Commit Graph

77 Commits

Author SHA1 Message Date
Linus Torvalds 2d60d96b6f compiler-based memory initialization
- Consolidate memory initialization Kconfigs (Kees)
 - Implement support for Clang's stack variable auto-init (Alexander)
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Merge tag 'meminit-v5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull compiler-based variable initialization updates from Kees Cook:
 "This is effectively part of my gcc-plugins tree, but as this adds some
  Clang support, it felt weird to still call it "gcc-plugins". :)

  This consolidates Kconfig for the existing stack variable
  initialization (via structleak and stackleak gcc plugins) and adds
  Alexander Potapenko's support for Clang's new similar functionality.

  Summary:

   - Consolidate memory initialization Kconfigs (Kees)

   - Implement support for Clang's stack variable auto-init (Alexander)"

* tag 'meminit-v5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  security: Implement Clang's stack initialization
  security: Move stackleak config to Kconfig.hardening
  security: Create "kernel hardening" config area
2019-05-07 12:44:49 -07:00
Kees Cook 9f671e5815 security: Create "kernel hardening" config area
Right now kernel hardening options are scattered around various Kconfig
files. This can be a central place to collect these kinds of options
going forward. This is initially populated with the memory initialization
options from the gcc-plugins.

Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-04-24 13:45:49 -07:00
Kees Cook 2623c4fbe2 LSM: Revive CONFIG_DEFAULT_SECURITY_* for "make oldconfig"
Commit 70b62c2566 ("LoadPin: Initialize as ordered LSM") removed
CONFIG_DEFAULT_SECURITY_{SELINUX,SMACK,TOMOYO,APPARMOR,DAC} from
security/Kconfig and changed CONFIG_LSM to provide a fixed ordering as a
default value. That commit expected that existing users (upgrading from
Linux 5.0 and earlier) will edit CONFIG_LSM value in accordance with
their CONFIG_DEFAULT_SECURITY_* choice in their old kernel configs. But
since users might forget to edit CONFIG_LSM value, this patch revives
the choice (only for providing the default value for CONFIG_LSM) in order
to make sure that CONFIG_LSM reflects CONFIG_DEFAULT_SECURITY_* from their
old kernel configs.

Note that since TOMOYO can be fully stacked against the other legacy
major LSMs, when it is selected, it explicitly disables the other LSMs
to avoid them also initializing since TOMOYO does not expect this
currently.

Reported-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Fixes: 70b62c2566 ("LoadPin: Initialize as ordered LSM")
Co-developed-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: James Morris <james.morris@microsoft.com>
2019-03-29 14:08:49 -07:00
Petr Vorel b102c11e1a LSM: Update list of SECURITYFS users in Kconfig
Remove modules not using it (SELinux and SMACK aren't
the only ones not using it).

Signed-off-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: James Morris <james.morris@microsoft.com>
2019-03-01 09:52:54 -08:00
Micah Morton aeca4e2ca6 LSM: add SafeSetID module that gates setid calls
SafeSetID gates the setid family of syscalls to restrict UID/GID
transitions from a given UID/GID to only those approved by a
system-wide whitelist. These restrictions also prohibit the given
UIDs/GIDs from obtaining auxiliary privileges associated with
CAP_SET{U/G}ID, such as allowing a user to set up user namespace UID
mappings. For now, only gating the set*uid family of syscalls is
supported, with support for set*gid coming in a future patch set.

Signed-off-by: Micah Morton <mortonm@chromium.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.morris@microsoft.com>
2019-01-25 11:22:45 -08:00
Kees Cook d6aed64b74 Yama: Initialize as ordered LSM
This converts Yama from being a direct "minor" LSM into an ordered LSM.

Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
2019-01-08 13:18:43 -08:00
Kees Cook 70b62c2566 LoadPin: Initialize as ordered LSM
This converts LoadPin from being a direct "minor" LSM into an ordered LSM.

Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
2019-01-08 13:18:43 -08:00
Kees Cook 79f7865d84 LSM: Introduce "lsm=" for boottime LSM selection
Provide a way to explicitly choose LSM initialization order via the new
"lsm=" comma-separated list of LSMs.

Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-08 13:18:42 -08:00
Kees Cook 13e735c0e9 LSM: Introduce CONFIG_LSM
This provides a way to declare LSM initialization order via the new
CONFIG_LSM. Currently only non-major LSMs are recognized. This will
be expanded in future patches.

Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-08 13:18:42 -08:00
Masahiro Yamada 8636a1f967 treewide: surround Kconfig file paths with double quotes
The Kconfig lexer supports special characters such as '.' and '/' in
the parameter context. In my understanding, the reason is just to
support bare file paths in the source statement.

I do not see a good reason to complicate Kconfig for the room of
ambiguity.

The majority of code already surrounds file paths with double quotes,
and it makes sense since file paths are constant string literals.

Make it treewide consistent now.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
2018-12-22 00:25:54 +09:00
Joerg Roedel 61a6bd83ab Revert "x86/mm/legacy: Populate the user page-table with user pgd's"
This reverts commit 1f40a46cf4.

It turned out that this patch is not sufficient to enable PTI on 32 bit
systems with legacy 2-level page-tables. In this paging mode the huge-page
PTEs are in the top-level page-table directory, where also the mirroring to
the user-space page-table happens. So every huge PTE exits twice, in the
kernel and in the user page-table.

