lkml.org 
[lkml]   [2021]   [Oct]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    Subject[PATCH v5 08/15] lkdtm: Use an opaque type for lkdtm_rodata_do_nothing
    From
    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
    \
     
     \ /
      Last update: 2021-10-13 20:18    [W:4.022 / U:0.096 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site