Commit graph

30 commits

Author SHA1 Message Date
Kees Cook
75f98b7ab7 lkdtm: Constify the crashtypes table
Since nothing in the crashtypes table ever changes, mark it const. Adds
some missing "static" markings as well.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-20 15:51:39 +02:00
Kees Cook
31c5c870a1 lkdtm: Convert from jprobe to kprobe
The jprobe subsystem is being removed, so convert to using kprobe instead.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-20 15:50:55 +02:00
Kees Cook
93e78c6b14 lkdtm: Add -fstack-protector-strong test
There wasn't an LKDTM test to distinguish between -fstack-protector and
-fstack-protector-strong in use. This adds CORRUPT_STACK_STRONG to see
the difference. Also adjusts the stack-clobber value to 0xff so execution
won't potentially jump into userspace when the stack protector is missing.

Signed-off-by: Kees Cook <keescook@chromium.org>
2017-08-15 12:27:35 -07:00
Kees Cook
7b25a85c9d lkdtm: Test VMAP_STACK allocates leading/trailing guard pages
Two new tests STACK_GUARD_PAGE_LEADING and STACK_GUARD_PAGE_TRAILING
attempt to read the byte before and after, respectively, of the current
stack frame, which should fault.

Signed-off-by: Kees Cook <keescook@chromium.org>
2017-08-04 13:04:21 -07:00
Kees Cook
c7fea48876 lkdtm: Provide timing tests for atomic_t vs refcount_t
While not a crash test, this does provide two tight atomic_t and
refcount_t loops for performance comparisons:

	cd /sys/kernel/debug/provoke-crash
	perf stat -B -- cat <(echo ATOMIC_TIMING) > DIRECT
	perf stat -B -- cat <(echo REFCOUNT_TIMING) > DIRECT

Looking a CPU cycles is the best way to example the fast-path (rather
than instruction counts, since conditional jumps will be executed but
will be negligible due to branch-prediction).

Signed-off-by: Kees Cook <keescook@chromium.org>
2017-07-26 14:38:04 -07:00
Kees Cook
95925c99b9 lkdtm: Provide more complete coverage for REFCOUNT tests
The existing REFCOUNT_* LKDTM tests were designed only for testing a narrow
portion of CONFIG_REFCOUNT_FULL. This moves the tests to their own file and
expands their testing to poke each boundary condition.

Since the protections (CONFIG_REFCOUNT_FULL and x86-fast) use different
saturation values and reach-zero behavior, those have to be build-time
set so the tests can actually validate things are happening at the
right places.

Notably, the x86-fast protection will fail REFCOUNT_INC_ZERO and
REFCOUNT_ADD_ZERO since those conditions are not checked (only overflow
is critical to protecting refcount_t). CONFIG_REFCOUNT_FULL will warn for
each REFCOUNT_*_NEGATIVE test since it provides zero-pinning behaviors
(which allows it to pass REFCOUNT_INC_ZERO and REFCOUNT_ADD_ZERO).

Signed-off-by: Kees Cook <keescook@chromium.org>
2017-07-26 14:38:03 -07:00
Kees Cook
e22aa9d781 lkdtm: add bad USER_DS test
This adds CORRUPT_USER_DS to check that the get_fs() test on syscall
return (via __VERIFY_PRE_USERMODE_STATE) still sees USER_DS. Since
trying to deal with values other than USER_DS and KERNEL_DS across all
architectures in a safe way is not sensible, this sets KERNEL_DS, but
since that could be extremely dangerous if the protection is not present,
it also raises SIGKILL for current, so that no matter what, the process
will die. A successful test will be visible with a BUG(), like all the
other LKDTM tests.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-08 17:56:02 +02:00
Linus Torvalds
e30aee9e10 char/misc driver patches for 4.11-rc1
Here is the big char/misc driver patchset for 4.11-rc1.
 
 Lots of different driver subsystems updated here.  Rework for the hyperv
 subsystem to handle new platforms better, mei and w1 and extcon driver
 updates, as well as a number of other "minor" driver updates.  Full
 details are in the shortlog below.
 
 All of these have been in linux-next for a while with no reported
 issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'char-misc-4.11-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 char/misc driver patchset for 4.11-rc1.

  Lots of different driver subsystems updated here: rework for the
  hyperv subsystem to handle new platforms better, mei and w1 and extcon
  driver updates, as well as a number of other "minor" driver updates.

