Re: [PATCH v11 00/20] Compile-time stack validation

From: Josh Poimboeuf
Date: Tue Aug 25 2015 - 11:26:08 EST


On Tue, Aug 25, 2015 at 10:05:00AM +0200, Ingo Molnar wrote:
> * Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote:
> > lib/Kconfig.debug | 11 +
> > scripts/Makefile | 1 +
> > scripts/Makefile.build | 37 +-
> > scripts/mod/Makefile | 2 +
> > scripts/stackvalidate/Makefile | 24 +
> > scripts/stackvalidate/arch-x86.c | 160 +++++
> > scripts/stackvalidate/arch.h | 44 ++
> > scripts/stackvalidate/elf.c | 427 +++++++++++++
> > scripts/stackvalidate/elf.h | 92 +++
> > scripts/stackvalidate/list.h | 217 +++++++
> > scripts/stackvalidate/special.c | 199 ++++++
> > scripts/stackvalidate/special.h | 42 ++
> > scripts/stackvalidate/stackvalidate.c | 976 ++++++++++++++++++++++++++++++
> > 43 files changed, 2803 insertions(+), 48 deletions(-)
> > create mode 100644 Documentation/stack-validation.txt
> > create mode 100644 arch/x86/include/asm/stackvalidate.h
> > create mode 100644 include/linux/stackvalidate.h
> > create mode 100644 scripts/stackvalidate/Makefile
> > create mode 100644 scripts/stackvalidate/arch-x86.c
> > create mode 100644 scripts/stackvalidate/arch.h
> > create mode 100644 scripts/stackvalidate/elf.c
> > create mode 100644 scripts/stackvalidate/elf.h
> > create mode 100644 scripts/stackvalidate/list.h
> > create mode 100644 scripts/stackvalidate/special.c
> > create mode 100644 scripts/stackvalidate/special.h
> > create mode 100644 scripts/stackvalidate/stackvalidate.c
>
> Btw., would you be against putting scripts/stackvalidate/ into
> tools/stackvalidate/ ?
>
> That way it would be more generic, and could be used in a standalone fashion as
> well I suspect. It would not change any of your current usage of it.
>
> (The other Kbuild glue changes still need to be in scripts/.)

I like that idea. It could indeed be useful for any other projects
which have asm code. In fact the musl project has been trying to solve
similar problems with their CFI generation awk script.

It does have some kernel-isms related to the reading of special sections
(.altinstructions, __jump_table, etc). But that should be harmless for
non-kernel code and could easily be factored out with a compile-time or
cmdline flag if needed.

BTW, since I'm planning on adding a CFI generation option to this tool,
I wonder if "stackvalidate" is a misnomer. I can't think of anything
better. Any naming ideas are welcome :-)

--
Josh
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