Re: [PATCH] security: declare member holding string literal const

From: Christian Göttsche
Date: Mon May 02 2022 - 09:38:47 EST


On Thu, 17 Feb 2022 at 23:50, Casey Schaufler <casey@xxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxx>
>
> Reviewed-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
>

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;
> >