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

* tag 'char-misc-4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (169 commits)
  goldfish: Sanitize the broken interrupt handler
  x86/platform/goldfish: Prevent unconditional loading
  vmbus: replace modulus operation with subtraction
  vmbus: constify parameters where possible
  vmbus: expose hv_begin/end_read
  vmbus: remove conditional locking of vmbus_write
  vmbus: add direct isr callback mode
  vmbus: change to per channel tasklet
  vmbus: put related per-cpu variable together
  vmbus: callback is in softirq not workqueue
  binder: Add support for file-descriptor arrays
  binder: Add support for scatter-gather
  binder: Add extra size to allocator
  binder: Refactor binder_transact()
  binder: Support multiple /dev instances
  binder: Deal with contexts in debugfs
  binder: Support multiple context managers
  binder: Split flat_binder_object
  auxdisplay: ht16k33: remove private workqueue
  auxdisplay: ht16k33: rework input device initialization
  ...
2017-02-22 11:38:22 -08:00
Kees Cook
ff86b30010 lkdtm: Convert to refcount_t testing
Since we'll be using refcount_t instead of atomic_t for refcounting,
change the LKDTM tests to reflect the new interface and test conditions.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Hans Liljestrand <ishkamiel@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: arnd@arndb.de
Cc: dhowells@redhat.com
Cc: dwindsor@gmail.com
Cc: elena.reshetova@intel.com
Cc: gregkh@linuxfoundation.org
Cc: h.peter.anvin@intel.com
Cc: kernel-hardening@lists.openwall.com
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1486164412-7338-3-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-10 09:04:20 +01:00
Juerg Haefliger
9ba6057363 lkdtm: Fix Oops when unloading the module
No jprobe is registered when the module is loaded without specifying a
crashpoint that uses a jprobe. At the moment, we unconditionally try to
unregister the jprobe on module unload which results in an Oops. Add a
check to fix this.

Signed-off-by: Juerg Haefliger <juerg.haefliger@hpe.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-25 11:41:44 +01:00
Kees Cook
6819d101dd lkdtm: Add tests for struct list corruption
When building under CONFIG_DEBUG_LIST, list addition and removal will be
sanity-checked. This validates that the check is working as expected by
setting up classic corruption attacks against list manipulations, available
with the new lkdtm tests CORRUPT_LIST_ADD and CORRUPT_LIST_DEL.

Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Rik van Riel <riel@redhat.com>
2016-10-31 13:01:58 -07:00
Kees Cook
6d2e91a662 lkdtm: silence warnings about function declarations
When building under W=1, the lack of lkdtm.h in lkdtm_usercopy.c and
lkdtm_rodata.c was discovered. This fixes the issue and consolidates
the common header and the pr_fmt macro for simplicity and regularity
across each test source file.

Signed-off-by: Kees Cook <keescook@chromium.org>
2016-07-15 16:14:45 -07:00
Arnd Bergmann
2b271cb720 lkdtm: hide unused functions
A conversion of the lkdtm core module added an "#ifdef CONFIG_KPROBES" check,
but a number of functions then become unused:

drivers/misc/lkdtm_core.c:340:16: error: 'lkdtm_debugfs_entry' defined but not used [-Werror=unused-function]
drivers/misc/lkdtm_core.c:122:12: error: 'jp_generic_ide_ioctl' defined but not used [-Werror=unused-function]
drivers/misc/lkdtm_core.c:114:12: error: 'jp_scsi_dispatch_cmd' defined but not used [-Werror=unused-function]
drivers/misc/lkdtm_core.c:106:12: error: 'jp_hrtimer_start' defined but not used [-Werror=unused-function]
drivers/misc/lkdtm_core.c:97:22: error: 'jp_shrink_inactive_list' defined but not used [-Werror=unused-function]
drivers/misc/lkdtm_core.c:89:13: error: 'jp_ll_rw_block' defined but not used [-Werror=unused-function]
drivers/misc/lkdtm_core.c:83:13: error: 'jp_tasklet_action' defined but not used [-Werror=unused-function]
drivers/misc/lkdtm_core.c:75:20: error: 'jp_handle_irq_event' defined but not used [-Werror=unused-function]
drivers/misc/lkdtm_core.c:68:21: error: 'jp_do_irq' defined but not used [-Werror=unused-function]

This adds the same #ifdef everywhere. There is probably a better way to do the
same thing, but for now this avoids the new warnings.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: c479e3fd88 ("lkdtm: use struct arrays instead of enums")
[kees: moved some code around to better consolidate the #ifdefs]
Signed-off-by: Kees Cook <keescook@chromium.org>
2016-07-15 16:14:44 -07:00
Kees Cook
c479e3fd88 lkdtm: use struct arrays instead of enums
This removes the use of enums in favor of much more readable and compact
structure arrays. This requires changing all the enum passing to pointers
instead, but the results are much cleaner.

Signed-off-by: Kees Cook <keescook@chromium.org>
2016-07-07 11:09:27 -07:00
Kees Cook
f2c6edc1ed lkdtm: move jprobe entry points to start of source
In preparation of referencing the jprobe entry points in a structure,
this moves them to the start of the source since they operate mostly
separately from everything else.

Signed-off-by: Kees Cook <keescook@chromium.org>
2016-07-07 11:09:26 -07:00
Kees Cook
d87c978830 lkdtm: reorganize module paramaters
This reorganizes module parameters and global variables in the source
so they're grouped together with comments. Also moves early function
declarations to the top of the file.

