The lkdtm selftest config fragment enables CONFIG_UBSAN_TRAP to make the
ARRAY_BOUNDS test kill the calling process when an out-of-bound access
is detected by UBSAN. However, after this [1] commit, UBSAN is triggered
under many new scenarios that weren't detected before, such as in struct
definitions with fixed-size trailing arrays used as flexible arrays. As
a result, CONFIG_UBSAN_TRAP=y has become a very aggressive option to
enable except for specific situations.
`make kselftest-merge` applies CONFIG_UBSAN_TRAP=y to the kernel config
for all selftests, which makes many of them fail because of system hangs
during boot.
This change removes the config option from the lkdtm kselftest and
configures the ARRAY_BOUNDS test to look for UBSAN reports rather than
relying on the calling process being killed.
[1] commit 2d47c6956a ("ubsan: Tighten UBSAN_BOUNDS on GCC")'
Signed-off-by: Ricardo Cañuelo <ricardo.canuelo@collabora.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230802063252.1917997-1-ricardo.canuelo@collabora.com
Signed-off-by: Kees Cook <keescook@chromium.org>
Upon a panic() the kernel will use either smp_send_stop() or
crash_smp_send_stop() to attempt to stop secondary CPUs via an IPI,
which may or may not be an NMI. Generally it's preferable that this is an
NMI so that CPUs can be stopped in as many situations as possible, but
it's not always possible to provide an NMI, and there are cases where
CPUs may be unable to handle the NMI regardless.
This patch adds a test for panic() where all other CPUs are stuck with
interrupts disabled, which can be used to check whether the kernel
gracefully handles CPUs failing to respond to a stop, and whether NMIs
actually work to stop CPUs.
For example, on arm64 *without* an NMI, this results in:
| # echo PANIC_STOP_IRQOFF > /sys/kernel/debug/provoke-crash/DIRECT
| lkdtm: Performing direct entry PANIC_STOP_IRQOFF
| Kernel panic - not syncing: panic stop irqoff test
| CPU: 2 PID: 24 Comm: migration/2 Not tainted 6.5.0-rc3-00077-ge6c782389895-dirty #4
| Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
| Stopper: multi_cpu_stop+0x0/0x1a0 <- stop_machine_cpuslocked+0x158/0x1a4
| Call trace:
| dump_backtrace+0x94/0xec
| show_stack+0x18/0x24
| dump_stack_lvl+0x74/0xc0
| dump_stack+0x18/0x24
| panic+0x358/0x3e8
| lkdtm_PANIC+0x0/0x18
| multi_cpu_stop+0x9c/0x1a0
| cpu_stopper_thread+0x84/0x118
| smpboot_thread_fn+0x224/0x248
| kthread+0x114/0x118
| ret_from_fork+0x10/0x20
| SMP: stopping secondary CPUs
| SMP: failed to stop secondary CPUs 0-3
| Kernel Offset: 0x401cf3490000 from 0xffff80008000000c0
| PHYS_OFFSET: 0x40000000
| CPU features: 0x00000000,68c167a1,cce6773f
| Memory Limit: none
| ---[ end Kernel panic - not syncing: panic stop irqoff test ]---
Note the "failed to stop secondary CPUs 0-3" message.
