Makefile: remove redundant tool coverage variables

Now Kbuild provides reasonable defaults for objtool, sanitizers, and
profilers.

Remove redundant variables.

Note:

This commit changes the coverage for some objects:

- include arch/mips/vdso/vdso-image.o into UBSAN, GCOV, KCOV
- include arch/sparc/vdso/vdso-image-*.o into UBSAN
- include arch/sparc/vdso/vma.o into UBSAN
- include arch/x86/entry/vdso/extable.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
- include arch/x86/entry/vdso/vdso-image-*.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
- include arch/x86/entry/vdso/vdso32-setup.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
- include arch/x86/entry/vdso/vma.o into GCOV, KCOV
- include arch/x86/um/vdso/vma.o into KASAN, GCOV, KCOV

I believe these are positive effects because all of them are kernel
space objects.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Roberto Sassu <roberto.sassu@huawei.com>

lkdtm: Disable CFI checking for perms functions

The EXEC_RODATA test plays a lot of tricks to live in the .rodata section,
and once again ran into objtool's (completely reasonable) assumptions
that executable code should live in an executable section. However, this
manifested only under CONFIG_CFI_CLANG=y, as one of the .cfi_sites was
pointing into the .rodata section.

Since we're testing non-CFI execution properties in perms.c (and
rodata.c), we can disable CFI for the involved functions, and remove the
CFI arguments from rodata.c entirely.

Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202308301532.d7acf63e-oliver.sang@intel.com
Fixes: 6342a20efbd8 ("objtool: Add elf_create_section_pair()")
Link: https://lore.kernel.org/r/20240430234953.work.760-kees@kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>

lkdtm: Disable return thunks in rodata.c

The following warning was seen:

WARNING: CPU: 0 PID: 0 at arch/x86/kernel/alternative.c:557 apply_returns (arch/x86/kernel/alternative.c:557 (discriminator 1))
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.19.0-rc4-00008-gee88d363d156 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-debian-1.16.0-4 04/01/2014
RIP: 0010:apply_returns (arch/x86/kernel/alternative.c:557 (discriminator 1))
Code: ff ff 74 cb 48 83 c5 04 49 39 ee 0f 87 81 fe ff ff e9 22 ff ff ff 0f 0b 48 83 c5 04 49 39 ee 0f 87 6d fe ff ff e9 0e ff ff ff <0f> 0b 48 83 c5 04 49 39 ee 0f 87 59 fe ff ff e9 fa fe ff ff 48 89

The warning happened when apply_returns() failed to convert "JMP
__x86_return_thunk" to RET. It was instead a JMP to nowhere, due to the
thunk relocation not getting resolved.

That rodata.o code is objcopy'd to .rodata, and later memcpy'd, so
relocations don't work (and are apparently silently ignored).

LKDTM is only used for testing, so the naked RET should be fine. So
just disable return thunks for that file.

While at it, disable objtool and KCSAN for the file.

Fixes: 0b53c374b9ef ("x86/retpoline: Use -mfunction-return")
Reported-by: kernel test robot <oliver.sang@intel.com>
Debugged-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/lkml/Ys58BxHxoDZ7rfpr@xsang-OptiPlex-9020/

lkdtm: Fix content of section containing lkdtm_rodata_do_nothing()

On a kernel without CONFIG_STRICT_KERNEL_RWX, running EXEC_RODATA
test leads to "Illegal instruction" failure.

Looking at the content of rodata_objcopy.o, we see that the
function content zeroes only:

Disassembly of section .rodata:

0000000000000000 <.lkdtm_rodata_do_nothing>:
0: 00 00 00 00 .long 0x0

Add the contents flag in order to keep the content of the section
while renaming it.

