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

Chris J Arges
2016-01-22T17:44:25Z

On Thu, Jan 21, 2016 at 04:49:04PM -0600, Josh Poimboeuf wrote:
> 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.
>
Josh,

Looks good, with my config [1] I do still get a few warnings building
linux/linux-next.

Here are the warnings:
$ grep ^stacktool build.log | grep -v staging
stacktool: arch/x86/kvm/vmx.o: vmx_handle_external_intr()+0x67: call without frame pointer save/setup
stacktool: fs/reiserfs/namei.o: set_de_name_and_namelen()+0x9e: return without frame pointer restore
stacktool: fs/reiserfs/namei.o: set_de_name_and_namelen()+0x89: duplicate frame pointer save
stacktool: fs/reiserfs/namei.o: set_de_name_and_namelen()+0x8a: duplicate frame pointer setup
stacktool: fs/reiserfs/namei.o: set_de_name_and_namelen()+0x9e: frame pointer state mismatch
stacktool: fs/reiserfs/namei.o: set_de_name_and_namelen()+0x0: frame pointer state mismatch
stacktool: fs/reiserfs/ibalance.o: .text: unexpected end of section
stacktool: fs/reiserfs/tail_conversion.o: .text: unexpected end of section

For vmx_handle_external_intr, I'm wondering if ignoring this function is the
best option.

--

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e2951b6..d19dfb2 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -33,6 +33,7 @@
#include <linux/slab.h>
#include <linux/tboot.h>
#include <linux/hrtimer.h>
+#include <linux/stacktool.h>
#include "kvm_cache_regs.h"
#include "x86.h"

@@ -8398,6 +8399,7 @@ static void vmx_handle_external_intr(struct kvm_vcpu *vcpu)
} else
local_irq_enable();
}
+STACKTOOL_IGNORE_FUNC(vmx_handle_external_intr);

static bool vmx_has_high_real_mode_segbase(void)
{

--chris

[1] http://paste.ubuntu.com/14599083/

> 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
>