Smack: Bring-up access mode

People keep asking me for permissive mode, and I keep saying "no".

Permissive mode is wrong for more reasons than I can enumerate,
but the compelling one is that it's once on, never off.

Nonetheless, there is an argument to be made for running a
process with lots of permissions, logging which are required,
and then locking the process down. There wasn't a way to do
that with Smack, but this provides it.

The notion is that you start out by giving the process an
appropriate Smack label, such as "ATBirds". You create rules
with a wide range of access and the "b" mode. On Tizen it
might be:

	ATBirds	System	rwxalb
	ATBirds	User	rwxalb
	ATBirds	_	rwxalb
	User	ATBirds	wb
	System	ATBirds	wb

Accesses that fail will generate audit records. Accesses
that succeed because of rules marked with a "b" generate
log messages identifying the rule, the program and as much
object information as is convenient.

When the system is properly configured and the programs
brought in line with the labeling scheme the "b" mode can
be removed from the rules. When the system is ready for
production the facility can be configured out.

This provides the developer the convenience of permissive
mode without creating a system that looks like it is
enforcing a policy while it is not.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

5 files changed, 294 insertions, 27 deletions

diff --git a/security/smack/Kconfig b/security/smack/Kconfig
index e69de9c642b..b065f978941 100644
--- a/security/smack/Kconfig
+++ b/security/smack/Kconfig
@@ -12,3 +12,19 @@ config SECURITY_SMACK
 	  of other mandatory security schemes.
 	  If you are unsure how to answer this question, answer N.
 
+config SECURITY_SMACK_BRINGUP
+	bool "Reporting on access granted by Smack rules"
+	depends on SECURITY_SMACK
+	default n
+	help
+	  Enable the bring-up ("b") access mode in Smack rules.
+	  When access is granted by a rule with the "b" mode a
+	  message about the access requested is generated. The
+	  intention is that a process can be granted a wide set
+	  of access initially with the bringup mode set on the
+	  rules. The developer can use the information to
+	  identify which rules are necessary and what accesses
+	  may be inappropriate. The developer can reduce the
+	  access rule set once the behavior is well understood.
+	  This is a superior mechanism to the oft abused
+	  "permissive" mode of other systems.
diff --git a/security/smack/smack.h b/security/smack/smack.h
index 020307ef097..2d13d5fb17e 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -191,6 +191,7 @@ struct smk_port_label {
  */
 #define MAY_TRANSMUTE	0x00001000	/* Controls directory labeling */
 #define MAY_LOCK	0x00002000	/* Locks should be writes, but ... */
+#define MAY_BRINGUP	0x00004000	/* Report use of this rule */
 
 /*
  * Just to make the common cases easier to deal with
@@ -200,9 +201,9 @@ struct smk_port_label {
 #define MAY_NOT		0
 
 /*
- * Number of access types used by Smack (rwxatl)
+ * Number of access types used by Smack (rwxatlb)
  */
-#define SMK_NUM_ACCESS_TYPE 6
+#define SMK_NUM_ACCESS_TYPE 7
 
 /* SMACK data */
 struct smack_audit_data {
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index f97d0842e62..9f02cb0ac85 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -178,16 +178,27 @@ int smk_access(struct smack_known *subject_known, char *object_label,
 				&subject_known->smk_rules);
 	rcu_read_unlock();
 
-	if (may > 0 && (request & may) == request)
+	if (may <= 0 || (request & may) != request) {
+		rc = -EACCES;
 		goto out_audit;
+	}
+#ifdef CONFIG_SECURITY_SMACK_BRINGUP
+	/*
+	 * Return a positive value if using bringup mode.
+	 * This allows the hooks to identify checks that
+	 * succeed because of "b" rules.
+	 */
+	if (may & MAY_BRINGUP)
+		rc = MAY_BRINGUP;
+#endif
 
-	rc = -EACCES;
 out_audit:
 #ifdef CONFIG_AUDIT
 	if (a)
 		smack_log(subject_known->smk_known, object_label, request,
 				rc, a);
 #endif
+
 	return rc;
 }
 
@@ -214,7 +225,7 @@ int smk_tskacc(struct task_smack *subject, char *obj_label,
 	 * Check the global rule list
 	 */
 	rc = smk_access(skp, obj_label, mode, NULL);
-	if (rc == 0) {
+	if (rc >= 0) {
 		/*
 		 * If there is an entry in the task's rule list
 		 * it can further restrict access.
@@ -328,6 +339,13 @@ void smack_log(char *subject_label, char *object_label, int request,
 	struct smack_audit_data *sad;
 	struct common_audit_data *a = &ad->a;
 