On arm64 *with* an NMI, this results in:
| # echo PANIC_STOP_IRQOFF > /sys/kernel/debug/provoke-crash/DIRECT
| lkdtm: Performing direct entry PANIC_STOP_IRQOFF
| Kernel panic - not syncing: panic stop irqoff test
| CPU: 1 PID: 19 Comm: migration/1 Not tainted 6.5.0-rc3-00077-ge6c782389895-dirty #4
| Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
| Stopper: multi_cpu_stop+0x0/0x1a0 <- stop_machine_cpuslocked+0x158/0x1a4
| Call trace:
| dump_backtrace+0x94/0xec
| show_stack+0x18/0x24
| dump_stack_lvl+0x74/0xc0
| dump_stack+0x18/0x24
| panic+0x358/0x3e8
| lkdtm_PANIC+0x0/0x18
| multi_cpu_stop+0x9c/0x1a0
| cpu_stopper_thread+0x84/0x118
| smpboot_thread_fn+0x224/0x248
| kthread+0x114/0x118
| ret_from_fork+0x10/0x20
| SMP: stopping secondary CPUs
| Kernel Offset: 0x55a9c0bc0000 from 0xffff800080000000
| PHYS_OFFSET: 0x40000000
| CPU features: 0x00000000,68c167a1,fce6773f
| Memory Limit: none
| ---[ end Kernel panic - not syncing: panic stop irqoff test ]---
Note the absence of a "failed to stop secondary CPUs" message, since we
don't log anything when secondary CPUs are successfully stopped.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Stephen Boyd <swboyd@chromium.org>
Cc: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20230921161634.4063233-1-mark.rutland@arm.com
Signed-off-by: Kees Cook <keescook@chromium.org>
Clarify the LKDTM FORTIFY tests, and add tests for the mem*() family of
functions, now that run-time checking is distinct.
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: linux-kselftest@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
To more clearly distinguish between the various heap types, rename the
slab tests to "slab".
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: linux-kselftest@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
In order to test various backward-edge control flow integrity methods,
add a test that manipulates the return address on the stack. Currently
only arm64 Pointer Authentication and Shadow Call Stack is supported.
$ echo CFI_BACKWARD | cat >/sys/kernel/debug/provoke-crash/DIRECT
Under SCS, successful test of the mitigation is reported as:
lkdtm: Performing direct entry CFI_BACKWARD
lkdtm: Attempting unchecked stack return address redirection ...
lkdtm: ok: redirected stack return address.
lkdtm: Attempting checked stack return address redirection ...
lkdtm: ok: control flow unchanged.
Under PAC, successful test of the mitigation is reported by the PAC
exception handler:
lkdtm: Performing direct entry CFI_BACKWARD
lkdtm: Attempting unchecked stack return address redirection ...
lkdtm: ok: redirected stack return address.
lkdtm: Attempting checked stack return address redirection ...
Unable to handle kernel paging request at virtual address bfffffc0088d0514
Mem abort info:
ESR = 0x86000004
EC = 0x21: IABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x04: level 0 translation fault
[bfffffc0088d0514] address between user and kernel address ranges
...
If the CONFIGs are missing (or the mitigation isn't working), failure
is reported as:
lkdtm: Performing direct entry CFI_BACKWARD
lkdtm: Attempting unchecked stack return address redirection ...
lkdtm: ok: redirected stack return address.
lkdtm: Attempting checked stack return address redirection ...
lkdtm: FAIL: stack return address was redirected!
lkdtm: This is probably expected, since this kernel was built *without* CONFIG_ARM64_PTR_AUTH_KERNEL=y nor CONFIG_SHADOW_CALL_STACK=y
Co-developed-by: Dan Li <ashimida@linux.alibaba.com>
Signed-off-by: Dan Li <ashimida@linux.alibaba.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/lkml/20220416001103.1524653-1-keescook@chromium.org
Add WRITE_OPD to check that you can't modify function
descriptors.
Gives the following result when function descriptors are
not protected:
lkdtm: Performing direct entry WRITE_OPD
lkdtm: attempting bad 16 bytes write at c00000000269b358
lkdtm: FAIL: survived bad write
lkdtm: do_nothing was hijacked!
Looks like a standard compiler barrier() is not enough to force
GCC to use the modified function descriptor. Had to add a fake empty
inline assembly to force GCC to reload the function descriptor.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/7eeba50d16a35e9d799820e43304150225f20197.1644928018.git.christophe.leroy@csgroup.eu
Introduce REPORT_STACK_CANARY to check for differing stack canaries
between two processes (i.e. that an architecture is correctly implementing
per-task stack canaries), using the task_struct canary as the hint to
locate in the stack. Requires that one of the processes being tested
not be pid 1.
