Forshee there is a continuation of the work to make the vfs
  ready for unpriviled mounts. We had thought the previous changes
  prevented the creation of files outside of s_user_ns of a filesystem,
  but it turns we missed the O_CREAT path. Ooops.

  Pavel Tikhomirov and Oleg Nesterov worked together to fix a long
  standing bug in the implemenation of PR_SET_CHILD_SUBREAPER where only
  children that are forked after the prctl are considered and not
  children forked before the prctl. The only known user of this prctl
  systemd forks all children after the prctl. So no userspace
  regressions will occur. Holding earlier forked children to the same
  rules as later forked children creates a semantic that is sane enough
  to allow checkpoing of processes that use this feature.

  There is a long delayed change by Nikolay Borisov to limit inotify
  instances inside a user namespace.

  Michael Kerrisk extends the API for files used to maniuplate
  namespaces with two new trivial ioctls to allow discovery of the
  hierachy and properties of namespaces.

  Konstantin Khlebnikov with the help of Al Viro adds code that when a
  network namespace exits purges it's sysctl entries from the dcache. As
  in some circumstances this could use a lot of memory.

  Vivek Goyal fixed a bug with stacked filesystems where the permissions
  on the wrong inode were being checked.

  I continue previous work on ptracing across exec. Allowing a file to
  be setuid across exec while being ptraced if the tracer has enough
  credentials in the user namespace, and if the process has CAP_SETUID
  in it's own namespace. Proc files for setuid or otherwise undumpable
  executables are now owned by the root in the user namespace of their
  mm. Allowing debugging of setuid applications in containers to work
  better.

  A bug I introduced with permission checking and automount is now
  fixed. The big change is to mark the mounts that the kernel initiates
  as a result of an automount. This allows the permission checks in sget
  to be safely suppressed for this kind of mount. As the permission
  check happened when the original filesystem was mounted.

  Finally a special case in the mount namespace is removed preventing
  unbounded chains in the mount hash table, and making the semantics
  simpler which benefits CRIU.

  The vfs fix along with related work in ima and evm I believe makes us
  ready to finish developing and merge fully unprivileged mounts of the
  fuse filesystem. The cleanups of the mount namespace makes discussing
  how to fix the worst case complexity of umount. The stacked filesystem
  fixes pave the way for adding multiple mappings for the filesystem
  uids so that efficient and safer containers can be implemented"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  proc/sysctl: Don't grab i_lock under sysctl_lock.
  vfs: Use upper filesystem inode in bprm_fill_uid()
  proc/sysctl: prune stale dentries during unregistering
  mnt: Tuck mounts under others instead of creating shadow/side mounts.
  prctl: propagate has_child_subreaper flag to every descendant
  introduce the walk_process_tree() helper
  nsfs: Add an ioctl() to return owner UID of a userns
  fs: Better permission checking for submounts
  exit: fix the setns() && PR_SET_CHILD_SUBREAPER interaction
  vfs: open() with O_CREAT should not create inodes with unknown ids
  nsfs: Add an ioctl() to return the namespace type
  proc: Better ownership of files for non-dumpable tasks in user namespaces
  exec: Remove LSM_UNSAFE_PTRACE_CAP
  exec: Test the ptracer's saved cred to see if the tracee can gain caps
  exec: Don't reset euid and egid when the tracee has CAP_SETUID
  inotify: Convert to using per-namespace limits
2017-02-23 20:33:51 -08:00
James Morris a2a15479d6 Merge branch 'stable-4.11' of git://git.infradead.org/users/pcmoore/selinux into next 2017-02-10 10:28:49 +11:00
James Morris 710584b9da Merge branch 'smack-for-4.11' of git://github.com/cschaufler/smack-next into next 2017-01-27 09:23:21 +11:00
Eric W. Biederman 9227dd2a84 exec: Remove LSM_UNSAFE_PTRACE_CAP
With previous changes every location that tests for
LSM_UNSAFE_PTRACE_CAP also tests for LSM_UNSAFE_PTRACE making the
LSM_UNSAFE_PTRACE_CAP redundant, so remove it.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2017-01-24 12:03:08 +13:00
Casey Schaufler d69dece5f5 LSM: Add /sys/kernel/security/lsm
I am still tired of having to find indirect ways to determine
what security modules are active on a system. I have added
/sys/kernel/security/lsm, which contains a comma separated
list of the active security modules. No more groping around
in /proc/filesystems or other clever hacks.