That means that accessed/dirty bits need to be fetched from two PTEs in
this mode to be safe, but this is not trivial to implement because it needs
changes to generic code just for the sake of enabling PTI with 32-bit
legacy paging. As all systems that need PTI should support PAE anyway,
remove support for PTI when 32-bit legacy paging is used.

Fixes: 7757d607c6 ('x86/pti: Allow CONFIG_PAGE_TABLE_ISOLATION for x86_32')
Reported-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: hpa@zytor.com
Cc: linux-mm@kvack.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Link: https://lkml.kernel.org/r/1536922754-31379-1-git-send-email-joro@8bytes.org
2018-09-14 17:08:45 +02:00
Linus Torvalds 8c479c2c0f - drop unneeded Kconfig "select BUG" (Kamal Mostafa)
- add "hardened_usercopy=off" rare performance needs (Chris von Recklinghausen)
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Merge tag 'hardened-usercopy-v4.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull hardened usercopy updates from Kees Cook:
 "This cleans up a minor Kconfig issue and adds a kernel boot option for
  disabling hardened usercopy for distro users that may have corner-case
  performance issues (e.g. high bandwidth small-packet UDP traffic).

  Summary:

   - drop unneeded Kconfig "select BUG" (Kamal Mostafa)

   - add "hardened_usercopy=off" rare performance needs (Chris von
     Recklinghausen)"

* tag 'hardened-usercopy-v4.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  usercopy: Allow boot cmdline disabling of hardening
  usercopy: Do not select BUG with HARDENED_USERCOPY
2018-08-15 08:45:54 -07:00
Joerg Roedel 7757d607c6 x86/pti: Allow CONFIG_PAGE_TABLE_ISOLATION for x86_32
Allow PTI to be compiled on x86_32.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Pavel Machek <pavel@ucw.cz>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: linux-mm@kvack.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Waiman Long <llong@redhat.com>
Cc: "David H . Gutteridge" <dhgutteridge@sympatico.ca>
Cc: joro@8bytes.org
Link: https://lkml.kernel.org/r/1531906876-13451-38-git-send-email-joro@8bytes.org
2018-07-20 01:11:48 +02:00
Kamal Mostafa 6aa56f4425 usercopy: Do not select BUG with HARDENED_USERCOPY
There is no need to "select BUG" when CONFIG_HARDENED_USERCOPY is enabled.
The kernel thread will always die, regardless of the CONFIG_BUG.

Signed-off-by: Kamal Mostafa <kamal@canonical.com>
[kees: tweak commit log]
Signed-off-by: Kees Cook <keescook@chromium.org>
2018-07-02 17:21:26 -07:00
Linus Torvalds 617aebe6a9 Currently, hardened usercopy performs dynamic bounds checking on slab
cache objects. This is good, but still leaves a lot of kernel memory
 available to be copied to/from userspace in the face of bugs. To further
 restrict what memory is available for copying, this creates a way to
 whitelist specific areas of a given slab cache object for copying to/from
 userspace, allowing much finer granularity of access control. Slab caches
 that are never exposed to userspace can declare no whitelist for their
 objects, thereby keeping them unavailable to userspace via dynamic copy
 operations. (Note, an implicit form of whitelisting is the use of constant
 sizes in usercopy operations and get_user()/put_user(); these bypass all
 hardened usercopy checks since these sizes cannot change at runtime.)
 
 This new check is WARN-by-default, so any mistakes can be found over the
 next several releases without breaking anyone's system.
 
 The series has roughly the following sections:
 - remove %p and improve reporting with offset
 - prepare infrastructure and whitelist kmalloc
 - update VFS subsystem with whitelists
 - update SCSI subsystem with whitelists
 - update network subsystem with whitelists
 - update process memory with whitelists
 - update per-architecture thread_struct with whitelists
 - update KVM with whitelists and fix ioctl bug
 - mark all other allocations as not whitelisted
 - update lkdtm for more sensible test overage
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Merge tag 'usercopy-v4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull hardened usercopy whitelisting from Kees Cook:
 "Currently, hardened usercopy performs dynamic bounds checking on slab
  cache objects. This is good, but still leaves a lot of kernel memory
  available to be copied to/from userspace in the face of bugs.

  To further restrict what memory is available for copying, this creates
  a way to whitelist specific areas of a given slab cache object for
  copying to/from userspace, allowing much finer granularity of access
  control.

  Slab caches that are never exposed to userspace can declare no
  whitelist for their objects, thereby keeping them unavailable to
  userspace via dynamic copy operations. (Note, an implicit form of
  whitelisting is the use of constant sizes in usercopy operations and
  get_user()/put_user(); these bypass all hardened usercopy checks since
  these sizes cannot change at runtime.)

  This new check is WARN-by-default, so any mistakes can be found over
  the next several releases without breaking anyone's system.

