4 files changed, 45 insertions, 10 deletions

diff --git a/security/smack/smack.h b/security/smack/smack.h
index 5e5a3bc..42ef313 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -132,6 +132,8 @@ struct smack_known {
 #define XATTR_NAME_SMACKIPIN	XATTR_SECURITY_PREFIX XATTR_SMACK_IPIN
 #define XATTR_NAME_SMACKIPOUT	XATTR_SECURITY_PREFIX XATTR_SMACK_IPOUT
 
+#define SMACK_CIPSO_OPTION 	"-CIPSO"
+
 /*
  * How communications on this socket are treated.
  * Usually it's determined by the underlying netlabel code
@@ -199,6 +201,7 @@ u32 smack_to_secid(const char *);
 extern int smack_cipso_direct;
 extern char *smack_net_ambient;
 extern char *smack_onlycap;
+extern const char *smack_cipso_option;
 
 extern struct smack_known smack_known_floor;
 extern struct smack_known smack_known_hat;
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index 5856419..ac0a270 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -261,6 +261,9 @@ char *smk_import(const char *string, int len)
 {
 	struct smack_known *skp;
 
+	/* labels cannot begin with a '-' */
+	if (string[0] == '-')
+		return NULL;
 	skp = smk_import_entry(string, len);
 	if (skp == NULL)
 		return NULL;
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 8ed502c..9215149 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -609,6 +609,9 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name,
 	    strcmp(name, XATTR_NAME_SMACKIPOUT) == 0) {
 		if (!capable(CAP_MAC_ADMIN))
 			rc = -EPERM;
+		/* a label cannot be void and cannot begin with '-' */
+		if (size == 0 || (size > 0 && ((char *)value)[0] == '-'))
+			rc = -EINVAL;
 	} else
 		rc = cap_inode_setxattr(dentry, name, value, size, flags);
 
@@ -1323,8 +1326,12 @@ static char *smack_host_label(struct sockaddr_in *sip)
 		* so we have found the most specific match
 		*/
 		if ((&snp->smk_host.sin_addr)->s_addr ==
-		    (siap->s_addr & (&snp->smk_mask)->s_addr))
+		    (siap->s_addr & (&snp->smk_mask)->s_addr)) {
+			/* we have found the special CIPSO option */
+			if (snp->smk_label == smack_cipso_option)
+				return NULL;
 			return snp->smk_label;
+		}
 
 	return NULL;
 }
@@ -1486,7 +1493,7 @@ static int smack_inode_setsecurity(struct inode *inode, const char *name,
 	struct socket *sock;
 	int rc = 0;
 
-	if (value == NULL || size > SMK_LABELLEN)
+	if (value == NULL || size > SMK_LABELLEN || size == 0)
 		return -EACCES;
 
 	sp = smk_import(value, size);
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 856c8a2..e03a7e1 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -86,6 +86,9 @@ LIST_HEAD(smack_rule_list);
 
 static int smk_cipso_doi_value = SMACK_CIPSO_DOI_DEFAULT;
 
+const char *smack_cipso_option = SMACK_CIPSO_OPTION;
+
+
 #define	SEQ_READ_FINISHED	1
 
 /*
@@ -565,6 +568,11 @@ static ssize_t smk_write_cipso(struct file *file, const char __user *buf,
 		goto unlockedout;
 	}
 
+	/* labels cannot begin with a '-' */
+	if (data[0] == '-') {
+		rc = -EINVAL;
+		goto unlockedout;
+	}
 	data[count] = '\0';
 	rule = data;
 	/*
@@ -808,9 +816,18 @@ static ssize_t smk_write_netlbladdr(struct file *file, const char __user *buf,
 	if (m > BEBITS)
 		return -EINVAL;
 
-	sp = smk_import(smack, 0);
-	if (sp == NULL)
-		return -EINVAL;
+	/* if smack begins with '-', its an option, don't import it */
+	if (smack[0] != '-') {
+		sp = smk_import(smack, 0);
+		if (sp == NULL)
+			return -EINVAL;
+	} else {
+		/* check known options */
+		if (strcmp(smack, smack_cipso_option) == 0)
+			sp = (char *)smack_cipso_option;
+		else
+			return -EINVAL;
+	}
 
 	for (temp_mask = 0; m > 0; m--) {
 		temp_mask |= mask_bits;
@@ -849,18 +866,23 @@ static ssize_t smk_write_netlbladdr(struct file *file, const char __user *buf,
 			smk_netlbladdr_insert(skp);
 		}
 	} else {
-		rc = netlbl_cfg_unlbl_static_del(&init_net, NULL,
-			&skp->smk_host.sin_addr, &skp->smk_mask,
-			PF_INET, &audit_info);
+		/* we delete the unlabeled entry, only if the previous label
+		 * wasnt the special CIPSO option */
+		if (skp->smk_label != smack_cipso_option)
+			rc = netlbl_cfg_unlbl_static_del(&init_net, NULL,
+					&skp->smk_host.sin_addr, &skp->smk_mask,
+					PF_INET, &audit_info);
+		else
+			rc = 0;
 		skp->smk_label = sp;
 	}
 
 	/*
 	 * Now tell netlabel about the single label nature of
 	 * this host so that incoming packets get labeled.
+	 * but only if we didn't get the special CIPSO option
 	 */
-
-	if (rc == 0)
+	if (rc == 0 && sp != smack_cipso_option)
 		rc = netlbl_cfg_unlbl_static_add(&init_net, NULL,
 			&skp->smk_host.sin_addr, &skp->smk_mask, PF_INET,
 			smack_to_secid(skp->smk_label), &audit_info);