[PATCH 00/33] Compile-time stack metadata validation

Josh Poimboeuf
2016-01-21T22:50:37Z

This is v16 of the compile-time stack metadata validation patch set,
along with proposed fixes for most of the warnings it found. It's based
on the tip/master branch.

v15 can be found here:

https://lkml.kernel.org/r/cover.1450442274.git.jpoimboe@redhat.com

For more information about the motivation behind this patch set, and
more details about what it does, see the first patch changelog and
tools/stacktool/Documentation/stack-validation.txt.

Patches 1-4 add stacktool and integrate it into the kernel build.

Patches 5-28 are some proposed fixes for several of the warnings
reported by stacktool. They've been compile-tested and boot-tested in a
VM, but I haven't attempted any meaningful testing for many of them.

Patches 29-33 add some directories, files, and functions to the
stacktool whitelist in order to silence false positive warnings.

v16:
- fix all allyesconfig warnings, except for staging
- get rid of STACKTOOL_IGNORE_INSN which is no longer needed
- remove several whitelists in favor of automatically whitelisting any
function with a special instruction like ljmp, lret, or vmrun
- split up stacktool patch into 3 parts as suggested by Ingo
- update the global noreturn function list
- detect noreturn function fallthroughs
- skip weak functions in noreturn call detection logic
- add empty function check to noreturn logic
- allow non-section rela symbols for __ex_table sections
- support rare switch table case with jmpq *[addr](%rip)
- don't warn on frame pointer restore without save
- rearrange patch order a bit

v15:
- restructure code for a new cmdline interface "stacktool check" using
the new subcommand framework in tools/lib/subcmd
- fix 32 bit build fail (put __sp at end) in paravirt_types.h patch 10
which was reported by 0day

v14:
- make tools/include/linux/list.h self-sufficient
- create FRAME_OFFSET to allow 32-bit code to be able to access function
arguments on the stack
- add FRAME_OFFSET usage in crypto patch 14/24: "Create stack frames in
aesni-intel_asm.S"
- rename "index" -> "idx" to fix build with some compilers

v13:
- LDFLAGS order fix from Chris J Arges
- new warning fix patches from Chris J Arges
- "--frame-pointer" -> "--check-frame-pointer"

v12:
- rename "stackvalidate" -> "stacktool"
- move from scripts/ to tools/:
- makefile rework
- make a copy of the x86 insn code (and warn if the code diverges)
- use tools/include/linux/list.h
- move warning macros to a new warn.h file
- change wording: "stack validation" -> "stack metadata validation"

v11:
- attempt to answer the "why" question better in the documentation and
commit message
- s/FP_SAVE/FRAME_BEGIN/ in documentation

v10:
- add scripts/mod to directory ignores
- remove circular dependencies for ignored objects which are built
before stackvalidate
- fix CONFIG_MODVERSIONS incompatibility

v9:
- rename FRAME/ENDFRAME -> FRAME_BEGIN/FRAME_END
- fix jump table issue for when the original instruction is a jump
- drop paravirt thunk alignment patch
- add maintainers to CC for proposed warning fixes

v8:
- add proposed fixes for warnings
- fix all memory leaks
- process ignores earlier and add more ignore checks
- always assume POPCNT alternative is enabled
- drop hweight inline asm fix
- drop __schedule() ignore patch
- change .Ltemp_\@ to .Lstackvalidate_ignore_\@ in asm macro
- fix CONFIG_* checks in asm macros
- add C versions of ignore macros and frame macros
- change ";" to "\n" in C macros
- add ifdef CONFIG_STACK_VALIDATION checks in C ignore macros
- use numbered label in C ignore macro
- add missing break in switch case statement in arch-x86.c

v7:
- sibling call support
- document proposed solution for inline asm() frame pointer issues
- say "kernel entry/exit" instead of "context switch"
- clarify the checking of switch statement jump tables
- discard __stackvalidate_ignore_* sections in linker script
- use .Ltemp_\@ to get a unique label instead of static 3-digit number
- change STACKVALIDATE_IGNORE_FUNC variable to a static
- move STACKVALIDATE_IGNORE_INSN to arch-specific .h file

v6:
- rename asmvalidate -> stackvalidate (again)
- gcc-generated object file support
- recursive branch state analysis
- external jump support
- fixup/exception table support
- jump label support
- switch statement jump table support
- added documentation
- detection of "noreturn" dead end functions
- added a Kbuild mechanism for skipping files and dirs
- moved frame pointer macros to arch/x86/include/asm/frame.h
- moved ignore macros to include/linux/stackvalidate.h

v5:
- stackvalidate -> asmvalidate
- frame pointers only required for non-leaf functions
- check for the use of the FP_SAVE/RESTORE macros instead of manually
analyzing code to detect frame pointer usage
- additional checks to ensure each function doesn't leave its boundaries
- make the macros simpler and more flexible
- support for analyzing ALTERNATIVE macros
- simplified the arch interfaces in scripts/asmvalidate/arch.h
- fixed some asmvalidate warnings
- rebased onto latest tip asm cleanups
- many more small changes

v4:
- Changed the default to CONFIG_STACK_VALIDATION=n, until all the asm
code can get cleaned up.
- Fixed a stackvalidate error path exit code issue found by Michal
Marek.