  The series has roughly the following sections:
   - remove %p and improve reporting with offset
   - prepare infrastructure and whitelist kmalloc
   - update VFS subsystem with whitelists
   - update SCSI subsystem with whitelists
   - update network subsystem with whitelists
   - update process memory with whitelists
   - update per-architecture thread_struct with whitelists
   - update KVM with whitelists and fix ioctl bug
   - mark all other allocations as not whitelisted
   - update lkdtm for more sensible test overage"

* tag 'usercopy-v4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (38 commits)
  lkdtm: Update usercopy tests for whitelisting
  usercopy: Restrict non-usercopy caches to size 0
  kvm: x86: fix KVM_XEN_HVM_CONFIG ioctl
  kvm: whitelist struct kvm_vcpu_arch
  arm: Implement thread_struct whitelist for hardened usercopy
  arm64: Implement thread_struct whitelist for hardened usercopy
  x86: Implement thread_struct whitelist for hardened usercopy
  fork: Provide usercopy whitelisting for task_struct
  fork: Define usercopy region in thread_stack slab caches
  fork: Define usercopy region in mm_struct slab caches
  net: Restrict unwhitelisted proto caches to size 0
  sctp: Copy struct sctp_sock.autoclose to userspace using put_user()
  sctp: Define usercopy region in SCTP proto slab cache
  caif: Define usercopy region in caif proto slab cache
  ip: Define usercopy region in IP proto slab cache
  net: Define usercopy region in struct proto slab cache
  scsi: Define usercopy region in scsi_sense_cache slab cache
  cifs: Define usercopy region in cifs_request slab cache
  vxfs: Define usercopy region in vxfs_inode slab cache
  ufs: Define usercopy region in ufs_inode_cache slab cache
  ...
2018-02-03 16:25:42 -08:00
Linus Torvalds f6cff79f1d Char/Misc driver patches for 4.16-rc1
Here is the big pull request for char/misc drivers for 4.16-rc1.
 
 There's a lot of stuff in here.  Three new driver subsystems were added
 for various types of hardware busses:
 	- siox
 	- slimbus
 	- soundwire
 as well as a new vboxguest subsystem for the VirtualBox hypervisor
 drivers.
 
 There's also big updates from the FPGA subsystem, lots of Android binder
 fixes, the usual handful of hyper-v updates, and lots of other smaller
 driver updates.
 
 All of these have been in linux-next for a long time, with no reported
 issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'char-misc-4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char/misc driver updates from Greg KH:
 "Here is the big pull request for char/misc drivers for 4.16-rc1.

  There's a lot of stuff in here. Three new driver subsystems were added
  for various types of hardware busses:

   - siox
   - slimbus
   - soundwire

  as well as a new vboxguest subsystem for the VirtualBox hypervisor
  drivers.

  There's also big updates from the FPGA subsystem, lots of Android
  binder fixes, the usual handful of hyper-v updates, and lots of other
  smaller driver updates.

  All of these have been in linux-next for a long time, with no reported
  issues"

* tag 'char-misc-4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (155 commits)
  char: lp: use true or false for boolean values
  android: binder: use VM_ALLOC to get vm area
  android: binder: Use true and false for boolean values
  lkdtm: fix handle_irq_event symbol for INT_HW_IRQ_EN
  EISA: Delete error message for a failed memory allocation in eisa_probe()
  EISA: Whitespace cleanup
  misc: remove AVR32 dependencies
  virt: vbox: Add error mapping for VERR_INVALID_NAME and VERR_NO_MORE_FILES
  soundwire: Fix a signedness bug
  uio_hv_generic: fix new type mismatch warnings
  uio_hv_generic: fix type mismatch warnings
  auxdisplay: img-ascii-lcd: add missing MODULE_DESCRIPTION/AUTHOR/LICENSE
  uio_hv_generic: add rescind support
  uio_hv_generic: check that host supports monitor page
  uio_hv_generic: create send and receive buffers
  uio: document uio_hv_generic regions
  doc: fix documentation about uio_hv_generic
  vmbus: add monitor_id and subchannel_id to sysfs per channel
  vmbus: fix ABI documentation
  uio_hv_generic: use ISR callback method
  ...
2018-02-01 10:31:17 -08:00
Kees Cook 2d891fbc3b usercopy: Allow strict enforcement of whitelists
This introduces CONFIG_HARDENED_USERCOPY_FALLBACK to control the
behavior of hardened usercopy whitelist violations. By default, whitelist
violations will continue to WARN() so that any bad or missing usercopy
whitelists can be discovered without being too disruptive.

If this config is disabled at build time or a system is booted with
"slab_common.usercopy_fallback=0", usercopy whitelists will BUG() instead
of WARN(). This is useful for admins that want to use usercopy whitelists
immediately.

Suggested-by: Matthew Garrett <mjg59@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
2018-01-15 12:07:48 -08:00
W. Trevor King a237f76268 security/Kconfig: Correct the Documentation reference for PTI
When the config option for PTI was added a reference to documentation was
added as well. But the documentation did not exist at that point. The final
documentation has a different file name.

Fix it up to point to the proper file.

Fixes: 385ce0ea ("x86/mm/pti: Add Kconfig")
Signed-off-by: W. Trevor King <wking@tremily.us>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-mm@kvack.org
Cc: linux-security-module@vger.kernel.org
Cc: James Morris <james.l.morris@oracle.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/3009cc8ccbddcd897ec1e0cb6dda524929de0d14.1515799398.git.wking@tremily.us
2018-01-14 11:42:10 +01:00
Thomas Gleixner 87faa0d9b4 x86/pti: Enable PTI by default
This really want's to be enabled by default. Users who know what they are
doing can disable it either in the config or on the kernel command line.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
2018-01-03 15:57:58 +01:00
Greg Kroah-Hartman b6a09416e8 Merge 4.15-rc6 into char-misc-next
We want the fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-02 14:46:35 +01:00
Dave Hansen 385ce0ea4c x86/mm/pti: Add Kconfig
Finally allow CONFIG_PAGE_TABLE_ISOLATION to be enabled.

