Merge branch 'next-general' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

Pull security subsystem updates from James Morris:

 - Extend LSM stacking to allow sharing of cred, file, ipc, inode, and
   task blobs. This paves the way for more full-featured LSMs to be
   merged, and is specifically aimed at LandLock and SARA LSMs. This
   work is from Casey and Kees.

 - There's a new LSM from Micah Morton: "SafeSetID gates the setid
   family of syscalls to restrict UID/GID transitions from a given
   UID/GID to only those approved by a system-wide whitelist." This
   feature is currently shipping in ChromeOS.

* 'next-general' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (62 commits)
  keys: fix missing __user in KEYCTL_PKEY_QUERY
  LSM: Update list of SECURITYFS users in Kconfig
  LSM: Ignore "security=" when "lsm=" is specified
  LSM: Update function documentation for cap_capable
  security: mark expected switch fall-throughs and add a missing break
  tomoyo: Bump version.
  LSM: fix return value check in safesetid_init_securityfs()
  LSM: SafeSetID: add selftest
  LSM: SafeSetID: remove unused include
  LSM: SafeSetID: 'depend' on CONFIG_SECURITY
  LSM: Add 'name' field for SafeSetID in DEFINE_LSM
  LSM: add SafeSetID module that gates setid calls
  LSM: add SafeSetID module that gates setid calls
  tomoyo: Allow multiple use_group lines.
  tomoyo: Coding style fix.
  tomoyo: Swicth from cred->security to task_struct->security.
  security: keys: annotate implicit fall throughs
  security: keys: annotate implicit fall throughs
  security: keys: annotate implicit fall through
  capabilities:: annotate implicit fall through
  ...

1 files changed, 33 insertions, 12 deletions

diff --git a/kernel/capability.c b/kernel/capability.c
index 1e1c0236f55b..1444f3954d75 100644
--- a/kernel/capability.c
+++ b/kernel/capability.c
@@ -93,9 +93,7 @@ static int cap_validate_magic(cap_user_header_t header, unsigned *tocopy)
 		break;
 	case _LINUX_CAPABILITY_VERSION_2:
 		warn_deprecated_v2();
-		/*
-		 * fall through - v3 is otherwise equivalent to v2.
-		 */
+		/* fall through - v3 is otherwise equivalent to v2. */
 	case _LINUX_CAPABILITY_VERSION_3:
 		*tocopy = _LINUX_CAPABILITY_U32S_3;
 		break;
@@ -299,7 +297,7 @@ bool has_ns_capability(struct task_struct *t,
 	int ret;
 
 	rcu_read_lock();
-	ret = security_capable(__task_cred(t), ns, cap);
+	ret = security_capable(__task_cred(t), ns, cap, CAP_OPT_NONE);
 	rcu_read_unlock();
 
 	return (ret == 0);
@@ -340,7 +338,7 @@ bool has_ns_capability_noaudit(struct task_struct *t,
 	int ret;
 
 	rcu_read_lock();
-	ret = security_capable_noaudit(__task_cred(t), ns, cap);
+	ret = security_capable(__task_cred(t), ns, cap, CAP_OPT_NOAUDIT);
 	rcu_read_unlock();
 
 	return (ret == 0);
@@ -363,7 +361,9 @@ bool has_capability_noaudit(struct task_struct *t, int cap)
 	return has_ns_capability_noaudit(t, &init_user_ns, cap);
 }
 
-static bool ns_capable_common(struct user_namespace *ns, int cap, bool audit)
+static bool ns_capable_common(struct user_namespace *ns,
+			      int cap,
+			      unsigned int opts)
 {
 	int capable;
 
@@ -372,8 +372,7 @@ static bool ns_capable_common(struct user_namespace *ns, int cap, bool audit)
 		BUG();
 	}
 
-	capable = audit ? security_capable(current_cred(), ns, cap) :
-			  security_capable_noaudit(current_cred(), ns, cap);
+	capable = security_capable(current_cred(), ns, cap, opts);
 	if (capable == 0) {
 		current->flags |= PF_SUPERPRIV;
 		return true;
@@ -394,7 +393,7 @@ static bool ns_capable_common(struct user_namespace *ns, int cap, bool audit)
  */
 bool ns_capable(struct user_namespace *ns, int cap)
 {
-	return ns_capable_common(ns, cap, true);
+	return ns_capable_common(ns, cap, CAP_OPT_NONE);
 }
 EXPORT_SYMBOL(ns_capable);
 
@@ -412,11 +411,30 @@ EXPORT_SYMBOL(ns_capable);
  */
 bool ns_capable_noaudit(struct user_namespace *ns, int cap)
 {
-	return ns_capable_common(ns, cap, false);
+	return ns_capable_common(ns, cap, CAP_OPT_NOAUDIT);
 }
 EXPORT_SYMBOL(ns_capable_noaudit);
 
 /**
+ * ns_capable_setid - Determine if the current task has a superior capability
+ * in effect, while signalling that this check is being done from within a
+ * setid syscall.
+ * @ns:  The usernamespace we want the capability in
+ * @cap: The capability to be tested for
+ *
+ * Return true if the current task has the given superior capability currently
+ * available for use, false if not.
+ *
+ * This sets PF_SUPERPRIV on the task if the capability is available on the
+ * assumption that it's about to be used.
+ */
+bool ns_capable_setid(struct user_namespace *ns, int cap)
+{
+	return ns_capable_common(ns, cap, CAP_OPT_INSETID);
+}
+EXPORT_SYMBOL(ns_capable_setid);
+
+/**
  * capable - Determine if the current task has a superior capability in effect
  * @cap: The capability to be tested for
  *
@@ -448,10 +466,11 @@ EXPORT_SYMBOL(capable);
 bool file_ns_capable(const struct file *file, struct user_namespace *ns,
 		     int cap)
 {
+
 	if (WARN_ON_ONCE(!cap_valid(cap)))
 		return false;
 
-	if (security_capable(file->f_cred, ns, cap) == 0)
+	if (security_capable(file->f_cred, ns, cap, CAP_OPT_NONE) == 0)
 		return true;
 
 	return false;
@@ -500,10 +519,12 @@ bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns)
 {
 	int ret = 0;  /* An absent tracer adds no restrictions */
 	const struct cred *cred;
+
 	rcu_read_lock();
 	cred = rcu_dereference(tsk->ptracer_cred);
 	if (cred)
-		ret = security_capable_noaudit(cred, ns, CAP_SYS_PTRACE);
+		ret = security_capable(cred, ns, CAP_SYS_PTRACE,
+				       CAP_OPT_NOAUDIT);
 	rcu_read_unlock();
 	return (ret == 0);
 }