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20211022223826.330653-3-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The FORTIFY_SOURCE tests were split between bugs.c and fortify.c. Move
tests into fortify.c, standardize their naming, add CONFIG hints, and
add them to the lkdtm selftests.
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210818174855.2307828-3-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add CONFIG hints about why the ARRAY_BOUNDS test might fail, and
similarly include the CONFIGs needed to pass the ARRAY_BOUNDS test via
the selftests, and add to selftests.
Cc: kernelci@groups.io
Suggested-by: Guillaume Tucker <guillaume.tucker@collabora.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210818174855.2307828-2-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add SLAB and page allocator tests for init_on_alloc. Testing for
init_on_free was already happening via the poisoning tests.
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210623203936.3151093-10-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Similar to the existing slab overflow and stack exhaustion tests, add
VMALLOC_LINEAR_OVERFLOW (and rename the slab test SLAB_LINEAR_OVERFLOW).
Additionally unmarks the test as destructive. (It should be safe in the
face of misbehavior.)
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210623203936.3151093-6-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Freed memory poisoning can be tested a few ways, so update the expected
text to reflect the non-Oopsing alternative.
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210623203936.3151093-4-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
- Switch to the generic C VDSO, as well as some cleanups of our VDSO
setup/handling code.
- Support for KUAP (Kernel User Access Prevention) on systems using the hashed
page table MMU, using memory protection keys.
- Better handling of PowerVM SMT8 systems where all threads of a core do not
share an L2, allowing the scheduler to make better scheduling decisions.
- Further improvements to our machine check handling.
- Show registers when unwinding interrupt frames during stack traces.
- Improvements to our pseries (PowerVM) partition migration code.
- Several series from Christophe refactoring and cleaning up various parts of
the 32-bit code.
- Other smaller features, fixes & cleanups.
Thanks to:
Alan Modra, Alexey Kardashevskiy, Andrew Donnellan, Aneesh Kumar K.V, Ard
Biesheuvel, Athira Rajeev, Balamuruhan S, Bill Wendling, Cédric Le Goater,
Christophe Leroy, Christophe Lombard, Colin Ian King, Daniel Axtens, David
Hildenbrand, Frederic Barrat, Ganesh Goudar, Gautham R. Shenoy, Geert
Uytterhoeven, Giuseppe Sacco, Greg Kurz, Harish, Jan Kratochvil, Jordan
Niethe, Kaixu Xia, Laurent Dufour, Leonardo Bras, Madhavan Srinivasan, Mahesh
Salgaonkar, Mathieu Desnoyers, Nathan Lynch, Nicholas Piggin, Oleg Nesterov,
Oliver O'Halloran, Oscar Salvador, Po-Hsu Lin, Qian Cai, Qinglang Miao, Randy
Dunlap, Ravi Bangoria, Sachin Sant, Sandipan Das, Sebastian Andrzej Siewior ,
Segher Boessenkool, Srikar Dronamraju, Tyrel Datwyler, Uwe Kleine-König,
Vincent Stehlé, Youling Tang, Zhang Xiaoxu.
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Merge tag 'powerpc-5.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
- Switch to the generic C VDSO, as well as some cleanups of our VDSO
setup/handling code.
- Support for KUAP (Kernel User Access Prevention) on systems using the
hashed page table MMU, using memory protection keys.
- Better handling of PowerVM SMT8 systems where all threads of a core
do not share an L2, allowing the scheduler to make better scheduling
decisions.
- Further improvements to our machine check handling.
- Show registers when unwinding interrupt frames during stack traces.
- Improvements to our pseries (PowerVM) partition migration code.
- Several series from Christophe refactoring and cleaning up various
parts of the 32-bit code.
- Other smaller features, fixes & cleanups.
