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

2 files changed, 11 insertions, 7 deletions

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 934dabe150fa..81fb4c1631e9 100644
--- a/security/smack/smack_lsm.c
+++ b/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
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index f6482e53d55a..06b517075ec0 100644
--- a/security/smack/smackfs.c
+++ b/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;
 }