Signed-off-by: Kees Cook <keescook@chromium.org>
2016-07-07 11:09:25 -07:00
Kees Cook
38f95fe296 lkdtm: rename globals for clarity
The global variables used to track the active crashpoint and crashtype
are hard to distinguish from local variable names, so add a "lkdtm_"
prefix to them (or in the case of "lkdtm", add a "_jprobe" suffix).

Signed-off-by: Kees Cook <keescook@chromium.org>
2016-07-07 11:09:25 -07:00
Kees Cook
76a10e2b3a lkdtm: rename "count" to "crash_count"
The "count" variable name was not easy to understand, since it was regularly
obscured by local variables of the same name, and it's purpose wasn't clear.
This renames it (and its lock) to "crash_count", which is more readable.

Signed-off-by: Kees Cook <keescook@chromium.org>
2016-07-07 11:09:24 -07:00
Kees Cook
329d416ca0 lkdtm: remove intentional off-by-one array access
There wasn't a good reason for keeping the enum and the names out of sync
by 1 position just to avoid "NONE" and "INVALID" from being in the string
lists.

Signed-off-by: Kees Cook <keescook@chromium.org>
2016-07-07 11:09:23 -07:00
Kees Cook
00f496c416 lkdtm: split remaining logic bug tests to separate file
This splits all the remaining tests from lkdtm_core.c into the new
lkdtm_bugs.c file to help separate things better for readability.

Signed-off-by: Kees Cook <keescook@chromium.org>
2016-07-07 11:09:22 -07:00
Kees Cook
ffc514f3fc lkdtm: split heap corruption tests to separate file
This splits the *_AFTER_FREE and related tests into the new lkdtm_heap.c
file to help separate things better for readability.

Signed-off-by: Kees Cook <keescook@chromium.org>
2016-07-07 11:09:22 -07:00
Kees Cook
0d9eb29b13 lkdtm: split memory permissions tests to separate file
This splits the EXEC_*, WRITE_* and related tests into the new lkdtm_perms.c
file to help separate things better for readability.

Signed-off-by: Kees Cook <keescook@chromium.org>
2016-07-07 11:09:21 -07:00
Kees Cook
a3dff71c1c lkdtm: split usercopy tests to separate file
This splits the USERCOPY_* tests into the new lkdtm_usercopy.c file to
help separate things better for readability.

Signed-off-by: Kees Cook <keescook@chromium.org>
2016-07-07 11:09:20 -07:00
Kees Cook
0edca7b5af lkdtm: drop "alloc_size" parameter
There is no good reason to have the alloc_size parameter currently. The
compiler-tricking value used to exercise the stack can just use a stack
address instead. Similarly hard-code cache_size.

Signed-off-by: Kees Cook <keescook@chromium.org>
2016-07-07 11:09:20 -07:00
Kees Cook
6c3521400c lkdtm: add usercopy test for blocking kernel text
The upcoming HARDENED_USERCOPY checks will also block access to the
kernel text, so provide a test for this as well.

Signed-off-by: Kees Cook <keescook@chromium.org>
2016-07-07 11:09:19 -07:00
Kees Cook
b54845276a lkdtm: split atomic test into over and underflow
Each direction of the atomic wrapping should be individually testable.

Signed-off-by: Kees Cook <keescook@chromium.org>
2016-06-10 15:57:51 -07:00
Kees Cook
aa981a665d lkdtm: add usercopy tests
This adds test to detect copy_to_user/copy_from_user problems that are
protected by PAX_USERCOPY (and will be protected by HARDENED_USERCOPY).
Explicitly tests both "to" and "from" directions of heap object size
problems, heap object markings and, stack frame misalignment.

Signed-off-by: Kees Cook <keescook@chromium.org>
2016-06-10 15:57:51 -07:00
Kees Cook
9a49a528dc lkdtm: add function for testing .rodata section
This adds a function that lives in the .rodata section. The section
flags are corrected using objcopy since there is no way with gcc to
declare section flags in an architecture-agnostic way.

Signed-off-by: Kees Cook <keescook@chromium.org>
2016-06-10 15:57:50 -07:00
Kees Cook
426f3a53d4 lkdtm: clean up after rename
This cleans up comments a bit to improve readability, adjusts the
name of the module after the source file renaming, and corrects the
MAINTAINERS for the upcoming lkdtm files.

Signed-off-by: Kees Cook <keescook@chromium.org>
2016-06-10 15:57:49 -07:00
Kees Cook
9e197e2f89 lkdtm: split build into multiple source files
Kbuild lacks a way to do in-place objcopy or other modifications of
built targets, so in order to move functions into non-text sections
without renaming the kernel module, the build of lkdtm must be split
into separate source files. This renames lkdtm.c to lkdtm_core.c in
preparation for adding the source file for the .rodata section.

Signed-off-by: Kees Cook <keescook@chromium.org>
2016-06-10 15:57:48 -07:00
Renamed from drivers/misc/lkdtm.c (Browse further)