+#ifdef CONFIG_SECURITY_SMACK_BRINGUP
+	/*
+	 * The result may be positive in bringup mode.
+	 */
+	if (result > 0)
+		result = 0;
+#endif
 	/* check if we have to log the current event */
 	if (result != 0 && (log_policy & SMACK_AUDIT_DENIED) == 0)
 		return;
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 7091b46adab..154548ea7d8 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -54,6 +54,149 @@
 
 LIST_HEAD(smk_ipv6_port_list);
 
+#ifdef CONFIG_SECURITY_SMACK_BRINGUP
+static void smk_bu_mode(int mode, char *s)
+{
+	int i = 0;
+
+	if (mode & MAY_READ)
+		s[i++] = 'r';
+	if (mode & MAY_WRITE)
+		s[i++] = 'w';
+	if (mode & MAY_EXEC)
+		s[i++] = 'x';
+	if (mode & MAY_APPEND)
+		s[i++] = 'a';
+	if (mode & MAY_TRANSMUTE)
+		s[i++] = 't';
+	if (mode & MAY_LOCK)
+		s[i++] = 'l';
+	if (i == 0)
+		s[i++] = '-';
+	s[i] = '\0';
+}
+#endif
+
+#ifdef CONFIG_SECURITY_SMACK_BRINGUP
+static int smk_bu_note(char *note, struct smack_known *sskp, char *osp,
+			int mode, int rc)
+{
+	char acc[SMK_NUM_ACCESS_TYPE + 1];
+
+	if (rc <= 0)
+		return rc;
+
+	smk_bu_mode(mode, acc);
+	pr_info("Smack Bringup: (%s %s %s) %s\n",
+		sskp->smk_known, osp, acc, note);
+	return 0;
+}
+#else
+#define smk_bu_note(note, sskp, osp, mode, RC) (RC)
+#endif
+
+#ifdef CONFIG_SECURITY_SMACK_BRINGUP
+static int smk_bu_current(char *note, char *osp, int mode, int rc)
+{
+	struct task_smack *tsp = current_security();
+	char acc[SMK_NUM_ACCESS_TYPE + 1];
+
+	if (rc <= 0)
+		return rc;
+
+	smk_bu_mode(mode, acc);
+	pr_info("Smack Bringup: (%s %s %s) %s %s\n",
+		tsp->smk_task->smk_known, osp, acc, current->comm, note);
+	return 0;
+}
+#else
+#define smk_bu_current(note, osp, mode, RC) (RC)
+#endif
+
+#ifdef CONFIG_SECURITY_SMACK_BRINGUP
+static int smk_bu_task(struct task_struct *otp, int mode, int rc)
+{
+	struct task_smack *tsp = current_security();
+	struct task_smack *otsp = task_security(otp);
+	char acc[SMK_NUM_ACCESS_TYPE + 1];
+
+	if (rc <= 0)
+		return rc;
+
+	smk_bu_mode(mode, acc);
+	pr_info("Smack Bringup: (%s %s %s) %s to %s\n",
+		tsp->smk_task->smk_known, otsp->smk_task->smk_known, acc,
+		current->comm, otp->comm);
+	return 0;
+}
+#else
+#define smk_bu_task(otp, mode, RC) (RC)
+#endif
+
+#ifdef CONFIG_SECURITY_SMACK_BRINGUP
+static int smk_bu_inode(struct inode *inode, int mode, int rc)
+{
+	struct task_smack *tsp = current_security();
+	char acc[SMK_NUM_ACCESS_TYPE + 1];
+
+	if (rc <= 0)
+		return rc;
+
+	smk_bu_mode(mode, acc);
+	pr_info("Smack Bringup: (%s %s %s) inode=(%s %ld) %s\n",
+		tsp->smk_task->smk_known, smk_of_inode(inode), acc,
+		inode->i_sb->s_id, inode->i_ino, current->comm);
+	return 0;
+}
+#else
+#define smk_bu_inode(inode, mode, RC) (RC)
+#endif
+
+#ifdef CONFIG_SECURITY_SMACK_BRINGUP
+static int smk_bu_file(struct file *file, int mode, int rc)
+{
+	struct task_smack *tsp = current_security();
+	struct smack_known *sskp = tsp->smk_task;
+	struct inode *inode = file->f_inode;
+	char acc[SMK_NUM_ACCESS_TYPE + 1];
+
+	if (rc <= 0)
+		return rc;
+
+	smk_bu_mode(mode, acc);
+	pr_info("Smack Bringup: (%s %s %s) file=(%s %ld %s) %s\n",
+		sskp->smk_known, (char *)file->f_security, acc,
+		inode->i_sb->s_id, inode->i_ino, file->f_dentry->d_name.name,
+		current->comm);
+	return 0;
+}
+#else
+#define smk_bu_file(file, mode, RC) (RC)
+#endif
+
+#ifdef CONFIG_SECURITY_SMACK_BRINGUP
+static int smk_bu_credfile(const struct cred *cred, struct file *file,
+				int mode, int rc)
+{
+	struct task_smack *tsp = cred->security;
+	struct smack_known *sskp = tsp->smk_task;
+	struct inode *inode = file->f_inode;
+	char acc[SMK_NUM_ACCESS_TYPE + 1];
+
+	if (rc <= 0)
+		return rc;
+
+	smk_bu_mode(mode, acc);
+	pr_info("Smack Bringup: (%s %s %s) file=(%s %ld %s) %s\n",
+		sskp->smk_known, smk_of_inode(inode), acc,
+		inode->i_sb->s_id, inode->i_ino, file->f_dentry->d_name.name,
+		current->comm);
+	return 0;
+}
+#else
+#define smk_bu_credfile(cred, file, mode, RC) (RC)
+#endif
+
 /**
  * smk_fetch - Fetch the smack label from a file.
  * @ip: a pointer to the inode
@@ -507,6 +650,7 @@ static int smack_sb_statfs(struct dentry *dentry)
 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
 
