Merge branch 'next-smack' of git://git.kernel.org/pub/scm/linux/kerne…

…l/git/jmorris/linux-security

Pull smack updates from James Morris:
 "From Casey: three patches for Smack for 4.20. Two clean up warnings
  and one is a rarely encountered ptrace capability check"

* 'next-smack' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  Smack: Mark expected switch fall-through
  Smack: ptrace capability use fixes
  Smack: remove set but not used variable 'root_inode'

security/smack/smack_lsm.c

@@ -421,6 +421,7 @@ static int smk_ptrace_rule_check(struct task_struct *tracer,
 	struct smk_audit_info ad, *saip = NULL;
 	struct task_smack *tsp;
 	struct smack_known *tracer_known;
+	const struct cred *tracercred;
 
 	if ((mode & PTRACE_MODE_NOAUDIT) == 0) {
 		smk_ad_init(&ad, func, LSM_AUDIT_DATA_TASK);
@@ -429,7 +430,8 @@ static int smk_ptrace_rule_check(struct task_struct *tracer,
 	}
 
 	rcu_read_lock();
-	tsp = __task_cred(tracer)->security;
+	tracercred = __task_cred(tracer);
+	tsp = tracercred->security;
 	tracer_known = smk_of_task(tsp);
 
 	if ((mode & PTRACE_MODE_ATTACH) &&
@@ -439,7 +441,7 @@ static int smk_ptrace_rule_check(struct task_struct *tracer,
 			rc = 0;
 		else if (smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)
 			rc = -EACCES;
-		else if (capable(CAP_SYS_PTRACE))
+		else if (smack_privileged_cred(CAP_SYS_PTRACE, tracercred))
 			rc = 0;
 		else
 			rc = -EACCES;
@@ -1841,6 +1843,7 @@ static int smack_file_send_sigiotask(struct task_struct *tsk,
 {
 	struct smack_known *skp;
 	struct smack_known *tkp = smk_of_task(tsk->cred->security);
+	const struct cred *tcred;
 	struct file *file;
 	int rc;
 	struct smk_audit_info ad;
@@ -1854,8 +1857,12 @@ static int smack_file_send_sigiotask(struct task_struct *tsk,
 	skp = file->f_security;
 	rc = smk_access(skp, tkp, MAY_DELIVER, NULL);
 	rc = smk_bu_note("sigiotask", skp, tkp, MAY_DELIVER, rc);
-	if (rc != 0 && has_capability(tsk, CAP_MAC_OVERRIDE))
+
+	rcu_read_lock();
+	tcred = __task_cred(tsk);
+	if (rc != 0 && smack_privileged_cred(CAP_MAC_OVERRIDE, tcred))
 		rc = 0;
+	rcu_read_unlock();
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
 	smk_ad_setfield_u_tsk(&ad, tsk);
@@ -3467,7 +3474,7 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
 		 */
 		final = &smack_known_star;
 		/*
-		 * No break.
+		 * Fall through.
 		 *
 		 * If a smack value has been set we want to use it,
 		 * but since tmpfs isn't giving us the opportunity

security/smack/smackfs.c

@@ -2853,7 +2853,6 @@ static const struct file_operations smk_ptrace_ops = {
 static int smk_fill_super(struct super_block *sb, void *data, int silent)
 {
 	int rc;
-	struct inode *root_inode;
 
 	static const struct tree_descr smack_files[] = {
 		[SMK_LOAD] = {
@@ -2917,8 +2916,6 @@ static int smk_fill_super(struct super_block *sb, void *data, int silent)
 		return rc;
 	}
 
-	root_inode = d_inode(sb->s_root);
-
 	return 0;
 }