--- David Howells <dhowells@xxxxxxxxxx> wrote:
> Remove the temporarily embedded task security record from task_struct.
> Instead
> it is made to dangle from the task_struct::sec and task_struct::act_as
> pointers
> with references counted for each.
>
> ...
>
> The LSM hooks for dealing with task security are modified to deal with the
> task
> security struct directly rather than going via the task_struct as appopriate.
>
> ...
> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
> index a49d94f..dbce607 100644
> --- a/security/smack/smack_lsm.c
> +++ b/security/smack/smack_lsm.c
> @@ -957,9 +957,22 @@ static int smack_task_alloc_security(struct task_struct
> *tsk)
> * points to an immutable list. The blobs never go away.
> * There is no leak here.
> */
> -static void smack_task_free_security(struct task_struct *task)
> +static void smack_task_free_security(struct task_security *sec)
> {
> - task->sec->security = NULL;
> + sec->security = NULL;
> +}
> +
> +/**
> + * task_dup_security - Duplicate task security
> + * @p points to the task_security struct that has been copied
> + *
> + * Duplicate the security structure currently attached to the p->security
> field
> + * and attach back to p->security (the pointer itself was copied, so there's
> + * nothing to be done here).
> + */
> +static int smack_task_dup_security(struct task_security *sec)
> +{
> + return 0;
> }
Thank you for adding this hook. The comment is helpful.
> /**
> @@ -2276,17 +2289,17 @@ static int smack_inet_conn_request(struct sock *sk,
> struct sk_buff *skb,
> /**
> * smack_key_alloc - Set the key security blob
> * @key: object
> - * @tsk: the task associated with the key
> + * @context: the task security associated with the key
> * @flags: unused
> *
> * No allocation required
> *
> * Returns 0
> */
> -static int smack_key_alloc(struct key *key, struct task_struct *tsk,
> +static int smack_key_alloc(struct key *key, struct task_security *context,
> unsigned long flags)
> {
> - key->security = tsk->act_as->security;
> + key->security = context->security;
> return 0;
> }
>
> @@ -2304,14 +2317,14 @@ static void smack_key_free(struct key *key)
> /*
> * smack_key_permission - Smack access on a key
> * @key_ref: gets to the object
> - * @context: task involved
> + * @context: task security involved
> * @perm: unused
> *
> * Return 0 if the task has read and write to the object,
> * an error code otherwise
> */
> static int smack_key_permission(key_ref_t key_ref,
> - struct task_struct *context, key_perm_t perm)
> + struct task_security *context, key_perm_t perm)
> {
> struct key *keyp;
>
> @@ -2327,10 +2340,10 @@ static int smack_key_permission(key_ref_t key_ref,
> /*
> * This should not occur
> */
> - if (context->act_as->security == NULL)
> + if (context->security == NULL)
> return -EACCES;
>
> - return smk_access(context->act_as->security, keyp->security,
> + return smk_access(context->security, keyp->security,
> MAY_READWRITE);
> }
> #endif /* CONFIG_KEYS */
> @@ -2430,6 +2443,7 @@ static struct security_operations smack_ops = {
>
> .task_alloc_security = smack_task_alloc_security,
> .task_free_security = smack_task_free_security,
> + .task_dup_security = smack_task_dup_security,
> .task_post_setuid = cap_task_post_setuid,
> .task_setpgid = smack_task_setpgid,
> .task_getpgid = smack_task_getpgid,
No objections from the Smack side. Thank you.
Casey Schaufler
casey@xxxxxxxxxxxxxxxx
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