PARAVIRT generally requires that the kernel not manage its own page tables.
It also means that the hypervisor and kernel must agree wholeheartedly
about what format the page tables are in and what they contain.
PAGE_TABLE_ISOLATION, unfortunately, changes the rules and they
can not be used together.

I've seen conflicting feedback from maintainers lately about whether they
want the Kconfig magic to go first or last in a patch series.  It's going
last here because the partially-applied series leads to kernels that can
not boot in a bunch of cases.  I did a run through the entire series with
CONFIG_PAGE_TABLE_ISOLATION=y to look for build errors, though.

[ tglx: Removed SMP and !PARAVIRT dependencies as they not longer exist ]

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Cc: linux-mm@kvack.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-12-23 21:13:01 +01:00
Kees Cook 22ec1a2aea /dev/mem: Add bounce buffer for copy-out
As done for /proc/kcore in

  commit df04abfd18 ("fs/proc/kcore.c: Add bounce buffer for ktext data")

this adds a bounce buffer when reading memory via /dev/mem. This
is needed to allow kernel text memory to be read out when built with
CONFIG_HARDENED_USERCOPY (which refuses to read out kernel text) and
without CONFIG_STRICT_DEVMEM (which would have refused to read any RAM
contents at all).

Since this build configuration isn't common (most systems with
CONFIG_HARDENED_USERCOPY also have CONFIG_STRICT_DEVMEM), this also tries
to inform Kconfig about the recommended settings.

This patch is modified from Brad Spengler/PaX Team's changes to /dev/mem
code in the last public patch of grsecurity/PaX based on my understanding
of the code. Changes or omissions from the original code are mine and
don't reflect the original grsecurity/PaX code.

Reported-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Fixes: f5509cc18d ("mm: Hardened usercopy")
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-18 15:59:17 +01:00
Daniel Micay 6974f0c455 include/linux/string.h: add the option of fortified string.h functions
This adds support for compiling with a rough equivalent to the glibc
_FORTIFY_SOURCE=1 feature, providing compile-time and runtime buffer
overflow checks for string.h functions when the compiler determines the
size of the source or destination buffer at compile-time.  Unlike glibc,
it covers buffer reads in addition to writes.

GNU C __builtin_*_chk intrinsics are avoided because they would force a
much more complex implementation.  They aren't designed to detect read
overflows and offer no real benefit when using an implementation based
on inline checks.  Inline checks don't add up to much code size and
allow full use of the regular string intrinsics while avoiding the need
for a bunch of _chk functions and per-arch assembly to avoid wrapper
overhead.

This detects various overflows at compile-time in various drivers and
some non-x86 core kernel code.  There will likely be issues caught in
regular use at runtime too.

Future improvements left out of initial implementation for simplicity,
as it's all quite optional and can be done incrementally:

* Some of the fortified string functions (strncpy, strcat), don't yet
  place a limit on reads from the source based on __builtin_object_size of
  the source buffer.

* Extending coverage to more string functions like strlcat.

* It should be possible to optionally use __builtin_object_size(x, 1) for
  some functions (C strings) to detect intra-object overflows (like
  glibc's _FORTIFY_SOURCE=2), but for now this takes the conservative
  approach to avoid likely compatibility issues.

* The compile-time checks should be made available via a separate config
  option which can be enabled by default (or always enabled) once enough
  time has passed to get the issues it catches fixed.

Kees said:
 "This is great to have. While it was out-of-tree code, it would have
  blocked at least CVE-2016-3858 from being exploitable (improper size
  argument to strlcpy()). I've sent a number of fixes for
  out-of-bounds-reads that this detected upstream already"

[arnd@arndb.de: x86: fix fortified memcpy]
  Link: http://lkml.kernel.org/r/20170627150047.660360-1-arnd@arndb.de
[keescook@chromium.org: avoid panic() in favor of BUG()]
  Link: http://lkml.kernel.org/r/20170626235122.GA25261@beast
[keescook@chromium.org: move from -mm, add ARCH_HAS_FORTIFY_SOURCE, tweak Kconfig help]
Link: http://lkml.kernel.org/r/20170526095404.20439-1-danielmicay@gmail.com
Link: http://lkml.kernel.org/r/1497903987-21002-8-git-send-email-keescook@chromium.org
Signed-off-by: Daniel Micay <danielmicay@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-12 16:26:03 -07:00
Daniel Jurgens d291f1a652 IB/core: Enforce PKey security on QPs
Add new LSM hooks to allocate and free security contexts and check for
permission to access a PKey.

Allocate and free a security context when creating and destroying a QP.
This context is used for controlling access to PKeys.

When a request is made to modify a QP that changes the port, PKey index,
or alternate path, check that the QP has permission for the PKey in the
PKey table index on the subnet prefix of the port. If the QP is shared
make sure all handles to the QP also have access.