v3:
- Added a patch to make the push/pop CFI macros arch-independent, as
suggested by H. Peter Anvin

v2:
- Fixed memory leaks reported by Petr Mladek

Cc: linux-kernel@vger.kernel.org
Cc: live-patching@vger.kernel.org
Cc: Michal Marek <mmarek@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Pedro Alves <palves@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>

Chris J Arges (1):
x86/uaccess: Add stack frame output operand in get_user inline asm

Josh Poimboeuf (32):
x86/stacktool: Compile-time stack metadata validation
kbuild/stacktool: Add CONFIG_STACK_VALIDATION option
x86/stacktool: Enable stacktool on x86_64
x86/stacktool: Add STACKTOOL_IGNORE_FUNC macro
x86/xen: Add stack frame dependency to hypercall inline asm calls
x86/asm/xen: Set ELF function type for xen_adjust_exception_frame()
x86/asm/xen: Create stack frames in xen-asm.S
x86/paravirt: Add stack frame dependency to PVOP inline asm calls
x86/paravirt: Create a stack frame in PV_CALLEE_SAVE_REGS_THUNK
x86/amd: Set ELF function type for vide()
x86/asm/crypto: Move .Lbswap_mask data to .rodata section
x86/asm/crypto: Move jump_table to .rodata section
x86/asm/crypto: Simplify stack usage in sha-mb functions
x86/asm/crypto: Don't use rbp as a scratch register
x86/asm/crypto: Create stack frames in crypto functions
x86/asm/entry: Create stack frames in thunk functions
x86/asm/acpi: Create a stack frame in do_suspend_lowlevel()
x86/asm: Create stack frames in rwsem functions
x86/asm/efi: Create a stack frame in efi_call()
x86/asm/power: Create stack frames in hibernate_asm_64.S
x86/asm/bpf: Annotate callable functions
x86/asm/bpf: Create stack frames in bpf_jit.S
x86/kprobes: Get rid of kretprobe_trampoline_holder()
x86/kvm: Set ELF function type for fastop functions
x86/kvm: Add stack frame dependency to test_cc() inline asm
watchdog/hpwdt: Create stack frame in asminline_call()
x86/locking: Create stack frame in PV unlock
x86/stacktool: Add directory and file whitelists
x86/xen: Add xen_cpuid() to stacktool whitelist
bpf: Add __bpf_prog_run() to stacktool whitelist
sched: Add __schedule() to stacktool whitelist
x86/kprobes: Add kretprobe_trampoline() to stacktool whitelist