Disassembly of section .rodata:

0000000000000000 <.lkdtm_rodata_do_nothing>:
0: 4e 80 00 20 blr

Fixes: e9e08a07385e ("lkdtm: support llvm-objcopy")
Cc: stable@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/8900731fbc05fb8b0de18af7133a8fc07c3c53a1.1633712176.git.christophe.leroy@csgroup.eu

powerpc/64s: Make hash MMU support configurable

This adds Kconfig selection which allows 64s hash MMU support to be
disabled. It can be disabled if radix support is enabled, the minimum
supported CPU type is POWER9 (or higher), and KVM is not selected.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211201144153.2456614-17-npiggin@gmail.com

drivers/misc/lkdtm: disable LTO for rodata.o

Disable LTO for rodata.o to allow objcopy to be used to
manipulate sections.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-14-samitolvanen@google.com

drivers/misc/lkdtm: add new file in LKDTM to test fortified strscpy

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>

lkdtm: disable KASAN for rodata.o

Building lkdtm with KASAN and Clang 11 or later results in the following
error when attempting to load the module:

kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
BUG: unable to handle page fault for address: ffffffffc019cd70
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0011) - permissions violation
...
RIP: 0010:asan.module_ctor+0x0/0xffffffffffffa290 [lkdtm]
...
Call Trace:
do_init_module+0x17c/0x570
load_module+0xadee/0xd0b0
__x64_sys_finit_module+0x16c/0x1a0
do_syscall_64+0x34/0x50
entry_SYSCALL_64_after_hwframe+0x44/0xa9

The reason is that rodata.o generates a dummy function that lives in
.rodata to validate that .rodata can't be executed; however, Clang 11 adds
KASAN globals support by generating module constructors to initialize
globals redzones. When Clang 11 adds a module constructor to rodata.o, it
is also added to .rodata: any attempt to call it on initialization results
in the above error.

Therefore, disable KASAN instrumentation for rodata.o.

Link: https://lkml.kernel.org/r/20201214191413.3164796-1-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lkdtm: don't move ctors to .rodata

When building with KASAN and LKDTM, clang may implictly generate an
asan.module_ctor function in the LKDTM rodata object. The Makefile moves
the lkdtm_rodata_do_nothing() function into .rodata by renaming the
file's .text section to .rodata, and consequently also moves the ctor
function into .rodata, leading to a boot time crash (splat below) when
the ctor is invoked by do_ctors().

Let's prevent this by marking the function as noinstr rather than
notrace, and renaming the file's .noinstr.text to .rodata. Marking the
function as noinstr will prevent tracing and kprobes, and will inhibit
any undesireable compiler instrumentation.

The ctor function (if any) will be placed in .text and will work
correctly.

Example splat before this patch is applied:

[ 0.916359] Unable to handle kernel execute from non-executable memory at virtual address ffffa0006b60f5ac
[ 0.922088] Mem abort info:
[ 0.922828] ESR = 0x8600000e
[ 0.923635] EC = 0x21: IABT (current EL), IL = 32 bits
[ 0.925036] SET = 0, FnV = 0
[ 0.925838] EA = 0, S1PTW = 0
[ 0.926714] swapper pgtable: 4k pages, 48-bit VAs, pgdp=00000000427b3000
[ 0.928489] [ffffa0006b60f5ac] pgd=000000023ffff003, p4d=000000023ffff003, pud=000000023fffe003, pmd=0068000042000f01
[ 0.931330] Internal error: Oops: 8600000e [#1] PREEMPT SMP
[ 0.932806] Modules linked in:
[ 0.933617] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.10.0-rc7 #2
[ 0.935620] Hardware name: linux,dummy-virt (DT)
[ 0.936924] pstate: 40400005 (nZcv daif +PAN -UAO -TCO BTYPE=--)
[ 0.938609] pc : asan.module_ctor+0x0/0x14
[ 0.939759] lr : do_basic_setup+0x4c/0x70
[ 0.940889] sp : ffff27b600177e30
[ 0.941815] x29: ffff27b600177e30 x28: 0000000000000000
[ 0.943306] x27: 0000000000000000 x26: 0000000000000000
[ 0.944803] x25: 0000000000000000 x24: 0000000000000000
[ 0.946289] x23: 0000000000000001 x22: 0000000000000000
[ 0.947777] x21: ffffa0006bf4a890 x20: ffffa0006befb6c0
[ 0.949271] x19: ffffa0006bef9358 x18: 0000000000000068
[ 0.950756] x17: fffffffffffffff8 x16: 0000000000000000
[ 0.952246] x15: 0000000000000000 x14: 0000000000000000
[ 0.953734] x13: 00000000838a16d5 x12: 0000000000000001
[ 0.955223] x11: ffff94000da74041 x10: dfffa00000000000
[ 0.956715] x9 : 0000000000000000 x8 : ffffa0006b60f5ac
[ 0.958199] x7 : f9f9f9f9f9f9f9f9 x6 : 000000000000003f
[ 0.959683] x5 : 0000000000000040 x4 : 0000000000000000
[ 0.961178] x3 : ffffa0006bdc15a0 x2 : 0000000000000005
[ 0.962662] x1 : 00000000000000f9 x0 : ffffa0006bef9350
[ 0.964155] Call trace:
[ 0.964844] asan.module_ctor+0x0/0x14
[ 0.965895] kernel_init_freeable+0x158/0x198
[ 0.967115] kernel_init+0x14/0x19c
[ 0.968104] ret_from_fork+0x10/0x30
[ 0.969110] Code: 00000003 00000000 00000000 00000000 (00000000)
[ 0.970815] ---[ end trace b5339784e20d015c ]---

