[PATCH] security: declare member holding string literal const

[Christian Göttsche]

On Thu, 17 Feb 2022 at 23:50, Casey Schaufler <casey at schaufler-ca.com> wrote:
>
> On 2/17/2022 6:18 AM, Christian Göttsche wrote:
> > The struct security_hook_list member lsm is assigned in
> > security_add_hooks() with string literals passed from the individual
> > security modules.  Declare the function parameter and the struct member
> > const to signal their immutability.
> >
> > Reported by Clang [-Wwrite-strings]:
> >
> >      security/selinux/hooks.c:7388:63: error: passing 'const char [8]' to parameter of type 'char *' discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers]
> >              security_add_hooks(selinux_hooks, ARRAY_SIZE(selinux_hooks), selinux);
> >                                                                           ^~~~~~~~~
> >      ./include/linux/lsm_hooks.h:1629:11: note: passing argument to parameter 'lsm' here
> >                                      char *lsm);
> >                                            ^
> >
> > Signed-off-by: Christian Göttsche <cgzones at googlemail.com>
>
> Reviewed-by: Casey Schaufler <casey at schaufler-ca.com>
>

Kindly ping;
any progress on this one?

> > ---
> >   include/linux/lsm_hooks.h | 4 ++--
> >   security/security.c       | 2 +-
> >   2 files changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
> > index 419b5febc3ca..47cdf3fbecef 100644
> > --- a/include/linux/lsm_hooks.h
> > +++ b/include/linux/lsm_hooks.h
> > @@ -1595,7 +1595,7 @@ struct security_hook_list {
> >       struct hlist_node               list;
> >       struct hlist_head               *head;
> >       union security_list_options     hook;
> > -     char                            *lsm;
> > +     const char                      *lsm;
> >   } __randomize_layout;
> >
> >   /*
> > @@ -1630,7 +1630,7 @@ extern struct security_hook_heads security_hook_heads;
> >   extern char *lsm_names;
> >
> >   extern void security_add_hooks(struct security_hook_list *hooks, int count,
> > -                             char *lsm);
> > +                             const char *lsm);
> >
> >   #define LSM_FLAG_LEGACY_MAJOR       BIT(0)
> >   #define LSM_FLAG_EXCLUSIVE  BIT(1)
> > diff --git a/security/security.c b/security/security.c
> > index 9663ffcca4b0..a48eb3badfdd 100644
> > --- a/security/security.c
> > +++ b/security/security.c
> > @@ -478,7 +478,7 @@ static int lsm_append(const char *new, char **result)
> >    * Each LSM has to register its hooks with the infrastructure.
> >    */
> >   void __init security_add_hooks(struct security_hook_list *hooks, int count,
> > -                             char *lsm)
> > +                             const char *lsm)
> >   {
> >       int i;
> >