 	rc = smk_curacc(sbp->smk_floor, MAY_READ, &ad);
+	rc = smk_bu_current("statfs", sbp->smk_floor, MAY_READ, rc);
 	return rc;
 }
 
@@ -697,11 +841,13 @@ static int smack_inode_link(struct dentry *old_dentry, struct inode *dir,
 
 	isp = smk_of_inode(old_dentry->d_inode);
 	rc = smk_curacc(isp, MAY_WRITE, &ad);
+	rc = smk_bu_inode(old_dentry->d_inode, MAY_WRITE, rc);
 
 	if (rc == 0 && new_dentry->d_inode != NULL) {
 		isp = smk_of_inode(new_dentry->d_inode);
 		smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
 		rc = smk_curacc(isp, MAY_WRITE, &ad);
+		rc = smk_bu_inode(new_dentry->d_inode, MAY_WRITE, rc);
 	}
 
 	return rc;
@@ -728,6 +874,7 @@ static int smack_inode_unlink(struct inode *dir, struct dentry *dentry)
 	 * You need write access to the thing you're unlinking
 	 */
 	rc = smk_curacc(smk_of_inode(ip), MAY_WRITE, &ad);
+	rc = smk_bu_inode(ip, MAY_WRITE, rc);
 	if (rc == 0) {
 		/*
 		 * You also need write access to the containing directory
@@ -735,6 +882,7 @@ static int smack_inode_unlink(struct inode *dir, struct dentry *dentry)
 		smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
 		smk_ad_setfield_u_fs_inode(&ad, dir);
 		rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad);
+		rc = smk_bu_inode(dir, MAY_WRITE, rc);
 	}
 	return rc;
 }
@@ -759,6 +907,7 @@ static int smack_inode_rmdir(struct inode *dir, struct dentry *dentry)
 	 * You need write access to the thing you're removing
 	 */
 	rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
+	rc = smk_bu_inode(dentry->d_inode, MAY_WRITE, rc);
 	if (rc == 0) {
 		/*
 		 * You also need write access to the containing directory
@@ -766,6 +915,7 @@ static int smack_inode_rmdir(struct inode *dir, struct dentry *dentry)
 		smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
 		smk_ad_setfield_u_fs_inode(&ad, dir);
 		rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad);
+		rc = smk_bu_inode(dir, MAY_WRITE, rc);
 	}
 
 	return rc;
@@ -797,11 +947,13 @@ static int smack_inode_rename(struct inode *old_inode,
 