MAINTAINERS | 6 +
Makefile | 5 +-
arch/Kconfig | 6 +
arch/x86/Kconfig | 1 +
arch/x86/boot/Makefile | 1 +
arch/x86/boot/compressed/Makefile | 3 +-
arch/x86/crypto/aesni-intel_asm.S | 75 +-
arch/x86/crypto/camellia-aesni-avx-asm_64.S | 15 +
arch/x86/crypto/camellia-aesni-avx2-asm_64.S | 15 +
arch/x86/crypto/cast5-avx-x86_64-asm_64.S | 9 +
arch/x86/crypto/cast6-avx-x86_64-asm_64.S | 13 +
arch/x86/crypto/crc32c-pcl-intel-asm_64.S | 8 +-
arch/x86/crypto/ghash-clmulni-intel_asm.S | 5 +
arch/x86/crypto/serpent-avx-x86_64-asm_64.S | 13 +
arch/x86/crypto/serpent-avx2-asm_64.S | 13 +
arch/x86/crypto/sha-mb/sha1_mb_mgr_flush_avx2.S | 35 +-
arch/x86/crypto/sha-mb/sha1_mb_mgr_submit_avx2.S | 36 +-
arch/x86/crypto/twofish-avx-x86_64-asm_64.S | 13 +
arch/x86/entry/Makefile | 4 +
arch/x86/entry/thunk_64.S | 4 +
arch/x86/entry/vdso/Makefile | 5 +-
arch/x86/include/asm/paravirt.h | 9 +-
arch/x86/include/asm/paravirt_types.h | 18 +-
arch/x86/include/asm/qspinlock_paravirt.h | 4 +
arch/x86/include/asm/uaccess.h | 5 +-
arch/x86/include/asm/xen/hypercall.h | 5 +-
arch/x86/kernel/Makefile | 5 +
arch/x86/kernel/acpi/wakeup_64.S | 3 +
arch/x86/kernel/cpu/amd.c | 5 +-
arch/x86/kernel/kprobes/core.c | 59 +-
arch/x86/kernel/vmlinux.lds.S | 5 +-
arch/x86/kvm/emulate.c | 33 +-
arch/x86/lib/rwsem.S | 11 +-
arch/x86/net/bpf_jit.S | 48 +-
arch/x86/platform/efi/Makefile | 2 +
arch/x86/platform/efi/efi_stub_64.S | 3 +
arch/x86/power/hibernate_asm_64.S | 7 +
arch/x86/purgatory/Makefile | 2 +
arch/x86/realmode/Makefile | 4 +-
arch/x86/realmode/rm/Makefile | 3 +-
arch/x86/xen/enlighten.c | 3 +-
arch/x86/xen/xen-asm.S | 10 +-
arch/x86/xen/xen-asm_64.S | 1 +
drivers/firmware/efi/libstub/Makefile | 1 +
drivers/watchdog/hpwdt.c | 8 +-
include/linux/stacktool.h | 23 +
kernel/bpf/core.c | 2 +
kernel/sched/core.c | 2 +
lib/Kconfig.debug | 12 +
scripts/Makefile.build | 38 +-
scripts/mod/Makefile | 2 +
tools/Makefile | 14 +-
tools/stacktool/.gitignore | 2 +
tools/stacktool/Build | 13 +
tools/stacktool/Documentation/stack-validation.txt | 333 +++++++
tools/stacktool/Makefile | 60 ++
tools/stacktool/arch.h | 44 +
tools/stacktool/arch/x86/Build | 12 +
tools/stacktool/arch/x86/decode.c | 172 ++++
.../stacktool/arch/x86/insn/gen-insn-attr-x86.awk | 387 ++++++++
tools/stacktool/arch/x86/insn/inat.c | 97 ++
tools/stacktool/arch/x86/insn/inat.h | 221 +++++
tools/stacktool/arch/x86/insn/inat_types.h | 29 +
tools/stacktool/arch/x86/insn/insn.c | 594 ++++++++++++
tools/stacktool/arch/x86/insn/insn.h | 201 +++++
tools/stacktool/arch/x86/insn/x86-opcode-map.txt | 984 ++++++++++++++++++++
tools/stacktool/builtin-check.c | 991 +++++++++++++++++++++
tools/stacktool/builtin.h | 22 +
tools/stacktool/elf.c | 403 +++++++++
tools/stacktool/elf.h | 79 ++
tools/stacktool/special.c | 193 ++++
tools/stacktool/special.h | 42 +
tools/stacktool/stacktool.c | 134 +++
tools/stacktool/warn.h | 60 ++
74 files changed, 5516 insertions(+), 189 deletions(-)
create mode 100644 include/linux/stacktool.h
create mode 100644 tools/stacktool/.gitignore
create mode 100644 tools/stacktool/Build
create mode 100644 tools/stacktool/Documentation/stack-validation.txt
create mode 100644 tools/stacktool/Makefile
create mode 100644 tools/stacktool/arch.h
create mode 100644 tools/stacktool/arch/x86/Build
create mode 100644 tools/stacktool/arch/x86/decode.c
create mode 100644 tools/stacktool/arch/x86/insn/gen-insn-attr-x86.awk
create mode 100644 tools/stacktool/arch/x86/insn/inat.c
create mode 100644 tools/stacktool/arch/x86/insn/inat.h
create mode 100644 tools/stacktool/arch/x86/insn/inat_types.h
create mode 100644 tools/stacktool/arch/x86/insn/insn.c
create mode 100644 tools/stacktool/arch/x86/insn/insn.h
create mode 100644 tools/stacktool/arch/x86/insn/x86-opcode-map.txt
create mode 100644 tools/stacktool/builtin-check.c
create mode 100644 tools/stacktool/builtin.h
create mode 100644 tools/stacktool/elf.c
create mode 100644 tools/stacktool/elf.h
create mode 100644 tools/stacktool/special.c
create mode 100644 tools/stacktool/special.h
create mode 100644 tools/stacktool/stacktool.c
create mode 100644 tools/stacktool/warn.h

--
2.4.3