Re: [PATCH v14 3/6] LSM: Explicit individual LSM associations

[Kees Cook]

On Thu, Jul 25, 2013 at 11:32 AM, Casey Schaufler
<casey@xxxxxxxxxxxxxxxx> wrote:
> Subject: [PATCH v14 3/6] LSM: Explicit individual LSM associations
> [...]
> Introduce feature specific security operation vectors
> for NetLabel, XFRM, secmark and presentation in the
> traditional /proc/.../attr interfaces. This allows
> proper handling of secids.
> [...]
> --- a/include/linux/lsm.h
> +++ b/include/linux/lsm.h
> @@ -164,9 +164,18 @@ static inline void lsm_init_secid(struct secids *secid, u32 lsecid, int order)
>  {
>         memset(secid, 0, sizeof(*secid));
>
> -       if (lsecid != 0)
> +       if (lsecid == 0)
> +               return;
> +       /*
> +        * An order of -1 means set it for all LSMs.
> +        */
> +       if (order < 0) {
> +               secid->si_lsm[0] = lsecid;
> +               secid->si_count++;
> +       } else {
> +               secid->si_lsm[order] = lsecid;
>                 secid->si_count = 1;
> -       secid->si_lsm[order] = lsecid;
> +       }
>  }
>
>  static inline int lsm_zero_secid(struct secids *secid)
> @@ -178,39 +187,64 @@ static inline int lsm_zero_secid(struct secids *secid)
>
>  #ifdef CONFIG_SECURITY
>
> +extern struct security_operations *present_ops;
>  static inline struct security_operations *lsm_present_ops(void)
>  {
> -       return security_ops;
> +       return present_ops;
>  }
>
>  static inline int lsm_present_order(void)
>  {
> -       return 0;
> +       return present_ops->order;
>  }
>
> +#ifdef CONFIG_NETLABEL
> +extern struct security_operations *netlbl_ops;
> +
>  static inline struct security_operations *lsm_netlbl_ops(void)
>  {
> -       return security_ops;
> +       return netlbl_ops;
>  }
>
>  static inline int lsm_netlbl_order(void)
>  {
> -       return 0;
> +       return netlbl_ops->order;
>  }
> +#endif /* CONFIG_NETLABEL */
> +
> +#ifdef CONFIG_SECURITY_NETWORK_XFRM
> +extern struct security_operations *xfrm_ops;
>
>  static inline struct security_operations *lsm_xfrm_ops(void)
>  {
> -       return security_ops;
> +       return xfrm_ops;
>  }
>
>  static inline int lsm_xfrm_order(void)
>  {
> -       return 0;
> +       return xfrm_ops->order;
>  }
> +#endif /* CONFIG_SECURITY_NETWORK_XFRM */
> +
> +#ifdef CONFIG_NETWORK_SECMARK
> +extern struct security_operations *secmark_ops;
>
>  static inline struct security_operations *lsm_secmark_ops(void)
>  {
> -       return security_ops;
> +       return secmark_ops;
> +}
> +
> +static inline int lsm_secmark_order(void)
> +{
> +       return secmark_ops->order;
> +}
> +#endif /* CONFIG_NETWORK_SECMARK */
> +
> +#else /* CONFIG_SECURITY */
> +
> +static inline int lsm_xfrm_order(void)
> +{
> +       return 0;
>  }
>
>  static inline int lsm_secmark_order(void)
> @@ -218,6 +252,11 @@ static inline int lsm_secmark_order(void)
>         return 0;
>  }
>
> +static inline struct security_operations *lsm_secmark_ops(void)
> +{
> +       return NULL;
> +}
> +
>  #endif /* CONFIG_SECURITY */
>
>  #endif /* ! _LINUX_LSM_H */

Something went wrong here with the #ifdef/#else stuff here. I built
without CONFIG_SECURITY_NETWORK_XFRM and it fails, missing
lsm_xfrm_order().

If I added an #else to the CONFIG_SECURITY_NETWORK_XFRM check and made
lsm_xfrm_order() return 0 there too, it built fine.

-Kees

-- 
Kees Cook
Chrome OS Security
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