 	isp = smk_of_inode(old_dentry->d_inode);
 	rc = smk_curacc(isp, MAY_READWRITE, &ad);
+	rc = smk_bu_inode(old_dentry->d_inode, MAY_READWRITE, rc);
 
 	if (rc == 0 && new_dentry->d_inode != NULL) {
 		isp = smk_of_inode(new_dentry->d_inode);
 		smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
 		rc = smk_curacc(isp, MAY_READWRITE, &ad);
+		rc = smk_bu_inode(new_dentry->d_inode, MAY_READWRITE, rc);
 	}
 	return rc;
 }
@@ -819,6 +971,7 @@ static int smack_inode_permission(struct inode *inode, int mask)
 {
 	struct smk_audit_info ad;
 	int no_block = mask & MAY_NOT_BLOCK;
+	int rc;
 
 	mask &= (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND);
 	/*
@@ -832,7 +985,9 @@ static int smack_inode_permission(struct inode *inode, int mask)
 		return -ECHILD;
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
 	smk_ad_setfield_u_fs_inode(&ad, inode);
-	return smk_curacc(smk_of_inode(inode), mask, &ad);
+	rc = smk_curacc(smk_of_inode(inode), mask, &ad);
+	rc = smk_bu_inode(inode, mask, rc);
+	return rc;
 }
 
 /**
@@ -845,6 +1000,8 @@ static int smack_inode_permission(struct inode *inode, int mask)
 static int smack_inode_setattr(struct dentry *dentry, struct iattr *iattr)
 {
 	struct smk_audit_info ad;
+	int rc;
+
 	/*
 	 * Need to allow for clearing the setuid bit.
 	 */
@@ -853,7 +1010,9 @@ static int smack_inode_setattr(struct dentry *dentry, struct iattr *iattr)
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
 
-	return smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
+	rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
+	rc = smk_bu_inode(dentry->d_inode, MAY_WRITE, rc);
+	return rc;
 }
 
 /**
@@ -867,13 +1026,16 @@ static int smack_inode_getattr(struct vfsmount *mnt, struct dentry *dentry)
 {
 	struct smk_audit_info ad;
 	struct path path;
+	int rc;
 
 	path.dentry = dentry;
 	path.mnt = mnt;
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
 	smk_ad_setfield_u_fs_path(&ad, path);
-	return smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ, &ad);
+	rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ, &ad);
+	rc = smk_bu_inode(dentry->d_inode, MAY_READ, rc);
+	return rc;
 }
 
 /**
@@ -932,8 +1094,10 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name,
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
 
-	if (rc == 0)
+	if (rc == 0) {
 		rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
+		rc = smk_bu_inode(dentry->d_inode, MAY_WRITE, rc);
+	}
 
 	return rc;
 }
@@ -993,11 +1157,14 @@ static void smack_inode_post_setxattr(struct dentry *dentry, const char *name,
 static int smack_inode_getxattr(struct dentry *dentry, const char *name)
 {
 	struct smk_audit_info ad;
+	int rc;
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
 
-	return smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ, &ad);
+	rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ, &ad);
+	rc = smk_bu_inode(dentry->d_inode, MAY_READ, rc);
+	return rc;
 }
 
 /**
@@ -1033,6 +1200,7 @@ static int smack_inode_removexattr(struct dentry *dentry, const char *name)
 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
 
 	rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
+	rc = smk_bu_inode(dentry->d_inode, MAY_WRITE, rc);
 	if (rc != 0)
 		return rc;
 
@@ -1213,11 +1381,15 @@ static int smack_file_ioctl(struct file *file, unsigned int cmd,
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
 	smk_ad_setfield_u_fs_path(&ad, file->f_path);
 
-	if (_IOC_DIR(cmd) & _IOC_WRITE)
+	if (_IOC_DIR(cmd) & _IOC_WRITE) {
 		rc = smk_curacc(file->f_security, MAY_WRITE, &ad);
+		rc = smk_bu_file(file, MAY_WRITE, rc);
+	}
 
