4 files changed, 45 insertions, 10 deletions

diff --git a/security/smack/smack.h b/security/smack/smack.h
index 5e5a3bcb599a..42ef313f9856 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 58564195bb09..ac0a2707f6d4 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 8ed502c2ad45..921514902eca 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 856c8a287523..e03a7e19c73b 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);