Re: [PATCH v4 00/13] Fix LKDTM for PPC64/IA64/PARISC v4

Kees Cook
2022-02-15T16:07:39Z

On Tue, Feb 15, 2022 at 01:40:55PM +0100, Christophe Leroy wrote:
> PPC64/IA64/PARISC have function descriptors. LKDTM doesn't work
> on those three architectures because LKDTM messes up function
> descriptors with functions.
>
> This series does some cleanup in the three architectures and
> refactors function descriptors so that it can then easily use it
> in a generic way in LKDTM.

Thanks for doing this! It looks good to me. :)

-Kees

>
> Changes in v4:
> - Added patch 1 which Fixes 'sparse' for powerpc64le after wrong report on previous series, refer https://github.com/ruscur/linux-ci/actions/runs/1351427671
> - Exported dereference_function_descriptor() to modules
> - Addressed other received comments
> - Rebased on latest powerpc/next (5a72345e6a78120368fcc841b570331b6c5a50da)
>
> Changes in v3:
> - Addressed received comments
> - Swapped some of the powerpc patches to keep func_descr_t renamed as struct func_desc and remove 'struct ppc64_opd_entry'
> - Changed HAVE_FUNCTION_DESCRIPTORS macro to a config item CONFIG_HAVE_FUNCTION_DESCRIPTORS
> - Dropped patch 11 ("Fix lkdtm_EXEC_RODATA()")
>
> Changes in v2:
> - Addressed received comments
> - Moved dereference_[kernel]_function_descriptor() out of line
> - Added patches to remove func_descr_t and func_desc_t in powerpc
> - Using func_desc_t instead of funct_descr_t
> - Renamed HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR to HAVE_FUNCTION_DESCRIPTORS
> - Added a new lkdtm test to check protection of function descriptors
>
> Christophe Leroy (13):
> powerpc: Fix 'sparse' checking on PPC64le
> powerpc: Move and rename func_descr_t
> powerpc: Use 'struct func_desc' instead of 'struct ppc64_opd_entry'
> powerpc: Remove 'struct ppc64_opd_entry'
> powerpc: Prepare func_desc_t for refactorisation
> ia64: Rename 'ip' to 'addr' in 'struct fdesc'
> asm-generic: Define CONFIG_HAVE_FUNCTION_DESCRIPTORS
> asm-generic: Define 'func_desc_t' to commonly describe function
> descriptors
> asm-generic: Refactor dereference_[kernel]_function_descriptor()
> lkdtm: Force do_nothing() out of line
> lkdtm: Really write into kernel text in WRITE_KERN
> lkdtm: Fix execute_[user]_location()
> lkdtm: Add a test for function descriptors protection
>
> arch/Kconfig | 3 +
> arch/ia64/Kconfig | 1 +
> arch/ia64/include/asm/elf.h | 2 +-
> arch/ia64/include/asm/sections.h | 24 +-------
> arch/ia64/kernel/module.c | 6 +-
> arch/parisc/Kconfig | 1 +
> arch/parisc/include/asm/sections.h | 16 ++----
> arch/parisc/kernel/process.c | 21 -------
> arch/powerpc/Kconfig | 1 +
> arch/powerpc/Makefile | 2 +-
> arch/powerpc/include/asm/code-patching.h | 2 +-
> arch/powerpc/include/asm/elf.h | 6 ++
> arch/powerpc/include/asm/sections.h | 29 ++--------
> arch/powerpc/include/asm/types.h | 6 --
> arch/powerpc/include/uapi/asm/elf.h | 8 ---
> arch/powerpc/kernel/module_64.c | 42 ++++++--------
> arch/powerpc/kernel/ptrace/ptrace.c | 6 ++
> arch/powerpc/kernel/signal_64.c | 8 +--
> drivers/misc/lkdtm/core.c | 1 +
> drivers/misc/lkdtm/lkdtm.h | 1 +
> drivers/misc/lkdtm/perms.c | 71 +++++++++++++++++++-----
> include/asm-generic/sections.h | 15 ++++-
> include/linux/kallsyms.h | 2 +-
> kernel/extable.c | 24 +++++++-
> tools/testing/selftests/lkdtm/tests.txt | 1 +
> 25 files changed, 155 insertions(+), 144 deletions(-)
>
> --
> 2.34.1
>

--
Kees Cook