[PATCH 0/5] Alter fcntl to handle int arguments correctly

From: Luca Vizzarro
Date: Fri Apr 14 2023 - 06:03:01 EST


According to the documentation of fcntl, some commands take an int as
argument. In practice not all of them enforce this behaviour, as they
instead accept a more permissive long and in most cases not even a
range check is performed.

An issue could possibly arise from a combination of the handling of the
varargs in user space and the ABI rules of the target, which may result
in the top bits of an int argument being non-zero.

This issue was originally raised and detailed in the following thread:
https://lore.kernel.org/linux-api/Y1%2FDS6uoWP7OSkmd@xxxxxxx/

This series modifies the interested commands so that they explicitly
take an int argument. It also propagates this change down to helper and
related functions as necessary.

This series is also available on my fork at:
https://git.morello-project.org/Sevenarth/linux/-/commits/fcntl-int-handling

Best regards,
Luca Vizzarro

Luca Vizzarro (5):
fcntl: Cast commands with int args explicitly
fs: Pass argument to fcntl_setlease as int
pipe: Pass argument of pipe_fcntl as int
memfd: Pass argument of memfd_fcntl as int
dnotify: Pass argument of fcntl_dirnotify as int

fs/cifs/cifsfs.c | 2 +-
fs/fcntl.c | 29 +++++++++++++++--------------
fs/libfs.c | 2 +-
fs/locks.c | 20 ++++++++++----------
fs/nfs/nfs4_fs.h | 2 +-
fs/nfs/nfs4file.c | 2 +-
fs/nfs/nfs4proc.c | 4 ++--
fs/notify/dnotify/dnotify.c | 4 ++--
fs/pipe.c | 6 +++---
include/linux/dnotify.h | 4 ++--
include/linux/filelock.h | 12 ++++++------
include/linux/fs.h | 6 +++---
include/linux/memfd.h | 4 ++--
include/linux/pipe_fs_i.h | 4 ++--
mm/memfd.c | 6 +-----
15 files changed, 52 insertions(+), 55 deletions(-)

--
2.34.1

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