Store which port and PKey index a QP is using. After the reset to init
transition the user can modify the port, PKey index and alternate path
independently. So port and PKey settings changes can be a merge of the
previous settings and the new ones.

In order to maintain access control if there are PKey table or subnet
prefix change keep a list of all QPs are using each PKey index on
each port. If a change occurs all QPs using that device and port must
have access enforced for the new cache settings.

These changes add a transaction to the QP modify process. Association
with the old port and PKey index must be maintained if the modify fails,
and must be removed if it succeeds. Association with the new port and
PKey index must be established prior to the modify and removed if the
modify fails.

1. When a QP is modified to a particular Port, PKey index or alternate
   path insert that QP into the appropriate lists.

2. Check permission to access the new settings.

3. If step 2 grants access attempt to modify the QP.

4a. If steps 2 and 3 succeed remove any prior associations.

4b. If ether fails remove the new setting associations.

If a PKey table or subnet prefix changes walk the list of QPs and
check that they have permission. If not send the QP to the error state
and raise a fatal error event. If it's a shared QP make sure all the
QPs that share the real_qp have permission as well. If the QP that
owns a security structure is denied access the security structure is
marked as such and the QP is added to an error_list. Once the moving
the QP to error is complete the security structure mark is cleared.

Maintaining the lists correctly turns QP destroy into a transaction.
The hardware driver for the device frees the ib_qp structure, so while
the destroy is in progress the ib_qp pointer in the ib_qp_security
struct is undefined. When the destroy process begins the ib_qp_security
structure is marked as destroying. This prevents any action from being
taken on the QP pointer. After the QP is destroyed successfully it
could still listed on an error_list wait for it to be processed by that
flow before cleaning up the structure.

If the destroy fails the QPs port and PKey settings are reinserted into
the appropriate lists, the destroying flag is cleared, and access control
is enforced, in case there were any cache changes during the destroy
flow.

To keep the security changes isolated a new file is used to hold security
related functionality.

Signed-off-by: Daniel Jurgens <danielj@mellanox.com>
Acked-by: Doug Ledford <dledford@redhat.com>
[PM: merge fixup in ib_verbs.h and uverbs_cmd.c]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-05-23 12:26:59 -04:00
James Morris d68c51e0b3 Sync to mainline for security submaintainers to work against 2017-05-22 16:32:40 +10:00
Geert Uytterhoeven 99c55fb18f security: Grammar s/allocates/allocated/
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2017-05-15 10:02:13 +10:00
Linus Torvalds 0302e28dee Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull security subsystem updates from James Morris:
 "Highlights:

  IMA:
   - provide ">" and "<" operators for fowner/uid/euid rules

  KEYS:
   - add a system blacklist keyring

   - add KEYCTL_RESTRICT_KEYRING, exposes keyring link restriction
     functionality to userland via keyctl()

  LSM:
   - harden LSM API with __ro_after_init

   - add prlmit security hook, implement for SELinux

   - revive security_task_alloc hook

  TPM:
   - implement contextual TPM command 'spaces'"

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (98 commits)
  tpm: Fix reference count to main device
  tpm_tis: convert to using locality callbacks
  tpm: fix handling of the TPM 2.0 event logs
  tpm_crb: remove a cruft constant
  keys: select CONFIG_CRYPTO when selecting DH / KDF
  apparmor: Make path_max parameter readonly
  apparmor: fix parameters so that the permission test is bypassed at boot
  apparmor: fix invalid reference to index variable of iterator line 836
  apparmor: use SHASH_DESC_ON_STACK
  security/apparmor/lsm.c: set debug messages
  apparmor: fix boolreturn.cocci warnings
  Smack: Use GFP_KERNEL for smk_netlbl_mls().
  smack: fix double free in smack_parse_opts_str()
  KEYS: add SP800-56A KDF support for DH
  KEYS: Keyring asymmetric key restrict method with chaining
  KEYS: Restrict asymmetric key linkage using a specific keychain
  KEYS: Add a lookup_restriction function for the asymmetric key type
  KEYS: Add KEYCTL_RESTRICT_KEYRING
  KEYS: Consistent ordering for __key_link_begin and restrict check
  KEYS: Add an optional lookup_restriction hook to key_type
  ...
2017-05-03 08:50:52 -07:00
Al Viro 2fefc97b21 HAVE_ARCH_HARDENED_USERCOPY is unconditional now
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-04-26 12:11:06 -04:00
James Morris dd0859dccb security: introduce CONFIG_SECURITY_WRITABLE_HOOKS
Subsequent patches will add RO hardening to LSM hooks, however, SELinux
still needs to be able to perform runtime disablement after init to handle
architectures where init-time disablement via boot parameters is not feasible.

Introduce a new kernel configuration parameter CONFIG_SECURITY_WRITABLE_HOOKS,
and a helper macro __lsm_ro_after_init, to handle this case.

Signed-off-by: James Morris <james.l.morris@oracle.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: Kees Cook <keescook@chromium.org>
2017-03-06 11:00:12 +11:00
Greg Kroah-Hartman 64e90a8acb Introduce STATIC_USERMODEHELPER to mediate call_usermodehelper()
Some usermode helper applications are defined at kernel build time, while
others can be changed at runtime.  To provide a sane way to filter these, add a
new kernel option "STATIC_USERMODEHELPER".  This option routes all
call_usermodehelper() calls through this binary, no matter what the caller
wishes to have called.

