Re: [RFC PATCH 1/2] NetLabel: Allow passing the LSM domain as a shared pointer

[Casey Schaufler <casey@schaufler-ca.com>]

--- Paul Moore <paul.moore@hp.com> wrote:

> Smack doesn't have the need to create a private copy of the LSM "domain" when
> setting NetLabel security attributes like SELinux, however, the current
> NetLabel code requires a private copy of the LSM "domain".  This patches
> fixes
> that by letting the LSM determine how it wants to pass the domain value.
> 
>  * NETLBL_SECATTR_DOMAIN_CPY
>    The current behavior, NetLabel assumes that the domain value is a copy and
>    frees it when done
> 
>  * NETLBL_SECATTR_DOMAIN
>    New, Smack-friendly behavior, NetLabel assumes that the domain value is a
>    reference to a string managed by the LSM and does not free it when done
> 
> Signed-off-by: Paul Moore <paul.moore@hp.com>

Acked-by: Casey Schaufler <casey@schaufler-ca.com>

Works fine for Smack. Sorry for the delay. Real Life and RSA
got in the way.

> ---
> 
>  include/net/netlabel.h         |   14 ++++++++++----
>  security/selinux/ss/services.c |    2 +-
>  security/smack/smack_lsm.c     |    2 +-
>  3 files changed, 12 insertions(+), 6 deletions(-)
> 
> diff --git a/include/net/netlabel.h b/include/net/netlabel.h
> index 0ca67d7..5e53a85 100644
> --- a/include/net/netlabel.h
> +++ b/include/net/netlabel.h
> @@ -162,7 +162,7 @@ struct netlbl_lsm_secattr_catmap {
>  
>  /**
>   * struct netlbl_lsm_secattr - NetLabel LSM security attributes
> - * @flags: indicate which attributes are contained in this structure
> + * @flags: indicate structure attributes, see NETLBL_SECATTR_*
>   * @type: indicate the NLTYPE of the attributes
>   * @domain: the NetLabel LSM domain
>   * @cache: NetLabel LSM specific cache
> @@ -180,17 +180,22 @@ struct netlbl_lsm_secattr_catmap {
>   * NetLabel itself when returning security attributes to the LSM.
>   *
>   */
> +struct netlbl_lsm_secattr {
> +	u32 flags;
> +	/* bitmap values for 'flags' */
>  #define NETLBL_SECATTR_NONE             0x00000000
>  #define NETLBL_SECATTR_DOMAIN           0x00000001
> +#define NETLBL_SECATTR_DOMAIN_CPY       (NETLBL_SECATTR_DOMAIN | \
> +					 NETLBL_SECATTR_FREE_DOMAIN)
>  #define NETLBL_SECATTR_CACHE            0x00000002
>  #define NETLBL_SECATTR_MLS_LVL          0x00000004
>  #define NETLBL_SECATTR_MLS_CAT          0x00000008
>  #define NETLBL_SECATTR_SECID            0x00000010
> +	/* bitmap meta-values for 'flags' */
> +#define NETLBL_SECATTR_FREE_DOMAIN      0x01000000
>  #define NETLBL_SECATTR_CACHEABLE        (NETLBL_SECATTR_MLS_LVL | \
>  					 NETLBL_SECATTR_MLS_CAT | \
>  					 NETLBL_SECATTR_SECID)
> -struct netlbl_lsm_secattr {
> -	u32 flags;
>  	u32 type;
>  	char *domain;
>  	struct netlbl_lsm_cache *cache;
> @@ -303,7 +308,8 @@ static inline void netlbl_secattr_init(struct
> netlbl_lsm_secattr *secattr)
>   */
>  static inline void netlbl_secattr_destroy(struct netlbl_lsm_secattr
> *secattr)
>  {
> -	kfree(secattr->domain);
> +	if (secattr->flags & NETLBL_SECATTR_FREE_DOMAIN)
> +		kfree(secattr->domain);
>  	if (secattr->flags & NETLBL_SECATTR_CACHE)
>  		netlbl_secattr_cache_free(secattr->cache);
>  	if (secattr->flags & NETLBL_SECATTR_MLS_CAT)
> diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
> index f374186..47295ac 100644
> --- a/security/selinux/ss/services.c
> +++ b/security/selinux/ss/services.c
> @@ -2649,7 +2649,7 @@ int security_netlbl_sid_to_secattr(u32 sid, struct
> netlbl_lsm_secattr *secattr)
>  		goto netlbl_sid_to_secattr_failure;
>  	secattr->domain = kstrdup(policydb.p_type_val_to_name[ctx->type - 1],
>  				  GFP_ATOMIC);
> -	secattr->flags |= NETLBL_SECATTR_DOMAIN;
> +	secattr->flags |= NETLBL_SECATTR_DOMAIN_CPY;
>  	mls_export_netlbl_lvl(ctx, secattr);
>  	rc = mls_export_netlbl_cat(ctx, secattr);
>  	if (rc != 0)
> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
> index 732ba27..e2d6f7c 100644
> --- a/security/smack/smack_lsm.c
> +++ b/security/smack/smack_lsm.c
> @@ -1275,7 +1275,7 @@ static void smack_to_secattr(char *smack, struct
> netlbl_lsm_secattr *nlsp)
>  
>  	switch (smack_net_nltype) {
>  	case NETLBL_NLTYPE_CIPSOV4:
> -		nlsp->domain = kstrdup(smack, GFP_ATOMIC);
> +		nlsp->domain = smack;
>  		nlsp->flags = NETLBL_SECATTR_DOMAIN | NETLBL_SECATTR_MLS_LVL;
>  
>  		rc = smack_to_cipso(smack, &cipso);
> 
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> 
> 
> 


Casey Schaufler
casey@schaufler-ca.com

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