This series improves the defensive posture of sysfs's use of seq_file to gain the vmap guard pages at the end of vmalloc buffers to stop a class of recurring flaw[1]. The long-term goal is to switch sysfs from a buffer to using seq_file directly, but this will take time to refactor.
Included is also a Clang fix for NULL arithmetic and an LKDTM test to validate vmalloc guard pages.
v4: - fix NULL arithmetic (Arnd) - add lkdtm test - reword commit message v3: https://lore.kernel.org/lkml/20210401022145.2019422-1-keescook@chromium.org/ v2: https://lore.kernel.org/lkml/20210315174851.622228-1-keescook@chromium.org/ v1: https://lore.kernel.org/lkml/20210312205558.2947488-1-keescook@chromium.org/
Thanks!
-Kees
Arnd Bergmann (1): seq_file: Fix clang warning for NULL pointer arithmetic
Kees Cook (2): lkdtm/heap: Add vmalloc linear overflow test sysfs: Unconditionally use vmalloc for buffer
drivers/misc/lkdtm/core.c | 3 ++- drivers/misc/lkdtm/heap.c | 21 +++++++++++++++++- drivers/misc/lkdtm/lkdtm.h | 3 ++- fs/kernfs/file.c | 9 +++++--- fs/seq_file.c | 5 ++++- fs/sysfs/file.c | 29 +++++++++++++++++++++++++ include/linux/seq_file.h | 6 +++++ tools/testing/selftests/lkdtm/tests.txt | 3 ++- 8 files changed, 71 insertions(+), 8 deletions(-)