-	if (rc == 0 && (_IOC_DIR(cmd) & _IOC_READ))
+	if (rc == 0 && (_IOC_DIR(cmd) & _IOC_READ)) {
 		rc = smk_curacc(file->f_security, MAY_READ, &ad);
+		rc = smk_bu_file(file, MAY_READ, rc);
+	}
 
 	return rc;
 }
@@ -1232,10 +1404,13 @@ static int smack_file_ioctl(struct file *file, unsigned int cmd,
 static int smack_file_lock(struct file *file, unsigned int cmd)
 {
 	struct smk_audit_info ad;
+	int rc;
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
 	smk_ad_setfield_u_fs_path(&ad, file->f_path);
-	return smk_curacc(file->f_security, MAY_LOCK, &ad);
+	rc = smk_curacc(file->f_security, MAY_LOCK, &ad);
+	rc = smk_bu_file(file, MAY_LOCK, rc);
+	return rc;
 }
 
 /**
@@ -1265,12 +1440,14 @@ static int smack_file_fcntl(struct file *file, unsigned int cmd,
 		smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
 		smk_ad_setfield_u_fs_path(&ad, file->f_path);
 		rc = smk_curacc(file->f_security, MAY_LOCK, &ad);
+		rc = smk_bu_file(file, MAY_LOCK, rc);
 		break;
 	case F_SETOWN:
 	case F_SETSIG:
 		smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
 		smk_ad_setfield_u_fs_path(&ad, file->f_path);
 		rc = smk_curacc(file->f_security, MAY_WRITE, &ad);
+		rc = smk_bu_file(file, MAY_WRITE, rc);
 		break;
 	default:
 		break;
@@ -1425,6 +1602,7 @@ static int smack_file_send_sigiotask(struct task_struct *tsk,
 	/* we don't log here as rc can be overriden */
 	skp = smk_find_entry(file->f_security);
 	rc = smk_access(skp, tkp->smk_known, MAY_WRITE, NULL);
+	rc = smk_bu_note("sigiotask", skp, tkp->smk_known, MAY_WRITE, rc);
 	if (rc != 0 && has_capability(tsk, CAP_MAC_OVERRIDE))
 		rc = 0;
 
@@ -1442,6 +1620,7 @@ static int smack_file_send_sigiotask(struct task_struct *tsk,
  */
 static int smack_file_receive(struct file *file)
 {
+	int rc;
 	int may = 0;
 	struct smk_audit_info ad;
 
@@ -1455,7 +1634,9 @@ static int smack_file_receive(struct file *file)
 	if (file->f_mode & FMODE_WRITE)
 		may |= MAY_WRITE;
 
-	return smk_curacc(file->f_security, may, &ad);
+	rc = smk_curacc(file->f_security, may, &ad);
+	rc = smk_bu_file(file, may, rc);
+	return rc;
 }
 
 /**
@@ -1485,6 +1666,7 @@ static int smack_file_open(struct file *file, const struct cred *cred)
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
 	smk_ad_setfield_u_fs_path(&ad, file->f_path);
 	rc = smk_access(tsp->smk_task, isp->smk_inode, MAY_READ, &ad);
+	rc = smk_bu_credfile(cred, file, MAY_READ, rc);
 	if (rc == 0)
 		file->f_security = isp->smk_inode;
 
@@ -1641,10 +1823,13 @@ static int smk_curacc_on_task(struct task_struct *p, int access,
 {
 	struct smk_audit_info ad;
 	struct smack_known *skp = smk_of_task(task_security(p));
+	int rc;
 
 	smk_ad_init(&ad, caller, LSM_AUDIT_DATA_TASK);
 	smk_ad_setfield_u_tsk(&ad, p);
-	return smk_curacc(skp->smk_known, access, &ad);
+	rc = smk_curacc(skp->smk_known, access, &ad);
+	rc = smk_bu_task(p, access, rc);
+	return rc;
 }
 
 /**
@@ -1798,6 +1983,7 @@ static int smack_task_kill(struct task_struct *p, struct siginfo *info,
 	struct smk_audit_info ad;
 	struct smack_known *skp;
 	struct smack_known *tkp = smk_of_task(task_security(p));
+	int rc;
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
 	smk_ad_setfield_u_tsk(&ad, p);
@@ -1805,15 +1991,20 @@ static int smack_task_kill(struct task_struct *p, struct siginfo *info,
 	 * Sending a signal requires that the sender
 	 * can write the receiver.
 	 */
-	if (secid == 0)
-		return smk_curacc(tkp->smk_known, MAY_WRITE, &ad);
+	if (secid == 0) {
+		rc = smk_curacc(tkp->smk_known, MAY_WRITE, &ad);
+		rc = smk_bu_task(p, MAY_WRITE, rc);
+		return rc;
+	}
 	/*
 	 * If the secid isn't 0 we're dealing with some USB IO
 	 * specific behavior. This is not clean. For one thing
 	 * we can't take privilege into account.
 	 */
 	skp = smack_from_secid(secid);
-	return smk_access(skp, tkp->smk_known, MAY_WRITE, &ad);
+	rc = smk_access(skp, tkp->smk_known, MAY_WRITE, &ad);
+	rc = smk_bu_note("USB signal", skp, tkp->smk_known, MAY_WRITE, rc);
+	return rc;
 }
 
