[PATCH v2 00/10] Improve the copy of task comm

[Yafang Shao]

Using {memcpy,strncpy,strcpy,kstrdup} to copy the task comm relies on the
length of task comm. Changes in the task comm could result in a destination
string that is overflow. Therefore, we should explicitly ensure the destination
string is always NUL-terminated, regardless of the task comm. This approach
will facilitate future extensions to the task comm.

As suggested by Linus [0], we can identify all relevant code with the
following git grep command:

  git grep 'memcpy.*->comm\>'
  git grep 'kstrdup.*->comm\>'
  git grep 'strncpy.*->comm\>'
  git grep 'strcpy.*->comm\>'

PATCH #2~#4:  memcpy
PATCH #5:     kstrdup
PATCH #6~#8:  strncpy
PATCH #9~#10: strcpy

Suggested-by: Linus Torvalds <torvalds at linux-foundation.org>
Link: https://lore.kernel.org/all/CAHk-=wjAmmHUg6vho1KjzQi2=psR30+CogFd4aXrThr2gsiS4g@mail.gmail.com/ [0]

Changes:
v1->v2:
- Add comment for dropping task_lock() in __get_task_comm() (Alexei)
- Drop changes in trace event (Steven)
- Fix comment on task comm (Matus)
  
v1: https://lore.kernel.org/all/20240602023754.25443-1-laoar.shao@gmail.com/

Yafang Shao (10):
  fs/exec: Drop task_lock() inside __get_task_comm()
  auditsc: Replace memcpy() with __get_task_comm()
  security: Replace memcpy() with __get_task_comm()
  bpftool: Ensure task comm is always NUL-terminated
  mm/util: Fix possible race condition in kstrdup()
  mm/kmemleak: Replace strncpy() with __get_task_comm()
  tsacct: Replace strncpy() with __get_task_comm()
  tracing: Replace strncpy() with __get_task_comm()
  net: Replace strcpy() with __get_task_comm()
  drm: Replace strcpy() with __get_task_comm()

 drivers/gpu/drm/drm_framebuffer.c     |  2 +-
 drivers/gpu/drm/i915/i915_gpu_error.c |  2 +-
 fs/exec.c                             | 10 ++++++++--
 include/linux/sched.h                 |  4 ++--
 kernel/auditsc.c                      |  6 +++---
 kernel/trace/trace.c                  |  2 +-
 kernel/trace/trace_events_hist.c      |  2 +-
 kernel/tsacct.c                       |  2 +-
 mm/kmemleak.c                         |  8 +-------
 mm/util.c                             |  4 +++-
 net/ipv6/ndisc.c                      |  2 +-
 security/lsm_audit.c                  |  4 ++--
 security/selinux/selinuxfs.c          |  2 +-
 tools/bpf/bpftool/pids.c              |  2 ++
 14 files changed, 28 insertions(+), 24 deletions(-)

-- 
2.39.1