proc,security: move restriction on writing /proc/pid/attr nodes to proc

Processes can only alter their own security attributes via
/proc/pid/attr nodes.  This is presently enforced by each individual
security module and is also imposed by the Linux credentials
implementation, which only allows a task to alter its own credentials.
Move the check enforcing this restriction from the individual
security modules to proc_pid_attr_write() before calling the security hook,
and drop the unnecessary task argument to the security hook since it can
only ever be the current task.

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/include/linux/security.h b/include/linux/security.h
index c2125e9093e8..f4ebac117fa6 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -361,7 +361,7 @@ int security_sem_semop(struct sem_array *sma, struct sembuf *sops,
 			unsigned nsops, int alter);
 void security_d_instantiate(struct dentry *dentry, struct inode *inode);
 int security_getprocattr(struct task_struct *p, char *name, char **value);
-int security_setprocattr(struct task_struct *p, char *name, void *value, size_t size);
+int security_setprocattr(const char *name, void *value, size_t size);
 int security_netlink_send(struct sock *sk, struct sk_buff *skb);
 int security_ismaclabel(const char *name);
 int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen);
@@ -1106,7 +1106,7 @@ static inline int security_getprocattr(struct task_struct *p, char *name, char *
 	return -EINVAL;
 }
 
-static inline int security_setprocattr(struct task_struct *p, char *name, void *value, size_t size)
+static inline int security_setprocattr(char *name, void *value, size_t size)
 {
 	return -EINVAL;
 }