The new binary (by default set to /sbin/usermode-helper, but can be changed
through the STATIC_USERMODEHELPER_PATH option) can properly filter the
requested programs to be run by the kernel by looking at the first argument
that is passed to it.  All other options should then be passed onto the proper
program if so desired.

To disable all call_usermodehelper() calls by the kernel, set
STATIC_USERMODEHELPER_PATH to an empty string.

Thanks to Neil Brown for the idea of this feature.

Cc: NeilBrown <neilb@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-19 12:59:45 +01:00
Linus Torvalds 80a77045da - force check_object_size() to be inline too
- move page-spanning check behind a CONFIG since it's triggering false positives
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Merge tag 'usercopy-v4.8-rc6-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull more hardened usercopyfixes from Kees Cook:

 - force check_object_size() to be inline too

 - move page-spanning check behind a CONFIG since it's triggering false
   positives

[ Changed the page-spanning config option to depend on EXPERT in the
  merge.  That way it still gets build testing, and you can enable it if
  you want to, but is never enabled for "normal" configurations ]

* tag 'usercopy-v4.8-rc6-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  usercopy: remove page-spanning test for now
  usercopy: force check_object_size() inline
2016-09-07 14:03:49 -07:00
Kees Cook 8e1f74ea02 usercopy: remove page-spanning test for now
A custom allocator without __GFP_COMP that copies to userspace has been
found in vmw_execbuf_process[1], so this disables the page-span checker
by placing it behind a CONFIG for future work where such things can be
tracked down later.

[1] https://bugzilla.redhat.com/show_bug.cgi?id=1373326

Reported-by: Vinson Lee <vlee@freedesktop.org>
Fixes: f5509cc18d ("mm: Hardened usercopy")
Signed-off-by: Kees Cook <keescook@chromium.org>
2016-09-07 11:33:26 -07:00
Linus Torvalds 6040e57658 Make the hardened user-copy code depend on having a hardened allocator
The kernel test robot reported a usercopy failure in the new hardened
sanity checks, due to a page-crossing copy of the FPU state into the
task structure.

This happened because the kernel test robot was testing with SLOB, which
doesn't actually do the required book-keeping for slab allocations, and
as a result the hardening code didn't realize that the task struct
allocation was one single allocation - and the sanity checks fail.

Since SLOB doesn't even claim to support hardening (and you really
shouldn't use it), the straightforward solution is to just make the
usercopy hardening code depend on the allocator supporting it.

Reported-by: kernel test robot <xiaolong.ye@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-19 12:47:01 -07:00
Kees Cook f5509cc18d mm: Hardened usercopy
This is the start of porting PAX_USERCOPY into the mainline kernel. This
is the first set of features, controlled by CONFIG_HARDENED_USERCOPY. The
work is based on code by PaX Team and Brad Spengler, and an earlier port
from Casey Schaufler. Additional non-slab page tests are from Rik van Riel.

This patch contains the logic for validating several conditions when
performing copy_to_user() and copy_from_user() on the kernel object
being copied to/from:
- address range doesn't wrap around
- address range isn't NULL or zero-allocated (with a non-zero copy size)
- if on the slab allocator:
  - object size must be less than or equal to copy size (when check is
    implemented in the allocator, which appear in subsequent patches)
- otherwise, object must not span page allocations (excepting Reserved
  and CMA ranges)
- if on the stack
  - object must not extend before/after the current process stack
  - object must be contained by a valid stack frame (when there is
    arch/build support for identifying stack frames)
- object must not overlap with kernel text

Signed-off-by: Kees Cook <keescook@chromium.org>
Tested-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
2016-07-26 14:41:47 -07:00
Kees Cook 9b091556a0 LSM: LoadPin for kernel file loading restrictions
This LSM enforces that kernel-loaded files (modules, firmware, etc)
must all come from the same filesystem, with the expectation that
such a filesystem is backed by a read-only device such as dm-verity
or CDROM. This allows systems that have a verified and/or unchangeable
filesystem to enforce module and firmware loading restrictions without
needing to sign the files individually.

Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2016-04-21 10:47:27 +10:00
Kees Cook 730daa164e Yama: remove needless CONFIG_SECURITY_YAMA_STACKED
Now that minor LSMs can cleanly stack with major LSMs, remove the unneeded
config for Yama to be made to explicitly stack. Just selecting the main
Yama CONFIG will allow it to work, regardless of the major LSM. Since
distros using Yama are already forcing it to stack, this is effectively
a no-op change.

Additionally add MAINTAINERS entry.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2015-07-28 13:18:19 +10:00
Iulia Manda 2813893f8b kernel: conditionally support non-root users, groups and capabilities
There are a lot of embedded systems that run most or all of their
functionality in init, running as root:root.  For these systems,
supporting multiple users is not necessary.

This patch adds a new symbol, CONFIG_MULTIUSER, that makes support for
non-root users, non-root groups, and capabilities optional.  It is enabled
under CONFIG_EXPERT menu.

When this symbol is not defined, UID and GID are zero in any possible case
and processes always have all capabilities.