Unchanged from previous versions except for being updated
to the latest security next branch.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2017-01-19 13:18:29 +11:00
Stephen Smalley 3a2f5a59a6 security,selinux,smack: kill security_task_wait hook
As reported by yangshukui, a permission denial from security_task_wait()
can lead to a soft lockup in zap_pid_ns_processes() since it only expects
sys_wait4() to return 0 or -ECHILD. Further, security_task_wait() can
in general lead to zombies; in the absence of some way to automatically
reparent a child process upon a denial, the hook is not useful.  Remove
the security hook and its implementations in SELinux and Smack.  Smack
already removed its check from its hook.

Reported-by: yangshukui <yangshukui@huawei.com>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-01-12 11:10:57 -05:00
Seung-Woo Kim 83a1e53f39 Smack: ignore private inode for file functions
The access to fd from anon_inode is always failed because there is
no set xattr operations. So this patch fixes to ignore private
inode including anon_inode for file functions.

It was only ignored for smack_file_receive() to share dma-buf fd,
but dma-buf has other functions like ioctl and mmap.

Reference: https://lkml.org/lkml/2015/4/17/16

Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-01-10 09:47:20 -08:00
Rafal Krypa 805b65a80b Smack: fix d_instantiate logic for sockfs and pipefs
Since 4b936885a (v2.6.32) all inodes on sockfs and pipefs are disconnected.
It caused filesystem specific code in smack_d_instantiate to be skipped,
because all inodes on those pseudo filesystems were treated as root inodes.
As a result all sockfs inodes had the Smack label set to floor.

In most cases access checks for sockets use socket_smack data so the inode
label is not important. But there are special cases that were broken.
One example would be calling fcntl with F_SETOWN command on a socket fd.

Now smack_d_instantiate expects all pipefs and sockfs inodes to be
disconnected and has the logic in appropriate place.

Signed-off-by: Rafal Krypa <r.krypa@samsung.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-01-10 09:47:20 -08:00
Himanshu Shukla c9d238a18b SMACK: Use smk_tskacc() instead of smk_access() for proper logging
smack_file_open() is first checking the capability of calling subject,
this check will skip the SMACK logging for success case. Use smk_tskacc()
for proper logging and SMACK access check.

Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-01-10 09:47:20 -08:00
Vishal Goel 348dc288d4 Smack: Traverse the smack_known_list using list_for_each_entry_rcu macro
In smack_from_secattr function,"smack_known_list" is being traversed
using list_for_each_entry macro, although it is a rcu protected
structure. So it should be traversed using "list_for_each_entry_rcu"
macro to fetch the rcu protected entry.

Signed-off-by: Vishal Goel <vishal.goel@samsung.com>
Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-01-10 09:47:20 -08:00
Himanshu Shukla 3d4f673a69 SMACK: Free the i_security blob in inode using RCU
There is race condition issue while freeing the i_security blob in SMACK
module. There is existing condition where i_security can be freed while
inode_permission is called from path lookup on second CPU. There has been
observed the page fault with such condition. VFS code and Selinux module
takes care of this condition by freeing the inode and i_security field
using RCU via call_rcu(). But in SMACK directly the i_secuirty blob is
being freed. Use call_rcu() to fix this race condition issue.

Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com>
Signed-off-by: Vishal Goel <vishal.goel@samsung.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-01-10 09:47:20 -08:00
Himanshu Shukla d54a197964 SMACK: Delete list_head repeated initialization
smk_copy_rules() and smk_copy_relabel() are initializing list_head though
they have been initialized already in new_task_smack() function. Delete
repeated initialization.

Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-01-10 09:47:20 -08:00
Vishal Goel 0c96d1f532 Smack: Fix the issue of wrong SMACK label update in socket bind fail case
Fix the issue of wrong SMACK label (SMACK64IPIN) update when a second bind
call is made to same IP address & port, but with different SMACK label
(SMACK64IPIN) by second instance of server. In this case server returns
with "Bind:Address already in use" error but before returning, SMACK label
is updated in SMACK port-label mapping list inside smack_socket_bind() hook

To fix this issue a new check has been added in smk_ipv6_port_label()
function before updating the existing port entry. It checks whether the
socket for matching port entry is closed or not. If it is closed then it
means port is not bound and it is safe to update the existing port entry
else return if port is still getting used. For checking whether socket is
closed or not, one more field "smk_can_reuse" has been added in the
"smk_port_label" structure. This field will be set to '1' in
"smack_sk_free_security()" function which is called to free the socket
security blob when the socket is being closed. In this function, port entry
is searched in the SMACK port-label mapping list for the closing socket.
If entry is found then "smk_can_reuse" field is set to '1'.Initially
"smk_can_reuse" field is set to '0' in smk_ipv6_port_label() function after
creating a new entry in the list which indicates that socket is in use.

Signed-off-by: Vishal Goel <vishal.goel@samsung.com>
Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-01-10 09:47:20 -08:00
Vishal Goel 9d44c97384 Smack: Fix the issue of permission denied error in ipv6 hook
Permission denied error comes when 2 IPv6 servers are running and client
tries to connect one of them. Scenario is that both servers are using same
IP and port but different protocols(Udp and tcp). They are using different
SMACK64IPIN labels.Tcp server is using "test" and udp server is using
"test-in". When we try to run tcp client with SMACK64IPOUT label as "test",
then connection denied error comes. It should not happen since both tcp
server and client labels are same.This happens because there is no check
for protocol in smk_ipv6_port_label() function while searching for the
earlier port entry. It checks whether there is an existing port entry on
the basis of port only. So it updates the earlier port entry in the list.
Due to which smack label gets changed for earlier entry in the
"smk_ipv6_port_list" list and permission denied error comes.

Now a check is added for socket type also.Now if 2 processes use same
port  but different protocols (tcp or udp), then 2 different port entries
will be  added in the list. Similarly while checking smack access in
smk_ipv6_port_check() function,  port entry is searched on the basis of
both port and protocol.

Signed-off-by: Vishal Goel <vishal.goel@samsung.com>
Signed-off-by: Himanshu Shukla <Himanshu.sh@samsung.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-01-10 09:47:20 -08:00
Vishal Goel 3c7ce34271 SMACK: Add the rcu synchronization mechanism in ipv6 hooks
Add the rcu synchronization mechanism for accessing smk_ipv6_port_list
in smack IPv6 hooks. Access to the port list is vulnerable to a race
condition issue,it does not apply proper synchronization methods while
working on critical section. It is possible that when one thread is
reading the list, at the same time another thread is modifying the
same port list, which can cause the major problems.

To ensure proper synchronization between two threads, rcu mechanism
has been applied while accessing and modifying the port list. RCU will
also not affect the performance, as there are more accesses than
modification where RCU is most effective synchronization mechanism.

Signed-off-by: Vishal Goel <vishal.goel@samsung.com>
Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-01-10 09:47:20 -08:00
Stephen Smalley b21507e272 proc,security: move restriction on writing /proc/pid/attr nodes to proc
Processes can only alter their own security attributes via
/proc/pid/attr nodes.  This is presently enforced by each individual
security module and is also imposed by the Linux credentials
implementation, which only allows a task to alter its own credentials.
Move the check enforcing this restriction from the individual
security modules to proc_pid_attr_write() before calling the security hook,
and drop the unnecessary task argument to the security hook since it can
only ever be the current task.

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-01-09 10:07:31 -05:00
Linus Torvalds 9a19a6db37 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs updates from Al Viro:

 - more ->d_init() stuff (work.dcache)

 - pathname resolution cleanups (work.namei)

 - a few missing iov_iter primitives - copy_from_iter_full() and
   friends. Either copy the full requested amount, advance the iterator
   and return true, or fail, return false and do _not_ advance the
   iterator. Quite a few open-coded callers converted (and became more
   readable and harder to fuck up that way) (work.iov_iter)