Thanks to: Alan Modra, Alexey Kardashevskiy, Andrew Donnellan, Aneesh
Kumar K.V, Ard Biesheuvel, Athira Rajeev, Balamuruhan S, Bill Wendling,
Cédric Le Goater, Christophe Leroy, Christophe Lombard, Colin Ian King,
Daniel Axtens, David Hildenbrand, Frederic Barrat, Ganesh Goudar,
Gautham R. Shenoy, Geert Uytterhoeven, Giuseppe Sacco, Greg Kurz,
Harish, Jan Kratochvil, Jordan Niethe, Kaixu Xia, Laurent Dufour,
Leonardo Bras, Madhavan Srinivasan, Mahesh Salgaonkar, Mathieu
Desnoyers, Nathan Lynch, Nicholas Piggin, Oleg Nesterov, Oliver
O'Halloran, Oscar Salvador, Po-Hsu Lin, Qian Cai, Qinglang Miao, Randy
Dunlap, Ravi Bangoria, Sachin Sant, Sandipan Das, Sebastian Andrzej
Siewior , Segher Boessenkool, Srikar Dronamraju, Tyrel Datwyler, Uwe
Kleine-König, Vincent Stehlé, Youling Tang, and Zhang Xiaoxu.
* tag 'powerpc-5.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (304 commits)
powerpc/32s: Fix cleanup_cpu_mmu_context() compile bug
powerpc: Add config fragment for disabling -Werror
powerpc/configs: Add ppc64le_allnoconfig target
powerpc/powernv: Rate limit opal-elog read failure message
powerpc/pseries/memhotplug: Quieten some DLPAR operations
powerpc/ps3: use dma_mapping_error()
powerpc: force inlining of csum_partial() to avoid multiple csum_partial() with GCC10
powerpc/perf: Fix Threshold Event Counter Multiplier width for P10
powerpc/mm: Fix hugetlb_free_pmd_range() and hugetlb_free_pud_range()
KVM: PPC: Book3S HV: Fix mask size for emulated msgsndp
KVM: PPC: fix comparison to bool warning
KVM: PPC: Book3S: Assign boolean values to a bool variable
powerpc: Inline setup_kup()
powerpc/64s: Mark the kuap/kuep functions non __init
KVM: PPC: Book3S HV: XIVE: Add a comment regarding VP numbering
powerpc/xive: Improve error reporting of OPAL calls
powerpc/xive: Simplify xive_do_source_eoi()
powerpc/xive: Remove P9 DD1 flag XIVE_IRQ_FLAG_EOI_FW
powerpc/xive: Remove P9 DD1 flag XIVE_IRQ_FLAG_MASK_FW
powerpc/xive: Remove P9 DD1 flag XIVE_IRQ_FLAG_SHIFT_BUG
...
This new test ensures that fortified strscpy has the same behavior than
vanilla strscpy (e.g. returning -E2BIG when src content is truncated).
Finally, it generates a crash at runtime because there is a write overflow
in destination string.
Link: https://lkml.kernel.org/r/20201122162451.27551-5-laniel_francis@privacyrequired.com
Signed-off-by: Francis Laniel <laniel_francis@privacyrequired.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Daniel Micay <danielmicay@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Once we can't manipulate the address limit, we also can't test what
happens when the manipulation is abused.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
I'd like arch-specific tests to XFAIL when on a mismatched architecture
so that we can more easily compare test coverage across all systems.
Lacking kernel configs or CPU features count as a FAIL, not an XFAIL.
Additionally fixes a build failure under 32-bit UML.
Fixes: b09511c253 ("lkdtm: Add a DOUBLE_FAULT crash type on x86")
Fixes: cea23efb4d ("lkdtm/bugs: Make double-fault test always available")
Fixes: 6cb6982f42 ("lkdtm: arm64: test kernel pointer authentication")
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20200625203704.317097-5-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This adds a basic framework for running all the "safe" LKDTM tests. This
will allow easy introspection into any selftest logs to examine the
results of most LKDTM tests.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
