Messages in this thread Patch in this message | | | Date | Wed, 13 Oct 2021 11:16:51 -0700 | Subject | [PATCH v5 08/15] lkdtm: Use an opaque type for lkdtm_rodata_do_nothing | From | Sami Tolvanen <> |
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Use an opaque type for lkdtm_rodata_do_nothing to stop the compiler from generating a CFI jump table entry that jumps to .rodata.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Acked-by: Kees Cook <keescook@chromium.org> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> --- drivers/misc/lkdtm/lkdtm.h | 2 +- drivers/misc/lkdtm/perms.c | 2 +- drivers/misc/lkdtm/rodata.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h index c212a253edde..35535c422939 100644 --- a/drivers/misc/lkdtm/lkdtm.h +++ b/drivers/misc/lkdtm/lkdtm.h @@ -137,7 +137,7 @@ void lkdtm_REFCOUNT_TIMING(void); void lkdtm_ATOMIC_TIMING(void); /* rodata.c */ -void lkdtm_rodata_do_nothing(void); +DECLARE_NOT_CALLED_FROM_C(lkdtm_rodata_do_nothing); /* usercopy.c */ void __init lkdtm_usercopy_init(void); diff --git a/drivers/misc/lkdtm/perms.c b/drivers/misc/lkdtm/perms.c index 2dede2ef658f..fa2bd90bd8ee 100644 --- a/drivers/misc/lkdtm/perms.c +++ b/drivers/misc/lkdtm/perms.c @@ -151,7 +151,7 @@ void lkdtm_EXEC_VMALLOC(void) void lkdtm_EXEC_RODATA(void) { - execute_location(lkdtm_rodata_do_nothing, CODE_AS_IS); + execute_location((void *)lkdtm_rodata_do_nothing, CODE_AS_IS); } void lkdtm_EXEC_USERSPACE(void) diff --git a/drivers/misc/lkdtm/rodata.c b/drivers/misc/lkdtm/rodata.c index baacb876d1d9..17ed0ad4e6ae 100644 --- a/drivers/misc/lkdtm/rodata.c +++ b/drivers/misc/lkdtm/rodata.c @@ -3,7 +3,7 @@ * This includes functions that are meant to live entirely in .rodata * (via objcopy tricks), to validate the non-executability of .rodata. */ -#include "lkdtm.h" +void lkdtm_rodata_do_nothing(void); void noinstr lkdtm_rodata_do_nothing(void) { -- 2.33.0.1079.g6e70778dc9-goog
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