The following syscalls are compiled out: setuid, setregid, setgid,
setreuid, setresuid, getresuid, setresgid, getresgid, setgroups,
getgroups, setfsuid, setfsgid, capget, capset.

Also, groups.c is compiled out completely.

In kernel/capability.c, capable function was moved in order to avoid
adding two ifdef blocks.

This change saves about 25 KB on a defconfig build.  The most minimal
kernels have total text sizes in the high hundreds of kB rather than
low MB.  (The 25k goes down a bit with allnoconfig, but not that much.

The kernel was booted in Qemu.  All the common functionalities work.
Adding users/groups is not possible, failing with -ENOSYS.

Bloat-o-meter output:
add/remove: 7/87 grow/shrink: 19/397 up/down: 1675/-26325 (-24650)

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Iulia Manda <iulia.manda21@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15 16:35:22 -07:00
Colin Cross 530b099dfe security: select correct default LSM_MMAP_MIN_ADDR on arm on arm64
Binaries compiled for arm may run on arm64 if CONFIG_COMPAT is
selected.  Set LSM_MMAP_MIN_ADDR to 32768 if ARM64 && COMPAT to
prevent selinux failures launching 32-bit static executables that
are mapped at 0x8000.

Signed-off-by: Colin Cross <ccross@android.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Eric Paris <eparis@redhat.com>
Acked-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2014-02-05 14:59:14 +00:00
David Howells f0894940ae KEYS: Move the key config into security/keys/Kconfig
Move the key config into security/keys/Kconfig as there are going to be a lot
of key-related options.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Mimi Zohar <zohar@us.ibm.com>
2012-05-11 10:56:56 +01:00
Kees Cook 2d514487fa security: Yama LSM
This adds the Yama Linux Security Module to collect DAC security
improvements (specifically just ptrace restrictions for now) that have
existed in various forms over the years and have been carried outside the
mainline kernel by other Linux distributions like Openwall and grsecurity.

Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
2012-02-10 09:18:52 +11:00
Mimi Zohar 982e617a31 encrypted-keys: remove trusted-keys dependency
Encrypted keys are decrypted/encrypted using either a trusted-key or,
for those systems without a TPM, a user-defined key.  This patch
removes the trusted-keys and TCG_TPM dependencies.

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
2011-09-14 15:23:49 -04:00
Mimi Zohar f381c27222 integrity: move ima inode integrity data management
Move the inode integrity data(iint) management up to the integrity directory
in order to share the iint among the different integrity models.

Changelog:
- don't define MAX_DIGEST_SIZE
- rename several globally visible 'ima_' prefixed functions, structs,
  locks, etc to 'integrity_'
- replace '20' with SHA1_DIGEST_SIZE
- reflect location change in appropriate Kconfig and Makefiles
- remove unnecessary initialization of iint_initialized to 0
- rebased on current ima_iint.c
- define integrity_iint_store/lock as static

There should be no other functional changes.

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com>
2011-07-18 12:29:38 -04:00
Paul Gortmaker 5806896019 security: select correct default LSM_MMAP_MIN_ADDR on ARM.
The default for this is universally set to 64k, but the help says:

   For most ia64, ppc64 and x86 users with lots of address space
   a value of 65536 is reasonable and should cause no problems.
   On arm and other archs it should not be higher than 32768.

The text is right, in that we are seeing selinux-enabled ARM targets
that fail to launch /sbin/init because selinux blocks a memory map.
So select the right value if we know we are building ARM.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: James Morris <jmorris@namei.org>
2011-03-22 09:35:12 +11:00
Mimi Zohar 7e70cb4978 keys: add new key-type encrypted
Define a new kernel key-type called 'encrypted'. Encrypted keys are kernel
generated random numbers, which are encrypted/decrypted with a 'trusted'
symmetric key. Encrypted keys are created/encrypted/decrypted in the kernel.
Userspace only ever sees/stores encrypted blobs.

Changelog:
- bug fix: replaced master-key rcu based locking with semaphore
  (reported by David Howells)
- Removed memset of crypto_shash_digest() digest output
- Replaced verification of 'key-type:key-desc' using strcspn(), with
  one based on string constants.
- Moved documentation to Documentation/keys-trusted-encrypted.txt
- Replace hash with shash (based on comments by David Howells)
- Make lengths/counts size_t where possible (based on comments by David Howells)
  Could not convert most lengths, as crypto expects 'unsigned int'
  (size_t: on 32 bit is defined as unsigned int, but on 64 bit is unsigned long)
- Add 'const' where possible (based on comments by David Howells)
- allocate derived_buf dynamically to support arbitrary length master key
  (fixed by Roberto Sassu)
- wait until late_initcall for crypto libraries to be registered
- cleanup security/Kconfig
- Add missing 'update' keyword (reported/fixed by Roberto Sassu)
- Free epayload on failure to create key (reported/fixed by Roberto Sassu)
- Increase the data size limit (requested by Roberto Sassu)
- Crypto return codes are always 0 on success and negative on failure,
  remove unnecessary tests.
- Replaced kzalloc() with kmalloc()

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: David Safford <safford@watson.ibm.com>
Reviewed-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: James Morris <jmorris@namei.org>
2010-11-29 08:55:29 +11:00
Mimi Zohar d00a1c72f7 keys: add new trusted key-type
Define a new kernel key-type called 'trusted'.  Trusted keys are random
number symmetric keys, generated and RSA-sealed by the TPM.  The TPM
only unseals the keys, if the boot PCRs and other criteria match.
Userspace can only ever see encrypted blobs.