 /**
@@ -2005,6 +2196,7 @@ static int smack_netlabel_send(struct sock *sk, struct sockaddr_in *sap)
 		sk_lbl = SMACK_UNLABELED_SOCKET;
 		skp = ssp->smk_out;
 		rc = smk_access(skp, hostsp, MAY_WRITE, &ad);
+		rc = smk_bu_note("IPv4 host check", skp, hostsp, MAY_WRITE, rc);
 	} else {
 		sk_lbl = SMACK_CIPSO_SOCKET;
 		rc = 0;
@@ -2107,6 +2299,7 @@ static int smk_ipv6_port_check(struct sock *sk, struct sockaddr_in6 *address,
 	unsigned short port = 0;
 	char *object;
 	struct smk_audit_info ad;
+	int rc;
 #ifdef CONFIG_AUDIT
 	struct lsm_network_audit net;
 #endif
@@ -2160,7 +2353,9 @@ auditout:
 	else
 		ad.a.u.net->v6info.daddr = address->sin6_addr;
 #endif
-	return smk_access(skp, object, MAY_WRITE, &ad);
+	rc = smk_access(skp, object, MAY_WRITE, &ad);
+	rc = smk_bu_note("IPv6 port check", skp, object, MAY_WRITE, rc);
+	return rc;
 }
 
 /**
@@ -2399,12 +2594,15 @@ static int smk_curacc_shm(struct shmid_kernel *shp, int access)
 {
 	char *ssp = smack_of_shm(shp);
 	struct smk_audit_info ad;
+	int rc;
 
 #ifdef CONFIG_AUDIT
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
 	ad.a.u.ipc_id = shp->shm_perm.id;
 #endif
-	return smk_curacc(ssp, access, &ad);
+	rc = smk_curacc(ssp, access, &ad);
+	rc = smk_bu_current("shm", ssp, access, rc);
+	return rc;
 }
 
 /**
@@ -2523,12 +2721,15 @@ static int smk_curacc_sem(struct sem_array *sma, int access)
 {
 	char *ssp = smack_of_sem(sma);
 	struct smk_audit_info ad;
+	int rc;
 
 #ifdef CONFIG_AUDIT
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
 	ad.a.u.ipc_id = sma->sem_perm.id;
 #endif
-	return smk_curacc(ssp, access, &ad);
+	rc = smk_curacc(ssp, access, &ad);
+	rc = smk_bu_current("sem", ssp, access, rc);
+	return rc;
 }
 
 /**
@@ -2653,12 +2854,15 @@ static int smk_curacc_msq(struct msg_queue *msq, int access)
 {
 	char *msp = smack_of_msq(msq);
 	struct smk_audit_info ad;
+	int rc;
 
 #ifdef CONFIG_AUDIT
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
 	ad.a.u.ipc_id = msq->q_perm.id;
 #endif
-	return smk_curacc(msp, access, &ad);
+	rc = smk_curacc(msp, access, &ad);
+	rc = smk_bu_current("msq", msp, access, rc);
+	return rc;
 }
 
 /**
@@ -2754,12 +2958,15 @@ static int smack_ipc_permission(struct kern_ipc_perm *ipp, short flag)
 	char *isp = ipp->security;
 	int may = smack_flags_to_may(flag);
 	struct smk_audit_info ad;
+	int rc;
 
 #ifdef CONFIG_AUDIT
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
 	ad.a.u.ipc_id = ipp->id;
 #endif
-	return smk_curacc(isp, may, &ad);
+	rc = smk_curacc(isp, may, &ad);
+	rc = smk_bu_current("svipc", isp, may, rc);
+	return rc;
 }
 
