[v2] Alter fcntl to handle int arguments correctly

[PATCH v2 0/5] Alter fcntl to handle int arguments correctly

Posted by Luca Vizzarro 2 years, 8 months ago

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@arm.com/
And was discovered during the porting of Linux to Morello [1].

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-v2

Best regards,
Luca Vizzarro

[1] https://git.morello-project.org/morello/kernel/linux

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

Re: [PATCH v2 0/5] Alter fcntl to handle int arguments correctly

Posted by Christian Brauner 2 years, 5 months ago

On Fri, Apr 14, 2023 at 04:24:54PM +0100, Luca Vizzarro wrote:
> 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@arm.com/
> And was discovered during the porting of Linux to Morello [1].
> 
> 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-v2
> 
> Best regards,
> Luca Vizzarro
> 
> [1] https://git.morello-project.org/morello/kernel/linux
> 
> 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

Applied, minus the already upstreamed memfd patch.