On Fri, Oct 01, 2021 at 10:55:21AM -0700, Todd Kjos wrote:
> Save the struct cred associated with a binder process
> at initial open to avoid potential race conditions
> when converting to a security ID.
>
> Since binder was integrated with selinux, it has passed
> 'struct task_struct' associated with the binder_proc
> to represent the source and target of transactions.
> The conversion of task to SID was then done in the hook
> implementations. It turns out that there are race conditions
> which can result in an incorrect security context being used.
>
> Fix by saving the 'struct cred' during binder_open and pass
> it to the selinux subsystem.
>
> Fixes: 79af73079d75 ("Add security hooks to binder and implement the
> hooks for SELinux.")
> Signed-off-by: Todd Kjos <tkjos@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx # 5.14+ (need backport for earlier stables)
> ---
> v2: updated comments as suggested by Paul Moore
>
> drivers/android/binder.c | 14 +++++----
> drivers/android/binder_internal.h | 4 +++
> include/linux/lsm_hook_defs.h | 14 ++++-----
> include/linux/lsm_hooks.h | 14 ++++-----
> include/linux/security.h | 28 +++++++++---------
> security/security.c | 14 ++++-----
> security/selinux/hooks.c | 48 +++++++++----------------------
> 7 files changed, 60 insertions(+), 76 deletions(-)
Ideally I could get an ack from the security developers before taking
this in my tree...
thanks,
greg k-h