Based on suggestions by Jason Gunthorpe, several new options have been
added to support additional usages.

The new options are:
migratable=  designates that the key may/may not ever be updated
             (resealed under a new key, new pcrinfo or new auth.)

pcrlock=n    extends the designated PCR 'n' with a random value,
             so that a key sealed to that PCR may not be unsealed
             again until after a reboot.

keyhandle=   specifies the sealing/unsealing key handle.

keyauth=     specifies the sealing/unsealing key auth.

blobauth=    specifies the sealed data auth.

Implementation of a kernel reserved locality for trusted keys will be
investigated for a possible future extension.

Changelog:
- Updated and added examples to Documentation/keys-trusted-encrypted.txt
- Moved generic TPM constants to include/linux/tpm_command.h
  (David Howell's suggestion.)
- trusted_defined.c: replaced kzalloc with kmalloc, added pcrlock failure
  error handling, added const qualifiers where appropriate.
- moved to late_initcall
- updated from hash to shash (suggestion by David Howells)
- reduced worst stack usage (tpm_seal) from 530 to 312 bytes
- moved documentation to Documentation directory (suggestion by David Howells)
- all the other code cleanups suggested by David Howells
- Add pcrlock CAP_SYS_ADMIN dependency (based on comment by Jason Gunthorpe)
- New options: migratable, pcrlock, keyhandle, keyauth, blobauth (based on
  discussions with Jason Gunthorpe)
- Free payload on failure to create key(reported/fixed by Roberto Sassu)
- Updated Kconfig and other descriptions (based on Serge Hallyn's suggestion)
- Replaced kzalloc() with kmalloc() (reported by Serge Hallyn)

Signed-off-by: David Safford <safford@watson.ibm.com>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2010-11-29 08:55:25 +11:00
Dan Rosenberg eaf06b241b Restrict unprivileged access to kernel syslog
The kernel syslog contains debugging information that is often useful
during exploitation of other vulnerabilities, such as kernel heap
addresses.  Rather than futilely attempt to sanitize hundreds (or
thousands) of printk statements and simultaneously cripple useful
debugging functionality, it is far simpler to create an option that
prevents unprivileged users from reading the syslog.

This patch, loosely based on grsecurity's GRKERNSEC_DMESG, creates the
dmesg_restrict sysctl.  When set to "0", the default, no restrictions are
enforced.  When set to "1", only users with CAP_SYS_ADMIN can read the
kernel syslog via dmesg(8) or other mechanisms.

[akpm@linux-foundation.org: explain the config option in kernel.txt]
Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Eugene Teo <eugeneteo@kernel.org>
Acked-by: Kees Cook <kees.cook@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-12 07:55:32 -08:00
John Johansen f9ad1af53d AppArmor: Enable configuring and building of the AppArmor security module
Kconfig and Makefiles to enable configuration and building of AppArmor.

Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
2010-08-02 15:38:34 +10:00
Serge E. Hallyn b3a222e52e remove CONFIG_SECURITY_FILE_CAPABILITIES compile option
As far as I know, all distros currently ship kernels with default
CONFIG_SECURITY_FILE_CAPABILITIES=y.  Since having the option on
leaves a 'no_file_caps' option to boot without file capabilities,
the main reason to keep the option is that turning it off saves
you (on my s390x partition) 5k.  In particular, vmlinux sizes
came to:

without patch fscaps=n:		 	53598392
without patch fscaps=y:		 	53603406
with this patch applied:		53603342

with the security-next tree.

Against this we must weigh the fact that there is no simple way for
userspace to figure out whether file capabilities are supported,
while things like per-process securebits, capability bounding
sets, and adding bits to pI if CAP_SETPCAP is in pE are not supported
with SECURITY_FILE_CAPABILITIES=n, leaving a bit of a problem for
applications wanting to know whether they can use them and/or why
something failed.

It also adds another subtly different set of semantics which we must
maintain at the risk of severe security regressions.

So this patch removes the SECURITY_FILE_CAPABILITIES compile
option.  It drops the kernel size by about 50k over the stock
SECURITY_FILE_CAPABILITIES=y kernel, by removing the
cap_limit_ptraced_target() function.

Changelog:
	Nov 20: remove cap_limit_ptraced_target() as it's logic
		was ifndef'ed.

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: Andrew G. Morgan" <morgan@kernel.org>
Signed-off-by: James Morris <jmorris@namei.org>
2009-11-24 15:06:47 +11:00
John Johansen 6e65f92ff0 Config option to set a default LSM
The LSM currently requires setting a kernel parameter at boot to select
a specific LSM.  This adds a config option that allows specifying a default
LSM that is used unless overridden with the security= kernel parameter.
If the the config option is not set the current behavior of first LSM
to register is used.

Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2009-11-09 08:40:07 +11:00
James Morris 3e1c2515ac security: remove root_plug
Remove the root_plug example LSM code.  It's unmaintained and
    increasingly broken in various ways.

    Made at the 2009 Kernel Summit in Tokyo!

    Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
    Signed-off-by: James Morris <jmorris@namei.org>
2009-10-20 14:26:16 +09:00