[PATCH v4 0/3] sysfs: Unconditionally use vmalloc for buffer

[Kees Cook]

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@xxxxxxxxxxxx/
v2: https://lore.kernel.org/lkml/20210315174851.622228-1-keescook@xxxxxxxxxxxx/
v1: https://lore.kernel.org/lkml/20210312205558.2947488-1-keescook@xxxxxxxxxxxx/

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(-)

-- 
2.25.1