 /**
@@ -3092,8 +3299,13 @@ static int smack_unix_stream_connect(struct sock *sock,
 		smk_ad_setfield_u_net_sk(&ad, other);
 #endif
 		rc = smk_access(skp, okp->smk_known, MAY_WRITE, &ad);
-		if (rc == 0)
+		rc = smk_bu_note("UDS connect", skp, okp->smk_known,
+					MAY_WRITE, rc);
+		if (rc == 0) {
 			rc = smk_access(okp, okp->smk_known, MAY_WRITE, NULL);
+			rc = smk_bu_note("UDS connect", okp, okp->smk_known,
+						MAY_WRITE, rc);
+		}
 	}
 
 	/*
@@ -3121,6 +3333,7 @@ static int smack_unix_may_send(struct socket *sock, struct socket *other)
 	struct socket_smack *osp = other->sk->sk_security;
 	struct smack_known *skp;
 	struct smk_audit_info ad;
+	int rc;
 
 #ifdef CONFIG_AUDIT
 	struct lsm_network_audit net;
@@ -3133,7 +3346,10 @@ static int smack_unix_may_send(struct socket *sock, struct socket *other)
 		return 0;
 
 	skp = ssp->smk_out;
-	return smk_access(skp, osp->smk_in->smk_known, MAY_WRITE, &ad);
+	rc = smk_access(skp, osp->smk_in->smk_known, MAY_WRITE, &ad);
+	rc = smk_bu_note("UDS send", skp, osp->smk_in->smk_known,
+				MAY_WRITE, rc);
+	return rc;
 }
 
 /**
@@ -3348,6 +3564,8 @@ static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
 		 * for networking.
 		 */
 		rc = smk_access(skp, ssp->smk_in->smk_known, MAY_WRITE, &ad);
+		rc = smk_bu_note("IPv4 delivery", skp, ssp->smk_in->smk_known,
+					MAY_WRITE, rc);
 		if (rc != 0)
 			netlbl_skbuff_err(skb, rc, 0);
 		break;
@@ -3528,6 +3746,8 @@ static int smack_inet_conn_request(struct sock *sk, struct sk_buff *skb,
 	 * here. Read access is not required.
 	 */
 	rc = smk_access(skp, ssp->smk_in->smk_known, MAY_WRITE, &ad);
+	rc = smk_bu_note("IPv4 connect", skp, ssp->smk_in->smk_known,
+				MAY_WRITE, rc);
 	if (rc != 0)
 		return rc;
 
@@ -3631,6 +3851,7 @@ static int smack_key_permission(key_ref_t key_ref,
 	struct smk_audit_info ad;
 	struct smack_known *tkp = smk_of_task(cred->security);
 	int request = 0;
+	int rc;
 
 	keyp = key_ref_to_ptr(key_ref);
 	if (keyp == NULL)
@@ -3655,7 +3876,9 @@ static int smack_key_permission(key_ref_t key_ref,
 		request = MAY_READ;
 	if (perm & (KEY_NEED_WRITE | KEY_NEED_LINK | KEY_NEED_SETATTR))
 		request = MAY_WRITE;
-	return smk_access(tkp, keyp->security, request, &ad);
+	rc = smk_access(tkp, keyp->security, request, &ad);
+	rc = smk_bu_note("key access", tkp, keyp->security, request, rc);
+	return rc;
 }
 #endif /* CONFIG_KEYS */
 
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 56a1439786a..49a2248b525 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -304,6 +304,10 @@ static int smk_perm_from_str(const char *string)
 		case 'L':
 			perm |= MAY_LOCK;
 			break;
+		case 'b':
+		case 'B':
+			perm |= MAY_BRINGUP;
+			break;
 		default:
 			return perm;
 		}
@@ -616,6 +620,8 @@ static void smk_rule_show(struct seq_file *s, struct smack_rule *srp, int max)
 		seq_putc(s, 't');
 	if (srp->smk_access & MAY_LOCK)
 		seq_putc(s, 'l');
+	if (srp->smk_access & MAY_BRINGUP)
+		seq_putc(s, 'b');
 
 	seq_putc(s, '\n');
 }
@@ -1880,7 +1886,10 @@ static ssize_t smk_user_access(struct file *file, const char __user *buf,
 	else if (res != -ENOENT)
 		return -EINVAL;
 
-	data[0] = res == 0 ? '1' : '0';
+	/*
+	 * smk_access() can return a value > 0 in the "bringup" case.
+	 */
+	data[0] = res >= 0 ? '1' : '0';
 	data[1] = '\0';
 
 	simple_transaction_set(file, 2);