 - several assorted patches, the big one being logfs removal

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  logfs: remove from tree
  vfs: fix put_compat_statfs64() does not handle errors
  namei: fold should_follow_link() with the step into not-followed link
  namei: pass both WALK_GET and WALK_MORE to should_follow_link()
  namei: invert WALK_PUT logics
  namei: shift interpretation of LOOKUP_FOLLOW inside should_follow_link()
  namei: saner calling conventions for mountpoint_last()
  namei.c: get rid of user_path_parent()
  switch getfrag callbacks to ..._full() primitives
  make skb_add_data,{_nocache}() and skb_copy_to_page_nocache() advance only on success
  [iov_iter] new primitives - copy_from_iter_full() and friends
  don't open-code file_inode()
  ceph: switch to use of ->d_init()
  ceph: unify dentry_operations instances
  lustre: switch to use of ->d_init()
2016-12-16 10:24:44 -08:00
Al Viro 450630975d don't open-code file_inode()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-04 18:29:28 -05:00
Casey Schaufler 152f91d4d1 Smack: Remove unnecessary smack_known_invalid
The invalid Smack label ("") and the Huh ("?") Smack label
serve the same purpose and having both is unnecessary.
While pulling out the invalid label it became clear that
the use of smack_from_secid() was inconsistent, so that
is repaired. The setting of inode labels to the invalid
label could never happen in a functional system, has
never been observed in the wild and is not what you'd
really want for a failure behavior in any case. That is
removed.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2016-11-15 09:34:39 -08:00
Tetsuo Handa 8c15d66e42 Smack: Use GFP_KERNEL for smack_parse_opts_str().
Since smack_parse_opts_str() is calling match_strdup() which uses
GFP_KERNEL, it is safe to use GFP_KERNEL from kcalloc() which is
called by smack_parse_opts_str().

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
2016-11-14 12:55:11 -08:00
Casey Schaufler 2e4939f702 Smack: ipv6 label match fix
The check for a deleted entry in the list of IPv6 host
addresses was being performed in the wrong place, leading
to most peculiar results in some cases. This puts the
check into the right place.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2016-11-10 11:22:18 -08:00
Himanshu Shukla b437aba85b SMACK: Fix the memory leak in smack_cred_prepare() hook
Memory leak in smack_cred_prepare()function.
smack_cred_prepare() hook returns error if there is error in allocating
memory in smk_copy_rules() or smk_copy_relabel() function.
If smack_cred_prepare() function returns error then the calling
function should call smack_cred_free() function for cleanup.
In smack_cred_free() function first credential is  extracted and
then all rules are deleted. In smack_cred_prepare() function security
field is assigned in the end when all function return success. But this
function may return before and memory will not be freed.

Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
2016-11-10 11:22:06 -08:00
Himanshu Shukla 7128ea159d SMACK: Do not apply star label in smack_setprocattr hook
Smack prohibits processes from using the star ("*") and web ("@") labels.
Checks have been added in other functions. In smack_setprocattr()
hook, only check for web ("@") label has been added and restricted
from applying web ("@") label.
Check for star ("*") label should also be added in smack_setprocattr()
hook. Return error should be "-EINVAL" not "-EPERM" as permission
is there for setting label but not the label value as star ("*") or
web ("@").

Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
2016-11-10 11:21:52 -08:00
Himanshu Shukla 2097f59920 smack: parse mnt opts after privileges check
In smack_set_mnt_opts()first the SMACK mount options are being
parsed and later it is being checked whether the user calling
mount has CAP_MAC_ADMIN capability.
This sequence of operationis will allow unauthorized user to add
SMACK labels in label list and may cause denial of security attack
by adding many labels by allocating kernel memory by unauthorized user.
Superblock smack flag is also being set as initialized though function
may return with EPERM error.
First check the capability of calling user then set the SMACK attributes
and smk_flags.

Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
2016-11-10 11:21:32 -08:00
jooseong lee 08382c9f6e Smack: Assign smack_known_web label for kernel thread's
Assign smack_known_web label for kernel thread's socket

Creating struct sock by sk_alloc function in various kernel subsystems
like bluetooth doesn't call smack_socket_post_create(). In such case,
received sock label is the floor('_') label and makes access deny.

Signed-off-by: jooseong lee <jooseong.lee@samsung.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
2016-11-04 17:42:57 -07:00