[PATCH v17 0/9] Compile-time stack metadata validation

From: Josh Poimboeuf
Date: Wed Feb 24 2016 - 11:37:35 EST

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This is v17 of the compile-time stack metadata validation patch set.

It's based on tip:x86/debug. However, note that when run against that
branch it will give a lot of warnings:

objtool: arch/x86/ia32/sys_ia32.o: __ex_table size not a multiple of 12
objtool: arch/x86/ia32/ia32_signal.o: __ex_table size not a multiple of 12
objtool: arch/x86/entry/common.o: __ex_table size not a multiple of 12
...

These warnings means that objtool is expecting the new exception table
format which was introduced with:

548acf19234d ("x86/mm: Expand the exception table logic to allow new handling options")

So that commit is needed for those warnings to go away.

v16 can be found here:

https://lkml.kernel.org/r/cover.1453405861.git.jpoimboe@xxxxxxxxxx

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

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

Patches 5-9 add some directories, files, and functions to the
objtool whitelist in order to silence false positive warnings.

v17:
- __ex_table fix
- rename stacktool -> objtool
- STACKTOOL_IGNORE_FUNCTION -> STACK_FRAME_NON_STANDARD
- 'STACKTOOL := n' -> 'OBJECT_FILES_NON_STANDARD := y'
- updated global_noreturns list

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@xxxxxxxxxxxxxxx
Cc: live-patching@xxxxxxxxxxxxxxx
Cc: Michal Marek <mmarek@xxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: Pedro Alves <palves@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxx>
Cc: Bernd Petrovitsch <bernd@xxxxxxxxxxxxxxxxxxx>
Cc: Chris J Arges <chris.j.arges@xxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Jiri Slaby <jslaby@xxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>

Josh Poimboeuf (9):
x86/objtool: Compile-time stack metadata validation
x86/objtool: Add CONFIG_STACK_VALIDATION option
x86/objtool: Enable objtool on x86_64
x86/objtool: Add STACK_FRAME_NON_STANDARD macro
x86/objtool: Add directory and file whitelists
x86/xen: Add xen_cpuid() to objtool whitelist
bpf: Add __bpf_prog_run() to objtool whitelist
sched: Add __schedule() to objtool whitelist
x86/kprobes: Add kretprobe_trampoline() to objtool whitelist

MAINTAINERS | 6 +
Makefile | 5 +-
arch/Kconfig | 6 +
arch/x86/Kconfig | 1 +
arch/x86/boot/Makefile | 3 +-
arch/x86/boot/compressed/Makefile | 3 +-
arch/x86/entry/Makefile | 4 +
arch/x86/entry/vdso/Makefile | 6 +-
arch/x86/kernel/Makefile | 11 +-
arch/x86/kernel/kprobes/core.c | 2 +
arch/x86/kernel/vmlinux.lds.S | 5 +-
arch/x86/platform/efi/Makefile | 2 +
arch/x86/purgatory/Makefile | 2 +
arch/x86/realmode/Makefile | 4 +-
arch/x86/realmode/rm/Makefile | 3 +-
arch/x86/xen/enlighten.c | 3 +-
drivers/firmware/efi/libstub/Makefile | 1 +
include/linux/objtool.h | 22 +
kernel/bpf/core.c | 2 +
kernel/sched/core.c | 2 +
lib/Kconfig.debug | 12 +
scripts/Makefile.build | 39 +-
scripts/mod/Makefile | 2 +
tools/Makefile | 14 +-
tools/objtool/.gitignore | 2 +
tools/objtool/Build | 13 +
tools/objtool/Documentation/stack-validation.txt | 340 ++++++++
tools/objtool/Makefile | 60 ++
tools/objtool/arch.h | 44 +
tools/objtool/arch/x86/Build | 12 +
tools/objtool/arch/x86/decode.c | 172 ++++
tools/objtool/arch/x86/insn/gen-insn-attr-x86.awk | 387 +++++++++
tools/objtool/arch/x86/insn/inat.c | 97 +++
tools/objtool/arch/x86/insn/inat.h | 221 +++++
tools/objtool/arch/x86/insn/inat_types.h | 29 +
tools/objtool/arch/x86/insn/insn.c | 594 +++++++++++++
tools/objtool/arch/x86/insn/insn.h | 201 +++++
tools/objtool/arch/x86/insn/x86-opcode-map.txt | 984 +++++++++++++++++++++
tools/objtool/builtin-check.c | 993 ++++++++++++++++++++++
tools/objtool/builtin.h | 22 +
tools/objtool/elf.c | 403 +++++++++
tools/objtool/elf.h | 79 ++
tools/objtool/objtool.c | 134 +++
tools/objtool/special.c | 193 +++++
tools/objtool/special.h | 42 +
tools/objtool/warn.h | 60 ++
46 files changed, 5220 insertions(+), 22 deletions(-)
create mode 100644 include/linux/objtool.h
create mode 100644 tools/objtool/.gitignore
create mode 100644 tools/objtool/Build
create mode 100644 tools/objtool/Documentation/stack-validation.txt
create mode 100644 tools/objtool/Makefile
create mode 100644 tools/objtool/arch.h
create mode 100644 tools/objtool/arch/x86/Build
create mode 100644 tools/objtool/arch/x86/decode.c
create mode 100644 tools/objtool/arch/x86/insn/gen-insn-attr-x86.awk
create mode 100644 tools/objtool/arch/x86/insn/inat.c
create mode 100644 tools/objtool/arch/x86/insn/inat.h
create mode 100644 tools/objtool/arch/x86/insn/inat_types.h
create mode 100644 tools/objtool/arch/x86/insn/insn.c
create mode 100644 tools/objtool/arch/x86/insn/insn.h
create mode 100644 tools/objtool/arch/x86/insn/x86-opcode-map.txt
create mode 100644 tools/objtool/builtin-check.c
create mode 100644 tools/objtool/builtin.h
create mode 100644 tools/objtool/elf.c
create mode 100644 tools/objtool/elf.h
create mode 100644 tools/objtool/objtool.c
create mode 100644 tools/objtool/special.c
create mode 100644 tools/objtool/special.h
create mode 100644 tools/objtool/warn.h

--
2.4.3

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