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kees Cook <keescook@chromium.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20201207170533.10738-1-mark.rutland@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

lkdtm/powerpc: Add SLB multihit test

To check machine check handling, add support to inject slb
multihit errors.

Co-developed-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
[mpe: Use CONFIG_PPC_BOOK3S_64 to fix compile errors reported by lkp@intel.com]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201130083057.135610-1-ganeshgr@linux.ibm.com

lkdtm: Add Control Flow Integrity test

This adds a simple test for forward CFI (indirect function calls) with
function prototype granularity (as implemented by Clang's CFI).

Signed-off-by: Kees Cook <keescook@chromium.org>

lkdtm: support llvm-objcopy

With CONFIG_LKDTM=y and make OBJCOPY=llvm-objcopy, llvm-objcopy errors:
llvm-objcopy: error: --set-section-flags=.text conflicts with
--rename-section=.text=.rodata

Rather than support setting flags then renaming sections vs renaming
then setting flags, it's simpler to just change both at the same time
via --rename-section. Adding the load flag is required for GNU objcopy
to mark .rodata Type as PROGBITS after the rename.

This can be verified with:
$ readelf -S drivers/misc/lkdtm/rodata_objcopy.o
...
Section Headers:
[Nr] Name Type Address Offset
Size EntSize Flags Link Info Align
...
[ 1] .rodata PROGBITS 0000000000000000 00000040
0000000000000004 0000000000000000 A 0 0 4
...

Which shows that .text is now renamed .rodata, the alloc flag A is set,
the type is PROGBITS, and the section is not flagged as writeable W.

Cc: stable@vger.kernel.org
Link: https://sourceware.org/bugzilla/show_bug.cgi?id=24554
Link: https://github.com/ClangBuiltLinux/linux/issues/448
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Suggested-by: Alan Modra <amodra@gmail.com>
Suggested-by: Jordan Rupprect <rupprecht@google.com>
Suggested-by: Kees Cook <keescook@chromium.org>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

lkdtm: Add a test for STACKLEAK

Introduce an lkdtm test for the STACKLEAK feature: check that the
current task stack is properly erased (filled with STACKLEAK_POISON).

Signed-off-by: Alexander Popov <alex.popov@linux.com>
Signed-off-by: Tycho Andersen <tycho@tycho.ws>
Tested-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>

lkdtm: Relocate code to subdirectory

The LKDTM modules keep expanding, and it's getting weird to have each file
get a prefix. Instead, move to a subdirectory for cleaner handling.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>